Employee Benefit Plans - Schedule of Changes to Post-Employment Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Beginning balance	$ 5,189	$ 6,024
Amounts accrued	135	53
Payments to employees/government managed plan	(452)	(266)
Foreign currency impacts	(165)	(622)
Ending balance	$ 4,707	$ 5,189

Amount of foreign currency translation adjustment increasing or decreasing the accrual for a specified type.

No definition available.

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Namespace Prefix:	nnbr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

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- Definition

Cash outflows for payments of postemployment benefits (such as severance pay and health insurance benefits) recognized during the period. Postemployment benefits are benefits paid to employees after employment but before retirement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3536-108585

+ Details

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Balance Type:	credit
Period Type:	duration

- Definition

For a classified balance sheet, the carrying amount as of the balance sheet date of the portion of the obligations recognized for the various benefits provided to former or inactive employees, their beneficiaries, and covered dependents after employment but before retirement that is payable after one year (or beyond the operating cycle if longer).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 712
-SubTopic 10
-Section 25
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6410138&loc=d3e79691-111665

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Period expense related to postemployment benefits.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration