Accounts Receivable (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Mar. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivable amounts	$ 283,738	$ 276,558
Less allowance for doubtful accounts	2,675	2,621
Accounts receivable, net	281,063	273,937
Trade Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivable amounts	280,257	269,844
Other Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivable amounts	$ 3,481	$ 6,714