Income Taxes - Components of the income tax provision (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Current taxes
Federal	$ 10,982	$ 9,303	$ 9,689
State	1,041	885	921
Total current taxes	12,023	10,188	10,610
Deferred taxes
Federal	(21)	143	(167)
State	(2)	14	(16)
Total deferred taxes	(23)	157	(183)
Total provision for income taxes	$ 12,000	$ 10,345	$ 10,427