Treasury Stock - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2016	Feb. 28, 2014
Equity, Class of Treasury Stock [Line Items]
Authorized repurchase amount		$ 300.0
Remaining authorized repurchase amount	$ 106.0
Treasury stock (shares)	27,078,911
2004 Amended and Restated Stock Incentive Plan
Equity, Class of Treasury Stock [Line Items]
Treasury shares issued (shares)	127,370
Issuance of treasury shares, average cost per share (usd per share)	$ 6.30
Shares repurchased to satisfy minumum employee withholding tax requirements resulting from the vesting of such restricted stock units (shares)	42,738
Average cost per share of treasury stock acquired	$ 51.57