CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2011
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) [Abstract]
Net income	$ 4,988	$ 2,850	$ 20,761	$ 8,385
Other comprehensive income:
Net change in unrealized gain (loss) on investments	(2)	(17)	36	(17)
Provision (benefit) for income taxes related to items of other comprehensive income	(1)	(3)	15	(3)
Other comprehensive income (loss), net of tax	(1)	(14)	21	(14)
Comprehensive income	$ 4,987	$ 2,836	$ 20,782	$ 8,371