ACQUISITIONS (Details) (USD $)	9 Months Ended							1 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Jan. 03, 2012 Pacific Western Bank PWE Finance	Apr. 03, 2012 Pacific Western Bank Celtic	Sep. 30, 2012 Pacific Western Bank Celtic Maximum	Aug. 31, 2012 Pacific Western Bank American Perspective	Aug. 01, 2012 Pacific Western Bank American Perspective item
Acquisition
Gross leases and leases in process outstanding	$ 2,981,749,000	$ 2,722,400,000	$ 2,803,527,000		$ 160,100,000	$ 54,400,000			$ 197,300,000
Assumed outstanding debt and other liabilities					154,800,000	46,800,000			219,600,000
Loan market considered in granting loan							5,000,000
Number of branches									2
Proceeds from sale of government-sponsored enterprise mortgage backed securities and collateralized mortgage obligations	45,639,000							45,600,000
Deposits	4,787,348,000	4,577,453,000	4,554,396,000	4,486,495,000					219,600,000
Assets Acquired:
Cash and due from banks					7,092,000	3,602,000			3,370,000
Interest-earning deposits in other financial institutions									10,081,000
Investment securities available-for-sale									48,887,000
FHLB stock									1,412,000
Loans and leases					140,959,000	54,433,000			197,279,000
Other real estate owned									1,561,000
Core deposit and customer relationship intangibles					1,700,000	1,300,000			1,924,000
Other intangible assets					1,420,000	670,000
Goodwill					19,033,000	5,855,000			15,563,000
Leases in process					19,162,000
Other assets					467,000	430,000			3,718,000
Total assets acquired					189,833,000	66,290,000			283,795,000
Liabilities Assumed:
Noninterest-bearing deposits									40,673,000
Interest-bearing deposits									178,891,000
Borrowings from parent					128,677,000
Other borrowings					15,839,000	46,804,000			5,315,000
Accrued interest payable and other liabilities					10,317,000	1,486,000			840,000
Total liabilities assumed					154,833,000	48,290,000			225,719,000
Consideration paid
Cash consideration paid					$ 35,000,000	$ 18,000,000			$ 58,076,000