Summary of Insurance Receivable Balances and Activity Related to Cumulative Trauma Product Liability Losses (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Commitments and Contingencies Disclosure [Abstract]
Balance beginning of period	$ 130.0	$ 112.1
Additions	24.9	29.7
Collections and settlements	(2.0)	(11.8)
Balance end of period	$ 152.9	$ 130.0