Statement of Financial Position [Abstract] Cash and cash equivalents CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD CASH AND CASH EQUIVALENTS AT END OF PERIOD Available for sale securities Trade excluding joint ventures, less allowance for doubtful accounts of $40,000 at February 28, 2015 and August 31, 2014, respectively Trade allowance (in Dollars) Trade joint ventures Fees for services provided to joint ventures Income taxes Inventories Prepaid expenses Deferred income taxes Total current assets PROPERTY AND EQUIPMENT, NET Investments in joint ventures Investments at carrying value (Note 7) Deferred income taxes Patents and trademarks, net Other Total other assets Total assets Total assets Accounts payable Payroll and related benefits Deferred joint venture royalties Other Total current liabilities COMMITMENTS AND CONTINGENCIES (Note 14) Preferred stock, no par value; authorized 10,000 shares; none issued and outstanding Preferred stock, par value (in Dollars per share) Preferred stock, shares authorized Preferred stock, shares issued Preferred stock, shares outstanding Common stock, $0.02 par value per share; authorized 10,000,000 shares; issued and outstanding 4,523,160 and 4,504,552, respectively Common stock par value (in Dollars per share) Common stock, shares authorized Common stock, shares issued Common stock, shares outstanding Additional paid-in capital Retained earnings Accumulated other comprehensive (loss) income Stockholders’ equity Non-controlling interest Total equity Total liabilities and equity Income Statement [Abstract] Net sales, excluding joint ventures Net sales, to joint ventures Total net sales Net sales by segment Total net sales Cost of goods sold Cost of Goods Sold Gross profit Equity in income of joint ventures Equity in income from joint ventures Company’s share of equity in income of joint ventures Fees for services provided to joint ventures Total joint venture operations Selling expenses General and administrative expenses Expenses incurred in support of joint ventures Research and development expenses Research and Development Expense Total operating expenses OPERATING INCOME Total operating income INTEREST INCOME INTEREST EXPENSE OTHER INCOME INCOME BEFORE INCOME TAX EXPENSE INCOME TAX EXPENSE NET (LOSS) INCOME NET (LOSS) INCOME Net income NET INCOME ATTRIBUTABLE TO NON-CONTROLLING INTERESTS NET (LOSS) INCOME ATTRIBUTABLE TO NTIC Net (loss) income attributable to NTIC (in Dollars) Basic (in Dollars per share) Basic earnings (loss) per share: (in Dollars per share) Diluted (in Dollars per share) Diluted earnings (loss) per share: (in Dollars per share) Basic (in Shares) Basic – weighted shares outstanding Diluted (in Shares) Diluted – weighted shares outstanding Statement of Comprehensive Income [Abstract] OTHER COMPREHENSIVE (LOSS) INCOME – FOREIGN CURRENCY TRANSLATION ADJUSTMENT COMPREHENSIVE (LOSS) INCOME COMPREHENSIVE INCOME ATTRIBUTABLE TO NON-CONTROLLING INTERESTS COMPREHENSIVE (LOSS) INCOME ATTRIBUTABLE TO NTIC Statement of Cash Flows [Abstract] Stock-based compensation Depreciation expense Amortization expense Loss on disposal of assets Dividends received from joint ventures Increase in allowance for doubtful accounts Trade, excluding joint ventures Trade, joint ventures Fees for services provided to joint ventures Income taxes Inventories Prepaid expenses and other Accounts payable Income tax payable Accrued liabilities Net cash provided by operating activities Proceeds from the sale of investment in joint ventures Proceeds from the sale of available for sale securities Additions to property and equipment Additions to patents Net cash provided by (used in) investing activities Repayment of note payable Investment by non-controlling interest Dividend received by non-controlling interest Proceeds from employee stock purchase plan Proceeds from exercise of stock options Net cash used in financing activities EFFECT OF EXCHANGE RATE CHANGES ON CASH: NET INCREASE IN CASH AND CASH EQUIVALENTS Disclosure Text Block [Abstract] Inventory Disclosure [Abstract] Inventories [Abstract] Production materials Finished goods Property, Plant and Equipment [Abstract] Components of Property and Equipment, Net [Abstract] Land Buildings and improvements Machinery and equipment Less accumulated depreciation Patents and Trademarks, Net [Abstract] Finite-Lived Intangible Assets by Major Class [Axis] Patents and Trademarks Intangible Assets [Member] Patents and trademarks Less accumulated amortization Equity Method Investments and Joint Ventures [Abstract] Condensed Balance Sheet of EXCOR and Tianjin Zerust, and All Other Joint Ventures [Abstract] Current assets Total