Condensed Consolidated Statement Of Changes In Equity (USD $) In Thousands, unless otherwise specified	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Shares Held In Treasury [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Non-Controlling Interests In Subsidiaries [Member]
Balance at Dec. 31, 2011	$ 1,808,063	$ 364	$ 1,256,209	$ 1,512,679	$ (971,687)	$ (7,958)	$ 18,456
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Employee Stock Purchase Plan	1,696	0	0	0	1,696	0	0
Exercise of stock options	4,562	1	4,561	0	0	0	0
Director stock awards	184	0	184	0	0	0	0
Restricted stock and restricted stock units	368	1	399	0	(32)	0	0
Stock Repurchased During Period, Value	(17,431)	0	0	0	(17,431)	0	0
Amortization of share awards	10,233	0	10,233	0	0	0	0
Stock Issued During Period, Value, Restricted Stock Award, Forfeitures	0	0	31	0	(31)	0	0
Acquisition of subsidiary with noncontrolling interests	13,268	0	0	0	0	0	13,268
Issuance of noncontrolling interests	83	0	0	0	0	0	83
Dividends paid to noncontrolling interests	(1,798)	0	0	0	0	0	(1,798)
Comprehensive income:
Net income	47,672	0	0	47,737	0	0	(65)
Other comprehensive income	2,284	0	0	0	0	2,127	157
Balance at Jun. 30, 2012	$ 1,869,184	$ 366	$ 1,271,617	$ 1,560,416	$ (987,485)	$ (5,831)	$ 30,101