Goodwill and Other Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended			3 Months Ended	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2012	Jun. 30, 2014	Dec. 31, 2013	Apr. 03, 2012	Aug. 01, 2012	May 31, 2013
Goodwill [Roll Forward]
Goodwill	$ 208,743	[1]	$ 39,141
Goodwill, Acquired During Period	1,518,381		19,033
Goodwill, Impairment Loss	(6,645)
Goodwill	1,720,479	[1]	79,866
Celtic Capital Corporation [Member]
Goodwill [Roll Forward]
Goodwill						6,645
Goodwill, Acquired During Period			6,645
Goodwill, Impairment Loss				6,600
Goodwill						6,645
American Perspective Bank [Member]
Goodwill [Roll Forward]
Goodwill							15,047
Goodwill, Other Changes					(193)
Goodwill, Acquired During Period			15,047
Goodwill							15,047
First California Financial Group, Inc. [Member]
Goodwill [Roll Forward]
Goodwill								129,070
Goodwill, Acquired During Period					129,070
Goodwill								$ 129,070

[1] (1)The increase in the goodwill for the Community Banking segment and National Lending segment during 2014 was due primarily to $1.5 billion from the CapitalSource merger.