Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Equity [Abstract]
Common stock, authorized (in shares)	206,000,000	206,000,000
Common stock, par value (in usd per share)	$ 0.01
Common stock, outstanding (in shares)	72,393,933	72,635,032
Preferred stock, authorized (in shares)	2,000,000	2,000,000
Preferred stock, par value (in usd per share)	$ 0.01	$ 0.01
Preferred stock, issued (in shares)	0	0
Shares repurchased (in shares)	500,000	2,500,000	3,000,000
Repurchase of common stock	$ 7,671	$ 39,946	$ 54,949