PENSION AND OTHER POSTRETIREMENT BENEFITS - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer			$ 4,629
Additional contributions to the plans	$ 2,101		2,101
Settlement loss	91	$ 0	609	$ 0
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer			261
Additional contributions to the plans	$ 256		$ 256