Fair Value Measurement - Additional Information (Detail) (Fair Value, Measurements, Nonrecurring, USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Fair Value, Measurements, Nonrecurring
Assets Measured On Nonrecurring Basis [Line Items]
Fair values reduced by estimated costs to sell	$ 0.4	$ 0	$ 1.3	$ 0.4