Employee Benefit Plans (Components of net periodic benefit costs post retirement benefits) (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Postemployment Benefits [Abstract]
Service cost for benefits earned during the period	$ 268	$ 256
Interest cost on accumulated postretirement benefit	217	204
Other components	15	22
Net periodic postretirement benefit cost	$ 500	$ 482