CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest
Beginning Balance at Dec. 31, 2013	$ 1,767,538	$ 855	$ 195,110	$ 1,610,964	$ (56,468)	$ 17,077
Beginning Balance (in shares) at Dec. 31, 2013		85,500,000
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)		1,061,000
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)		(1,677,000)
Purchase/ cancellation of treasury stock	(194,066)	(17)	0	(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 at Dec. 31, 2014	1,917,185	849	289,211	1,743,371	(138,419)	22,173
Ending Balance (in shares) at Dec. 31, 2014	84,883,517	84,884,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	75,810			75,458		352
Currency translation adjustment	(64,501)				(63,681)	(820)
Change in qualifying cash flow hedge, net of tax	(4,334)				(4,334)
Issuance of common stock for exercise of options, restricted stock units and employee stock purchases (in shares)		425,000
Issuance of common stock for exercise of options, restricted stock units and employee stock purchases	28,512	4	28,508
Purchase/ cancellation of treasury stock (in shares)	(100,713)	(101,000)
Purchase/ cancellation of treasury stock	(13,771)	(1)	0	(13,770)
Stock compensation expense	5,487		5,487
Excess tax benefit of stock options exercised	8,222		8,222
Reduction to noncontrolling interests due to additional ownership	(2,603)		0			(2,603)
Ending Balance at Mar. 31, 2015	$ 1,950,007	$ 852	$ 331,428	$ 1,805,059	$ (206,434)	$ 19,102
Ending Balance (in shares) at Mar. 31, 2015	85,208,191	85,208,000