Bank of Marin Bancorp (BMRC) 10-Q 8 May 15 2015 Q1 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 30, 2015
Document and Entity Information [Abstract]
Entity Registrant Name	Bank of Marin Bancorp
Entity Central Index Key	1403475
Current Fiscal Year End Date	-19
Entity Filer Category	Accelerated Filer
Document Type	10-Q
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		5,973,424

CONSOLIDATED_STATEMENTS_OF_CON

CONSOLIDATED STATEMENTS OF CONDITION (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Assets
Cash and due from banks	$103,164	$41,367
Investment securities
Held-to-maturity, at amortized cost	107,476	116,437
Available-for-sale, at fair value (amortized cost $201,568 and $199,045 at March 31, 2015 and December 31, 2014, respectively)	204,680	200,848
Total investment securities	312,156	317,285
Loans, net of allowance for loan losses of $15,156 and $15,099 at March 31, 2015 and December 31, 2014, respectively	1,331,328	1,348,252
Bank premises and equipment, net	9,852	9,859
Goodwill	6,436	6,436
Core deposit intangible	3,577	3,732
Interest receivable and other assets	59,636	60,199
Total assets	1,826,149	1,787,130
Deposits
Non-interest-bearing	716,719	670,890
Interest-bearing
Transaction accounts	95,439	93,758
Savings accounts	133,792	133,714
Money market accounts	478,145	503,543
CDARS® time accounts	11,493	0
Other time accounts	149,532	149,714
Total deposits	1,585,120	1,551,619
Federal Home Loan Bank (FHLB) borrowings	15,000	15,000
Subordinated debentures	5,238	5,185
Interest payable and other liabilities	16,285	15,300
Total liabilities	1,621,643	1,587,104
Stockholders' Equity
Preferred stock, no par value Authorized - 5,000,000 shares, none issued	0	0
Common stock, no par value Authorized - 15,000,000 shares; Issued and outstanding - 5,967,614 and 5,939,482 at March 31, 2015 and December 31, 2014, respectively	83,011	82,436
Retained earnings	119,652	116,502
Accumulated other comprehensive income, net	1,843	1,088
Total stockholders' equity	204,506	200,026
Total liabilities and stockholders' equity	$1,826,149	$1,787,130

CONSOLIDATED_STATEMENTS_OF_CON1

CONSOLIDATED STATEMENTS OF CONDITION (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, except Share data, unless otherwise specified
Investment Securities
Available-for-sale, amortized cost	$201,568	$199,045
Loans, allowance for loan losses	$15,156	$15,099
Stockholders' Equity
Preferred stock, no par value	$0	$0
Preferred stock, authorized (in shares)	5,000,000	5,000,000
Preferred stock, issued	0	0
Common stock, no par value (in dollars per share)	$0	$0
Common stock, authorized (in shares)	15,000,000	15,000,000
Common stock, issued (in shares)	5,967,614	5,939,482
Common stock, outstanding (in shares)	5,967,614	5,939,482

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Interest income
Interest and fees on loans	$15,379	$16,319
Interest on investment securities
Securities of U.S. government agencies	1,035	1,232
Obligations of state and political subdivisions	540	634
Corporate debt securities and other	205	268
Interest on Federal funds sold and due from banks	21	51
Total interest income	17,180	18,504
Interest expense
Interest on interest-bearing transaction accounts	30	23
Interest on savings accounts	12	11
Interest on money market accounts	127	158
Interest on CDARS® time accounts	11	0
Interest on other time accounts	220	235
Interest on FHLB and overnight borrowings	78	78
Interest on subordinated debentures	104	105
Total interest expense	582	610
Net interest income	16,598	17,894
Provision for loan losses	0	150
Net interest income after provision for loan losses	16,598	17,744
Non-interest income
Service charges on deposit accounts	525	556
Wealth Management and Trust Services	638	564
Debit card interchange fees	347	300
Merchant interchange fees	130	198
Earnings on bank-owned life insurance	203	213
Gains (losses) on investment securities, net	8	-8
Other income	338	393
Total non-interest income	2,189	2,216
Non-interest expense
Salaries and related benefits	6,790	6,930
Occupancy and equipment	1,342	1,334
Depreciation and amortization	421	416
Federal Deposit Insurance Corporation insurance	236	250
Data processing	786	1,360
Professional services	564	628
Reversal of losses on off-balance sheet commitments	-201	0
Other expense	1,910	1,925
Total non-interest expense	11,848	12,843
Income before provision for income taxes	6,939	7,117
Provision for income taxes	2,482	2,584
Net income	4,457	4,533
Net income per common share:
Basic (usd per share)	$0.75	$0.77
Diluted (usd per share)	$0.74	$0.76
Weighted average shares used to compute net income per common share:
Basic (shares)	5,921	5,870
Diluted (shares)	6,048	5,980
Dividends declared per common share (usd per share)	$0.22	$0.19
Comprehensive income:
Net income	4,457	4,533
Other comprehensive income
Change in net unrealized gain on available-for-sale securities	1,317	1,415
Reclassification adjustment for (gain) loss on available-for-sale securities included in net income	-8	15
Net change in unrealized gain on available-for-sale securities, before tax	1,309	1,430
Deferred tax expense	554	519
Other comprehensive income, net of tax	755	911
Comprehensive income	$5,212	$5,444

CONSOLIDATED_STATEMENTS_OF_CHA

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (USD $)	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income, Net of Taxes
In Thousands, except Share data, unless otherwise specified
Balance at Dec. 31, 2013	$180,887	$80,095	$101,464	($672)
Balance (in shares) at Dec. 31, 2013		5,877,524
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	19,771		19,771
Other comprehensive income (loss)	1,760			1,760
Stock options exercised (in shares)		49,415
Stock options exercised	1,452	1,452
Excess tax benefit - stock-based compensation	172	172
Stock issued under employee stock purchase plan (in shares)		521
Stock issued under employee stock purchase plan	23	23
Restricted stock granted (in shares)		8,523
Restricted stock granted	0	0
Restricted stock forfeited/cancelled (in shares)		-2,067
Restricted stock forfeited/cancelled	0	0
Stock-based compensation - stock options	200	200
Stock-based compensation - restricted stock	246	246
Cash dividends paid on common stock	-4,733		-4,733
Stock purchased by directors under director stock plan (in shares)		260
Stock purchased by directors under director stock plan	12	12
Stock issued in payment of director fees (in shares)		5,306
Stock issued in payment of director fees	236	236
Balance at Dec. 31, 2014	200,026	82,436	116,502	1,088
Balance (in shares) at Dec. 31, 2014	5,939,482	5,939,482
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	4,457		4,457
Other comprehensive income (loss)	755			755
Stock options exercised (in shares)		9,371
Stock options exercised	312	312
Excess tax benefit - stock-based compensation	28	28
Stock issued under employee stock purchase plan (in shares)		96
Stock issued under employee stock purchase plan	5	5
Restricted stock granted (in shares)		15,970
Restricted stock granted	0	0
Stock-based compensation - stock options	36	36
Stock-based compensation - restricted stock	56	56
Cash dividends paid on common stock	-1,307		-1,307
Stock issued in payment of director fees (in shares)		2,695
Stock issued in payment of director fees	138	138
Balance at Mar. 31, 2015	$204,506	$83,011	$119,652	$1,843
Balance (in shares) at Mar. 31, 2015	5,967,614	5,967,614