assets Current liabilities Noncurrent liabilities Joint ventures’ equity Northern Technologies International Corporation’s share of joint ventures’ equity Northern Technologies International Corporation’s share of joint ventures’ undistributed earnings Investment, Name [Axis] EXCOR [Member] All Other [Member] Tianjin Zerust [Member] Condensed Income Statement of EXCOR and Tianjin Zerust, and All Other Joint Ventures [Abstract] Net sales Gross profit Net income Fair Value Disclosures [Abstract] Investment in Tianjin Zerust [Abstract] Debt Disclosure [Abstract] Stockholders' Equity Note [Abstract] Exercised Stock Options [Abstract] Exercise Price Range [Axis] Exercise 1 [Member] Options Exercised Excercise Price Exercise 2 [Member] Earnings Per Share [Abstract] Reconciliation of the Earnings Per Share Computations [Abstract] Weighted shares assumed upon exercise of stock options Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Black-Scholes Option-pricing Model Assumptions [Abstract] Dividend yield Expected volatility Expected life of option (in years) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Average risk-free interest rate Segment Reporting [Abstract] Net Sales by Geographic Location as Percentage of Total Consolidated Net Sales [Abstract] Concentration Risk Benchmark [Axis] Sales Revenue, Net [Member] Concentration Risk Type [Axis] Geographic Concentration Risk [Member] Scenario [Axis] Inside the U.S.A to Unaffiliated Customers [Member] Net Sales, Percentage Joint Ventures In Which The Company Is A Shareholder Directly And Indirectly - Outside the U.S.A [Member] Unaffiliated Customers - Outside the U.S.A [Member] Income Statement Location [Axis] Fees For Services Provided to Joint Ventures [Member] Fees for Services Provided to Joint Ventures by Geographic Location as a Percentage of Total Fees for Services Provided to Joint Ventures [Abstract] Geographical [Axis] GERMANY THAILAND JAPAN POLAND UNITED KINGDOM FRANCE INDIA SWEDEN FINLAND CHINA Other Countries [Member] Net Sales by Segment [Abstract] Segments [Axis] ZERUST [Member] Natur-Tec [Member] Cost of Goods Sold by Segment [Abstract] Cost of Goods Sold, Type [Axis] Direct Cost of Goods Sold [Member] Products and Services [Axis] % of Product Sales Indirect Cost of Goods Sold [Member] Total Assets by Geographic Distribution [Abstract] BRAZIL North America [Member] Total Net Sales by Geographic Distribution [Abstract] Operating Income by Geographic Distribution [Abstract] Research and Development [Abstract] Commitments and Contingencies Disclosure [Abstract] Assets and Liabilities Measured at Fair Value Recurring Basis [Abstract] Available for sale securities Fair Value, Hierarchy [Axis] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 3 [Member] ASSETS CURRENT ASSETS: Receivables: OTHER ASSETS: LIABILITIES AND EQUITY CURRENT LIABILITIES: Accrued liabilities: EQUITY: NET SALES: JOINT VENTURE OPERATIONS: OPERATING EXPENSES: NET (LOSS) INCOME ATTRIBUTABLE TO NTIC PER COMMON SHARE: WEIGHTED AVERAGE COMMON SHARES ASSUMED OUTSTANDING: CASH FLOWS FROM OPERATING ACTIVITIES: Adjustments to reconcile net income to net cash used in operating activities: Changes in current assets and liabilities: Receivables: CASH FLOWS FROM INVESTING ACTIVITIES: CASH FLOWS FROM FINANCING ACTIVITIES: Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Description of New Accounting Pronouncements Not yet Adopted [Text Block] Inventory Disclosure [Text Block] Schedule of Inventory, Current [Table Text Block] Property, Plant and Equipment Disclosure [Text Block] Property, Plant and Equipment [Table Text Block] Intangible Assets Disclosure [Text Block] Schedule of Finite-Lived Intangible Assets [Table Text Block] Equity Method Investments and Joint Ventures Disclosure [Text Block] Condensed Balance Sheet [Table Text Block] Condensed Income Statement [Table Text Block] Fair Value Disclosures [Text Block] Equity Method Investments [Table Text Block] Equity method investment – August 31, 2014 Equity in earnings – six months ended February 28, 2015 Investment at carrying value – February 28, 2015 Debt Disclosure [Text Block] Stockholders' Equity Note Disclosure [Text Block] Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block] Earnings Per Share [Text Block] Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Denominator: Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Segment Reporting Disclosure [Text Block] Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Table Text Block] Outside the U.S.A to: Reconciliation of Revenue from Segments to Consolidated [Table Text Block] Fees fro services provided (in Dollars) Fees fro services provided, percentage