Employee Benefit Plans (Components of net periodic benefit costs post retirement benefits) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Postemployment Benefits [Abstract]
Service cost for benefits earned during the period	$ 292	$ 277	$ 876	$ 831
Other components of net periodic benefit costs:
Interest cost on accumulated postretirement benefit	241	235	723	707
Other components	22	18	67	53
Net periodic postretirement benefit cost	$ 555	$ 530	$ 1,666	$ 1,591