Employee Benefit Plans (Components of net periodic post retirement benefit cost) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Postemployment Benefits [Abstract]
Service cost for benefits earned during the period	$ 961	$ 827	$ 726
Interest cost on accumulated postretirement benefit	752	720	564
Other components	35	14	19
Net periodic postretirement benefit cost	$ 1,748	$ 1,561	$ 1,309