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Cash Flows from Operating Activities:
Net income	$4,457	$4,533	$19,771
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	0	150
(Reversal of) provision for losses on off-balance sheet commitments	-201	0
Compensation expense--common stock for director fees	74	58
Stock-based compensation expense	92	99
Excess tax benefits from exercised stock options	-16	-37
Amortization of core deposit intangible	155	193
Amortization of investment security premiums, net of accretion of discounts	570	660
Accretion of discount on acquired loans	-490	-1,510
Accretion of discount on subordinated debentures	53	54
Net amortization of deferred loan origination costs/fees	-164	-81
Write-down of other real estate owned	40	0
(Gain) loss on sale of investment securities	-8	8
Depreciation and amortization	421	416
Earnings on bank owned life insurance policies	-203	-213
Net change in operating assets and liabilities:
Interest receivable	456	111
Interest payable	-5	-33
Deferred rent and other rent-related expenses	-11	76
Other assets	674	-479
Other liabilities	-8	-1,865
Total adjustments	1,429	-2,393
Net cash provided by operating activities	5,886	2,140
Cash Flows from Investing Activities:
Purchase of held-to-maturity securities	-2,375	0
Purchase of available-for-sale securities	-11,493	-9,872
Proceeds from sale of available-for-sale securities	1,559	2,023
Proceeds from sale of held-to-maturity securities	0	725
Proceeds from paydowns/maturity of held-to-maturity securities	11,043	3,678
Proceeds from paydowns/maturity of available-for-sale securities	7,133	8,429
Loans originated and principal collected, net	18,149	-7,750
Purchase of premises and equipment	-414	-342
Cash paid for low income housing tax credit investment	-218	-69
Net cash provided by (used in) investing activities	23,384	-3,178
Cash Flows from Financing Activities:
Net increase (decrease) in deposits	33,501	-10,762
Proceeds from stock options exercised	312	670
Proceeds from stock issued under employee and director stock purchase plans	5	7
Cash dividends paid on common stock	-1,307	-1,120
Excess tax benefits from exercised stock options	16	37
Net cash provided by (used in) financing activities	32,527	-11,168
Net increase (decrease) in cash and cash equivalents	61,797	-12,206
Cash and cash equivalents at beginning of period	41,367	103,773	103,773
Cash and cash equivalents at end of period	103,164	91,567	41,367
Supplemental disclosure of cash flow information:
Cash paid for interest	534	594
Cash paid for income taxes	30	0
Supplemental disclosure of non-cash investing and financing activities:
Change in unrealized gain on available-for-sale securities	1,309	1,430
Securities transferred from available-for-sale to held-to-maturity	0	14,297
Subscription in low income housing tax credit investment	1,023	1,000
Stock issued in payment of director fees	$138	$103

Basis_of_Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation
	The consolidated financial statements include the accounts of Bank of Marin Bancorp (“Bancorp”), a bank holding company, and its wholly-owned bank subsidiary, Bank of Marin (the “Bank”), a California state-chartered commercial bank. References to “we,” “our,” “us” mean the holding company and the Bank that are consolidated for financial reporting purposes. The accompanying unaudited consolidated interim financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission ("SEC"). Certain information and note disclosures normally included in annual financial statements prepared in accordance with generally accepted accounting principles ("GAAP") have been condensed or omitted pursuant to those rules and regulations. Although we believe that the disclosures made are adequate to make the information not misleading, we suggest that these interim financial statements be read in conjunction with the financial statements and the notes thereto included in our 2014 Annual Report on Form 10-K.  In the opinion of Management, the unaudited consolidated financial statements reflect all adjustments which are necessary for a fair presentation of the consolidated financial position, the results of operations, changes in comprehensive income, changes in stockholders’ equity, and cash flows for the periods presented. All material intercompany transactions have been eliminated. The results of these interim periods may not be indicative of the results for the full year or for any other period. We have evaluated subsequent events through the date of filing with the SEC and have determined that there are no subsequent events that require additional recognition or disclosure.
	On November 29, 2013, we completed the merger of NorCal Community Bancorp ("NorCal"), parent company of Bank of Alameda, to enhance our market presence (the “Acquisition”). On the date of acquisition, Bancorp assumed ownership of NorCal Community Bancorp Trusts I and II, respectively (the "Trusts"), which were formed for the sole purpose of issuing trust preferred securities. Bancorp is not considered the primary beneficiary of the Trusts (variable interest entities), therefore the Trusts are not consolidated in our consolidated financial statements, but rather the subordinated debentures are shown as a liability on our consolidated statements of condition. Bancorp's investment in the common stock of the Trusts is accounted for under the equity method and is included in interest receivable and other assets on the consolidated statements of condition.
	The following table shows: 1) weighted average basic shares, 2) potentially dilutive common shares related to stock options, unvested restricted stock awards and stock warrant, and 3) weighted average diluted shares. Basic earnings per share (“EPS”) are calculated by dividing net income by the weighted average number of common shares outstanding during each period, excluding unvested restricted stock awards. Diluted EPS are calculated using the weighted average diluted shares. The number of potentially dilutive common shares included in quarterly diluted EPS is computed using the average market prices during the three months included in the reporting period under the treasury stock method. The number of potentially dilutive common shares included in year-to-date diluted EPS is a year-to-date weighted average of potentially dilutive common shares included in each quarterly diluted EPS computation. We have two forms of outstanding stock: common stock and unvested restricted stock awards. Holders of unvested restricted stock awards receive non-forfeitable dividends at the same rate as common shareholders and they both share equally in undistributed earnings. Therefore, under the two-class method, the difference in EPS is not significant for these participating securities.
		Three months ended
	(in thousands, except per share data; unaudited)	March 31, 2015		March 31, 2014
	Weighted average basic shares outstanding	5,921		5,870
	Add: Potentially dilutive common shares related to stock options	47		43
	Potentially dilutive common shares related to unvested restricted stock	6		6
	Potentially dilutive common shares related to the warrant	74		61
	Weighted average diluted shares outstanding	6,048		5,980
	Net income	$	4,457	$	4,533
	Basic EPS	$	0.75	$	0.77
	Diluted EPS	$	0.74	$	0.76
	Weighted average anti-dilutive shares not included in the calculation of diluted EPS	24		44

Recently_Issued_Accounting_Sta

Recently Issued Accounting Standards	3 Months Ended
	Mar. 31, 2015
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recently Issued Accounting Standards	Recently Issued Accounting Standards
	In January 2014, the FASB issued ASU No. 2014-04, Receivables - Troubled Debt Restructurings by Creditors (Subtopic 310-40) Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure. Current accounting literature on troubled debt restructurings includes guidance on the receipt of one or more collateral assets in satisfaction of all or part of a receivable. The accounting literature indicates that a creditor should reclassify a collateralized mortgage loan such that the loan should be de-recognized and the collateral asset recognized when it is determined that there has been in substance a repossession or foreclosure by the creditor. However, in substance repossession or foreclosure and physical possession were not defined, leaving uncertainty about when a creditor should de-recognize the loan receivable and recognize the real estate property. This ASU clarifies when an in substance repossession or foreclosure occurs. ASU 2014-04 is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2014 for public entities. Since we currently do not hold any in substance foreclosures, the adoption of this ASU has not had any impact on our financial condition or results of operations.
	In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). The ASU is a converged standard involving FASB and International Financial Reporting Standards that provides a single comprehensive revenue recognition model for all contracts with customers across transactions and industries. The guidance in this ASU affects any entity that either enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of nonfinancial assets unless those contracts are within the scope of other standards. The core principal of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. For public entities, the ASU is effective on a retrospective basis for annual reporting periods, and interim periods within those annual periods, beginning after December 15, 2016. Since this ASU does not apply to financial instruments and we do not have a significant source of non-interest income subject to this ASU, we do not expect it to have a significant impact on our financial condition or results of operations.
	In June 2014, the FASB issued ASU No. 2014-12, Compensation - Stock Compensation (Topic 718) Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period. This ASU provides guidance for entities that grant their employees share-based payment awards where a performance target that affects vesting could be achieved after the requisite service period. That is the case when an employee is eligible to retire or otherwise terminate employment before the end of the period in which a performance target could be achieved and still be eligible to vest in the award if and when the performance target is achieved. This ASU stipulates that compensation expense should be recognized in the period where the performance target becomes probable of being achieved as opposed to the date that the award was granted. ASU 2014-12 is effective for annual periods and interim periods within those annual periods beginning after December 15, 2015. As of March 31, 2015 we have not granted share-based payment awards where a performance target that affects vesting could be achieved after the requisite service period. We do not expect this ASU to have a material impact on our financial condition or results of operations.

Fair_Value_of_Assets_and_Liabi

Fair Value of Assets and Liabilities	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value of Assets and Liabilities	Fair Value of Assets and Liabilities
	Fair Value Hierarchy and Fair Value Measurement
	We group our assets and liabilities that are measured at fair value in three levels within the fair value hierarchy, based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine fair value. These levels are:
	Level 1: Valuations are based on quoted prices in active markets for identical assets or liabilities. Since valuations are based on quoted prices that are readily and regularly available in an active market, valuation of these products does not involve a significant degree of judgment.
	Level 2: Valuations are based on quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active and model-based valuations for which all significant assumptions are observable or can be corroborated by observable market data.
	Level 3: Valuations are based on unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Values are determined using pricing models and discounted cash flow models and include Management judgment and estimation which may be significant.
	Transfers between levels of the fair value hierarchy are recognized on the actual date of the event or circumstances that caused the transfer, which generally coincides with our monthly and/or quarterly valuation process.
	The following table summarizes our assets and liabilities that were required to be recorded at fair value on a recurring basis.
	(in thousands)	Carrying Value			Quoted Prices in Active Markets for Identical Assets (Level 1)			Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
	Description of Financial Instruments
	At March 31, 2015 (unaudited):
	Securities available-for-sale:
	Mortgage-backed securities and collateralized mortgage obligations issued by U.S. government-sponsored agencies	$	152,142		$	—		$	149,472		$	2,670
	Debentures of government-sponsored agencies	$	26,174		$	—		$	26,174		$	—
	Privately-issued collateralized mortgage obligations	$	5,493		$	—		$	5,493		$	—
	Obligations of state and political subdivisions	$	15,850		$	—		$	15,850		$	—
	Corporate bonds	$	5,021		$	—		5,021			$	—
	Derivative financial assets (interest rate contracts)	$	—		$	—		$	—		$	—
	Derivative financial liabilities (interest rate contracts)	$	2,481		$	—		$	2,481		$	—
	At December 31, 2014:
	Securities available-for-sale:
	Mortgage-backed securities and collateralized mortgage obligations issued by U.S. government-sponsored agencies	$	158,119		$	—		$	155,421		$	2,698
	Debentures of government-sponsored agencies	$	14,557		$	—		$	14,557		$	—
	Privately-issued collateralized mortgage obligations	$	7,294		$	—		$	7,294		$	—
	Obligations of state and political subdivisions	$	15,880		$	—		$	15,771		$	—
	Corporate bonds	$	4,998		$	—		$	5,437		$	—
	Derivative financial assets (interest rate contracts)	$	61		$	—		$	61		$	—
	Derivative financial liabilities (interest rate contracts)	$	1,996		$	—		$	1,996		$	—
	Securities available-for-sale are recorded at fair value on a recurring basis. When available, quoted market prices (Level 1) are used to determine the fair value of securities available-for-sale. If quoted market prices are not available, we obtain pricing information from a reputable third-party service provider, who may utilize valuation techniques that use current market-based or independently sourced parameters, such as bid/ask prices, dealer-quoted prices, interest rates, benchmark yield curves, prepayment speeds, probability of default, loss severity and credit spreads (Level 2).   Level 2 securities include U.S. agencies or government sponsored agencies' debt securities, mortgage-backed securities, government agency-issued and privately-issued collateralized mortgage obligations. As of March 31, 2015 and December 31, 2014, there are no securities that are considered Level 1 securities. As of March 31, 2015, we have one available-for-sale security that is considered a Level 3 security. The security is a U.S. government agency obligation collateralized by a small pool of business equipment loans guaranteed by the Small Business Administration program. This security is not actively traded and is owned only by a few investors. The significant unobservable data that is reflected in the fair value measurement include dealer quotes, projected prepayment speeds/average life and credit information, among other things. It was transferred to a Level 3 security during the second quarter of 2014. The increase in unrealized gain during the first quarter of 2015 is $10 thousand.
	Securities held-to-maturity may be written down to fair value (determined using the same techniques discussed above for securities available-for-sale) as a result of an other-than-temporary impairment, if any.
	On a recurring basis, derivative financial instruments are recorded at fair value, which is based on the income approach using observable Level 2 market inputs, reflecting market expectations of future interest rates as of the measurement date.  Standard valuation techniques are used to calculate the present value of the future expected cash flows assuming an orderly transaction.  Valuation adjustments may be made to reflect both our own credit risk and the counterparties’ credit quality in determining the fair value of the derivatives. Level 2 inputs for the valuations are limited to observable market prices for London Interbank Offered Rate ("LIBOR") cash rates and Overnight Index Swap ("OIS") rates (for the very short term), quoted prices for LIBOR futures contracts, observable market prices for LIBOR and OIS swap rates, and one-month and three-month LIBOR basis spreads at commonly quoted intervals.  Mid-market pricing of the inputs is used as a practical expedient in the fair value measurements.  We project spot rates at reset days specified by each swap to determine future cash flows, then discount to present value using either LIBOR or OIS curves depending on the collateral posted as of the measurement date.  When the value of any collateral placed with counterparties is less than the interest rate derivative liability, an additional discount is applied to reflect our potential credit risk to counterparties.  We have used the spread between the Standard & Poor's BBB rated U.S. Bank Composite rate and LIBOR for the closest maturity term corresponding to the duration of the swaps to derive the credit-risk-related component of the discount rate of future cash flows from the collateral shortfall.
	Certain financial assets may be measured at fair value on a non-recurring basis. These assets are subject to fair value adjustments that result from the application of the lower of cost or fair value accounting or write-downs of individual assets, such as impaired loans and other real estate owned ("OREO").
	The following table presents the carrying value of financial instruments that were measured at fair value on a non-recurring basis and that were still held in the consolidated statements of condition at each respective period end, by level within the fair value hierarchy as of March 31, 2015 and December 31, 2014.
	(in thousands)	Carrying Value1			Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs			Significant Unobservable Inputs
	Description of Financial Instruments				(Level 1)			(Level 2)			(Level 3) 1
	At March 31, 2015 (unaudited):
	Impaired loans carried at fair value:
	Installment and other consumer	13			—			—			13
	Total	$	13		$	—		$	—		$	13
	At December 31, 2014:
	Impaired loans carried at fair value:
	Installment and other consumer	77			—			—			77
	Total	$	77		$	—		$	—		$	77
	1 Represents collateral-dependent loan principal balances that had been generally written down to the values of the underlying collateral, net of specific valuation allowances of $10 thousand and $26 thousand at March 31, 2015 and December 31, 2014, respectively. The carrying value of loans fully charged-off, which includes unsecured lines of credit, overdrafts and all other loans, is zero.
	When a loan is identified as impaired, it is reported at the lower of cost or fair value, measured based on the loan's observable market price (Level 1) or the current net realizable value of the underlying collateral securing the loan, if the loan is collateral dependent (Level 3).  Net realizable value of the underlying collateral is the fair value of the collateral less estimated selling costs and any prior liens. Appraisals, recent comparable sales, offers and listing prices are factored in when valuing the collateral. We review and verify the qualifications and licenses of  the certified general appraisers used for appraising commercial properties or certified residential appraisers for residential properties. Real estate appraisals may utilize a combination of approaches including replacement cost, sales comparison and the income approach. Comparable sales and income data are analyzed by the appraisers and adjusted to reflect differences between them and the subject property such as type, leasing status and physical condition. When appraisals are received, Management reviews the assumptions and methodology utilized in the appraisal, as well as the overall resulting value in conjunction with independent data sources such as recent market data and industry-wide statistics. We generally use a 6% discount for selling costs which is applied to all properties, regardless of size. Appraised values may be adjusted to reflect changes in market conditions that have occurred subsequent to the appraisal date, or for revised estimates regarding the timing or cost of the property sale. These adjustments are based on qualitative judgments made by Management on a case-by-case basis and are generally unobservable valuation inputs as they are specific to the underlying collateral. There have been no significant changes in the valuation techniques during the quarter ended March 31, 2015.
	OREO represents collateral acquired through foreclosure and is initially recorded at fair value as established by a current appraisal, adjusted for disposition costs. Subsequently, OREO is measured at lower of cost or fair value. OREO values are reviewed on an ongoing basis and any subsequent decline in fair value is recorded as a foreclosed asset expense in the current period. The value of OREO is determined based on independent appraisals, similar to the process used for impaired loans, discussed above, and is generally classified as Level 3. We had $421 thousand and $461 thousand of OREO as of March 31, 2015 and December 31, 2014, respectively, all of which was acquired from Bank of Alameda as part of the Acquisition. There was a $40 thousand decline in the estimated fair value of the OREO during the first three months ended March 31, 2015.
	Disclosures about Fair Value of Financial Instruments
	The table below is a summary of fair value estimates for financial instruments as of March 31, 2015 and December 31, 2014, excluding financial instruments recorded at fair value on a recurring basis (summarized in the first table in this note). The carrying amounts in the following table are recorded in the consolidated statements of condition under the indicated captions. We have excluded non-financial assets and non-financial liabilities defined by the Codification (ASC 820-10-15-1A), such as Bank premises and equipment, deferred taxes and other liabilities.  In addition, we have not disclosed the fair value of financial instruments specifically excluded from disclosure requirements of the Financial Instruments Topic of the Codification (ASC 825-10-50-8), such as Bank-owned life insurance policies.
		March 31, 2015						December 31, 2014
	(in thousands; 2015 unaudited)	Carrying Amounts		Fair Value			Fair Value Hierarchy	Carrying Amounts		Fair Value			Fair Value Hierarchy
	Financial assets
	Cash and cash equivalents	$	103,164	$	103,164		Level 1	$	41,367	$	41,367		Level 1
	Investment securities held-to-maturity	107,476		109,785			Level 2	116,437		118,643			Level 2
	Loans, net	1,331,328		1,341,118			Level 3	1,348,252		1,361,244			Level 3
	Interest receivable	5,453		5,453			Level 2	5,909		5,909			Level 2
	Financial liabilities
	Deposits	1,585,120		1,585,907			Level 2	1,551,619		1,552,446			Level 2
	Federal Home Loan Bank borrowings	15,000		15,514			Level 2	15,000		15,484			Level 2
	Subordinated debentures	5,238		5,274			Level 3	5,185		5,290			Level 3
	Interest payable	208		208			Level 2	213		213			Level 2
	Following is a description of methods and assumptions used to estimate the fair value of each class of financial instrument not recorded at fair value but required for disclosure purposes:
	Cash and Cash Equivalents - The carrying amounts of cash and cash equivalents approximate their fair value because of the short-term nature of these instruments.
	Held-to-maturity Securities - Held-to-maturity securities, which generally consist of mortgage-backed securities, obligations of state and political subdivisions and corporate bonds, are recorded at their amortized cost. Their fair value for disclosure purposes is determined using methodologies similar to those described above for available-for-sale securities using Level 2 inputs. If Level 2 inputs are not available, we may utilize pricing models that incorporate unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities (Level 3).  As of March 31, 2015 and December 31, 2014, we did not hold any held-to-maturity securities whose fair value was measured using significant unobservable inputs.
	Loans - The fair value of loans with variable interest rates approximates current carrying value, because their rates are regularly adjusted to current market rates. The fair value of fixed rate loans or variable loans at negotiated interest rate floors or ceilings with remaining maturities in excess of one year is estimated by discounting the future cash flows using current market rates at which similar loans would be made to borrowers with similar creditworthiness and similar remaining maturities. The allowance for loan losses (“ALLL”) is considered to be a reasonable estimate of the portion of loan discount attributable to credit risks.
Interest Receivable and Payable - The interest receivable and payable balances approximate their fair value due to the short-term nature of their settlement dates.
Deposits - The fair value of deposits without stated maturity, such as transaction accounts, savings accounts and money market accounts, is the amount payable on demand at the reporting date. The fair value of time deposits is estimated by discounting the future cash flows using current rates offered for deposits of similar remaining maturities.
Federal Home Loan Bank Borrowings - The fair value is estimated by discounting the future cash flows using current rates offered by the Federal Home Loan Bank of San Francisco ("FHLB") for similar credit advances corresponding to the remaining duration of our fixed-rate credit advances.
Subordinated Debentures - As part of the Acquisition, we assumed two subordinated debentures from NorCal. See Note 6 for further information. The fair values of the subordinated debentures were estimated by discounting the future cash flows (interest payment at a rate of three-month LIBOR plus 3.05% and 1.40%, respectively) to their present values using current market rates at which similar debt securities would be issued with similar credit ratings as ours and similar remaining maturities. Each interest payment was discounted at the spot rate for the corresponding term, determined based on the yields and terms of comparable trust preferred securities, plus a liquidity premium. In July 2010, the Dodd-Frank Act was signed into law and limits the ability of certain bank holding companies to treat trust preferred security debt issuances as Tier 1 capital. This law effectively closed the trust-preferred securities markets for new issuance and led to the absence of observable or comparable transactions in the market place. Due to the use of unobservable inputs of trust preferred securities, we consider the fair value to be a Level 3 measurement.
Commitments - Loan commitments and standby letters of credit generate ongoing fees, which are recognized over the term of the commitment period. We record an allowance reserve for these off-balance sheet commitments which is based on an estimate of probabilities of these commitments being drawn upon according to our historical utilization experience on different types of commitments and expected loss severity. We have set aside an allowance for losses in the amount of $811 thousand and $1.0 million as of March 31, 2015 and December 31, 2014, respectively.

Investment_Securities

Investment Securities	3 Months Ended
	Mar. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Investment Securities	Investment Securities
	Our investment securities portfolio consists of obligations of state and political subdivisions, corporate bonds, U.S. government agency securities, including mortgage-backed securities (“MBS”) and collateralized mortgage obligations (“CMOs”) issued or guaranteed by Federal National Mortgage Association ("FNMA"), Federal Home Loan Mortgage Corporation ("FHLMC"), or Government National Mortgage Association ("GNMA"), debentures issued by government-sponsored agencies such as FNMA and FHLMC, as well as privately issued CMOs, as reflected in the table below:
		31-Mar-15													31-Dec-14
		Amortized			Fair			Gross Unrealized							Amortized			Fair			Gross Unrealized
	(in thousands; 2015 unaudited)	Cost			Value			Gains			(Losses)				Cost			Value			Gains			(Losses)
	Held-to-maturity
	Obligations of state and	$	60,529		$	62,257		$	1,741		$	(13	)		$	63,425		$	65,121		$	1,736		$	(40	)
	political subdivisions
	Corporate bonds	32,175			32,345			173			(3		)		40,257			40,448			216			(25		)
	MBS pass-through securities issued by FHLMC and FNMA	14,772			15,183			411			—				12,755			13,074			319			—
	Total held-to-maturity	107,476			109,785			2,325			(16		)		116,437			118,643			2,271			(65		)
	Available-for-sale
	Securities of U.S. government agencies:
	MBS pass-through securities issued by FHLMC and FNMA	90,215			92,057			1,842			—				92,963			94,214			1,262			(11		)
	CMOs issued by FNMA	13,896			14,055			197			(38		)		14,771			14,790			77			(58		)
	CMOs issued by FHLMC	29,482			29,799			339			(22		)		31,238			31,260			109			(87		)
	CMOs issued by GNMA	15,933			16,231			308			(10		)		17,573			17,855			298			(16		)
	Debentures of government- sponsored agencies	26,154			26,174			119			(99		)		14,694			14,557			95			(232		)
	Privately issued CMOs	5,353			5,493			142			(2		)		7,137			7,294			172			(15		)
	Obligations of state and	15,596			15,850			256			(2		)		15,733			15,880			155			(8		)
	political subdivisions
	Corporate bonds	4,939			5,021			82			—				4,936			4,998			66			(4		)
	Total available-for-sale	201,568			204,680			3,285			(173		)		199,045			200,848			2,234			(431		)
	Total investment securities	$	309,044		$	314,465		$	5,610		$	(189	)		$	315,482		$	319,491		$	4,505		$	(496	)
	The amortized cost and fair value of investment debt securities by contractual maturity at March 31, 2015 are shown below. Expected maturities will differ from contractual maturities because the issuers of the securities may have the right to call or prepay obligations with or without call or prepayment penalties.
		March 31, 2015																31-Dec-14
		Held-to-Maturity								Available-for-Sale								Held-to-Maturity								Available-for-Sale
	(in thousands; 2015 unaudited)	Amortized Cost				Fair Value				Amortized Cost				Fair Value				Amortized Cost				Fair Value				Amortized Cost		Fair Value
	Within one year	$	36,925			$	37,015			$	5,769			$	5,816			$	39,778			$	39,913			$	2,378	$	2,388
	After one year but within five years	44,701				45,804				50,411				50,686				50,983				51,953				43,866		43,919
	After five years through ten years	12,216				12,871				9,312				9,471				11,679				12,426				9,644		9,749
	After ten years	13,634				14,095				136,076				138,707				13,997				14,351				143,157		144,792
	Total	$	107,476			$	109,785			$	201,568			$	204,680			$	116,437			$	118,643			$	199,045	$	200,848
	We sold two available-for-sale securities in 2015 with total proceeds of $1.6 million and realized a gross gain of $8 thousand.
	We sold one available-for-sale and three held-to-maturity securities in the first quarter of 2014 with total proceeds of $2.0 million and $725 thousand, respectively, and incurred a loss of $15 thousand and a gross gain of $7 thousand, respectively. The sales of the held-to-maturity securities were due to evidence of significant deterioration in issuer creditworthiness since purchase.
	Investment securities carried at $69.2 million and $74.7 million at March 31, 2015 and December 31, 2014, respectively, were pledged to the State of California: $68.4 million and $73.8 million to secure public deposits in compliance with the Local Agency Security Program at March 31, 2015 and December 31, 2014, respectively, and $852 thousand and $856 thousand to provide collateral for trust deposits at March 31, 2015 and December 31, 2014, respectively. In addition, investment securities carried at $1.1 million were pledged to collateralize an internal Wealth Management and Trust Services (“WMTS”) checking account at both March 31, 2015 and December 31, 2014.
	Other-Than-Temporarily Impaired Debt Securities
	We have evaluated the credit of our investment securities and their issuer and/or insurers. Based on our evaluation, Management has determined that no investment security in our investment portfolio is other-than-temporarily impaired as of March 31, 2015. We do not have the intent, and it is more likely than not that we will not have to sell securities temporarily impaired at March 31, 2015 before recovery of the cost basis.
	Twelve and twenty-eight investment securities were in unrealized loss positions at March 31, 2015 and December 31, 2014, respectively. Those securities are summarized and classified according to the duration of the loss period in the table below:
	March 31, 2015		< 12 continuous months								> 12 continuous months								Total securities
																			in a loss position
	(in thousands; unaudited)		Fair value				Unrealized loss				Fair value				Unrealized loss				Fair value				Unrealized loss
	Held-to-maturity
	Obligations of state & political subdivisions		$	2,556			$	(3	)		361				(10		)		$	2,917			$	(13	)
	Corporate bonds		1,997				(3		)		—				—				1,997				(3		)
	Total held-to-maturity		4,553				(6		)		361				(10		)		4,914				(16		)
	Available-for-sale
	CMOs issued by FNMA		—				—				3,918				(38		)		3,918				(38		)
	CMOs issued by FHLMC		—				—				2,232				(22		)		2,232				(22		)
	CMOs issued by GNMA		3,074				(10		)		—				—				3,074				(10		)
	Debentures of government- sponsored agencies		—				—				9,901				(99		)		9,901				(99		)
	Privately issued CMOs		458				(2		)		—				—				458				(2		)
	Obligations of state & political subdivisions		—				—				588				(2		)		588				(2		)
	Total available-for-sale		3,532				(12		)		16,639				(161		)		20,171				(173		)
	Total temporarily impaired securities		$	8,085			$	(18	)		$	17,000			$	(171	)		$	25,085			$	(189	)
	31-Dec-14		< 12 continuous months								> 12 continuous months								Total securities
																			in a loss position
	(dollars in thousands)		Fair value				Unrealized loss				Fair value				Unrealized loss				Fair value				Unrealized loss
	Held-to-maturity
	Obligations of state & political subdivisions		$	5,830			$	(27	)		$	359			$	(13	)		$	6,189			$	(40	)
	Corporate bonds		3,009				(1		)		3,533				(24		)		6,542				(25		)
	Total held-to-maturity		8,839				(28		)		3,892				(37		)		12,731				(65		)
	Available-for-sale
	MBS pass-through securities issued by FNMA and FHLMC		1,960				(11		)		—				—				1,960				(11		)
CMOs issued by FNMA		—				—				4,115				(58		)		4,115				(58		)
CMOs issued by FHLMC		17,157				(44		)		2,291				(43		)		19,448				(87		)
CMOs issued by GNMA		3,262				(16		)		—				—				3,262				(16		)
Debentures of government- sponsored agencies		494				(1		)		9,769				(231		)		10,263				(232		)
Privately issued CMOs		817				(15		)		—				—				817				(15		)
Obligations of state & political subdivisions		2,695				(3		)		1,112				(5		)		3,807				(8		)
Corporate bonds		1,002				(1		)		990				(3		)		1,992				(4		)
Total available-for-sale		27,387				(91		)		18,277				(340		)		45,664				(431		)
Total temporarily impaired securities		$	36,226			$	(119	)		$	22,169			$	(377	)		$	58,395			$	(496	)
As of March 31, 2015, there were six investment positions that had been in a continuous loss position for more than twelve months. These securities consisted of a government-sponsored agency debenture, obligations of U.S. state and political subdivisions, and CMOs. We have evaluated each of the bonds and believe that the decline in fair value is primarily driven by factors other than credit. It is probable that we will be able to collect all amounts due according to the contractual terms and no other-than-temporary impairment exists on these securities. The CMOs issued by FNMA and FHLMC are supported by the U.S. Federal Government to protect us from credit losses. Additionally, the obligations of state and political subdivisions were deemed creditworthy based on our review of the issuers' recent financial information and their insurers, if any. Based upon our assessment of the credit fundamentals and the credit enhancements, we concluded that these securities were not other-than-temporarily impaired at March 31, 2015.
Six investment securities in our portfolio were in a temporary loss position for less than twelve months as of March 31, 2015. They consisted of a U.S. Agency CMO, obligations of U.S. state and political subdivisions, a corporate bond and privately issued CMOs. We determine that the strengths of GNMA through the U.S. Federal Government guarantee is sufficient to protect us from credit losses. Other temporarily impaired securities are deemed creditworthy after internal analysis. Additionally, all are rated as investment grade by at least one major rating agency. As a result of this impairment analysis, we concluded that these securities were not other-than-temporarily impaired at March 31, 2015.
Non-Marketable Securities
As a member of the FHLB, we are required to maintain a minimum investment in the FHLB capital stock determined by the Board of Directors of the FHLB. The minimum investment requirements can increase in the event we increase our total asset size or borrowings with the FHLB. Shares cannot be purchased or sold except between the FHLB and its members at its $100 per share par value. We held $8.2 million of FHLB stock recorded at cost in other assets on the consolidated statements of condition at both March 31, 2015 and December 31, 2014. The carrying amounts of these investments are reasonable estimates of fair value because the securities are restricted to member banks and they do not have a readily determinable market value. Management does not believe that the FHLB stock is other-than-temporarily-impaired, as we expect to be able to redeem this stock at cost. On April 29, 2015, the FHLB distributed a cash dividend for the first quarter of 2015 at an annualized dividend rate of 7.67%.
As a member bank of Visa U.S.A., we hold 16,939 shares of Visa Inc. Class B common stock with a carrying value of zero, which is equal to our cost basis. These shares are restricted from resale until their conversion into Class A (voting) shares upon the termination of Visa Inc.'s covered litigation escrow account. As a result of the restriction, these shares are not considered available-for-sale and are not carried at fair value. On January 28, 2015, Visa's Board of Directors approved a 4-for-1 split of Visa's Class A common stock. As Class B holders, the conversion rate was adjusted to 1.6483 when converting this Class B common stock to Class A common stock, the value would be $1.8 million at both March 31, 2015 and December 31, 2014. The conversion rate is subject to further reduction upon the final settlement of the covered litigation against Visa Inc. and its member banks. See Note 8 herein.
We invest in low income housing tax credit funds as a limited partner, which totaled $2.8 million and $1.8 million recorded in other assets as of March 31, 2015 and December 31, 2014, respectively. In the first three months of 2015, we recognized $72 thousand of low income housing tax credits and other tax benefits, net of $56 thousand of amortization expense of low income housing tax credit investment, as a component of income tax benefit. As of March 31, 2015, our unfunded commitments for these low income housing tax credit funds totaled $2.2 million. We did not recognize any impairment losses on these low income housing tax credit investments during the first three months of 2015, or the year ended December 31, 2014.

