Condensed Consolidating Financial Statements - Condensed Consolidating Balance Sheet (Details) - USD ($)	Dec. 27, 2015	Dec. 28, 2014	May. 31, 2014	Dec. 29, 2013	Dec. 30, 2012
Condensed Financial Statements, Captions [Line Items]
Principal	$ 452,700,000.0	$ 669,800,000.0
Ownership percentage	100.00%
Current assets:
Cash and cash equivalents	$ 28,500,000	33,500,000		$ 54,200,000	$ 48,400,000
Accounts receivable, net	206,800,000	217,500,000
Amounts due from affiliated companies	0	0
Inventoried costs	55,600,000	47,400,000
Other current assets	29,500,000	21,000,000
Current assets of discontinued operations	0	53,800,000
Total current assets	320,400,000	373,200,000
Property, plant and equipment, net	56,200,000	61,600,000
Goodwill	483,400,000	483,400,000
Intangible assets, net	36,500,000	49,500,000
Investment in subsidiaries	0	0
Other assets	6,800,000	26,500,000
Non-current assets of discontinued operations	0	137,000,000
Total assets	903,300,000	1,131,200,000
Current liabilities:
Accounts payable	48,300,000	44,600,000
Accrued expenses	37,000,000	38,000,000
Accrued compensation	36,800,000	41,100,000
Billings in excess of costs and earnings on uncompleted contracts	42,300,000	49,600,000
Deferred income tax liability	0	30,300,000
Amounts due to affiliated companies	0	0
Other current liabilities	6,100,000	7,900,000
Current liabilities of discontinued operations	1,900,000	14,600,000
Total current liabilities	172,400,000	226,100,000
Long-term debt, net of current portion	444,100,000	655,400,000
Other long-term liabilities	28,500,000	24,900,000
Non-current liabilities of discontinued operations	4,100,000	500,000
Total liabilities	649,100,000	906,900,000
Total stockholders’ equity	254,200,000	224,300,000		$ 295,800,000	$ 324,100,000
Total liabilities and stockholders’ equity	903,300,000	1,131,200,000
Parent Company
Current assets:
Cash and cash equivalents	22,500,000	28,700,000
Accounts receivable, net	0	0
Amounts due from affiliated companies	207,800,000	341,900,000
Inventoried costs	0	0
Other current assets	16,400,000	2,700,000
Current assets of discontinued operations		0
Total current assets	246,700,000	373,300,000
Property, plant and equipment, net	2,000,000	2,000,000
Goodwill	0	0
Intangible assets, net	0	0
Investment in subsidiaries	477,800,000	498,300,000
Other assets	700,000	21,900,000
Non-current assets of discontinued operations		0
Total assets	727,200,000	895,500,000
Current liabilities:
Accounts payable	4,300,000	3,100,000
Accrued expenses	4,700,000	6,300,000
Accrued compensation	4,100,000	5,200,000
Billings in excess of costs and earnings on uncompleted contracts	0	0
Deferred income tax liability		0
Amounts due to affiliated companies	0	0
Other current liabilities	4,300,000	300,000
Current liabilities of discontinued operations	1,800,000	700,000
Total current liabilities	19,200,000	15,600,000
Long-term debt, net of current portion	442,400,000	652,600,000
Other long-term liabilities	7,300,000	3,000,000
Non-current liabilities of discontinued operations	4,100,000	0
Total liabilities	473,000,000	671,200,000
Total stockholders’ equity	254,200,000	224,300,000
Total liabilities and stockholders’ equity	727,200,000	895,500,000
Subsidiary Guarantors on a Combined Basis
Current assets:
Cash and cash equivalents	(4,800,000)	(5,500,000)
Accounts receivable, net	179,000,000	196,400,000
Amounts due from affiliated companies	0	0
Inventoried costs	36,900,000	32,200,000
Other current assets	11,700,000	15,500,000
Current assets of discontinued operations		38,700,000
Total current assets	222,800,000	277,300,000
Property, plant and equipment, net	47,500,000	52,000,000
