Income Taxes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Income Tax Disclosure [Line Items]
Deferred tax asset, gross	$ 30.2	$ 42.8
Reversal of valuation allowance on net deferred tax allowance	40.3
Expected reversal of valuation allowance on net deferred tax allowance	2.5
Tax (benefit) at statutory rate, rate	35.00%	35.00%
Operating Income (Loss) [Member]
Income Tax Disclosure [Line Items]
Reversal of valuation allowance on net deferred tax allowance	1.6
Management's change in judgment [Member]
Income Tax Disclosure [Line Items]
Reversal of valuation allowance on net deferred tax allowance	$ 38.7