Condensed Consolidating Financial Statements - Balance Sheet (Details) (USD $)	Mar. 31, 2013	Dec. 30, 2012	Mar. 25, 2012	Dec. 25, 2011	Mar. 31, 2013 Parent Company	Dec. 30, 2012 Parent Company	Mar. 31, 2013 Guarantors on a Combined Basis	Dec. 30, 2012 Guarantors on a Combined Basis	Mar. 31, 2013 Non-Guarantors on a Combined Basis	Dec. 30, 2012 Non-Guarantors on a Combined Basis	Mar. 31, 2013 Eliminations	Dec. 30, 2012 Eliminations	Mar. 31, 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	$ 630,500,000.0	$ 630,700,000.0											$ 625,000,000	$ 115,000,000	$ 285,000,000	$ 225,000,000
Current assets:
Cash and cash equivalents	51,600,000	49,000,000	74,200,000	69,600,000	34,300,000	37,800,000	(1,900,000)	(4,000,000)	19,200,000	15,200,000	0	0
Accounts receivable, net	281,800,000	271,900,000			0	0	264,700,000	253,500,000	17,100,000	18,400,000	0	0
Amounts due from affiliated companies	0	0			482,700,000	480,200,000	0	0	0	0	(482,700,000)	(480,200,000)
Inventoried costs	88,200,000	94,300,000			0	0	70,700,000	75,400,000	17,500,000	18,900,000	0	0
Other current assets	33,500,000	40,200,000			8,800,000	9,100,000	21,600,000	28,000,000	3,100,000	3,100,000	0	0
Total current assets	455,100,000	455,400,000			525,800,000	527,100,000	355,100,000	352,900,000	56,900,000	55,600,000	(482,700,000)	(480,200,000)
Property, plant and equipment, net	84,000,000	85,600,000			1,300,000	1,300,000	73,000,000	74,700,000	9,700,000	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	96,800,000	106,100,000			0	0	94,500,000	103,400,000	2,300,000	2,700,000	0	0
Investment in subsidiaries	0	0			448,500,000	439,800,000	30,100,000	28,800,000	0	0	(478,600,000)	(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	38,300,000	40,400,000			16,400,000	17,600,000	21,500,000	22,400,000	400,000	400,000	0	0
Total assets	1,270,600,000	1,283,900,000			992,000,000	985,800,000	1,172,900,000	1,180,900,000	91,000,000	90,000,000	(985,300,000)	(972,800,000)
Current liabilities:
Accounts payable	71,600,000	83,600,000			1,900,000	2,800,000	66,500,000	75,200,000	3,200,000	5,600,000	0	0
Accrued expenses	63,400,000	52,700,000			22,600,000	7,000,000	38,100,000	42,300,000	2,700,000	3,400,000	0	0
Accrued compensation	43,400,000	47,800,000			3,800,000	2,900,000	36,600,000	41,800,000	3,000,000	3,100,000	0	0
Billings in excess of costs and earnings on uncompleted contracts	48,400,000	43,700,000			0	0	42,300,000	40,500,000	6,100,000	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	457,300,000	455,100,000	25,400,000	25,100,000	(482,700,000)	(480,200,000)
Other current liabilities	19,800,000	22,100,000			1,100,000	1,100,000	16,800,000	19,100,000	1,900,000	1,900,000	0	0
Total current liabilities	275,600,000	278,800,000			29,400,000	13,800,000	686,600,000	702,900,000	42,300,000	42,300,000	(482,700,000)	(480,200,000)
Long-term debt, net of current portion	647,200,000	648,400,000			642,700,000	643,600,000	0		4,500,000	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	32,200,000	32,600,000			4,300,000	4,300,000	25,800,000	26,200,000	2,100,000	2,100,000	0	0
Total liabilities	955,000,000	959,800,000			676,400,000	661,700,000	712,400,000	729,100,000	72,900,000	73,200,000	(506,700,000)	(504,200,000)
Total stockholders' equity	315,600,000	324,100,000			315,600,000	324,100,000	460,500,000	451,800,000	18,100,000	16,800,000	(478,600,000)	(468,600,000)
Total liabilities and stockholders’ equity	$ 1,270,600,000	$ 1,283,900,000			$ 992,000,000	$ 985,800,000	$ 1,172,900,000	$ 1,180,900,000	$ 91,000,000	$ 90,000,000	$ (985,300,000)	$ (972,800,000)