Condensed Consolidating Financial Statements - Balance Sheet (Details) - USD ($)	Mar. 27, 2016	Dec. 27, 2015	Mar. 29, 2015	Dec. 28, 2014	May. 31, 2014
Condensed Financial Statements, Captions [Line Items]
Principal	$ 452,500,000	$ 452,700,000
Current assets:
Cash and cash equivalents	20,100,000	28,500,000	$ 32,700,000	$ 33,500,000
Accounts receivable, net	208,800,000	206,800,000
Amounts due from affiliated companies	0	0
Inventoried costs	52,600,000	55,600,000
Other current assets	23,800,000	29,500,000
Total current assets	305,300,000	320,400,000
Property, plant and equipment, net	53,800,000	56,200,000
Goodwill	483,400,000	483,400,000
Intangible assets, net	33,800,000	36,500,000
Investment in subsidiaries	0	0
Other assets	8,100,000	6,800,000
Total assets	884,400,000	903,300,000
Current liabilities:
Accounts payable	39,800,000	48,300,000
Accrued expenses	41,600,000	37,000,000
Accrued compensation	32,600,000	36,800,000
Billings in excess of costs and earnings on uncompleted contracts	49,000,000	42,300,000
Amounts due to affiliated companies	0	0
Other current liabilities	5,900,000	6,100,000
Current liabilities of discontinued operations	1,400,000	1,900,000
Total current liabilities	170,300,000	172,400,000
Long-term debt, net of current portion	444,400,000	444,100,000
Other long-term liabilities	31,100,000	28,500,000
Non-current liabilities of discontinued operations	3,900,000	4,100,000
Total liabilities	649,700,000	649,100,000
Total stockholders’ equity	234,700,000	254,200,000
Total liabilities and stockholders’ equity	$ 884,400,000	903,300,000
Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Ownership percentage	100.00%
Parent Company
Current assets:
Cash and cash equivalents	$ 15,800,000	22,500,000
Accounts receivable, net	0	0
Amounts due from affiliated companies	223,600,000	207,800,000
Inventoried costs	0	0
Other current assets	4,700,000	16,400,000
Total current assets	244,100,000	246,700,000
Property, plant and equipment, net	2,100,000	2,000,000
Goodwill	0	0
Intangible assets, net	0	0
Investment in subsidiaries	465,600,000	477,800,000
Other assets	700,000	700,000
Total assets	712,500,000	727,200,000
Current liabilities:
Accounts payable	3,200,000	4,300,000
Accrued expenses	13,100,000	4,700,000
Accrued compensation	2,900,000	4,100,000
Billings in excess of costs and earnings on uncompleted contracts	0	0
Amounts due to affiliated companies	0	0
Other current liabilities	200,000	4,300,000
Current liabilities of discontinued operations	1,400,000	1,800,000
Total current liabilities	20,800,000	19,200,000
Long-term debt, net of current portion	442,900,000	442,400,000
Other long-term liabilities	10,200,000	7,300,000
Non-current liabilities of discontinued operations	3,900,000	4,100,000
Total liabilities	477,800,000	473,000,000
Total stockholders’ equity	234,700,000	254,200,000
Total liabilities and stockholders’ equity	712,500,000	727,200,000
Subsidiary Guarantors on a Combined Basis
Current assets:
Cash and cash equivalents	(5,700,000)	(4,800,000)
Accounts receivable, net	182,400,000	179,000,000
Amounts due from affiliated companies	0	0
Inventoried costs	34,500,000	36,900,000
Other current assets	16,100,000	11,700,000
Total current assets	227,300,000	222,800,000
Property, plant and equipment, net	45,100,000	47,500,000
Goodwill	442,600,000	442,600,000
Intangible assets, net	33,800,000	36,500,000
Investment in subsidiaries	62,200,000	60,300,000
Other assets	7,400,000	6,100,000
Total assets	818,400,000	815,800,000
Current liabilities:
Accounts payable	30,400,000	36,500,000
Accrued expenses	25,100,000	29,300,000
Accrued compensation	26,100,000	29,200,000
Billings in excess of costs and earnings on uncompleted contracts	45,100,000	37,100,000
Amounts due to affiliated companies	191,800,000	175,700,000
Other current liabilities	4,500,000	200,000
Current liabilities of discontinued operations	0	0
Total current liabilities	323,000,000	308,000,000
Long-term debt, net of current portion	0	0
Other long-term liabilities	17,800,000	18,000,000
Non-current liabilities of discontinued operations	0	0
Total liabilities	340,800,000	326,000,000
Total stockholders’ equity	477,600,000	489,800,000
Total liabilities and stockholders’ equity	818,400,000	815,800,000
Non-Guarantors on a Combined Basis
Current assets:
Cash and cash equivalents	10,000,000	10,800,000
Accounts receivable, net	26,400,000	27,800,000
Amounts due from affiliated companies	0	0
Inventoried costs	18,100,000	18,700,000
Other current assets	3,000,000	1,400,000
Total current assets	57,500,000	58,700,000
Property, plant and equipment, net	6,600,000	6,700,000
Goodwill	40,800,000	40,800,000
Intangible assets, net	0	0
Investment in subsidiaries	0	0
Other assets	0	0
Total assets	104,900,000	106,200,000
Current liabilities:
Accounts payable	6,200,000	7,500,000
Accrued expenses	3,400,000	3,000,000
Accrued compensation	3,600,000	3,500,000
Billings in excess of costs and earnings on uncompleted contracts	3,900,000	5,200,000
Amounts due to affiliated companies	31,800,000	32,100,000
Other current liabilities	1,200,000	1,600,000
Current liabilities of discontinued operations	0	100,000
Total current liabilities	50,100,000	53,000,000
Long-term debt, net of current portion	1,500,000	1,700,000
Other long-term liabilities	3,100,000	3,200,000
Non-current liabilities of discontinued operations	0	0
Total liabilities	54,700,000	57,900,000
Total stockholders’ equity	50,200,000	48,300,000
Total liabilities and stockholders’ equity	104,900,000	106,200,000
Eliminations
Current assets:
Cash and cash equivalents	0	0
Accounts receivable, net	0	0
Amounts due from affiliated companies	(223,600,000)	(207,800,000)
Inventoried costs	0	0
Other current assets	0	0
Total current assets	(223,600,000)	(207,800,000)
Property, plant and equipment, net	0	0
Goodwill	0	0
Intangible assets, net	0	0
Investment in subsidiaries	(527,800,000)	(538,100,000)
Other assets	0	0
Total assets	(751,400,000)	(745,900,000)
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
Amounts due to affiliated companies	(223,600,000)	(207,800,000)
Other current liabilities	0	0
Current liabilities of discontinued operations	0	0
Total current liabilities	(223,600,000)	(207,800,000)
Long-term debt, net of current portion	0	0
Other long-term liabilities	0	0
Non-current liabilities of discontinued operations	0	0
Total liabilities	(223,600,000)	(207,800,000)
Total stockholders’ equity	(527,800,000)	(538,100,000)
Total liabilities and stockholders’ equity	(751,400,000)	$ (745,900,000)
Senior notes | 7% Senior Notes due 2019
Condensed Financial Statements, Captions [Line Items]
Principal	$ 450,000,000				$ 625,000,000.0