Employee Benefit Plans (Components of net periodic benefit costs post retirement benefits) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Postemployment Benefits [Abstract]
Service cost for benefits earned during the period	$ 269	$ 256	$ 805	$ 769
Interest cost on accumulated postretirement benefit	218	204	652	611
Other components	13	22	43	66
Net periodic postretirement benefit cost	$ 500	$ 482	$ 1,500	$ 1,446