PENSION BENEFIT PLANS - Narrative (Details) $ in Thousands	12 Months Ended
	Mar. 31, 2019 USD ($) employee	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Retirement plan employee's contribution, percentage matched	50.00%
Retirement plan employee's contribution, percentage of match	6.00%
Retirement plan employer contributions vest at rate per year of service, percentage	25.00%
Retirement plan employer contributions	$ 6,600	$ 8,000	$ 9,400
Unrecognized actuarial gains, before tax	3,300
Unrecognized actuarial gains, net of tax	2,300
Employer direct benefit payments	$ 302	$ 288
United States
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Number of employees in the U.S. participating in noncontributory defined benefit pension plants | employee	0