ACQUISITIONS (Details 2) (USD $)	3 Months Ended								12 Months Ended				0 Months Ended	3 Months Ended	12 Months Ended		0 Months Ended	12 Months Ended		0 Months Ended			0 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	May 31, 2013 First California Financial Group	Sep. 30, 2013 First California Financial Group	Dec. 31, 2013 First California Financial Group Pacific Western Bank item	Dec. 31, 2013 First California Financial Group FCB item	Aug. 03, 2012 APB	Dec. 31, 2013 APB	Aug. 01, 2012 APB	Aug. 03, 2012 APB Pacific Western Bank item	Apr. 03, 2012 Celtic	Apr. 03, 2012 Celtic Pacific Western Bank Maximum	Jan. 03, 2012 Pacific Western Equipment Finance	Jul. 22, 2013 Capital Source	Feb. 13, 2014 Capital Source	Dec. 31, 2013 Capital Source item
Acquisitions
Number of shares of entity receivable by stockholders of acquiree for each share of acquiree													0.2966											0.2837
Measuring period for determining weighted average price per share for fluctuating shares													20 days
Issuance of common stock (in shares)													8,400,000
Common stock of acquiree cancelled in merger (in shares)													1,094,000
Cost of common stock of acquiree cancelled in merger													$ 4,100,000
Closing price of common stock (in dollars per share)	$ 42.22								$ 42.22				$ 28.83												$ 40.11
Total consideration paid													251,568,000				58,076,000				18,000,000		35,000,000	2,800,000,000
Number of operating branches																15				2
Number of locations added to branch network as a result of integration and consolidation plan															7
Goodwill	208,743,000				79,866,000				208,743,000	79,866,000	39,141,000	47,301,000	129,070,000						15,047,000		6,645,000		19,033,000
Non-taxable gain in earnings on previously-held equity interest																		0
Unrealized gain included in stockholders' equity											8,160,000			5,200,000
Threshold limit of asset-based loans																						5,000,000
Remaining merger-related liability	0								0
Amount of expenses incurred related to acquisition	4,253,000	5,450,000	17,997,000	692,000	1,092,000	2,101,000	871,000	25,000	28,392,000	4,089,000	600,000
Cash receivable by stockholders of acquiree for each share of acquiree																								$ 2.47
Shares acquired (in dollars per share)																									$ 13.85
Pro forma consolidated assets																										$ 15,400,000,000
Pro forma consolidated branches																										94