CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Net income	$ 32,716	$ 31,630	$ 27,331
Other comprehensive income (loss):
Net change in unrealized gain (loss) on investments	(8)	2	(5)
Tax provision (benefit) on other comprehensive income (loss)	(3)	1	(2)
Other comprehensive income (loss), net of tax	(5)	1	(3)
Comprehensive income	$ 32,711	$ 31,631	$ 27,328