USE OF DERIVATIVES, OFFSETTING DISCLOSURES AND CHANGES IN OTHER COMPREHENSIVE INCOME BY COMPONENT - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2010
Derivative Instruments And Hedging Activities Disclosures [Line Items]
SWAP agreement notional amount during period	$ 5,770.0	$ 100.0
SWAP agreement average interest rate during period	0.57%	4.09%
SWAP agreement terminated notional amount during period	$ 9,400.0
SWAP agreement terminated average interest rate during period	1.54%
SWAP agreement notional amount expiring during period	$ 800.0
SWAP agreement average interest rate expiring during period	2.20%
Derivative instruments unrealized gains to be recognized	$ 6.1
Interest Rate Swap Agreements [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Payment term of LIBOR interest rate agreement		20 years
Minimum [Member] | Interest Rate Swap Agreements [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Payment term of LIBOR interest rate agreement	18 months
Maximum [Member] | Interest Rate Swap Agreements [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Payment term of LIBOR interest rate agreement	3 years