Condensed, Consolidated Statements of Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income	Noncontrolling Interests
Beginning Balances, shares at Dec. 31, 2013		88,508
Beginning Balances at Dec. 31, 2013	$ 1,317,616	$ 89	$ 384,797	$ 928,720	$ (6,190)	$ 10,200
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (excludes $877 and $749 related to redeemable and mandatorily redeemable noncontrolling interests as of June 30, 2015 and $417 and $739 as of June 30, 2014)	80,667			79,627		1,040
Other comprehensive loss (excludes $136 and $30 as of June 30, 2015 and 2014, respectively, related to mandatorily redeemable noncontrolling interests)	(682)				(662)	(20)
Formation of noncontrolling interests	933					933
Distribution to noncontrolling interests	(970)					(970)
Purchase of noncontrolling interests	30		30
Share-based compensation	8,571		8,571
Issuance of common stock under stock incentive plans, shares		377
Issuance of common stock under stock incentive plans	467		467
Stock repurchases, shares		(1,471)
Stock repurchases	(49,091)	$ (2)	(49,089)
Excess tax benefit from stock based compensation	2,092		2,092
Ending Balances, shares at Jun. 30, 2014		87,414
Ending Balances at Jun. 30, 2014	$ 1,359,633	$ 87	346,868	1,008,347	(6,852)	11,183
Beginning Balances, shares at Dec. 31, 2014	82,937	82,937
Beginning Balances at Dec. 31, 2014	$ 1,211,621	$ 83	155,802	1,064,158	(19,397)	10,975
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (excludes $877 and $749 related to redeemable and mandatorily redeemable noncontrolling interests as of June 30, 2015 and $417 and $739 as of June 30, 2014)	93,850			92,600		1,250
Other comprehensive loss (excludes $136 and $30 as of June 30, 2015 and 2014, respectively, related to mandatorily redeemable noncontrolling interests)	(11,133)				(10,934)	(199)
Formation of noncontrolling interests	(14)					(14)
Distribution to noncontrolling interests	(1,118)					(1,118)
Purchase of noncontrolling interests	(690)		(217)			(473)
Share-based compensation	8,269		8,269
Issuance of common stock under stock incentive plans, shares		376
Issuance of common stock under stock incentive plans	679		679
Stock repurchases, shares		(1,865)
Stock repurchases	(96,674)	$ (2)	(96,672)
Excess tax benefit from stock based compensation	$ 4,729		4,729
Ending Balances, shares at Jun. 30, 2015	81,448	81,448
Ending Balances at Jun. 30, 2015	$ 1,209,519	$ 81	$ 72,590	$ 1,156,758	$ (30,331)	$ 10,421