Condensed Consolidating Financial Statements - Balance Sheet (Details) (USD $)	Sep. 28, 2014	Dec. 29, 2013	Sep. 29, 2013	Dec. 30, 2012	Sep. 28, 2014 Subsidiaries	Sep. 28, 2014 Parent Company	Dec. 29, 2013 Parent Company	Sep. 28, 2014 Guarantors on a Combined Basis	Dec. 29, 2013 Guarantors on a Combined Basis	Sep. 28, 2014 Non-Guarantors on a Combined Basis	Dec. 29, 2013 Non-Guarantors on a Combined Basis	Sep. 28, 2014 Eliminations	Dec. 29, 2013 Eliminations	Sep. 28, 2014 Senior notes 7.00% Senior Notes due 2019	May 31, 2014 Senior notes 7.00% Senior Notes due 2019
Condensed Financial Statements, Captions [Line Items]
Principal	$ 670,000,000	$ 629,800,000												$ 625,000,000	$ 625,000,000.0
Ownership percentage					100.00%
Current assets:
Cash and cash equivalents	16,200,000	55,700,000	49,800,000	49,000,000		13,700,000	42,700,000	(5,900,000)	(3,000,000)	8,400,000	16,000,000	0	0
Accounts receivable, net	255,100,000	265,800,000				0	0	223,700,000	238,600,000	31,400,000	27,200,000	0	0
Amounts due from affiliated companies	0	0				398,100,000	410,200,000	0	0	0	0	(398,100,000)	(410,200,000)
Inventoried costs	80,400,000	74,600,000				0	0	61,700,000	59,100,000	18,700,000	15,500,000	0	0
Other current assets	25,000,000	34,200,000				5,000,000	10,700,000	16,100,000	19,400,000	3,900,000	4,100,000	0	0
Total current assets	376,700,000	430,300,000				416,800,000	463,600,000	295,600,000	314,100,000	62,400,000	62,800,000	(398,100,000)	(410,200,000)
Property, plant and equipment, net	82,600,000	84,800,000				2,000,000	2,100,000	70,300,000	71,900,000	10,300,000	10,800,000	0	0
Goodwill	596,400,000	596,400,000				0	0	572,400,000	574,800,000	24,000,000	21,600,000	0	0
Intangible assets, net	57,800,000	69,900,000				0	0	57,400,000	68,500,000	400,000	1,400,000	0	0
Investment in subsidiaries	0	0				492,200,000	474,200,000	41,900,000	36,700,000	0	0	(534,100,000)	(510,900,000)
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	32,400,000	35,200,000				7,900,000	12,900,000	24,500,000	23,000,000	0	(700,000)	0	0
Total assets	1,145,900,000	1,216,600,000				918,900,000	952,800,000	1,086,100,000	1,113,000,000	97,100,000	95,900,000	(956,200,000)	(945,100,000)
Current liabilities:
Accounts payable	49,200,000	61,900,000				3,200,000	2,800,000	41,900,000	54,100,000	4,100,000	5,000,000	0	0
Accrued expenses	53,700,000	51,400,000				17,400,000	6,600,000	32,200,000	40,900,000	4,100,000	3,900,000	0	0
Accrued compensation	37,100,000	44,900,000				4,100,000	4,000,000	29,400,000	36,900,000	3,600,000	4,000,000	0	0
Billings in excess of costs and earnings on uncompleted contracts	47,200,000	52,500,000				0	0	40,900,000	45,400,000	6,300,000	7,100,000	0	0
Deferred income tax liability	28,400,000	28,400,000				(800,000)	0	29,200,000	28,400,000	0	0	0	0
Amounts due to affiliated companies	0	0				0	0	379,200,000	390,200,000	18,900,000	20,000,000	(398,100,000)	(410,200,000)
Other current liabilities	11,600,000	11,900,000				1,000,000	1,300,000	9,600,000	9,500,000	1,000,000	1,100,000	0	0
Total current liabilities	227,200,000	251,000,000				24,900,000	14,700,000	562,400,000	605,400,000	38,000,000	41,100,000	(398,100,000)	(410,200,000)
Long-term debt, net of current portion	662,900,000	643,300,000				659,900,000	639,500,000	0		3,000,000	3,800,000	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	24,800,000	26,500,000				3,100,000	2,800,000	19,500,000	21,400,000	2,200,000	2,300,000	0	0
Total liabilities	914,900,000	920,800,000				687,900,000	657,000,000	581,900,000	626,800,000	67,200,000	71,200,000	(422,100,000)	(434,200,000)
Total stockholders' equity	231,000,000	295,800,000				231,000,000	295,800,000	504,200,000	486,200,000	29,900,000	24,700,000	(534,100,000)	(510,900,000)
Total liabilities and stockholders’ equity	$ 1,145,900,000	$ 1,216,600,000				$ 918,900,000	$ 952,800,000	$ 1,086,100,000	$ 1,113,000,000	$ 97,100,000	$ 95,900,000	$ (956,200,000)	$ (945,100,000)