Employee Retirement Plans (Expected Return on Plan Assets) (Details) - Pension Plan - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Sep. 30, 2017	Sep. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 634	$ 1,263
Expected return on assets	(725)	(1,451)
Net periodic benefit cost (income)	$ (91)	$ (188)