DERIVATIVE FINANCIAL INSTRUMENTS AND BALANCE SHEET OFFSETTING (Details 4) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Liabilities, Resale Agreements
Net Amounts of Liabilities presented in the Condensed Consolidated Balance Sheets	$ 995,000	$ 995,000
Counterparties assets
Assets, Derivatives
Gross Amounts of Recognized Assets	8,148	992
Net Amounts of Assets presented in the Condensed Consolidated Balance Sheets	8,148	992
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets
Financial Instruments	(5,970)	(366)
Collateral Received	(2,178)	(626)
Assets, Resale Agreements
Gross Amounts of Recognized Assets	1,550,000	1,750,000
Net Amounts of Assets presented in the Condensed Consolidated Balance Sheets	1,550,000	1,750,000
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets
Financial Instruments	(545,000)	(545,000)
Collateral Received	(1,005,000)	(1,205,000)
Counterparties liabilities
Liabilities, Derivatives
Gross Amounts of Recognized Liabilities	24,975	38,513
Net Amounts of Liabilities presented in the Condensed Consolidated Balance Sheets	24,975	38,513
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets
Financial Instruments	(5,970)	(366)
Collateral Posted	(19,005)	(38,147)
Liabilities, Resale Agreements
Gross Amounts of Recognized Liabilities	995,000	995,000
Net Amounts of Liabilities presented in the Condensed Consolidated Balance Sheets	995,000	995,000
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets
Financial Instruments	(545,000)	(545,000)
Collateral Posted	$ (450,000)	$ (450,000)