Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance, shares at Dec. 31, 2014		89,343
Beginning Balance at Dec. 31, 2014	$ 1,014,167	$ 1	$ 605,511	$ 492,441	$ (83,786)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	127,844			127,844
Shares repurchased and retire, shares		(2,528)
Shares repurchased and retired	(97,430)		(97,430)
Shares issued in connection with share-based compensation (in shares)		1,413
Shares issued in connection with share-based compensation	22,569		22,569
Tax withholdings related to net share settlements	(15,230)		(15,230)
Share-based compensation	35,786		35,786
Adjust redeemable noncontrolling interests to redemption value	(1,886)			(1,886)
Other comprehensive income (loss)	(36,330)				(36,330)
Ending Balance, shares at Dec. 31, 2015		88,228
Ending Balance at Dec. 31, 2015	1,049,490	$ 1	551,206	618,399	(120,116)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	106,550			106,550
Shares repurchased and retire, shares		(5,000)
Shares repurchased and retired	(195,003)		(195,003)
Shares issued in connection with share-based compensation (in shares)		1,140
Shares issued in connection with share-based compensation	14,907		14,907
Tax withholdings related to net share settlements	(10,507)		(10,507)
Share-based compensation	39,849		39,849
Other comprehensive income (loss)	$ (2,302)				(2,302)
Ending Balance, shares at Dec. 31, 2016	84,368	84,368
Ending Balance at Dec. 31, 2016	$ 1,002,984	$ 1	400,452	724,949	(122,418)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	152,162			152,162
Shares repurchased and retire, shares		(4,638)
Shares repurchased and retired	(207,416)		(207,416)
Shares issued in connection with share-based compensation (in shares)		1,155
Shares issued in connection with share-based compensation	9,595		9,595
Tax withholdings related to net share settlements	(14,043)		(14,043)
Share-based compensation	35,867		35,867
Other comprehensive income (loss)	$ 28,727				28,727
Ending Balance, shares at Dec. 31, 2017	80,885	80,885
Ending Balance at Dec. 31, 2017	$ 1,007,876	$ 1	$ 224,455	$ 877,111	$ (93,691)