CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Net sales	$ 542,205	$ 501,913	$ 819,044	$ 752,507
Cost of sales	269,181	250,026	416,001	385,655
Gross profit	273,024	251,887	403,043	366,852
Selling, general and administrative expenses	175,893	161,475	337,329	315,854
Income from operations	97,131	90,412	65,714	50,998
Interest income	(1,530)	(814)	(4,396)	(2,400)
Interest expense	1,524	1,640	2,670	2,874
Other income, net	(86)	(189)	(178)	(200)
Total other (income) expense, net	(92)	637	(1,904)	274
Income before income taxes	97,223	89,775	67,618	50,724
Income tax expense	19,413	15,403	9,159	6,759
Net income	77,810	74,372	58,459	43,965
Other comprehensive income (loss), net of tax
Unrealized gain (loss) on cash flow hedges	1,497		1,180
Unrealized gain (loss) on cash flow hedges		(1,197)		4,126
Foreign currency translation loss	(3,391)	(3,861)	(3,323)	(11,324)
Total other comprehensive loss	(1,894)	(5,058)	(2,143)	(7,198)
Comprehensive income	$ 75,916	$ 69,314	$ 56,316	$ 36,767
Net income per share
Basic (in dollars per share)	$ 2.73	$ 2.49	$ 2.03	$ 1.46
Diluted (in dollars per share)	$ 2.71	$ 2.48	$ 2.01	$ 1.45
Weighted-average common shares outstanding
Basic (in shares)	28,483	29,849	28,785	30,134
Diluted (in shares)	28,705	30,028	29,039	30,327