XML 13 R46.htm IDEA: XBRL DOCUMENT v2.4.0.6

Subsequent Events (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Subsequent Events (Textual) [Abstract]
Loan Duration	10 years
Loan Principal	$ 5.7
Loan Interest Rate	4.50%

X

- Definition

Subsequent events interest rate of arrangements.

+ References

No definition available.

+ Details

Name:	nwpx_SubsequentEventsInterestRateOfArrangements
Namespace Prefix:	nwpx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	nwpx_SubsequentEventsTextualAbstract
Namespace Prefix:	nwpx_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Reflects the known or estimated financial effect of the event, or transaction that occurred between the balance sheet date and the date the financial statements are issued or available to be issued.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 855

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6842918&loc=SL6314017-165662



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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 165

-Paragraph 13

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

+ Details

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

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- Definition

Period the contract is outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_SubsequentEventTermOfContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration