CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Preferred Stock Series A Preferred Stock	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest
Beginning Balance (in shares) at Dec. 31, 2012		0	85,988
Beginning Balance at Dec. 31, 2012	$ 1,557,323	$ 0	$ 860	$ 116,720	$ 1,463,277	$ (39,064)	$ 15,530
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	313,084				311,372		1,712
Currency translation adjustment	(19,160)					(17,718)	(1,442)
Change in qualifying cash flow hedge, net of tax	314					314
Issuance of common stock for exercise of options, restricted stock units and employee stock purchases (in shares)			973
Issuance of common stock for exercise of options, restricted stock units and employee stock purchases	48,001		$ 10	47,991
Purchase/ cancellation of treasury stock (in shares)			(1,461)
Purchase and cancellation of treasury stock	(163,700)		$ (15)		(163,685)
Stock compensation expense	17,457			17,457
Excess tax benefit of stock options exercised	17,153			17,153
Noncontrolling interests attributable to acquisitions	4,211						4,211
Reduction to noncontrolling interests due to additional ownership	(7,145)			(4,211)			(2,934)
Ending Balance (in shares) at Dec. 31, 2013		0	85,500
Ending Balance at Dec. 31, 2013	1,767,538	$ 0	$ 855	195,110	1,610,964	(56,468)	17,077
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	328,146				326,456		1,690
Currency translation adjustment	(82,871)					(80,221)	(2,650)
Change in qualifying cash flow hedge, net of tax	(1,730)					(1,730)
Issuance of common stock for exercise of options, restricted stock units and employee stock purchases (in shares)			1,061
Issuance of common stock for exercise of options, restricted stock units and employee stock purchases	58,562		$ 11	58,551
Purchase/ cancellation of treasury stock (in shares)			(1,677)
Purchase and cancellation of treasury stock	(194,066)		$ (17)		(194,049)
Stock compensation expense	17,773			17,773
Excess tax benefit of stock options exercised	17,906			17,906
Noncontrolling interests attributable to acquisitions	6,781						6,781
Reduction to noncontrolling interests due to additional ownership	(854)			(129)			(725)
Ending Balance (in shares) at Dec. 31, 2014		0	84,884
Ending Balance at Dec. 31, 2014	1,917,185	$ 0	$ 849	289,211	1,743,371	(138,419)	22,173
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	268,013				267,046		967
Currency translation adjustment	(140,648)					(140,809)	161
Change in qualifying cash flow hedge, net of tax	(3,403)					(3,403)
Issuance of common stock for exercise of options, restricted stock units and employee stock purchases (in shares)			973
Issuance of common stock for exercise of options, restricted stock units and employee stock purchases	68,640		$ 10	68,630
Issuance of mandatory convertible preferred stock (in shares)		770
Issuance of mandatory convertible preferred stock	746,900	$ 8		746,892
Purchase/ cancellation of treasury stock (in shares)			(1,004)
Purchase and cancellation of treasury stock	(131,676)		$ (10)		(131,666)
Preferred stock dividend	(10,106)				(10,106)
Stock compensation expense	21,750			21,750
Excess tax benefit of stock options exercised	16,897			16,897
Reduction to noncontrolling interests due to additional ownership	(5,714)			(360)			(5,354)
Ending Balance (in shares) at Dec. 31, 2015		770	84,853
Ending Balance at Dec. 31, 2015	$ 2,747,838	$ 8	$ 849	$ 1,143,020	$ 1,868,645	$ (282,631)	$ 17,947