Loans_and_Allowance_for_Loan_L

Loans and Allowance for Loan Losses	3 Months Ended
	Mar. 31, 2015
Receivables [Abstract]
Loans and Allowance for Loan Losses	Loans and Allowance for Loan Losses
	Credit Quality of Loans
	Outstanding loans by class and payment aging as of March 31, 2015 and December 31, 2014 are as follows:
	Loan Aging Analysis by Class as of March 31, 2015 and December 31, 2014
	(dollars in thousands; 2015 unaudited)	Commercial and industrial				Commercial real estate, owner-occupied				Commercial real estate, investor				Construction				Home equity				Other residential 1				Installment and other consumer				Total
	31-Mar-15
	30-59 days past due	$	13			$	—			$	—			$	—			$	295			$	161			$	184			$	653
	60-89 days past due	296				—				—				—				—				—				—				296
	Greater than 90 days past due (non-accrual) 2	373				1,403				2,354				5,107				166				—				79				9,482
	Total past due	682				1,403				2,354				5,107				461				161				263				10,431
	Current	195,760				233,934				651,494				51,943				112,816				73,214				16,892				1,336,053
	Total loans 3	$	196,442			$	235,337			$	653,848			$	57,050			$	113,277			$	73,375			$	17,155			$	1,346,484
	Non-accrual loans to total loans	0.2		%		0.6		%		0.4		%		9		%		0.1		%		—		%		0.5		%		0.7		%
	December 31, 2014
	30-59 days past due	$	183			$	—			$	—			$	—			$	646			$	—			$	180			$	1,009
	60-89 days past due	—				—				—				—				—				—				—				—
	Greater than 90 days past due (non-accrual) 2	—				1,403				2,429				5,134				280				—				104				9,350
	Total past due	183				1,403				2,429				5,134				926				—				284				10,359
	Current	210,040				229,202				671,070				43,279				109,862				73,035				16,504				1,352,992
	Total loans 3	$	210,223			$	230,605			$	673,499			$	48,413			$	110,788			$	73,035			$	16,788			$	1,363,351
	Non-accrual loans to total loans	—		%		0.6		%		0.4		%		10.6		%		0.3		%		—		%		0.6		%		0.7		%
	1 Our residential loan portfolio does not include sub-prime loans, nor is it our practice to underwrite loans commonly referred to as "Alt-A mortgages", the characteristics of which are loans lacking full documentation, borrowers having low FICO scores or higher loan-to-value ratios.
	2 Amounts include $1.4 million of Purchased Credit Impaired ("PCI") loans that have stopped accreting interest at both March 31, 2015 and December 31, 2014. Amounts exclude accreting PCI loans of $3.7 million and $3.8 million at March 31, 2015 and December 31, 2014, respectively, as we have a reasonable expectation about future cash flows to be collected and we continue to recognize accretable yield on these loans in interest income. There were no accruing loans past due more than ninety days at March 31, 2015 or December 31, 2014.
	3 Amounts include net deferred loan costs of $651 thousand and $487 thousand at March 31, 2015 and December 31, 2014, respectively. Amounts are also net of unaccreted purchase discounts on non-PCI loans of $4.2 million and $4.4 million at March 31, 2015 and December 31, 2014, respectively.
	Our commercial loans are generally made to established small and mid-sized businesses to provide financing for their working capital needs, equipment purchases, acquisitions, or refinancings.  Management examines historical, current, and projected cash flows to determine the ability of the borrower to repay obligations as agreed. Commercial loans are made based primarily on the identified cash flows of the borrower and secondarily on the underlying collateral or guarantor support. The cash flows of borrowers, however, may not occur as expected, and the collateral securing these loans may fluctuate in value. Most commercial and industrial loans are secured by the assets being financed, such as accounts receivable or inventory, and include a personal guarantee. Some short-term loans may be made on an unsecured basis. We target stable local businesses with guarantors that have proven to be more resilient in periods of economic stress.  Typically, the guarantors provide an additional source of repayment for most of our credit extensions.
	Commercial real estate loans are subject to underwriting standards and processes similar to commercial loans discussed above. We underwrite these loans to be repaid from cash flow and to be supported by real property collateral. Repayment of commercial real estate loans is largely dependent on the successful operation of the property securing the loan, or of the business conducted on the property securing the loan. Underwriting standards for commercial real estate loans include, but are not limited to, conservative debt coverage and loan-to-value ratios. Furthermore, substantially all of our loans are guaranteed by the owners of the properties.  Commercial real estate loans may be adversely affected by conditions in the real estate markets or in the general economy. In the event of a vacancy, strong guarantors have historically carried the loans until a replacement tenant could be found.  The owner's substantial equity investment provides a strong economic incentive to continue to support the commercial real estate projects. As such, we have generally experienced a relatively low level of loss and delinquencies in this portfolio.
	Construction loans are generally made to developers and builders to finance construction, renovation and occasionally land acquisitions. These loans are underwritten after evaluation of the borrower's financial strength, reputation, prior track record, and independent appraisals. The construction industry can be impacted by significant events, including: the inherent volatility of real estate markets and vulnerability to delays due to weather, change orders, inability to obtain construction permits, labor or material shortages, and price changes. Estimates of construction costs and value associated with the complete project may be inaccurate. Repayment of construction loans is largely dependent on the ultimate success of the project.
	Consumer loans primarily consist of home equity lines of credit, other residential (tenancy-in-common, or “TIC”) loans, and installment and other consumer loans. We originate consumer loans utilizing credit score information, debt-to-income ratio and loan-to-value ratio analysis. Diversification, coupled with relatively small loan amounts that are spread across many individual borrowers, mitigates risk. Additionally, trend reports are reviewed by Management on a regular basis. Underwriting standards for home equity lines of credit include, but are not limited to, a conservative loan-to-value ratio, the number of such loans a borrower can have at one time, and documentation requirements. Our residential loan portfolio includes TIC units in San Francisco. These loans tend to have more equity in their properties than conventional residential mortgages, which mitigates risk. Installment and other consumer loans include mostly floating home loans and mobile home loans along with a small number of installment loans.
	We use a risk rating system to evaluate asset quality, and to identify and monitor credit risk in individual loans, and ultimately in the portfolio. Definitions of loans that are risk graded “Special Mention” or worse are consistent with those used by the Federal Deposit Insurance Corporation ("FDIC").  Our internally assigned grades are as follows:
	Pass – Loans to borrowers of acceptable or better credit quality. Borrowers in this category demonstrate fundamentally sound financial positions, repayment capacity, credit history and management expertise.  Loans in this category must have an identifiable and stable source of repayment and meet the Bank’s policy regarding debt service coverage ratios.  These borrowers are capable of sustaining normal economic, market or operational setbacks without significant financial impacts.  Negative external industry factors are generally not present.  The loan may be secured, unsecured or supported by non-real estate collateral for which the value is more difficult to determine and/or marketability is more uncertain. This category also includes “Watch” loans, where the primary source of repayment has been delayed. “Watch” is intended to be a transitional grade, with either an upgrade or downgrade within a reasonable period.
	Special Mention - Potential weaknesses that deserve close attention. If left uncorrected, those potential weaknesses may result in deterioration of the payment prospects for the asset. Special Mention assets do not present sufficient risk to warrant adverse classification.
	Substandard - Inadequately protected by either the current sound worth and paying capacity of the obligor or the collateral pledged, if any. A Substandard asset has a well-defined weakness or weaknesses that jeopardize(s) the liquidation of the debt. Substandard assets are characterized by the distinct possibility that we will sustain some loss if such weaknesses or deficiencies are not corrected. Well-defined weaknesses include adverse trends or developments of the borrower’s financial condition, managerial weaknesses and/or significant collateral deficiencies.
