Schedule II VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Valuation and qualifying accounts
Balance at Beginning of Year	$ 32,354	$ 30,195
Balance at End of Year	33,462	32,354	$ 30,195
Total Allowances	32,354	30,195	30,195
Allowance for doubtful accounts
Valuation and qualifying accounts
Balance at Beginning of Year	5,979	5,494	2,297
Additions	4,168	2,847	5,120
Deductions	(6,660)	(2,362)	(1,923)
Balance at End of Year	3,487	5,979	5,494
Total Allowances	5,979	5,494	2,297
Allowance for sales discounts
Valuation and qualifying accounts
Balance at Beginning of Year	3,100	2,672	2,348
Additions	19,972	20,259	25,560
Deductions	(21,672)	(19,831)	(25,236)
Balance at End of Year	1,400	3,100	2,672
Total Allowances	3,100	2,672	2,348
Allowance for chargebacks
Valuation and qualifying accounts
Balance at Beginning of Year	7,028	4,968	4,041
Additions	19,019	19,584	15,750
Deductions	(18,320)	(17,524)	(14,823)
Balance at End of Year	7,727	7,028	4,968
Total Allowances	7,028	4,968	4,041
Allowance for sales returns
Valuation and qualifying accounts
Balance at Beginning of Year	16,247	17,061	9,532
Additions	51,677	62,122	42,392
Deductions	(47,076)	(62,936)	(34,863)
Balance at End of Year	20,848	16,247	17,061
Total Allowances	$ 16,247	$ 17,061	$ 9,532