EMPLOYEE BENEFIT PLANS - Components of Net Periodic Pension Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Defined Benefit Plan [Abstract]
Service cost for benefits earned during the period	$ 152	$ 210	$ 311	$ 429
Interest cost on pension benefit obligation	2,799	3,221	5,718	6,585
Expected return on assets	(3,841)	(4,247)	(7,846)	(8,681)
Prior service cost	34	0	69	0
Amortization of unrecognized losses	1,976	1,970	4,037	4,027
Net periodic pension cost	$ 1,120	$ 1,154	$ 2,289	$ 2,360