Inventories (Details) - USD ($)	Dec. 31, 2015	Mar. 31, 2015
Inventory [Line Items]
Raw materials	$ 75,999,000	$ 62,513,000
Work-in-process	18,588,000	16,893,000
Finished goods	42,327,000	41,807,000
At cost - FIFO basis:	136,914,000	121,213,000
LIFO cost less than FIFO cost	(18,017,000)	(18,026,000)
Net inventories	118,897,000	$ 103,187,000
Magnetek [Member]
Inventory [Line Items]
Net inventories	$ 15,631,000