Name:	np_PercentageOfHourlyEmployeesEligibleToBeRepresentedByMiningChemicalsAndEnergyTradeUnionIGBCE
Namespace Prefix:	np_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the percentage of salaried employees eligible to be represented by Mining, Chemicals and Energy Trade Union (Industriegewerkschaft Bergbau, Chemie and Energie).

No definition available.

Name:	np_PercentageOfSalariedEmployeesEligibleToBeRepresentedByMiningChemicalsAndEnergyTradeIGBCE
Namespace Prefix:	np_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents amount of income tax assessment received from German tax authorities.

No definition available.

Name:	np_TaxAssessmentAmount
Namespace Prefix:	np_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Represents the payments made for tax assessments during the period.

No definition available.

Name:	np_TaxAssessmentAmountPaid
Namespace Prefix:	np_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Represents the number of employees covered by a collective bargaining agreement that will expire within one year after the balance sheet date.

No definition available.

Name:	np_WorkforceSubjectToCollectiveBargainingArrangementsExpiringWithinOneYear
Namespace Prefix:	np_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_IncomeTaxContingencyLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Carrying amount due within one year of the balance sheet date (or one operating cycle, if longer) from tax authorities as of the balance sheet date representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 10

-Article 9

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.3(a)(4))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Subparagraph a

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 5

-Subparagraph c

-Article 7

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 109

-Section Appendix E

-Paragraph 289

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.10)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.5(c))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910