Inventories (Tables)

9 Months Ended

Jan. 31, 2018

Inventory, Net [Abstract]

Components of Inventories

The components of inventories were: 

	January 31,			April 30,
(in thousands)	2018			2017
Raw materials	$	49,503		$	18,230
Work-in-process	40,330			18,704
Finished goods	31,617			19,372
Total FIFO inventories	121,450			56,306
Reserve to adjust inventories to LIFO value	(13,447		)	(13,447		)
Total inventories	$	108,003		$	42,859