Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current income tax provision:
Federal									$ 9,628	$ 7,008	$ 6,403
State									3,466	2,329	2,026
Total current income tax provision									13,094	9,337	8,429
Deferred income tax provision (benefit):
Federal									(1,789)	(3,129)	1,262
State									(586)	(621)	298
Total deferred income tax provision (benefit)									(2,375)	(3,750)	1,560
Total income tax provision	2,889	3,410	2,855	1,565	2,474	1,846	91	1,176	10,719	5,587	9,989
Reconciliation from statutory federal income taxes to the company's effective income taxes
Statutory federal income tax provision									9,459	5,103	8,760
California franchise tax, net of federal income tax effect									1,926	1,027	1,842
Other, including tax exempt income									(666)	(543)	(613)
Total income tax provision	2,889	3,410	2,855	1,565	2,474	1,846	91	1,176	10,719	5,587	9,989
Deferred tax assets:
Accrued expenses	1,616				891				1,616	891	442
Net operating loss	2,703				3,353				2,703	3,353	3,673
Allowance for loan losses, net of bad debt charge-offs	5,158				3,336				5,158	3,336	3,390
Directors deferred compensation	1,750				1,896				1,750	1,896
Unrealized loss on available for sale securities	(362)				2,160				(362)	2,160
State taxes	1,238				858				1,238	858	765
Other-than-temporary impairment					684					684	2,180
Stock based compensation	313				273				313	273	6
Total deferred tax assets	12,416				13,451				12,416	13,451	10,884
Deferred tax liabilities:
Federal Home Loan Bank stock dividends	(169)				(306)				(169)	(306)	(560)
Deferred FDIC gain	(1,731)				(1,944)				(1,731)	(1,944)	(2,367)
Core deposit intangibles	(1,518)				(1,813)				(1,518)	(1,813)
Depreciation	321				(216)				321	(216)	(111)
Other	(991)				(695)				(991)	(695)	(187)
Total deferred tax liabilities	(4,088)				(4,974)				(4,088)	(4,974)	(3,997)
Net deferred tax asset	$ 9,383				$ 8,477				$ 9,383	$ 8,477	$ 6,887