CORPORATE LOANS AND ALLOWANCE FOR LOAN LOSSES (Details 6) (USD $)	3 Months Ended
	Mar. 31, 2013 loan item	Mar. 31, 2012	Dec. 31, 2012 loan
Troubled debt restructurings:
Troubled debt restructurings on a recorded investment basis	$ 65,600,000		$ 25,500,000
Troubled debt restructurings, included in non-accrual loans	65,600,000		25,500,000
Sustained period of repayment performance for determining the reclassification of restructured loans from non-accrual to accrual status	6 months
Specific reserves allocated to the issuer	1,900,000		500,000
Financing Receivable Modifications Extension Period of Maturity Date	4 years
Number of loans	4		1
Pre-modification outstanding recorded investment	70,028,000
Post-modification outstanding recorded investment	40,659,000
Estimated fair value of equity received from the TDRs	2,100,000
Number of TDRs identified as impaired	3
Charge-offs recorded related to TDR's	26,800,000
Charge-offs related to TDR's as a percentage of charge-offs related to loans and losses	95.00%
Charge-offs recorded	28,313,000	2,098,000
Lending commitment to borrower whose loans had been modified in the troubled debt restructuring	0
Number of loans modified as TDRs in default			0
Loans held for investment
Troubled debt restructurings:
Modified amortized cost of corporate loans that did not qualify as TDRs	1,000,000,000	457,100,000
Number of loans	2
Pre-modification outstanding recorded investment	68,358,000
Post-modification outstanding recorded investment	39,430,000
Number of TDRs identified as impaired	2
Loans at estimated fair value
Troubled debt restructurings:
Number of loans	1
Pre-modification outstanding recorded investment	1,670,000
Post-modification outstanding recorded investment	$ 1,229,000