Reconciliation of Cost of Good Sold from Segments to Consolidated [Table Text Block] Direct cost of goods sold Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block] Revenue from External Customers by Geographic Areas [Table Text Block] Schedule of Segment Reporting Information, by Segment [Table Text Block] Research, Development, and Computer Software Disclosure [Text Block] Commitments and Contingencies Disclosure [Text Block] Fair Value, Measurement Inputs, Disclosure [Text Block] Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Table Text Block] Reclassification of translation gains on foreign currency translation Patents and Trademarks [Member] Mutec [Member] Legal Entity of Counterparty, Type [Axis] Nature of Expense [Axis] Termination of Joint Venture and Formation of NTIC China [Member] Credit Facility [Axis] Revolving Credit Facility [Member] Lender Name [Axis] PNC Bank [Member] Variable Rate [Axis] London Interbank Offered Rate (LIBOR) [Member] Debt Instrument [Axis] Term Loan and Line of Credit Agreements "Loan Agreements" [Member] Plan Name [Axis] 2007 Plan [Member] Range [Axis] Minimum [Member] Vesting [Axis] One Year after Date of Grant [Member] Maximum [Member] ESPP [Member] Award Type [Axis] Employee Stock Option [Member] Net of Estimated Forfeitures [Member] Deferred Bonus and Profit Sharing Arrangements, Individual Contracts, Type of Deferred Compensation [Axis] Fiscal 2013 Bonus Plan [Member] Title of Individual [Axis] Executive Officer [Member] Finite-Lived Intangible Asset, Useful Life Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months Finite-Lived Intangible Assets, Amortization Expense, Year Two Finite-Lived Intangible Assets, Amortization Expense, Year Three Finite-Lived Intangible Assets, Amortization Expense, Year Four Finite-Lived Intangible Assets, Amortization Expense, Year Five Payments to Acquire Interest in Joint Venture Other than Temporary Impairment Losses, Investments Financing Receivable, Net Notes Receivable, Term Due from Joint Ventures Professional Fees Line of Credit Facility, Maximum Borrowing Capacity Long-term Line of Credit Debt Instrument, Basis Spread on Variable Rate Debt Instrument, Covenants, Fixed Charge Coverage Ratio Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in Shares) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in Dollars per share) Stock Repurchased and Retired During Period, Shares Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in Shares) Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Offering Date Stock or Unit Option Plan Expense Allocated Share-based Compensation Expense, Estimate, Remainder of Fiscal Year Allocated Share-based Compensation Expense, Estimate, Next Fiscal Year Allocated Share-based Compensation Expense, Estimate, Fiscal Year Two Estimated Forfeiture Rate For Stock Options Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in Dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Research and Development Arrangement, Contract to Perform for Others, Costs Incurred, Gross Percentage of Individual Bonus Payout Determined By Actual Versus Targeted EBITOI Results Percentage of Individual's Payout Determined Upon Achievement of Certain Pre-Established Individual Performance Objectives Accrued Bonuses (in Dollars) Entity-Wide Trade Joint Venture Receivables, Two Joint Ventures, Percentage Entity-Wide Trade Joint Venture Receivables, Three Joint Ventures, Percentage Income Statement Location [Domain] Note 12 - Geographic and Segment Information (Tables) [Table] Note 12 - Geographic and Segment Information (Tables) [Line Items] Finite-Lived Intangible Assets, Major Class Name [Domain] Schedule of Finite-Lived Intangible Assets [Table] Finite-Lived Intangible Assets [Line Items] Investment, Name [Domain] Condensed Balance Sheet Statement [Table] Condensed Balance Sheet Statements, Captions [Line Items] Condensed Income Statement [Table] Condensed Income Statements, Captions [Line Items] Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Line Items] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Domain] Note 9 - Stockholders' Equity (Details) - Exercised Stock Options [Table] Note 9 - Stockholders' Equity (Details) - Exercised Stock Options [Line Items] Scenario, Unspecified [Domain] Concentration Risk Benchmark [Domain] Concentration Risk Type [Domain] Note 12 - Geographic and Segment Information (Details) - Net Sales by Geographic Location as Percentage of Total Consolidated Net Sales [Table] Note 12 - Geographic and Segment Information (Details) - Net Sales by Geographic Location as Percentage of Total Consolidated Net Sales [Line Items] Geographical [Domain] Reconciliation of Revenue