Employee Benefit Plans (Components of Postretirement Benefit Liabilities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning of year	$ 18,554	$ 16,119
Service cost for benefits earned during the period	961	827	$ 726
Interest cost on accumulated post retirement benefit	752	720	564
Net benefit payments and expense	(541)	(450)
Actuarial loss	1,065	1,338
Accumulated postretirement benefit obligation	20,791	18,554	$ 16,119
Liabilities:
Current liabilities	658	513
Non-currrent liabilities	20,133	18,041
Total post retirement benefit liability recognized in statement of financial position	20,791	18,554
Components included in accumulated other comprehensive income (loss):
Unrecognized net loss	(2,847)	(1,817)
Cumulative net periodic benefit cost (in excess of employer contribution)	$ 17,944	$ 16,737