XML 46 R34.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Interim Financial Statements - Additional Information (Detail) $ in Millions | 6 Months Ended
--- | ---
Jun. 30, 2017 USD ($) Segment ManufacturingPlants
Interim Reporting [Line Items] |
Number of manufacturing plants | ManufacturingPlants | 40
Number of reportable segments | Segment | 3
Wuxi Weifu Autocam Precision Machinery Company, Ltd. [Member] |
Interim Reporting [Line Items] |
Investment in joint venture | 49.00%
ASU 2016-09 [Member] |
Interim Reporting [Line Items] |
Reclassification of tax benefits from deferred taxes to retained earnings | $ | $ 0.7

X
- Definition Interim Reporting [Line Items] + References No definition available. + Details
Name: | nnbr_InterimReportingLineItems
Namespace Prefix: | nnbr_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of manufacturing plants. + References No definition available. + Details
Name: | nnbr_NumberOfManufacturingPlants
Namespace Prefix: | nnbr_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of the cumulative effect on retained earnings net of related income tax effect. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 9 -URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22663-107794 + Details
Name: | us-gaap_CumulativeEffectOnRetainedEarningsNetOfTax1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571 + Details
Name: | us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements. + References No definition available. + Details
Name: | us-gaap_NumberOfReportableSegments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=nnbr_WuxiWeifuAutocamPrecisionMachineryCompanyLtdMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201609Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |