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, 2010	$ 1,009,485	$ 86	$ 347,848	$ 650,253	$ 737	$ 10,561
Beginning Balances, shares at Dec. 31, 2010		86,179
Net income	100,387	0	0	98,620	0	1,767
Foreign currency translation adjustment	(373)
Other Comprehensive Income (Loss), Net of Tax	(599)	0	0	0	(599)	0
Distribution to noncontrolling interests	(1,046)	0	0	0	0	(1,046)
Purchase of noncontrolling interests	(612)	0	263	0	0	(875)
Share-based compensation	6,610	0	6,610	0	0	0
Issuance of common stock under stock incentive plans	2,596	1	2,595	0	0	0
Stock Repurchased During Period, Shares		(113)
Stock Issued During Period, Value, Acquisitions	0
Issuance of common stock under stock incentive plans, shares		596
Stock repurchases	(2,663)	0	(2,663)	0	0	0
Excess tax benefit from stock options	963	0	963	0	0	0
Tax shortfall and other from stock options and awards	(539)	0	(539)	0	0	0
Ending Balances at Sep. 30, 2011
Beginning Balances at Dec. 31, 2011	1,117,952	87	361,715	745,658	418	10,074
Beginning Balances, shares at Dec. 31, 2011		86,796
Net income	105,680	0	0	103,602	0	2,078
Foreign currency translation adjustment	2,173
Other Comprehensive Income (Loss), Net of Tax	2,465	0	0	0	2,465	0
Distribution to noncontrolling interests	(1,102)	0	0	0	0	(1,102)
Share-based compensation	10,466	0	10,466	0	0	0
Issuance of common stock under stock incentive plans	3,322	1	3,321	0	0	0
Stock Repurchased During Period, Shares		(185)
Stock Issued During Period, Shares, Acquisitions		473
Stock Issued During Period, Value, Acquisitions	10,500	0	10,500	0	0	0
Issuance of common stock under stock incentive plans, shares		745
Stock repurchases	(3,933)	0	(3,933)	0	0	0
Excess tax benefit from stock options	358	0	358	0	0	0
Tax shortfall and other from stock options and awards	52	0	52	0	0	0
Ending Balances at Sep. 30, 2012	$ 1,245,760	$ 88	$ 382,479	$ 849,260	$ 2,883	$ 11,050
Ending Balances, shares at Sep. 30, 2012		87,829