Condensed Consolidating Financial Statements - Balance Sheet (Details) (USD $)	Jun. 30, 2013	Dec. 30, 2012	Jun. 24, 2012	Dec. 25, 2011	Jun. 30, 2013 Parent Company	Dec. 30, 2012 Parent Company	Jun. 30, 2013 Guarantors on a Combined Basis	Dec. 30, 2012 Guarantors on a Combined Basis	Jun. 30, 2013 Non-Guarantors on a Combined Basis	Dec. 30, 2012 Non-Guarantors on a Combined Basis	Jun. 30, 2013 Eliminations	Dec. 30, 2012 Eliminations	Jun. 30, 2013 Senior notes Senior Notes due June 2017	Jul. 27, 2011 Senior notes Senior Notes due June 2017	Mar. 25, 2011 Senior notes Senior Notes due June 2017	May 19, 2010 Senior notes Senior Notes due June 2017
Condensed Financial Statements, Captions [Line Items]
Principal amount outstanding	$ 630,300,000.0	$ 630,700,000.0											$ 625,000,000	$ 115,000,000	$ 285,000,000	$ 225,000,000
Current assets:
Cash and cash equivalents	49,700,000	49,000,000	145,700,000	69,600,000	32,000,000	37,800,000	(3,500,000)	(4,000,000)	21,200,000	15,200,000	0	0
Accounts receivable, net	253,600,000	271,900,000			0	0	237,000,000	253,500,000	16,600,000	18,400,000	0	0
Amounts due from affiliated companies	0	0			451,900,000	480,200,000	0	0	0	0	(451,900,000)	(480,200,000)
Inventoried costs	85,300,000	94,300,000			0	0	69,000,000	75,400,000	16,300,000	18,900,000	0	0
Other current assets	29,200,000	40,200,000			10,900,000	9,100,000	15,400,000	28,000,000	2,900,000	3,100,000	0	0
Total current assets	417,800,000	455,400,000			494,800,000	527,100,000	317,900,000	352,900,000	57,000,000	55,600,000	(451,900,000)	(480,200,000)
Property, plant and equipment, net	83,500,000	85,600,000			1,700,000	1,300,000	71,800,000	74,700,000	10,000,000	9,600,000	0	0
Goodwill	596,400,000	596,400,000			0	0	574,700,000	574,700,000	21,700,000	21,700,000	0	0
Intangible assets, net	87,800,000	106,100,000			0	0	85,800,000	103,400,000	2,000,000	2,700,000	0	0
Investment in subsidiaries	0	0			456,200,000	439,800,000	32,100,000	28,800,000	0	0	(488,300,000)	(468,600,000)
Amounts due from affiliated companies	0	0			0	0	24,000,000	24,000,000	0	0	(24,000,000)	(24,000,000)
Other assets	36,800,000	40,400,000			15,100,000	17,600,000	21,500,000	22,400,000	200,000	400,000	0	0
Total assets	1,222,300,000	1,283,900,000			967,800,000	985,800,000	1,127,800,000	1,180,900,000	90,900,000	90,000,000	(964,200,000)	(972,800,000)
Current liabilities:
Accounts payable	64,900,000	83,600,000			4,100,000	2,800,000	57,000,000	75,200,000	3,800,000	5,600,000	0	0
Accrued expenses	45,200,000	52,700,000			7,200,000	7,000,000	35,400,000	42,300,000	2,600,000	3,400,000	0	0
Accrued compensation	39,800,000	47,800,000			3,300,000	2,900,000	33,800,000	41,800,000	2,700,000	3,100,000	0	0
Billings in excess of costs and earnings on uncompleted contracts	45,600,000	43,700,000			0	0	38,400,000	40,500,000	7,200,000	3,200,000	0	0
Deferred income tax liability	29,000,000	28,900,000			0	0	29,000,000	28,900,000	0	0	0	0
Amounts due to affiliated companies	0	0			0	0	429,200,000	455,100,000	22,700,000	25,100,000	(451,900,000)	(480,200,000)
Other current liabilities	14,100,000	22,100,000			900,000	1,100,000	12,000,000	19,100,000	1,200,000	1,900,000	0	0
Total current liabilities	238,600,000	278,800,000			15,500,000	13,800,000	634,800,000	702,900,000	40,200,000	42,300,000	(451,900,000)	(480,200,000)
Long-term debt, net of current portion	645,900,000	648,400,000			641,600,000	643,600,000	0		4,300,000	4,800,000	0	0
Amounts due to affiliated companies	0	0			0	0	0	0	24,000,000	24,000,000	(24,000,000)	(24,000,000)
Other long-term liabilities	29,700,000	32,600,000			2,600,000	4,300,000	24,800,000	26,200,000	2,300,000	2,100,000	0	0
Total liabilities	914,200,000	959,800,000			659,700,000	661,700,000	659,600,000	729,100,000	70,800,000	73,200,000	(475,900,000)	(504,200,000)
Total stockholders' equity	308,100,000	324,100,000			308,100,000	324,100,000	468,200,000	451,800,000	20,100,000	16,800,000	(488,300,000)	(468,600,000)
Total liabilities and stockholders’ equity	$ 1,222,300,000	$ 1,283,900,000			$ 967,800,000	$ 985,800,000	$ 1,127,800,000	$ 1,180,900,000	$ 90,900,000	$ 90,000,000	$ (964,200,000)	$ (972,800,000)