USE OF DERIVATIVES, OFFSETTING DISCLOSURES AND CHANGES IN OTHER COMPREHENSIVE INCOME BY COMPONENT - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2010
Derivative Instruments And Hedging Activities Disclosures [Line Items]
SWAP agreement notional amount during period	$ 2,000.0	$ 100.0
SWAP agreement average interest rate during period	2.71%	4.09%
Swap agreement notional amount expiring during period	$ 3,500.0
SWAP agreement average interest rate expiring during period	0.87%
Derivative instruments unrealized gains to be recognized	$ 26.4
Interest Rate Swap Agreements [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Payment term of LIBOR interest rate agreement		20 years