CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2011
Net income	$ 10,173	$ 77,489	$ 67,699	$ 256,069
Change in net unrealized holding (loss) gain on available-for-sale securities	(214)	(1,159)	2,234	(5,112)
Change in net foreign currency translation adjustment	299	0	1,439	0
Other comprehensive income (loss)	85	(1,159)	3,673	(5,112)
Total comprehensive income	$ 10,258	$ 76,330	$ 71,372	$ 250,957