Condensed Consolidated Statement of Stockholder's Equity (Unaudited) - 6 months ended Jun. 30, 2017 - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]
Beginning balance, shares at Dec. 31, 2016	84,368	84,368
Beginning balance at Dec. 31, 2016	$ 1,002,984	$ 1	$ 400,452	$ 724,949	$ (122,418)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	56,698			56,698
Shares issued in connection with share-based compensation (shares)		935
Shares issued in connection with share-based compensation (value)	4,504		4,504
Tax withholdings related to net share settlements of restricted stock units	(13,420)		(13,420)
Share-based compensation	20,939		20,939
Shares repurchased and retired, shares		(1,000)
Shares repurchased and retired	(40,950)		(40,950)
Other comprehensive income	$ 19,888				19,888
Ending balance, shares at Jun. 30, 2017	84,303	84,303
Ending balance at Jun. 30, 2017	$ 1,050,643	$ 1	$ 371,525	$ 781,647	$ (102,530)