Acquisitions - Assets Acquired and Liabilities Assumed (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 30, 2012	Jul. 02, 2012 Composite Engineering, Inc.	Dec. 30, 2011 Critical Infrastructure Business
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Cash			$ 8.9
Accounts receivable			9.3
Inventoried costs			12.3
Other current assets			8.9
Property and equipment			8.1
Intangible assets			38.0
Goodwill	596.4	596.4	104.2
Total assets			189.7
Current liabilities			(25.7)
Net assets acquired			164.0
Business Acquisition, Purchase Price Allocation [Abstract]
Accounts receivable				23.4
Other assets				0.5
Intangible assets				2.0
Goodwill				2.6
Total assets				28.5
Current liabilities				(9.7)
Net assets acquired				$ 18.8