Subsequent Events (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	0 Months Ended	6 Months Ended			0 Months Ended
	Feb. 11, 2011	Jun. 24, 2012	Jun. 26, 2011	Jun. 24, 2012 Revolving credit facility	May 14, 2012 Composite Engineering, Inc.	Jul. 02, 2012 Business acquisition Composite Engineering, Inc.	May 14, 2012 Business acquisition Composite Engineering, Inc.	May 10, 2012 Business acquisition Composite Engineering, Inc.	Jul. 02, 2012 Business acquisition Composite Engineering, Inc. Key CEI personnel Restricted Stock Units (RSUs)
Subsequent Event [Line Items]
Total purchase price						$ 161.3
Cash paid as part of purchase price						135.0
Common stock issued to fund purchase of CEI (shares)					20.0	4.0		20.0
Purchase price per share	$ 13.25				$ 5.00	$ 5.94		$ 5.00
Common stock issued as part of purchase price						23.8
Eliminated accounts payable from CEI						2.3
Additional tax liability incurred by the shareholders of CEI for making a Section 338(h)(10) IRC election						0.2
Estimated tax-deductible goodwill, amount						130.0
Tax deduction realization period						15 years
Number of Restricted Stock Units granted to key CEI personnel									2.0
Gross proceeds from issuance of common stock	64.8				100.0			100.0
Proceeds from the issuance of common stock	61.1	97.0	61.1		97.0		97.0
Line of credit borrowings to fund acquisition				$ 0		$ 40.0