Schedule II Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Accounts receivable allowances
Valuation and Qualifying Accounts
Balance at Beginning of Period	$ 1,576	$ 1,283	$ 1,363
Additions Charged to Costs and Expenses	5,299	4,035	5,188
Charged to Other Accounts	0	0	0
Deductions	4,677	3,742	5,268
Balance At End of Period	2,198	1,576	1,283
Accrued customer programs
Valuation and Qualifying Accounts
Balance at Beginning of Period	12,793	5,030	3,275
Additions Charged to Costs and Expenses	26,866	15,940	9,716
Charged to Other Accounts	53	11,147	2,296
Deductions	27,611	19,324	10,257
Balance At End of Period	$ 12,101	$ 12,793	$ 5,030