COMMITMENTS AND CONTINGENCIES (Details) (USD $)	9 Months Ended	12 Months Ended	20 Months Ended		1 Months Ended	2 Months Ended	25 Months Ended	2 Months Ended				9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Jun. 05, 2013 item	Sep. 23, 2011	Oct. 31, 2013 CapitalSource Merger-Related Litigation Subsequent event item	Sep. 30, 2013 CapitalSource Merger-Related Litigation Subsequent event item	Oct. 31, 2013 CapitalSource Merger-Related Litigation Subsequent event item	Sep. 30, 2013 CapitalSource Merger-Related Litigation California Subsequent event item	Sep. 30, 2013 CapitalSource Merger-Related Litigation Delaware Subsequent event item	Sep. 30, 2013 Standby letters of credit	Dec. 31, 2012 Standby letters of credit	Sep. 30, 2013 Standby letters of credit Maximum
COMMITMENTS AND CONTINGENCIES
Loan commitments to extend credit	$ 1,069,451,000	$ 849,607,000
Commitments and contingencies
Credit commitments										39,586,000	27,534,000
Expiration period of guarantees												1 year
Number of lawsuits			11		3	11	14	5	6
Commitments to purchase equipment being acquired for lease to others	2,964,000	4,399,000
Commitments to extend credit	1,112,001,000	881,540,000
Commitment to contribute capital to miscellaneous investments	9,300,000	10,800,000
Interpleader amounts on deposit				$ 2,539,049