Consolidated Statements of Changes in Equity (USD $) In Thousands, except Share data in Millions, unless otherwise specified	Total	Common Stock	Additional Paid in Capital (Deficit)	Accumulated Earnings	Accum. Other Comprehensive Income (Loss)	Treasury Stock	Noncontrolling Interests
Balance at Dec. 31, 2008	$ 1,368,569	$ 171	$ 22,746	$ 1,467,099	$ (140,591)		$ 19,144
Balance (in shares) at Dec. 31, 2008		171
Increase (Decrease) In Shareholders' Equity
Net income	327,216			317,834			9,382
Translation adjustments	22,521				23,793		(1,272)
Revaluation of interest rate derivatives	13,354				13,354
Defined benefit plan liability adjustment	3,354				3,354
Purchase of noncontrolling interests	(15,896)		(14,529)				(1,367)
Acquisitions resulting in noncontrolling interests	983						983
Distributions to shareholders of noncontrolling interests	(10,129)						(10,129)
Stock compensation	131		131
Stock options exercised, including tax benefit	42,783	3	42,780
Stock options exercised, including tax benefit (in shares)		2
Dividends declared	(10,308)			(10,308)
Stock-based compensation expense	20,240		20,240
Balance at Dec. 31, 2009	1,762,818	174	71,368	1,774,625	(100,090)		16,741
Balance (in shares) at Dec. 31, 2009		173
Increase (Decrease) In Shareholders' Equity
Net income	502,413			496,405			6,008
Translation adjustments	18,504				17,465		1,039
Revaluation of interest rate derivatives	2,363				2,363
Defined benefit plan liability adjustment	(4,495)				(4,495)
Purchase of noncontrolling interests	(20,167)		(12,375)				(7,792)
Acquisitions resulting in noncontrolling interests	10,285						10,285
Distributions to shareholders of noncontrolling interests	(4,421)						(4,421)
Stock options exercised, including tax benefit	60,479	2	60,477
Stock options exercised, including tax benefit (in shares)		3
Dividends declared	(10,449)			(10,449)
Stock-based compensation expense	25,385		25,385
Balance at Dec. 31, 2010	2,342,715	176	144,855	2,260,581	(84,757)		21,860
Balance (in shares) at Dec. 31, 2010		176
Increase (Decrease) In Shareholders' Equity
Net income	528,842			524,191			4,651
Translation adjustments	(9,679)				(10,154)		475
Revaluation of interest rate derivatives	(287)				(287)
Defined benefit plan liability adjustment	(24,859)				(24,859)
Purchase of noncontrolling interests	(24,854)		(15,962)				(8,892)
Distributions to shareholders of noncontrolling interests	(5,077)						(5,077)
Purchase of treasury stock	(672,191)					(672,191)
Retirement of treasury stock		(13)		(672,178)		672,191
Retirement of treasury stock (in shares)		(13)
Stock options exercised, including tax benefit	31,594		31,594
Dividends declared	(10,097)			(10,097)
Stock-based compensation expense	28,679		28,679
Balance at Dec. 31, 2011	$ 2,184,786	$ 163	$ 189,166	$ 2,102,497	$ (120,057)		$ 13,017
Balance (in shares) at Dec. 31, 2011		163