CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) [Abstract]
Net income	$ 4,226	$ 6,844	$ 17,157	$ 25,166
Other comprehensive income (loss):
Net change in unrealized gain (loss) on investments	(55)	(18)	(87)	(8)
Tax provision (benefit) on other comprehensive income (loss)	(23)	(8)	(35)	(4)
Other comprehensive income (loss), net of tax	(32)	(10)	(52)	(4)
Comprehensive income	$ 4,194	$ 6,834	$ 17,105	$ 25,162