Stockholders' Equity - Schedule of Stock Repurchases (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017	Jun. 30, 2016
Stockholders Equity [Line Items]
Total cost		$ 102,513
Stock Repurchase Program
Stockholders Equity [Line Items]
Shares of common stock repurchased and retired	1,887	2,767	85
Average price paid per share	$ 34.74	$ 37.03	$ 34.12
Total cost	$ 65,556	$ 102,457	$ 2,903