Condensed, Consolidated Statements of Equity (Unaudited) (USD $) In Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive (Loss) Income	Noncontrolling Interests
Beginning Balances at Dec. 31, 2009	$ 886,476	$ 86	$ 335,114	$ 540,010	$ (163)	$ 11,429
Beginning Balances, shares at Dec. 31, 2009		85,584
Net income (excludes $382 and $225 in 2010 and $830 and $227 related to redeemable and mandatorily redeemable noncontrolling interests, respectively)	62,842			61,339		1,503
Foreign currency translation adjustment	(69)				(69)
Unrealized gain (loss) on foreign currency, net of tax	(47)				(47)
Unrealized loss on hedging instruments, net of tax	(1)				(1)
Losses on hedging instruments reclassified to income, net of tax	233				233
Distribution to noncontrolling interests	(1,535)					(1,535)
Purchase of noncontrolling interests	(233)					(233)
Share-based compensation	5,855		5,855
Issuance of common stock under stock incentive plans	3,770		3,770
Issuance of common stock under stock incentive plans, shares		392
Stock repurchases	(2,253)		(2,253)
Excess tax benefit from stock options	331		331
Tax shortfall and other from stock options and awards	(478)		(478)
Ending Balances at Jun. 30, 2010	954,891	86	342,339	601,349	(47)	11,164
Ending Balances, shares at Jun. 30, 2010		85,976
Beginning Balances at Dec. 31, 2010	1,009,485	86	347,848	650,253	737	10,561
Beginning Balances, shares at Dec. 31, 2010		86,179
Net income (excludes $382 and $225 in 2010 and $830 and $227 related to redeemable and mandatorily redeemable noncontrolling interests, respectively)	69,504			68,451		1,053
Foreign currency translation adjustment	296				296
Unrealized gain (loss) on foreign currency, net of tax	145				145
Distribution to noncontrolling interests	(607)					(607)
Purchase of noncontrolling interests	(611)		263			(874)
Share-based compensation	2,531		2,531
Issuance of common stock under stock incentive plans	2,456	1	2,455
Issuance of common stock under stock incentive plans, shares		416
Stock repurchases	(2,337)		(2,337)
Excess tax benefit from stock options	906		906
Tax shortfall and other from stock options and awards	(460)		(460)
Ending Balances at Jun. 30, 2011	$ 1,081,308	$ 87	$ 351,206	$ 718,704	$ 1,178	$ 10,133
Ending Balances, shares at Jun. 30, 2011		86,595