Stockholders' Equity - Schedule of Stock Repurchases (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Total cost	$ 168,094	$ 21,489	$ 26,532
2016 Stock Repurchase Program
Class of Stock [Line Items]
Shares of common stock repurchased and retired	4,674	452
Average price per share	$ 35.94	$ 41.06
Total cost	$ 168,001	$ 18,577
2015 Stock Repurchase Program
Class of Stock [Line Items]
Shares of common stock repurchased and retired		85	765
Average price per share		$ 34.16	$ 34.68
Total cost		$ 2,902	$ 26,516