	Doubtful - Critical weaknesses that make collection or liquidation in full improbable. There may be specific pending events that work to strengthen the asset; however, the amount or timing of the loss may not be determinable. Pending events generally occur within one year of the asset being classified as Doubtful. Examples include: merger, acquisition, or liquidation; capital injection; guarantee; perfecting liens on additional collateral; and refinancing. Such loans are placed on nonaccrual status and usually are collateral-dependent.
	We regularly review our credits for accuracy of risk grades whenever new information is received. Borrowers are required to submit financial information at regular intervals:
	•	Generally, commercial borrowers with lines of credit are required to submit financial information with reporting intervals ranging from monthly to annually depending on credit size, risk and complexity.
	•	Investor commercial real estate borrowers are generally required to submit rent rolls or property income statements at least annually.
	•	Construction loans are monitored monthly, and reviewed on an ongoing basis.
	•	Home equity and other consumer loans are reviewed based on delinquency.
	•	Loans graded “Watch” or more severe, regardless of loan type, are reviewed no less than quarterly.
	The following table represents an analysis of loans by internally assigned grades, including the PCI loans, at March 31, 2015 and December 31, 2014:
	(in thousands; 2015 unaudited)	Commercial and industrial				Commercial real estate, owner-occupied				Commercial real estate, investor				Construction				Home equity				Other residential				Installment and other consumer				Purchased credit-impaired			Total
	Credit Risk Profile by Internally Assigned Grade:
	31-Mar-15
	Pass	$	181,842			$	211,551			$	640,656			$	50,305			$	111,227			$	71,768			$	16,816			$	2,202		$	1,286,367
	Special Mention	9,424				10,281				3,853				1,078				321				—				—				1,031			25,988
	Substandard	4,974				10,876				7,175				5,657				1,662				1,607				339				1,839			34,129
	Total loans	$	196,240			$	232,708			$	651,684			$	57,040			$	113,210			$	73,375			$	17,155			$	5,072		$	1,346,484
	December 31, 2014
	Pass	$	197,659			$	205,820			$	651,548			$	41,710			$	107,933			$	70,987			$	16,101			$	2,210		$	1,293,968
	Special Mention	6,776				10,406				13,304				1,008				322				—				190				1,140			33,146
	Substandard	5,464				11,763				6,473				5,684				2,466				2,048				497				1,842			36,237
	Total loans	$	209,899			$	227,989			$	671,325			$	48,402			$	110,721			$	73,035			$	16,788			$	5,192		$	1,363,351
	Troubled Debt Restructuring
	Our loan portfolio includes certain loans that have been modified in a Troubled Debt Restructuring (“TDR”), where economic concessions have been granted to borrowers experiencing financial difficulties. These concessions typically result from our loss mitigation activities and could include reductions in the interest rate, payment extensions, forgiveness of principal, forbearance or other actions. TDRs on nonaccrual status at the time of restructure may be returned to accruing status after considering the borrower’s sustained repayment performance for a reasonable period, generally six months, and there is reasonable assurance of repayment and performance.
	When a loan is modified, Management evaluates any possible impairment based on the present value of expected future cash flows, discounted at the contractual interest rate of the original loan agreement, except when the sole (remaining) source of repayment for the loan is the operation or liquidation of the collateral. In these cases Management uses the current fair value of the collateral, less selling costs, instead of discounted cash flows. If Management determines that the value of the modified loan is less than the recorded investment in the loan (net of previous charge-offs and unamortized premium or discount), impairment is recognized through a specific allowance or a charge-off of the loan.
	A loan may no longer be reported as a TDR if it is subsequently refinanced or restructured at market terms through the normal underwriting process, the borrower is no longer considered to be in financial difficulty and performance on the loan is reasonably assured. The removal of TDR status must be approved by the same management level that approved the upgrading of the loan classification. During the first quarter of 2015, a loan with a recorded investment of $108 thousand was removed from TDR designation. There were no loans removed from TDR designation during 2014.
	The table below summarizes outstanding TDR loans by loan class as of March 31, 2015 and December 31, 2014. The summary includes both TDRs that are on non-accrual status and those that continue to accrue interest.
	(in thousands; 2015 unaudited)		As of
	Recorded investment in Troubled Debt Restructurings 1		March 31, 2015				December 31, 2014
	Commercial and industrial		$	3,477			$	3,584
	Commercial real estate, owner-occupied		8,427				8,459
	Commercial real estate, investor		522				524
	Construction		5,657				5,684
	Home equity		561				694
Other residential		2,037				2,045
Installment and other consumer		1,636				1,713
Total		$	22,317			$	22,703
1 Includes $15.6 million and $15.9 million of TDR loans that were accruing interest as of March 31, 2015 and December 31, 2014, respectively. Includes $1.6 million and $1.8 million of acquired loans at March 31, 2015 and December 31, 2014, respectively.
The table below presents the following information for loans modified in a TDR during the quarter ended March 31, 2014: number of contracts modified, the recorded investment in the loans prior to modification, and the recorded investment in the loans after the loans were restructured. The table below excludes fully paid-off and fully charged-off TDR loans. There were no loans modified in a TDR during 2015.
(dollars in thousands; unaudited)	Number of Contracts Modified			Pre-Modification Outstanding Recorded Investment				Post-Modification Outstanding Recorded Investment				Post-Modification Outstanding Recorded Investment at period end
Troubled Debt Restructurings during the three months ended March 31, 2014:
Commercial and industrial	3			$	1,420			$	1,405			$	1,405
Home equity	1			150				150				150
Installment and other consumer	3			170				168				169
Total	7			$	1,740			$	1,723			$	1,724
Modifications during the three months ended March 31, 2014 primarily involved maturity extensions and interest rate concessions. During the first three months of 2015 and 2014, there were no defaults on loans that had been modified in a TDR within the prior twelve-month period. We report defaulted TDRs based on a payment default definition of more than ninety days past due.
Impaired Loan Balances and Their Related Allowance by Major Classes of Loans
The tables below summarize information on impaired loans and their related allowance. Total impaired loans include non-accrual loans, accruing TDR loans and accreting PCI loans that have experienced post-acquisition declines in cash flows expected to be collected.
(in thousands; unaudited)		Commercial and industrial				Commercial real estate, owner-occupied				Commercial real estate, investor				Construction				Home equity				Other residential				Installment and other consumer				Total
31-Mar-15
Recorded investment in impaired loans:
With no specific allowance recorded		$	1,318			$	5,545			$	2,875			$	5,107			$	263			$	1,024			$	295			$	16,427
With a specific allowance recorded		2,533				2,882				—				560				298				1,012				1,398				8,683
Total recorded investment in impaired loans		$	3,851			$	8,427			$	2,875			$	5,667			$	561			$	2,036			$	1,693			$	25,110
Unpaid principal balance of impaired loans:
With no specific allowance recorded		$	1,315			$	6,545			$	4,867			$	7,797			$	263			$	1,024			$	295			$	22,106
With a specific allowance recorded		2,604				2,882				—				745				298				1,012				1,398				8,939
Total unpaid principal balance of impaired loans		$	3,919			$	9,427			$	4,867			$	8,542			$	561			$	2,036			$	1,693			$	31,045
Specific allowance		$	652			$	32			$	—			$	3			$	1			$	85			$	188			$	961
Average recorded investment in impaired loans during the quarter ended March 31, 2015		$	3,718			$	8,443			$	2,915			$	5,681			$	627			$	2,041			$	1,743			$	25,168
Interest income recognized on impaired loans during the quarter ended March 31, 2015		$	62			$	66			$	6			$	9			$	5			$	23			$	19			$	190
Average recorded investment in impaired loans during the quarter ended March 31, 2014		$	5,945			$	5,484			$	3,283			$	6,524			$	577			$	2,054			$	1,884			$	25,751
Interest income recognized on impaired loans during the quarter ended March 31, 2014		$	118			$	83			$	7			$	21			$	4			$	23			$	18			$	274
(in thousands)		Commercial and industrial				Commercial real estate, owner-occupied				Commercial real estate, investor				Construction				Home equity				Other residential				Installment and other consumer				Total
31-Dec-14
Recorded investment in impaired loans:
With no specific allowance recorded		$	1,141			$	5,577			$	2,954			$	5,134			$	393			$	1,026			$	239			$	16,464
With a specific allowance recorded		2,443				2,882				—				561				300				1,019				1,554				$	8,759
