General - Narrative (Details) $ in Thousands	12 Months Ended
	Mar. 31, 2018 USD ($) segment	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Apr. 01, 2018 USD ($)	Mar. 31, 2015 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of reportable segments | segment	5
Money market funds	$ 268,976	$ 198,992
Return period for damaged goods	1 year
Sales and allowances period	30 days
Asset retirement obligation	$ 8,670	7,554
Impairment of intangible and other long-lived assets	2,417	13,222	$ 9,773
Research and development expense	22,372	21,256	22,176
Marketing and advertising expense	111,658	109,579	109,738
Prepaid advertising	$ 2,545	900
Employer matching contribution, percent of match	50.00%
Employer matching contribution, percent of employees' gross pay	6.00%
Cost recognized	$ 2,269	2,124	2,182
Non-qualified deferred compensation liability	0	0
New ASU impact		1,558
Deferred tax assets, net	38,381	44,708
Accumulated other comprehensive loss	12,983	26,451
Retained earnings	785,871	819,589
Allowance for sales returns	(33,462)	(32,354)	(30,195)
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New ASU impact		1,558
Accounting Standards Update 2016-09, Excess Tax Benefit Component
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred tax assets, net		1,365
Accounting Standards Update 2016-09, Excess Tax Benefit Component | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New ASU impact		1,365
Accounting Standards Update 2018-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated other comprehensive loss	0
Retained earnings	$ 0
Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Useful life	1 year
Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Derivative contract term	15 months
Subsequent Event | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Refund liability				$ 20,848
Subsequent Event | Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings				1,000
Allowance for chargebacks
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for sales returns	$ (7,727)	(7,028)	(4,968)		$ (4,041)
Allowance for chargebacks | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for sales returns				$ 20,848
Retail Store Fixed Assets And Software
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Impairment of intangible and other long-lived assets	$ 2,400	$ 11,300	$ 19,000