Condensed Consolidating Financial Statements (Details Textual)	6 Months Ended
Jun. 25, 2013
Condensed Consolidating Financial Statements (Textual) [Abstract]
Ownership percentage held by holding company	100.00%
Ownership Percentage of Co Issuer held by Company	100.00%

Ownership percentage of co issuer held by company.

No definition available.

Name:	npci_OwnershipPercentageOfCoIssuerHeldByCompany
Namespace Prefix:	npci_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration