ACQUISITIONS (Details) (USD $) In Thousands, unless otherwise specified					0 Months Ended			0 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	May 31, 2013 First California Financial Group	Aug. 03, 2012 American Perspective Bank	Aug. 01, 2012 American Perspective Bank	Apr. 03, 2012 Celtic Capital Corporation	Jan. 03, 2012 Pacific Western Equipment Finance
Assets Acquired:
Cash and due from banks					$ 6,124		$ 3,370	$ 3,435	$ 7,092
Interest-earning deposits in financial institutions					266,889		10,081
Investment securities available-for-sale					4,444		48,887
FHLB stock					9,518		1,412
Loans and leases					1,049,613		197,279	54,963	140,959
Other real estate owned					13,772		1,561
Premises and equipment					15,322
FDIC loss sharing asset					17,241
Cash surrender value of life insurance					13,265
Goodwill	208,743	79,866	39,141	47,301	129,070		15,047	6,645	19,033
Core deposit and customer relationship intangibles					7,927		1,924	1,300	1,700
Other intangible assets								670	1,420
Leases in process									19,162
Other assets					47,671		4,234	69	467
Total assets acquired					1,580,856		283,795	67,082	189,833
Liabilities Assumed:
Noninterest-bearing deposits					361,166		40,673
Interest-bearing deposits					739,713		178,891
Borrowings from parent									128,677
Other borrowings							5,315	46,804	15,839
Subordinated debentures					24,061
Discontinued operations					184,619
Accrued interest payable and other liabilities					19,729		840	2,278	10,317
Total liabilities assumed					1,329,288		225,719	49,082	154,833
Total consideration paid					251,568	58,076		18,000	35,000
Summary of consideration:
Cash paid						58,076		18,000	35,000
PacWest common stock issued					242,268
Cancellation of FCAL common stock owned by PacWest					9,300
Total consideration paid					$ 251,568	$ 58,076		$ 18,000	$ 35,000