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, 2014		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 during the six months ended June 30, 2015 and $1, 300 and $827 during the six months ended June 30, 2016 related to redeemable and mandatorily redeemable noncontrolling interests, respectively)	93,850			92,600		1,250
Other comprehensive income (excludes $136 for the six months ended June 30, 2015 and $168 for the six months ended June 30, 2016 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 share-based compensation	4,729		4,729
Ending Balances, shares at Jun. 30, 2015		81,448
Ending Balances at Jun. 30, 2015	$ 1,209,519	$ 81	72,590	1,156,758	(30,331)	10,421
Beginning Balances, shares at Dec. 31, 2015	80,764	80,764
Beginning Balances at Dec. 31, 2015	$ 1,257,034	$ 81	19,708	1,275,207	(50,034)	12,072
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (excludes $877 and $749 during the six months ended June 30, 2015 and $1, 300 and $827 during the six months ended June 30, 2016 related to redeemable and mandatorily redeemable noncontrolling interests, respectively)	112,021			110,277		1,744
Other comprehensive income (excludes $136 for the six months ended June 30, 2015 and $168 for the six months ended June 30, 2016 related to mandatorily redeemable noncontrolling interests)	12,462				12,207	255
Formation of noncontrolling interests	88,949					88,949
Distribution to noncontrolling interests	(1,166)					(1,166)
Purchase of noncontrolling interests	(3,730)		(1,822)			(1,908)
Share-based compensation	9,104		9,104
Issuance of common stock under stock incentive plans, shares		117
Issuance of common stock under stock incentive plans	1,122		1,122
Stock repurchases, shares		(18)
Stock repurchases	(843)		(843)
Excess tax benefit from share-based compensation	1,421		1,421
Other	$ (79)		6			(85)
Ending Balances, shares at Jun. 30, 2016	80,863	80,863
Ending Balances at Jun. 30, 2016	$ 1,476,295	$ 81	$ 28,696	$ 1,385,484	$ (37,827)	$ 99,861