Basis Of Presentation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Unamortized Debt Issuance Expense	$ 7,757				$ 9,149				$ 7,757	$ 9,149
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax									(23,076)	(15,058)	$ (14,694)
Advertising Expense									96,800	63,500	60,500
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	(54,649)				(31,573)				(54,649)	(31,573)	(16,515)
Revenues									874,255	720,815	599,030
Net earnings	$ 43,157	$ 45,569	$ 33,770	$ 29,943	$ 35,467	$ 37,375	$ 38,916	$ 21,878	$ 152,439	$ 133,636	$ 124,336
Basic earnings per share (in dollars per share)	$ 0.90	$ 0.95	$ 0.69	$ 0.62	$ 0.73	$ 0.77	$ 0.81	$ 0.45	$ 3.15	$ 2.76	$ 2.60
Diluted earnings per share (in dollars per share)	$ 0.89	$ 0.94	$ 0.69	$ 0.61	$ 0.72	$ 0.77	$ 0.80	$ 0.45	$ 3.13	$ 2.73	$ 2.58
Foreign Currency Transaction Gain (Loss), Realized									$ (700)	$ (100)	$ (100)
Operating Leases, Future Minimum Payments Due	$ 74,220								$ 74,220
Minimum [Member]
Identifiable intangible assets minimum useful life (years)									1 year
Property, Plant and Equipment, Useful Life									1 year
Maximum [Member]
Identifiable intangible assets minimum useful life (years)									20 years
Property, Plant and Equipment, Useful Life									10 years