Accounts Receivable - Net, Warranty Returns (Details) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Mar. 31, 2015
Warranty Returns [Abstract]
Warranty accrual included in customer returns RGA issued	$ 4,369,000		$ 4,369,000		$ 3,746,000
Warranty accrual included in customer finished goods returns accrual	5,835,000		5,835,000		$ 7,158,000
Change in warranty return accrual [Roll Forward]
Balance at beginning of period	9,785,000	$ 7,048,000	10,904,000	$ 8,039,000
Charged to expense/additions	22,442,000	17,352,000	39,813,000	30,359,000
Amounts processed	(22,023,000)	(15,979,000)	(40,513,000)	(29,977,000)
Balance at end of period	$ 10,204,000	$ 8,421,000	$ 10,204,000	$ 8,421,000