Condensed Consolidating Financial Statements - Balance Sheet (Details) (USD $)	Sep. 29, 2013	Dec. 30, 2012	Sep. 30, 2012	Dec. 25, 2011	Sep. 29, 2013 Parent Company	Dec. 30, 2012 Parent Company	Sep. 29, 2013 Guarantors on a Combined Basis	Dec. 30, 2012 Guarantors on a Combined Basis	Sep. 29, 2013 Non-Guarantors on a Combined Basis	Dec. 30, 2012 Non-Guarantors on a Combined Basis	Sep. 29, 2013 Eliminations	Dec. 30, 2012 Eliminations	Sep. 29, 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	$ 630,000,000.0	$ 630,700,000.0											$ 625,000,000	$ 115,000,000	$ 285,000,000	$ 225,000,000
Current assets:
Cash and cash equivalents	49,800,000	49,000,000	37,600,000	69,600,000	34,200,000	37,800,000	(3,400,000)	(4,000,000)	19,000,000	15,200,000	0	0
Accounts receivable, net	269,000,000	271,900,000			0	0	248,600,000	253,500,000	20,400,000	18,400,000	0	0
Amounts due from affiliated companies	0	0			450,800,000	480,200,000	0	0	0	0	(450,800,000)	(480,200,000)
Inventoried costs	83,400,000	94,300,000			0	0	67,800,000	75,400,000	15,600,000	18,900,000	0	0
Other current assets	27,100,000	40,200,000			9,500,000	9,100,000	14,700,000	28,000,000	2,900,000	3,100,000	0	0
Total current assets	429,300,000	455,400,000			494,500,000	527,100,000	327,700,000	352,900,000	57,900,000	55,600,000	(450,800,000)	(480,200,000)
Property, plant and equipment, net	84,500,000	85,600,000			1,900,000	1,300,000	72,300,000	74,700,000	10,300,000	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	78,800,000	106,100,000			0	0	77,100,000	103,400,000	1,700,000	2,700,000	0	0
Investment in subsidiaries	0	0			463,900,000	439,800,000	33,100,000	28,800,000	0	0	(497,000,000)	(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	35,700,000	40,400,000			13,800,000	17,600,000	21,700,000	22,400,000	200,000	400,000	0	0
Total assets	1,224,700,000	1,283,900,000			974,100,000	985,800,000	1,130,600,000	1,180,900,000	91,800,000	90,000,000	(971,800,000)	(972,800,000)
Current liabilities:
Accounts payable	57,700,000	83,600,000			3,000,000	2,800,000	51,000,000	75,200,000	3,700,000	5,600,000	0	0
Accrued expenses	67,400,000	52,700,000			22,800,000	7,000,000	40,900,000	42,300,000	3,700,000	3,400,000	0	0
Accrued compensation	37,100,000	47,800,000			2,200,000	2,900,000	31,200,000	41,800,000	3,700,000	3,100,000	0	0
Billings in excess of costs and earnings on uncompleted contracts	51,200,000	43,700,000			0	0	44,700,000	40,500,000	6,500,000	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	428,900,000	455,100,000	21,900,000	25,100,000	(450,800,000)	(480,200,000)
Other current liabilities	13,800,000	22,100,000			1,300,000	1,100,000	11,500,000	19,100,000	1,000,000	1,900,000	0	0
Total current liabilities	256,200,000	278,800,000			29,300,000	13,800,000	637,200,000	702,900,000	40,500,000	42,300,000	(450,800,000)	(480,200,000)
Long-term debt, net of current portion	644,600,000	648,400,000			640,600,000	643,600,000	0		4,000,000	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	22,200,000	32,600,000			2,500,000	4,300,000	17,500,000	26,200,000	2,200,000	2,100,000	0	0
Total liabilities	923,000,000	959,800,000			672,400,000	661,700,000	654,700,000	729,100,000	70,700,000	73,200,000	(474,800,000)	(504,200,000)
Total stockholders' equity	301,700,000	324,100,000			301,700,000	324,100,000	475,900,000	451,800,000	21,100,000	16,800,000	(497,000,000)	(468,600,000)
Total liabilities and stockholders’ equity	$ 1,224,700,000	$ 1,283,900,000			$ 974,100,000	$ 985,800,000	$ 1,130,600,000	$ 1,180,900,000	$ 91,800,000	$ 90,000,000	$ (971,800,000)	$ (972,800,000)