USE OF DERIVATIVES, OFFSETTING DISCLOSURES AND CHANGES IN OTHER COMPREHENSIVE INCOME BY COMPONENT - Schedule of Offsetting of Derivative Assets (Details) - USD ($) $ in Thousands		Jun. 30, 2018	Dec. 31, 2017
Offsetting of derivative assets [Abstract]
Net Amounts of Assets Presented in the Balance Sheet		$ 16,568	$ 24,256
Offsetting Derivatives Assets [Member] | Counterparty 4 [Member]
Offsetting of derivative assets [Abstract]
Gross Amounts of Recognized Assets	[1]	51,399	30,676
Gross Amounts Offset in the Balance Sheet	[1]	(51,399)	(30,676)
Net Amounts of Assets Presented in the Balance Sheet		0	0
Financial Instruments	[2]	0	0
Cash Collateral Received	[2]	0	0
Net Amount		$ 0	$ 0

[1] Included in gross amounts of recognized assets at June 30, 2018 is the fair value of exchange-traded swap agreements, calculated including accrued interest. Included in gross amounts offset in the balance sheet are variation margin amounts associated with these swaps at June 30, 2018.

[2] Amounts presented are limited to recognized liabilities and cash collateral received associated with the indicated counterparty sufficient to reduce the related Net Amount to zero in accordance with ASU No. 2011-11, as amended by ASU No. 2013-01.