Note 12 - Commitments and Contingencies (Details Textual) - USD ($)	9 Months Ended
May 31, 2020	Aug. 31, 2019	May 31, 2019
Lessee, Operating Lease, Option to Extend Term One (Year)	5 years
Lessee, Operating Lease, Option to Extend Term Two (Year)	10 years
Finance and Operating Lease, Weighted Average Remaining Lease Term (Year)	1 year 328 days
Operating Lease, Weighted Average Discount Rate, Percent	4.32%
Accrued Bonuses	$ 1,200,000		$ 1,450,000
Entity Wide Trade Joint Venture Receivables, Three Joint Ventures, Percentage	56.20%	69.60%
Fiscal 2018 Bonus Plan [Member] \| Executive Officer [Member]
Percentage of Individual Bonus Payout Determined by Actual Versus Targeted EBITOI Results	75.00%
Percentage of Individuals Payout Determined Upon Achievement of Certain Pre-Established Individual Performance Objectives	25.00%
Buildings, Equipment and Vehicles [Member]
Number of Operating Lease	12

Percentage of total trade joint venture receivables accounted for by three joint ventures.

No definition available.

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- Definition

Weighted average remaining lease term for operating and finance lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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Namespace Prefix:	ntic_
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Balance Type:	na
Period Type:	duration

- Definition

Represents option to extend term one for operating lease.

+ References

No definition available.

+ Details

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Namespace Prefix:	ntic_
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Balance Type:	na
Period Type:	duration

- Definition

Represents option to extend term two for operating lease.

+ References

No definition available.

+ Details

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Namespace Prefix:	ntic_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents number of operating lease.

+ References

No definition available.

+ Details

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- Definition

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.

+ References

No definition available.

+ Details

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Namespace Prefix:	ntic_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of individual's payout determined based upon achievement of certain pre-established individual performance objectives.

+ References

No definition available.

+ Details

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Namespace Prefix:	ntic_
Data Type:	num:percentItemType
Balance Type:	na
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- Definition

Carrying value as of the balance sheet date of obligations incurred and payable for incentive compensation awarded to employees and directors or earned by them based on the terms of one or more relevant arrangements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.15(a))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.15(5))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Weighted average discount rate for operating lease calculated at point in time.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (g)(4)
-URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918686-209980

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 55
-Paragraph 53
-URI http://asc.fasb.org/extlink&oid=121568110&loc=SL77918982-209971

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- Details

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- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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