EMPLOYEE BENEFIT PLANS Defined Benefit Plan Narrative (Details) $ in Millions	12 Months Ended
	Mar. 31, 2018 USD ($) Plans Objectives
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Amortization, Next Fiscal Year | $	$ 6.5
Pension Plan Investment Strategy, Number Of Objectives | Objectives	3
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year | $	$ 18.0
Pension Plan [Member] | UK Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Number Of Original Closed Defined Benefit Pension Plans	2
Minimum Contribution Match	5.00%
Number Of Other Defined Contribution Plans	3
Number Of Other Defined Contribution Plans Closed To New Members	2
Pension Plan [Member] | UK Pension Plan [Member] | Other Employee [Member]
Defined Benefit Plan Disclosure [Line Items]
Closed Plan Maximum Contribution	7.00%
Pension Plan [Member] | UK Pension Plan [Member] | Pilot [Member]
Defined Benefit Plan Disclosure [Line Items]
Closed Plan Maximum Contribution	7.35%
Pension Plan [Member] | UK Pension Plan [Member] | Maximum
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Average Period Salary	3 years
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase	5.00%