Derivative Instruments and Hedging Activities (Details 2) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES [Abstract]
Derivative Assets, Fair Value, Gross Assets	$ 48,094	$ 41,151
Gross Amount of Eligible Offsetting Recognized Derivative Liabilities	0	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	48,094	41,151
Derivative Asset, Not Offset, Policy Election Deduction	(31,838)	(28,113)
Cash Collateral Received	(4,866)	(5,279)
Derivative Asset, Fair Value, Amount Offset Against Collateral	11,390	7,759
Derivative Liability, Fair Value, Gross Liability	(41,351)	(36,439)
Gross Amount of Eligible Offsetting Recognized Derivative Assets	0	0
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	(41,351)	(36,439)
Derivative Liability, Not Offset, Policy Election Deduction	31,838	28,113
Cash Collateral Paid	671	176
Derivative Liability, Fair Value, Amount Offset Against Collateral	$ (8,842)	$ (8,150)