TAXES Narrative (Details) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2018 USD ($) aircraft	Dec. 31, 2017	Mar. 31, 2018 USD ($) aircraft	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Mar. 31, 2015 USD ($)
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	35.00%	31.60%	35.00%	35.00%
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount			$ 52,900
Effective Income Tax Rate Reconciliation, Tax Credit, Foreign, Amount			22,600
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	$ 9,140		9,140	$ 39,554
Net operating loss	149,000		149,000
Deferred Tax Assets, Valuation Allowance	$ 71,987		$ 71,987	$ 74,727	$ 29,373	$ 11,700
Effective Income Tax Rate Reconciliation, Percent			13.50%	(22.60%)	2.60%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Impairment Losses, Amount			$ 27,000
Impairment of goodwill			$ 0	$ 8,706	$ 41,579
Number of aircraft involved in intercompany leasing transaction | aircraft	11		11
Remaining useful life of an intercompany leasing transaction			13 years
Tax benefit from intercompany leasing transaction				2,400	2,800
Unrecognized tax benefits period increase decrease			$ 5,400	200	400
Unrecognized tax benefit, Interest and penalties			100	200	300
Unrecognized Tax Benefits	$ 6,682		6,682	1,332	1,093
Unremitted foreign earnings reinvested abroad	517,900		517,900
Income taxes paid			26,700	28,100	$ 28,000
Valuation Allowance, Foreign Operating Loss Carryforwards
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Valuation Allowance	50,510		50,510	34,321
Valuation Allowance, State Operating Loss Carryforward
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Valuation Allowance	12,337		12,337	8,432
Valuation Allowance, Foreign Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount			22,800
Deferred Tax Assets, Valuation Allowance	9,140		9,140	31,974
Valuation Allowance of Deferred Tax Assets
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount				$ 37,000
Valuation Allowance of Deferred Tax Liabilities
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount			53,000
Year 2036
Operating Loss Carryforwards [Line Items]
Net operating loss	2,500		2,500
Year 2037
Operating Loss Carryforwards [Line Items]
Net operating loss	119,700		119,700
Year 2038
Operating Loss Carryforwards [Line Items]
Net operating loss	26,800		26,800
Year 2022
Operating Loss Carryforwards [Line Items]
Net operating loss	$ 199,700		$ 199,700