LONG-TERM DEBT, LETTERS OF CREDIT AND DERIVATIVES - Credit Facility Financial Covenant Requirements (Details)	Mar. 31, 2020
March 31, 2020
Debt Instrument [Line Items]
Maximum Senior Secured Leverage Ratio	2.75
Maximum Net Leverage Ratio	5.50
Minimum Debt Service Coverage Ratio	1.25
June 30, 2020
Debt Instrument [Line Items]
Maximum Senior Secured Leverage Ratio	2.75
Maximum Net Leverage Ratio	5.25
Minimum Debt Service Coverage Ratio	1.25
September 30, 2020
Debt Instrument [Line Items]
Maximum Senior Secured Leverage Ratio	2.75
Maximum Net Leverage Ratio	5.00
Minimum Debt Service Coverage Ratio	1.25
December 31, 2020 and thereafter
Debt Instrument [Line Items]
Maximum Senior Secured Leverage Ratio	2.50
Maximum Net Leverage Ratio	4.50
Minimum Debt Service Coverage Ratio	1.50