Inventories (Narratives) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Business Acquisition [Line Items]
Increase (Decrease) in Inventories	$ 12,249	$ (8,173)	$ (2,483)
LIFO liquidations		$ 547	$ 384