Comprehensive Income and Equity - Schedule of Comprehensive Income (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Equity [Abstract]
Tax expense, unrecognized pension transition asset	$ 0	$ 0.1	$ 0	$ 0.1
Tax expense, unrecognized prior service cost	0	0	0	0
Tax expense, unrecognized pension net loss	$ 0.8	$ 0.8	$ 2.3	$ 2.3