USE OF DERIVATIVE FINANCIAL INSTRUMENTS, OFFSETTING DISCLOSURES AND CHANGES IN OTHER COMPREHENSIVE INCOME BY COMPONENT - Offsetting Assets (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Offsetting of derivative assets [Abstract]
Gross Amounts of Recognized Assets	$ 285		$ 1,657
Net Amounts of Assets Presented in the Balance Sheet	45,408		34,893
Cash Collateral Received	61,669		53,139
Offsetting Derivatives Assets [Member] | Counterparty 2 [Member]
Offsetting of derivative assets [Abstract]
Gross Amounts of Recognized Assets			0
Gross Amounts Offset in the Balance Sheet			95
Net Amounts of Assets Presented in the Balance Sheet			95
Financial Instruments			(95)	[1]
Cash Collateral Received			0	[1]
Net Amount			0
Offsetting Derivatives Assets [Member] | Counter party 4 [Member]
Offsetting of derivative assets [Abstract]
Gross Amounts of Recognized Assets	14		1,128
Gross Amounts Offset in the Balance Sheet	271		434
Net Amounts of Assets Presented in the Balance Sheet	285		1,562
Financial Instruments	(285)	[1]	(1,562)	[1]
Cash Collateral Received	0	[1]	0	[1]
Net Amount	0		0
Offsetting Derivatives Assets [Member] | Derivative Counterparties [Member]
Offsetting of derivative assets [Abstract]
Gross Amounts of Recognized Assets	14		1,128
Gross Amounts Offset in the Balance Sheet	271		529
Net Amounts of Assets Presented in the Balance Sheet	285		1,657
Financial Instruments	(285)	[1]	(1,657)	[1]
Cash Collateral Received	0	[1]	0	[1]
Net Amount	$ 0		$ 0

[1] 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.