Goodwill	442,600,000	442,600,000
Intangible assets, net	36,500,000	49,400,000
Investment in subsidiaries	60,300,000	48,100,000
Other assets	6,100,000	4,600,000
Non-current assets of discontinued operations		134,500,000
Total assets	815,800,000	1,008,500,000
Current liabilities:
Accounts payable	36,500,000	37,100,000
Accrued expenses	29,300,000	28,900,000
Accrued compensation	29,200,000	32,700,000
Billings in excess of costs and earnings on uncompleted contracts	37,100,000	45,700,000
Deferred income tax liability		30,300,000
Amounts due to affiliated companies	175,700,000	287,400,000
Other current liabilities	200,000	6,100,000
Current liabilities of discontinued operations	0	10,800,000
Total current liabilities	308,000,000	479,000,000
Long-term debt, net of current portion	0	0
Other long-term liabilities	18,000,000	19,000,000
Non-current liabilities of discontinued operations	0	200,000
Total liabilities	326,000,000	498,200,000
Total stockholders’ equity	489,800,000	510,300,000
Total liabilities and stockholders’ equity	815,800,000	1,008,500,000
Non-Guarantors on a Combined Basis
Current assets:
Cash and cash equivalents	10,800,000	10,300,000
Accounts receivable, net	27,800,000	21,100,000
Amounts due from affiliated companies	0	0
Inventoried costs	18,700,000	15,200,000
Other current assets	1,400,000	2,800,000
Current assets of discontinued operations		15,100,000
Total current assets	58,700,000	64,500,000
Property, plant and equipment, net	6,700,000	7,600,000
Goodwill	40,800,000	40,800,000
Intangible assets, net	0	100,000
Investment in subsidiaries	0	0
Other assets	0	0
Non-current assets of discontinued operations		2,500,000
Total assets	106,200,000	115,500,000
Current liabilities:
Accounts payable	7,500,000	4,400,000
Accrued expenses	3,000,000	2,800,000
Accrued compensation	3,500,000	3,200,000
Billings in excess of costs and earnings on uncompleted contracts	5,200,000	3,900,000
Deferred income tax liability		0
Amounts due to affiliated companies	32,100,000	54,500,000
Other current liabilities	1,600,000	1,500,000
Current liabilities of discontinued operations	100,000	3,100,000
Total current liabilities	53,000,000	73,400,000
Long-term debt, net of current portion	1,700,000	2,800,000
Other long-term liabilities	3,200,000	2,900,000
Non-current liabilities of discontinued operations	0	300,000
Total liabilities	57,900,000	79,400,000
Total stockholders’ equity	48,300,000	36,100,000
Total liabilities and stockholders’ equity	106,200,000	115,500,000
Eliminations
Current assets:
Cash and cash equivalents	0	0
Accounts receivable, net	0	0
Amounts due from affiliated companies	(207,800,000)	(341,900,000)
Inventoried costs	0	0
Other current assets	0	0
Current assets of discontinued operations		0
Total current assets	(207,800,000)	(341,900,000)
Property, plant and equipment, net	0	0
Goodwill	0	0
Intangible assets, net	0	0
Investment in subsidiaries	(538,100,000)	(546,400,000)
Other assets	0	0
Non-current assets of discontinued operations		0
Total assets	(745,900,000)	(888,300,000)
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
Amounts due to affiliated companies	(207,800,000)	(341,900,000)
Other current liabilities	0	0
Current liabilities of discontinued operations	0	0
Total current liabilities	(207,800,000)	(341,900,000)
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	(207,800,000)	(341,900,000)
Total stockholders’ equity	(538,100,000)	(546,400,000)
Total liabilities and stockholders’ equity	(745,900,000)	$ (888,300,000)
Senior notes | 7% Senior Notes due 2019
Condensed Financial Statements, Captions [Line Items]
Principal	$ 450,000,000		$ 625,000,000.0