Condensed Consolidating Financial Statements - Balance Sheet (Details) (USD $)	Dec. 28, 2014	Dec. 29, 2013	Dec. 30, 2012	Dec. 25, 2011	May 31, 2014
Condensed Financial Statements, Captions [Line Items]
Principal	$ 669,800,000.0	$ 629,800,000.0
Ownership percentage	100.00%
Current assets:
Cash and cash equivalents	34,700,000	55,700,000	49,000,000	69,600,000
Accounts receivable, net	248,200,000	265,800,000
Amounts due from affiliated companies	0	0
Inventoried costs	68,000,000	74,600,000
Other current assets	24,000,000	34,200,000
Total current assets	374,900,000	430,300,000
Property, plant and equipment, net	82,600,000	84,800,000
Goodwill	596,400,000	596,400,000	596,400,000
Intangible assets, net	52,300,000	69,900,000
Investment in subsidiaries	0	0
Amounts due from affiliated companies, long-term	0	0
Other assets	32,600,000	35,200,000
Total assets	1,138,800,000	1,216,600,000
Current liabilities:
Accounts payable	48,400,000	61,900,000
Accrued expenses	39,800,000	51,400,000
Accrued compensation	46,400,000	44,900,000
Billings in excess of costs and earnings on uncompleted contracts	52,100,000	52,500,000
Deferred income tax liability	30,300,000	28,400,000
Amounts due to affiliated companies	0	0
Other current liabilities	9,100,000	11,900,000
Total current liabilities	226,100,000	251,000,000
Long-term debt, net of current portion	663,000,000	643,300,000
Amounts due to affiliated companies	0	0
Other long-term liabilities	25,400,000	26,500,000
Total liabilities	914,500,000	920,800,000
Total stockholders' equity	224,300,000	295,800,000	324,100,000	312,600,000
Total liabilities and stockholders’ equity	1,138,800,000	1,216,600,000
Parent Company
Current assets:
Cash and cash equivalents	28,700,000	42,700,000
Accounts receivable, net	0	0
Amounts due from affiliated companies	341,900,000	410,200,000
Inventoried costs	0	0
Other current assets	4,400,000	10,700,000
Total current assets	375,000,000	463,600,000
Property, plant and equipment, net	2,000,000	2,100,000
Goodwill	0	0
Intangible assets, net	0	0
Investment in subsidiaries	498,300,000	474,200,000
Amounts due from affiliated companies, long-term	0	0
Other assets	27,800,000	12,900,000
Total assets	903,100,000	952,800,000
Current liabilities:
Accounts payable	3,100,000	2,800,000
Accrued expenses	6,300,000	6,600,000
Accrued compensation	5,200,000	4,000,000
Billings in excess of costs and earnings on uncompleted contracts	0	0
Deferred income tax liability	0	0
Amounts due to affiliated companies	0	0
Other current liabilities	1,000,000	1,300,000
Total current liabilities	15,600,000	14,700,000
Long-term debt, net of current portion	660,200,000	639,500,000
Amounts due to affiliated companies	0	0
Other long-term liabilities	3,000,000	2,800,000
Total liabilities	678,800,000	657,000,000
Total stockholders' equity	224,300,000	295,800,000
Total liabilities and stockholders’ equity	903,100,000	952,800,000
Guarantors on a Combined Basis
Current assets:
Cash and cash equivalents	(6,000,000)	(3,000,000)
Accounts receivable, net	217,700,000	238,600,000
Amounts due from affiliated companies	0	0
Inventoried costs	49,900,000	59,100,000
Other current assets	16,300,000	19,400,000
Total current assets	277,900,000	314,100,000
Property, plant and equipment, net	70,600,000	71,900,000
Goodwill	572,400,000	574,800,000
Intangible assets, net	52,200,000	68,500,000
Investment in subsidiaries	48,300,000	36,700,000
Amounts due from affiliated companies, long-term	3,200,000	24,000,000
