Condensed Consolidated Statements of Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Net sales	$ 784,678	$ 736,048	$ 1,476,420	$ 1,292,858
Cost of sales	369,539	359,848	750,636	679,934
Gross profit	415,139	376,200	725,784	612,924
Selling, general and administrative expenses	200,558	174,701	502,102	407,679
Income from operations	214,581	201,499	223,682	205,245
Other expense (income), net:
Interest income	(38)	(18)	(122)	(34)
Interest expense	1,308	1,293	3,746	2,740
Other, net	(5)	(173)	(130)	(508)
Total other expense (income), net	1,265	1,102	3,494	2,198
Income before income taxes	213,316	200,397	220,188	203,047
Income tax expense	56,610	59,500	59,814	58,365
Net income	156,706	140,897	160,374	144,682
Other comprehensive loss, net of tax:
Unrealized (loss) gain on foreign currency hedging	(682)	(34)	759	(2,016)
Foreign currency translation adjustment	(6,647)	(1,892)	(11,147)	(83)
Total other comprehensive loss	(7,329)	(1,926)	(10,388)	(2,099)
Comprehensive income	$ 149,377	$ 138,971	$ 149,986	$ 142,583
Net income per share:
Basic (in dollars per share)	$ 4.54	$ 4.08	$ 4.64	$ 4.19
Diluted (in dollars per share)	$ 4.50	$ 4.04	$ 4.59	$ 4.15
Weighted-average common shares outstanding:
Basic (in shares)	34,537	34,541	34,598	34,496
Diluted (in shares)	34,853	34,893	34,912	34,855