Accounts Receivable (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivable amounts	$ 245,323	$ 232,719
Less allowance for doubtful accounts	2,918	2,764
Accounts receivable, net	242,405	229,955
Trade Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivable amounts	243,383	230,469
Other Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivable amounts	$ 1,940	$ 2,250