CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (USD $)	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest
Beginning Balance at Dec. 31, 2008	$ 670,638,000	$ 852,000	$ 67,776,000	$ 633,927,000	$ (32,075,000)	$ 158,000
Beginning Balance (in shares) at Dec. 31, 2008		85,253,000
Net income	176,389,000			175,691,000		698,000
Currency translation adjustment	18,430,000				17,595,000	835,000
Change in fair value of cash flow hedge, net of tax of $216 for year ended 2011 and $1353 for year ended 2010 and $1,446 for year 2009	2,188,000				2,188,000
Comprehensive income	197,007,000
Issuance of common stock for exercise of options and employee stock purchases (in shares)		1,132,000
Issuance of common stock for exercise of options and employee stock purchases	15,901,000	12,000	15,889,000
Purchase/ cancellation of treasury stock (in shares)		(1,670,000)
Purchase/ cancellation of treasury stock	(73,181,000)	(17,000)	(73,164,000)
Stock compensation expense	14,638,000		14,638,000
Excess tax benefit of disqualifying dispositions of stock options and exercise of non-qualified stock options	22,383,000		22,383,000
Change in noncontrolling interest	9,787,000					9,787,000
Ending Balance at Dec. 31, 2009	857,173,000	847,000	47,522,000	809,618,000	(12,292,000)	11,478,000
Ending Balance (in shares) at Dec. 31, 2009		84,715,000
Net income	210,457,000			207,879,000		2,578,000
Currency translation adjustment	394,000				(2,544,000)	2,938,000
Change in fair value of cash flow hedge, net of tax of $216 for year ended 2011 and $1353 for year ended 2010 and $1,446 for year 2009	(2,033,000)				(2,033,000)
Comprehensive income	208,818,000
Issuance of common stock for exercise of options and employee stock purchases (in shares)		1,988,000
Issuance of common stock for exercise of options and employee stock purchases	50,511,000	20,000	50,491,000
Purchase/ cancellation of treasury stock (in shares)		(1,461,000)
Purchase/ cancellation of treasury stock	(94,335,000)	(15,000)	(94,320,000)
Stock compensation expense	18,565,000		18,565,000
Excess tax benefit of disqualifying dispositions of stock options and exercise of non-qualified stock options	24,687,000		24,687,000
Change in noncontrolling interest	14,931,000					14,931,000
Ending Balance at Dec. 31, 2010	1,080,350,000	852,000	46,945,000	1,017,497,000	(16,869,000)	31,925,000
Ending Balance (in shares) at Dec. 31, 2010	85,242,387	85,242,387
Net income	237,343,000			234,751,000		2,592,000
Currency translation adjustment	(32,893,000)				(29,456,000)	(3,437,000)
Change in fair value of cash flow hedge, net of tax of $216 for year ended 2011 and $1353 for year ended 2010 and $1,446 for year 2009	341,000				341,000
Comprehensive income	204,791,000
Issuance of common stock for exercise of options and employee stock purchases (in shares)		1,016,000
Issuance of common stock for exercise of options and employee stock purchases	36,405,000	11,000	36,394,000
Purchase/ cancellation of treasury stock (in shares)		(1,562,000)
Purchase/ cancellation of treasury stock	(124,056,000)	(16,000)	(115,095,000)	(8,945,000)
Stock compensation expense	15,367,000		15,367,000
Excess tax benefit of disqualifying dispositions of stock options and exercise of non-qualified stock options	17,410,000		17,410,000
Change in noncontrolling interest	(3,016,000)		(1,021,000)			(1,995,000)
Ending Balance at Dec. 31, 2011	$ 1,227,251,000	$ 847,000	$ 0	$ 1,243,303,000	$ (45,984,000)	$ 29,085,000
Ending Balance (in shares) at Dec. 31, 2011	84,696,227	84,696,227