DERIVATIVE FINANCIAL INSTRUMENTS - Effect of Interest Rate Derivatives (Details) - Interest rate swaps - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Dec. 31, 2018
Derivative Instruments
Derivatives
Deferred gain (losses) included in AOCI (pretax)	$ (26,700)	$ (26,700)	$ 3,200
Loss included in AOCI to be recognized in the next 12 months		(6,500)
Cash flow hedges
Derivatives
Unrealized loss recognized in AOCI, pretax	(2,856)	(28,349)
Deferred gain (loss) reclassified from AOCI to interest expense	$ (176)	$ 700