Commitments and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended	12 Months Ended
	Dec. 31, 2011	Oct. 01, 2011	Jun. 30, 2012	Dec. 31, 2011	Jul. 02, 2011	Jan. 01, 2011 Cliffstar	Aug. 17, 2010 Cliffstar
Commitments And Contingencies [Line Items]
Loss related to single contingency	$ 2.9			$ 2.9
Acquisition, contingent consideration payable upon achievement of milestones						15.0	15.0
Maximum contingent consideration						55.0
Additional contingent consideration for business acquisition	12.1			12.1
Interim payments to the seller	8.6	21.0
Refund of contingent consideration payment to buyer		4.7
Settlement of seller's objections to contingent consideration	0.9
Current estimated amount of payments previously made to seller			34.3
Standby letters of credit outstanding			$ 11.0		$ 9.5