Organization (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended		0 Months Ended
	Dec. 31, 2014 bank_branch		Apr. 07, 2014	May 31, 2013	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Business Acquisition [Line Items]
Total assets	$ 16,234,800				$ 6,533,363
Accounting Policies [Abstract]
Total loans and leases, net	11,797,977				4,230,318
Total deposits	11,755,128	[1]			5,280,987	[1]
Total stockholders' equity	$ 3,506,425				$ 809,093		$ 589,121	$ 546,203
Number Of Branches	80
Number of Businesses Acquired	27
Capitalsource, Inc. [Member]
Accounting Policies [Abstract]
Business Acquisition, Effective Date of Acquisition	Apr. 07, 2014		Apr. 07, 2014
First California Financial Group, Inc. [Member]
Accounting Policies [Abstract]
Business Acquisition, Effective Date of Acquisition				May 31, 2013

[1] (2)The negative balance for total deposits in the “Other” segment represents the elimination of holding company cash held in deposit accounts at the Bank.