Acquisitions Acquisitions (Details Textuals) (USD $)	0 Months Ended	1 Months Ended				0 Months Ended	3 Months Ended	1 Months Ended
	Apr. 07, 2014	May 31, 2013 bank_branch	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Apr. 07, 2014 Capitalsource, Inc. [Member] bank_branch	Jun. 30, 2014 Capitalsource, Inc. [Member]	May 31, 2013 First California Financial Group, Inc. [Domain] bank_branch
Business Acquisition [Line Items]
Business Acquisition, Share Price						$ 2.47
Business Acquisition Shares Receivable By Stockholders Of Acquiree Ratio						0.2837		0.2966
Stock Issued During Period, Shares, New Issues						56,700,000		8,400,000
Business Acquisition, Effective Date of Acquisition						Apr. 07, 2014
Common Stock, Par or Stated Value Per Share			$ 0.01	$ 0.01		$ 45.83
Common Stock, Value, Outstanding						$ 3,100,000,000
Business integration completion date						April 12, 2014
Number Of Operating Branches Closed As Part Of Integration And Consolidation Plan						12
Number Of Operating Branches Which Overlapped With Existing Branches						1
Goodwill	1,523,055,000	129,070,000	1,725,153,000	208,743,000	209,190,000
number of branches						21		15
Business Acquisition Measuring Period Of Weighted Average Price Per Share For Fluctuating Shares Deliverable								20
Business Combination Owned Common Stock Of Acquiree Cancelled								1,094,000
Cancellation of FCAL common stock owned by PacWest (at acquisition date fair value)	0	9,300,000						4,100,000
Goodwill, Purchase Accounting Adjustments								5,200,000
Share Price								$ 28.83
Total consideration paid	3,077,188,000	251,568,000				3,077,188,000		251,568,000
Number Of Locations Added To Branch Network As Result Of Integration And Consolidation Plan		7
Pro forma revenues (net interest income plus noninterest income)							126,000,000
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual							$ 11,100,000