Derivative Instruments and Hedging Activities (Details 2) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES [Abstract]
Derivative Assets, Fair Value, Gross Assets	$ 142,148	$ 54,765
Gross Amount of Eligible Offsetting Recognized Derivative Liabilities	0	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	142,148	54,765
Derivative Asset, Not Offset, Policy Election Deduction	(105,671)	(34,935)
Cash Collateral Received	(14,633)	(7,362)
Derivative Asset, Fair Value, Amount Offset Against Collateral	21,844	12,468
Derivative Liability, Fair Value, Gross Liability	(130,555)	(41,935)
Gross Amount of Eligible Offsetting Recognized Derivative Assets	0	0
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	(130,555)	(41,935)
Derivative Liability, Not Offset, Policy Election Deduction	105,671	34,935
Cash Collateral Paid	1,760	827
Derivative Liability, Fair Value, Amount Offset Against Collateral	$ (23,124)	$ (6,173)