Income Tax Provision (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2011
Components of income tax provision
Current
Deferred	172,039		83,774
Total	$ 172,039		$ 83,774