Capital Stock and Treasury Stock - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2018	Jun. 11, 2018	Jun. 10, 2018	Oct. 17, 2016
Equity, Class of Treasury Stock [Line Items]
Common Stock, Shares Authorized		400,000,000	200,000,000
Common Stock, Par Value Per Share		$ 0.01
Preferred Stock, Shares Authorized		10,000,000
Preferred Stock, Par Value Per Share		$ 0.01
Common Stock, Capital Shares Reserved for Issuance		410,000,000
Aggregate stock authorized for repurchase program (shares)				$ 300,000,000.0
Remaining authorized repurchase amount	$ 129,400,000
Shares repurchased (shares)	0
Treasury stock (shares)	64,494,600
2004 Amended and Restated Stock Incentive Plan
Equity, Class of Treasury Stock [Line Items]
Treasury shares issued for restricted stock units that vested during the period	339,972
Average cost of treasury shares that were issued for restricted stock units that vested during the period (usd per share)	$ 3.12
Shares repurchased to satisfy minimum employee withholding tax requirements resulting from the vesting of such restricted stock units (shares)	107,420
Average cost per share of treasury stock acquired to satisfy minimum employee withholding requirements (usd per share)	$ 28.46