CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Revenues	$ 361,736	$ 312,766	$ 974,445	$ 967,614
Cost of sales	154,967	148,942	453,581	476,796
Gross profit	206,769	163,824	520,864	490,818
Selling, general and administrative expenses	134,683	123,940	371,371	370,525
Income from operations	72,086	39,884	149,493	120,293
Foreign currency gains (losses), net	(516)	585	(1,434)	(893)
Interest income	43	167	189	493
Interest expense	(1,502)	(2,505)	(5,593)	(6,743)
Other income (expense), net	(27)	(34)	901	(48)
Income before income taxes	70,084	38,097	143,556	113,102
Income tax expense	8,195	2,421	14,025	13,518
Net income	$ 61,889	$ 35,676	$ 129,531	$ 99,584
Net income per common share:
Basic (in dollars per share)	$ 0.92	$ 0.52	$ 1.92	$ 1.40
Diluted (in dollars per share)	$ 0.91	$ 0.51	$ 1.89	$ 1.38
Weighted average common shares outstanding:
Basic (in shares)	67,473	69,097	67,606	71,003
Diluted (in shares)	68,385	70,176	68,608	72,342