Accrued Liabilities and Other Non-current Liabilities Accrued Liabilities (Narrative) (Details) - USD ($)	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Business Acquisition [Line Items]
Other non-current liabilities	$ 212,783,000	$ 129,639,000
Other Liabilities	38,889,000
Profit Sharing Payable	14,103,000
Magnetek [Member]
Business Acquisition [Line Items]
Other non-current liabilities	$ 102,436,000