Other assets	4,600,000	23,000,000
Total assets	1,029,200,000	1,113,000,000
Current liabilities:
Accounts payable	40,400,000	54,100,000
Accrued expenses	30,200,000	40,900,000
Accrued compensation	37,700,000	36,900,000
Billings in excess of costs and earnings on uncompleted contracts	47,000,000	45,400,000
Deferred income tax liability	30,300,000	28,400,000
Amounts due to affiliated companies	306,600,000	390,200,000
Other current liabilities	6,500,000	9,500,000
Total current liabilities	498,700,000	605,400,000
Long-term debt, net of current portion	0	0
Amounts due to affiliated companies	0	0
Other long-term liabilities	20,200,000	21,400,000
Total liabilities	518,900,000	626,800,000
Total stockholders' equity	510,300,000	486,200,000
Total liabilities and stockholders’ equity	1,029,200,000	1,113,000,000
Non-Guarantors on a Combined Basis
Current assets:
Cash and cash equivalents	12,000,000	16,000,000
Accounts receivable, net	30,500,000	27,200,000
Amounts due from affiliated companies	0	0
Inventoried costs	18,100,000	15,500,000
Other current assets	3,300,000	4,100,000
Total current assets	63,900,000	62,800,000
Property, plant and equipment, net	10,000,000	10,800,000
Goodwill	24,000,000	21,600,000
Intangible assets, net	100,000	1,400,000
Investment in subsidiaries	0	0
Amounts due from affiliated companies, long-term	0	0
Other assets	200,000	(700,000)
Total assets	98,200,000	95,900,000
Current liabilities:
Accounts payable	4,900,000	5,000,000
Accrued expenses	3,300,000	3,900,000
Accrued compensation	3,500,000	4,000,000
Billings in excess of costs and earnings on uncompleted contracts	5,100,000	7,100,000
Deferred income tax liability	0	0
Amounts due to affiliated companies	35,300,000	20,000,000
Other current liabilities	1,600,000	1,100,000
Total current liabilities	53,700,000	41,100,000
Long-term debt, net of current portion	2,800,000	3,800,000
Amounts due to affiliated companies	3,200,000	24,000,000
Other long-term liabilities	2,200,000	2,300,000
Total liabilities	61,900,000	71,200,000
Total stockholders' equity	36,300,000	24,700,000
Total liabilities and stockholders’ equity	98,200,000	95,900,000
Eliminations
Current assets:
Cash and cash equivalents	0	0
Accounts receivable, net	0	0
Amounts due from affiliated companies	(341,900,000)	(410,200,000)
Inventoried costs	0	0
Other current assets	0	0
Total current assets	(341,900,000)	(410,200,000)
Property, plant and equipment, net	0	0
Goodwill	0	0
Intangible assets, net	0	0
Investment in subsidiaries	(546,600,000)	(510,900,000)
Amounts due from affiliated companies, long-term	(3,200,000)	(24,000,000)
Other assets	0	0
Total assets	(891,700,000)	(945,100,000)
Current liabilities:
Accounts payable	0	0
Accrued expenses	0	0
Accrued compensation	0	0
Billings in excess of costs and earnings on uncompleted contracts	0	0
Deferred income tax liability	0	0
Amounts due to affiliated companies	(341,900,000)	(410,200,000)
Other current liabilities	0	0
Total current liabilities	(341,900,000)	(410,200,000)
Long-term debt, net of current portion	0	0
Amounts due to affiliated companies	(3,200,000)	(24,000,000)
Other long-term liabilities	0	0
Total liabilities	(345,100,000)	(434,200,000)
Total stockholders' equity	(546,600,000)	(510,900,000)
Total liabilities and stockholders’ equity	(891,700,000)	(945,100,000)
Senior notes | 7% Senior Notes due 2019
Condensed Financial Statements, Captions [Line Items]
Principal	$ 625,000,000				$ 625,000,000.0