Condensed Consolidating Financial Statements - Balance Sheet (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 25, 2011	Sep. 25, 2011	Dec. 26, 2010	Sep. 30, 2012 Parent Company	Dec. 25, 2011 Parent Company	Sep. 30, 2012 Guarantors on a Combined Basis	Dec. 25, 2011 Guarantors on a Combined Basis	Sep. 30, 2012 Non-Guarantors on a Combined Basis	Dec. 25, 2011 Non-Guarantors on a Combined Basis	Sep. 30, 2012 Eliminations	Dec. 25, 2011 Eliminations	Sep. 30, 2012 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	$ 631.0	$ 631.8											$ 625.0	$ 115.0	$ 285.0	$ 225.0
Current assets:
Cash and cash equivalents	37.6	69.6	109.1	10.8	20.9	52.6	(1.3)	2.8	18.0	14.2	0	0
Accounts receivable, net	281.4	245.3			0	0	262.7	225.4	18.7	19.9	0	0
Amounts due from affiliated companies	0	0			509.9	449.3	0	0	0	0	(509.9)	(449.3)
Inventoried costs	99.9	76.6			0	0	82.1	64.2	17.8	12.4	0	0
Other current assets	37.7	29.5			10.9	3.3	23.5	22.1	3.3	4.1	0	0
Total current assets	456.6	421.0			541.7	505.2	367.0	314.5	57.8	50.6	(509.9)	(449.3)
Property, plant and equipment, net	84.6	72.5			1.3	1.2	73.9	62.2	9.4	9.1	0	0
Goodwill	678.5	571.6			0	0	658.0	551.1	20.5	20.5	0	0
Intangible assets, net	132.2	124.6			0	0	129.1	119.8	3.1	4.8	0	0
Investment in subsidiaries	0	0			542.2	466.0	14.6	8.8	0	0	(556.8)	(474.8)
Amounts due from affiliated companies	0	0			0	0	26.0	26.0	0	0	(26.0)	(26.0)
Other assets	21.0	26.3			18.5	21.5	1.7	4.0	0.8	0.8	0	0
Total assets	1,372.9	1,216.0			1,103.7	993.9	1,270.3	1,086.4	91.6	85.8	(1,092.7)	(950.1)
Current liabilities:
Accounts payable	81.0	48.8			5.0	8.5	70.0	37.5	6.0	2.8	0	0
Accrued expenses	73.4	55.8			3.0	2.4	67.8	50.4	2.6	3.0	0	0
Accrued compensation	41.9	39.8			3.8	3.7	36.0	33.3	2.1	2.8	0	0
Billings in excess of costs and earnings on uncompleted contracts	44.0	36.2			0	0	40.0	34.3	4.0	1.9	0	0
Amounts due to affiliated companies	0	0			0	0	480.7	418.9	29.2	30.4	(509.9)	(449.3)
Other current liabilities	33.8	33.2			32.5	13.5	1.3	17.4	0	2.3	0	0
Total current liabilities	274.1	213.8			44.3	28.1	695.8	591.8	43.9	43.2	(509.9)	(449.3)
Long-term debt, net of current portion	649.7	653.6			644.7	647.8	0	0	5.0	5.8	0	0
Amounts due to affiliated companies	0	0			0	0	0	0	26.0	26.0	(26.0)	(26.0)
Other long-term liabilities	36.5	36.0			2.1	5.4	32.3	28.6	2.1	2.0	0	0
Total liabilities	960.3	903.4			691.1	681.3	728.1	620.4	77.0	77.0	(535.9)	(475.3)
Total stockholders' equity	412.6	312.6			412.6	312.6	542.2	466.0	14.6	8.8	(556.8)	(474.8)
Total liabilities and stockholders' equity	$ 1,372.9	$ 1,216.0			$ 1,103.7	$ 993.9	$ 1,270.3	$ 1,086.4	$ 91.6	$ 85.8	$ (1,092.7)	$ (950.1)