Related Party Transactions (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Mar. 31, 2013
Related Party Transactions [Abstract]
Accounts receivable	$ 99,053	$ 111,878	$ 99,053	$ 111,878	$ 55,696
Accounts payable	27,907	64,757	27,907	64,757	26,084
Purchases	$ 57,766	$ 62,824	$ 85,709	$ 89,142