Condensed Consolidating Financial Statements (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 26, 2013	Mar. 27, 2012
Condensed Consolidating Statements of Income
Total sales	$ 278,969	$ 270,414
Total costs and expenses	(253,118)	(245,538)
Operating income	25,851	24,876
Interest expense	(10,240)	(12,914)
Equity in net income of subsidiary		0
Income before income taxes	15,611	11,962
Income tax expense	(2,367)	(2,957)
Net income	13,244	9,005
Parent Guarantor: Holdings [Member]
Condensed Consolidating Statements of Income
Total sales		0
Total costs and expenses		0
Operating income		0
Interest expense		0
Equity in net income of subsidiary	13,244	9,005
Income before income taxes	13,244	9,005
Income tax expense		0
Net income	13,244	9,005
Subsidiary Issuer: NPC [Member]
Condensed Consolidating Statements of Income
Total sales	278,969	270,414
Total costs and expenses	(253,118)	(245,538)
Operating income	25,851	24,876
Interest expense	(10,240)	(12,914)
Equity in net income of subsidiary		0
Income before income taxes	15,611	11,962
Income tax expense	(2,367)	(2,957)
Net income	13,244	9,005
Subsidiary Co-Issuer: NPC Op Co A [Member]
Condensed Consolidating Statements of Income
Total sales		0
Total costs and expenses		0
Operating income		0
Interest expense		0
Equity in net income of subsidiary		0
Income before income taxes		0
Income tax expense		0
Net income		0
Subsidiary Co-Issuer: NPC Op Co B [Member]
Condensed Consolidating Statements of Income
Total sales		0
Total costs and expenses		0
Operating income		0
Interest expense		0
Equity in net income of subsidiary		0
Income before income taxes		0
Income tax expense		0
Net income		0
Eliminations [Member]
Condensed Consolidating Statements of Income
Total sales		0
Total costs and expenses		0
Operating income		0
Interest expense		0
Equity in net income of subsidiary	(13,244)	(9,005)
Income before income taxes	(13,244)	(9,005)
Income tax expense		0
Net income	$ (13,244)	$ (9,005)