from Segments to Consolidated [Table] Segment Reporting, Revenue Reconciling Item [Line Items] Segments [Domain] CostOfGoodsSoldType [Domain] Products and Services [Domain] Note 12 - Geographic and Segment Information (Details) - Cost of Goods Sold by Segment [Table] Note 12 - Geographic and Segment Information (Details) - Cost of Goods Sold by Segment [Line Items] Schedule of Revenues from External Customers and Long-Lived Assets [Table] Revenues from External Customers and Long-Lived Assets [Line Items] Note 12 - Geographic and Segment Information (Details) - Total Net Sales by Geographic Distribution [Table] Note 12 - Geographic and Segment Information (Details) - Total Net Sales by Geographic Distribution [Line Items] Schedule of Segment Reporting Information, by Segment [Table] Segment Reporting Information [Line Items] Fair Value Hierarchy [Domain] Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Table] Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] Note 5 - Patents and Trademarks, Net (Details) [Table] Note 5 - Patents and Trademarks, Net (Details) [Line Items] Legal Entity Type of Counterparty [Domain] Note 6 - Investments in Joint Ventures (Details) [Table] Note 6 - Investments in Joint Ventures (Details) [Line Items] Interim Period, Costs Not Allocable [Domain] Note 7 - China Operations (Details) [Table] Note 7 - China Operations (Details) [Line Items] Debt Instrument, Name [Domain] Credit Facility [Domain] Variable Rate [Domain] Line of Credit Facility, Lender [Domain] Note 8 - Corporate Debt (Details) [Table] Note 8 - Corporate Debt (Details) [Line Items] Plan Name [Domain] Note 9 - Stockholders' Equity (Details) [Table] Note 9 - Stockholders' Equity (Details) [Line Items] Equity Award [Domain] Vesting [Domain] Range [Domain] Note 11 - Stock-Based Compensation (Details) [Table] Note 11 - Stock-Based Compensation (Details) [Line Items] Deferred Bonus and Profit Sharing Arrangement, Individual Contract, Type of Deferred Compensation [Domain] Relationship to Entity [Domain] Note 14 - Commitments and Contingencies (Details) [Table] Note 14 - Commitments and Contingencies (Details) [Line Items] Estimated expense to be recognized for the second fiscal year following the most recent fiscal year arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. Estimated expense to be recognized for the next fiscal year following the most recent fiscal year arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. Estimated expense to be recognized for the remainder of the fiscal year arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. Represents the cost of goods sold as a percentage of product sales. Represents the fixed charge coverage ratio for the debt instrument under the covenant terms. Percentage of entity wide fees for services provided to joint ventures generated from geographic location. Percentage of total trade joint venture receivables accounted for by three joint ventures. Percentage of total trade joint venture receivables accounted for by two joint ventures. Estimated forfeiture rate used for stock options. Royalties and service fees from transactions directly with the reporting entity's joint ventures outside the normal course of business. Amounts due for royalties and service fees outside of the normal course of business from entities in which the reporting entity shares joint control with another party or group, due within 1 year (or 1 business cycle). The net change during the reporting period in amount due within one year (or one business cycle) from joint ventures for royalties and service fees outside of the normal course of business. The net change during the reporting period in amount due within one year (or one business cycle) from customers or clients, but not joint ventures, for the credit sale of goods and services. The net change during the reporting period in amount due within one year (or one business cycle) from joint ventures for the credit sale of goods and services that have been delivered or sold to joint ventures in the normal course of business. Represents the fair value investments in joint ventures. Net sales either directly to end users or to distributors worldwide, but not sales to the reporting entity's joint ventures and not sales by the reporting entity's joint ventures. Net sales by the reporting entity to the reporting entity's joint ventures, but not sales by the reporting entity either directly to end users or to distributors or sales by the reporting entity’s joint ventures. Represents the repayment term. Percentage of individual's bonus payout determined based upon the Company's actual EBITOI for the fiscal year compared to pre-established target EBITOI for the fiscal year. Percentage of individual's payout determined based upon achievement of certain pre-established individual performance objectives. Tabular disclosure of all significant reconciling items in the reconciliation of total cost of goods sold from reportable segments to the entity's consolidated revenues. Total fees for services provided to joint ventures by geographic locations. Amount due from customers or clients, but not joint ventures, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection. Amounts due from joint ventures, within one year of the balance sheet date (or the normal operating cycle, whichever is longer) for goods or services (including trade receivables) that have been delivered or sold to joint ventures in the normal course of business. Cost Of Goods Sold Type [Axis] All Other [Member] Common Stock Bonuses [Member] Direct Cost Of Goods Sold [Member] ESPP [Member] Employee stock purchase plan. EXCOR [Member] Exercise 1 [Member] Exercise price range 1. Exercise 2 [Member] Fees For Services Provided To Joint Ventures [Member] Fiscal 2013 Bonus Plan [Member] Indirect Cost Of Goods Sold [Member] Inside The USA To Unaffiliated Customers [Member] Joint Venture Fees [Member] Joint Ventures In Which The Company Is A Shareholder Directly And Indirectly Outside The USA [Member] Mutec [Member] NTIC China [Member] NTIC Shanghai Co. Ltd. (NTIC China) is a wholly owned subsidiary of the company. Natur Tec [Member] Net Of Estimated Forfeitures [Member] One Year After Date Of Grant [Member] The vesting term that options become exercisable. Other Countries [Member] PNC Bank [Member] Represents PNC Bank. Patents And Trademarks Intangible Assets [Member] Represents the patents and trademarks. Patents And Trademarks [Member] Term Loan And Line Of Credit Agreements Loan Agreements [Member] Term Loan [Member] Termination Of Joint Venture And Formation Of NTIC China [Member] The direct expenses associated with the termination of the joint venture in China and the formation of the wholly owned subsidiary NTIC China. Such expenses include, but not limited to: legal expenses, formation expenses, and hiring expenses. Tianjin Zerust [Member] Represents the Tianjin Zerust. Two Thousand Seven Plan [Member] Represents the 2007 plan. Unaffiliated Customers Outside The USA [Member] ZERUST [Member] Document and Entity Information [Abstract] IncreaseDecreaseInTradeReceivablesExcludingJointVentures ReceivablesAbstract0 IncreaseDecreaseInFeesReceivableForServicesProvidedToJointVentures FeesForServicesProvidedToJointVentures IncreaseDecreaseInTradeReceivablesJointVentures Cash and Cash Equivalents, Period Increase (Decrease) Assets, Current Finite-Lived Intangible Assets, Accumulated Amortization Payments to Acquire Property, Plant, and Equipment Available-for-sale Securities Operating Expenses Liabilities, Current Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive Income (Loss), Net of Tax, Attributable to Parent Repayments of Notes Payable Entity Common Stock, Shares Outstanding Deferred Tax Assets, Net, Current Assets Entity Well-known Seasoned Issuer Entity Registrant Name Entity Voluntary Filers Entity Filer Category Entity Public Float Gross Profit Document Fiscal Period Focus Current Fiscal Year End Date Earnings Per Share, Diluted Property, Plant and Equipment, Gross Interest Expense Inventory, Net Net Cash Provided by (Used in) Operating Activities, Continuing Operations Increase (Decrease) in Inventories Amendment Flag Equity Method Investment, Summarized Financial Information, Net Income (Loss) Net Cash Provided by (Used in) Investing Activities, Continuing Operations Net Cash Provided by (Used in) Financing Activities, Continuing Operations Foreign Currency Transaction Gain (Loss), before Tax Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Document Period End Date Assets, Noncurrent Payments to Acquire Intangible Assets Increase (Decrease) in Accounts Payable Increase (Decrease) in Income Taxes Receivable Increase (Decrease) in Prepaid Expense and Other Assets Entity Central Index Key Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Net Income (Loss) Attributable to Parent Income (Loss), Including Portion Attributable to Noncontrolling Interest Entity Current Reporting Status Payments of Ordinary Dividends, Noncontrolling Interest Other Operating Income Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property Document Fiscal Year Focus Liabilities and Equity Other Accrued Liabilities, Current Increase (Decrease) in Income Taxes Payable Amendment Description Document Type Stockholders' Equity Attributable to Parent Statement [Table] Statement [Line Items]