CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Net sales	$ 2,132,689	$ 2,020,437	$ 1,903,339
Cost of sales	1,029,016	980,187	971,697
Gross profit	1,103,673	1,040,250	931,642
Selling, general and administrative expenses	765,538	712,930	709,058
Income from operations	338,135	327,320	222,584
Interest income	(7,261)	(6,028)	(3,057)
Interest expense	5,046	4,661	4,585
Other (income) expense, net	(516)	(247)	360
Total other (income) expense, net	(2,731)	(1,614)	1,888
Income before income taxes	340,866	328,934	220,696
Income tax expense	64,724	64,626	106,302
Net income	276,142	264,308	114,394
Other comprehensive (loss) income, net of tax
Unrealized loss on cash flow hedges	0
Unrealized loss on cash flow hedges		(243)	(613)
Foreign currency translation (loss) gain	(2,905)	(9,428)	14,081
Total other comprehensive (loss) income	(2,905)	(9,671)	13,468
Comprehensive income	$ 273,237	$ 254,637	$ 127,862
Net income per share
Basic (in dollars per share)	$ 9.73	$ 8.92	$ 3.60
Diluted (in dollars per share)	$ 9.62	$ 8.84	$ 3.58
Weighted-average common shares outstanding
Basic (in shares)	28,385	29,641	31,758
Diluted (in shares)	28,694	29,903	31,996