FAIR VALUE DISCLOSURES - Fair Value of Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Mar. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt component - net carrying value	$ 1,215,266	$ 1,293,364
Fair value of total debt	1,194,955	1,215,065
Senior Notes | 6¼% Senior Notes due 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt component - net carrying value	401,535	401,535
Fair value of total debt	328,777	323,236
Convertible Debt | 4½% Convertible Senior Notes due 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt component - net carrying value	106,124	0
Fair value of total debt	158,571	0
Unamortized discount	37,626
Term Loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt component - net carrying value	52,546	261,907
Fair value of total debt	52,546	261,907
Term Loan Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt component - net carrying value	0	45,900
Fair value of total debt	0	45,900
Revolving Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt component - net carrying value	0	139,100
Fair value of total debt	0	139,100
Secured Debt | Lombard Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt component - net carrying value	206,831	196,832
Fair value of total debt	206,831	196,832
Secured Debt | Macquarie Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt component - net carrying value	188,528	200,000
Fair value of total debt	188,528	200,000
Secured Debt | PK Air Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt component - net carrying value	230,000	0
Fair value of total debt	230,000	0
Other Debt | Airnorth Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt component - net carrying value	14,507	16,471
Fair value of total debt	14,507	16,471
Other Debt | Eastern Airways Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt component - net carrying value	12,772	15,326
Fair value of total debt	12,772	15,326
Other Debt | Other Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt component - net carrying value	2,423	16,293
Fair value of total debt	$ 2,423	$ 16,293