Common and Preferred Stock (Additional Information) (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
	Nov. 06, 2014	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Stockholders Equity Note [Line Items]
Increase in share repurchase authorized amount	$ 300,000
Purchase of common stock (in shares)		628,493	829,744
Repurchase of common stock, including subsequent settlements		$ 45,800	$ 62,100
Purchase of common stock		46,864	62,132
Remaining authorized repurchase amount		$ 589,200
Common stock, authorized (in shares)		150,000,000		150,000,000
Common stock, par value (in dollars per share)		$ 0.01		$ 0.01
Preferred stock, authorized (in shares)		5,000,000		5,000,000
Preferred stock, par value (in dollars per share)		$ 0.01		$ 0.01
Preferred stock, issued (in shares)		0		0
October Settlement
Stockholders Equity Note [Line Items]
Purchase of common stock		$ 1,200	$ 2,700