Other Financial Statements Details Accounts Receivable (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Mar. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivable amounts	$ 531,092	$ 480,457
Less allowance for doubtful accounts	2,138	2,084
Accounts receivable, net	528,954	478,373
Trade Accounts Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivable amounts	525,101	473,238
Other Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivable amounts	$ 5,991	$ 7,219