Total recorded investment in impaired loans		$	3,584			$	8,459			$	2,954			$	5,695			$	693			$	2,045			$	1,793			$	25,223
Unpaid principal balance of impaired loans:
With no specific allowance recorded		$	1,186			$	6,577			$	4,945			$	7,824			$	880			$	1,026			$	239			$	22,677
With a specific allowance recorded		2,524				2,882				—				749				300				1,019				1,554				9,028
Total recorded investment in impaired loans		$	3,710			$	9,459			$	4,945			$	8,573			$	1,180			$	2,045			$	1,793			$	31,705
Specific allowance		$	694			$	65			$	—			$	3			$	—			$	92			$	284			$	1,138
Average recorded investment in impaired loans during 2014		5,354				6,604				3,138				6,471				741				1,744				1,857				25,909
Interest income recognized on impaired loans during 2014		378				288				28				85				19				74				76				948
The gross interest income that would have been recorded, had non-accrual loans been current, totaled $231 thousand and $205 thousand in the quarters ended March 31, 2015, and March 31, 2014, respectively. PCI loans are excluded from the foregone interest data above as their accretable yield interest recognition is independent from the underlying contractual loan delinquency status. See “Purchased Credit-Impaired Loans” below for further discussion.
Management monitors delinquent loans continuously and identifies problem loans, generally loans graded substandard or worse, to be evaluated individually for impairment testing. Generally, we charge off our estimated losses related to specifically-identified impaired loans when it is deemed uncollectible. The charged-off portion of impaired loans outstanding at March 31, 2015 totaled approximately $5.4 million.  At March 31, 2015, there were $1.2 million outstanding commitments to extend credit on impaired loans, including loans to borrowers whose terms have been modified in TDRs.
The following tables disclose loans by major portfolio category and activity in the ALLL, as well as the related ALLL disaggregated by impairment evaluation method.
Allowance for Loan Losses Rollforward for the Period
(in thousands; unaudited)		Commercial and industrial				Commercial real estate, owner-occupied				Commercial real estate, investor				Construction				Home equity				Other residential				Installment and other consumer				Unallocated			Total
For the three months ended March 31, 2015
Allowance for loan losses:
Beginning balance		$	2,837			$	1,924			$	6,672			$	839			$	859			$	433			$	566			$	969		$	15,099
Provision (reversal)		(275		)		170				(383		)		(61		)		63				(3		)		(99		)		588			—
Charge-offs		(2		)		—				—				—				—				—				(6		)		—			(8		)
Recoveries		60				—				3				—				1				—				1				—			65
Ending balance		$	2,620			$	2,094			$	6,292			$	778			$	923			$	430			$	462			$	1,557		$	15,156
For the three months ended March 31, 2014
Allowance for loan losses:
Beginning balance		$	3,056			$	2,012			$	6,196			$	633			$	875			$	317			$	629			$	506		$	14,224
Provision (reversal)		(255		)		(27		)		268				100				11				92				(142		)		103			150
Charge-offs		(61		)		—				—				(197		)		—				—				(3		)		—			(261		)
Recoveries		32				—				5				—				1				—				81				—			119
Ending balance		$	2,772			$	1,985			$	6,469			$	536			$	887			$	409			$	565			$	609		$	14,232
Allowance for Loan Losses and Recorded Investment in Loans
(dollars in thousands; unaudited)		Commercial and industrial				Commercial real estate, owner-occupied				Commercial real estate, investor				Construction				Home equity				Other residential				Installment and other consumer				Unallocated			Total
As of March 31, 2015:
Ending ALLL related to loans collectively evaluated for impairment		$	1,968			$	2,062			$	6,292			$	775			$	922			$	345			$	274			$	1,557		$	14,195
Ending ALLL related to loans  individually evaluated for impairment		$	648			$	32			$	—			$	—			$	1			$	85			$	188			$	—		$	954
Ending ALLL related to purchased  credit-impaired loans		$	4			$	—			$	—			$	3			$	—			$	—			$	—			$	—		$	7
Loans outstanding:
Collectively evaluated for impairment		$	192,557			$	225,684			$	648,809			$	51,383			$	112,649			$	71,339			$	15,462			$	—		$	1,317,883
Individually evaluated for impairment1		3,683				7,024				2,875				5,657				561				2,036				1,693				—			23,529
Purchased credit-impaired		202				2,629				2,164				10				67				—				—				—			5,072
Total		$	196,442			$	235,337			$	653,848			$	57,050			$	113,277			$	73,375			$	17,155			$	—		$	1,346,484
Ratio of allowance for loan losses to total loans		1.33		%		0.89		%		0.96		%		1.36		%		0.81		%		0.59		%		2.69		%		NM			1.13		%
Allowance for loan losses to non-accrual loans		702		%		149		%		267		%		15		%		556		%		NM				585		%		NM			160		%
1 Total excludes $1.6 million of PCI loans that have experienced post-acquisition declines in cash flows expected to be collected. These loans are included in the "purchased credit-impaired" amount in the next line below.
NM - Not Meaningful
Allowance for Loan Losses and Recorded Investment in Loans
(dollars in thousands)		Commercial and industrial				Commercial real estate, owner-occupied				Commercial real estate, investor				Construction				Home equity				Other residential				Installment and other consumer				Unallocated			Total
As of December 31, 2014:
Ending ALLL related to loans collectively evaluated for impairment		$	2,143			$	1,859			$	6,672			$	836			$	859			$	341			$	282			$	969		$	13,961
Ending ALLL related to loans  individually evaluated for impairment		$	690			$	65			$	—			$	—			$	—			$	92			$	284			$	—		$	1,131
Ending ALLL related to purchased  credit-impaired loans		$	4			$	—			$	—			$	3			$	—			$	—			$	—			$	—		$	7
Loans outstanding:
Collectively evaluated for impairment		$	206,603			$	220,933			$	668,371			$	42,718			$	110,028			$	70,990			$	14,995			$	—		$	1,334,638
Individually evaluated for impairment1		3,296				7,056				2,954				5,684				693				2,045				1,793				—			23,521
Purchased credit-impaired		324				2,616				2,174				11				67				—				—				—			5,192
Total		$	210,223			$	230,605			$	673,499			$	48,413			$	110,788			$	73,035			$	16,788			$	—		$	1,363,351
Ratio of allowance for loan losses to total loans		1.35		%		0.83		%		0.99		%		1.73		%		0.78		%		0.59		%		3.37		%		NM			1.11		%
Allowance for loan losses to non-accrual loans		NM				137		%		275		%		16		%		307		%		NM				544		%		NM			161		%
1 Total excludes $1.7 million PCI loans that have experienced credit deterioration post-acquisition, which are included in the "purchased credit-impaired" amount in the next line below.
NM - Not Meaningful
Purchased Credit-Impaired Loans
We evaluated loans purchased in acquisitions in accordance with accounting guidance in ASC 310-30 related to loans acquired with deteriorated credit quality. Acquired loans are considered credit-impaired if there is evidence of deterioration of credit quality since origination and it is probable, at the acquisition date, that we will be unable to collect all contractually required payments receivable. Management has determined certain loans purchased in our two acquisitions to be PCI loans based on credit indicators such as nonaccrual status, past due status, loan risk grade, loan-to-value ratio, etc. Revolving credit agreements (e.g., home equity lines of credit and revolving commercial loans) are not considered PCI loans as cash flows cannot be reasonably estimated.
The following table reflects the outstanding balance and related carrying value of PCI loans as of March 31, 2015 and December 31, 2014.
	31-Mar-15								31-Dec-14
PCI Loans	Unpaid principal balance				Carrying value				Unpaid principal balance				Carrying value
(in thousands; 2015 unaudited)
Commercial and industrial	$	301			$	202			$	479			$	324
Commercial real estate	6,806				4,793				6,831				4,790
Construction	132				10				136				11
Home equity	230				67				232				67
Total purchased credit-impaired loans	$	7,469			$	5,072			$	7,678			$	5,192
The activities in the accretable yield, or income expected to be earned, for PCI loans were as follows:
Accretable Yield	Three months ended
(dollars in thousands, unaudited)	March 31, 2015				March 31, 2014
Balance at beginning of period	$	4,027			$	3,649
Removals 1	(77		)		—
Accretion	(119		)		(180		)
Reclassifications from nonaccretable difference 2	—				1,832
Balance at end of period	$	3,831			$	5,301
1 Represents the accretable difference that is relieved when a loan exits the PCI population due to payoff, full charge-off, or transfer to repossessed assets, etc.
2 Primarily relates to changes in expected credit performance and changes in expected timing of cash flows.
Pledged Loans
Our FHLB line of credit is secured under terms of a blanket collateral agreement by a pledge of certain qualifying loans with an unpaid principal balance of $863.6 million and $868.1 million at March 31, 2015 and December 31, 2014, respectively. Our FHLB line of credit totaled $446.7 million and $450.6 million at March 31, 2015 and December 31, 2014, respectively. In addition, we pledge a certain residential loan portfolio, which totaled $30.9 million and $27.7 million at March 31, 2015 and December 31, 2014, respectively, to secure our borrowing capacity with the Federal Reserve Bank (“FRB”). Also see Note 6 below.

Borrowings

Borrowings	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Borrowings	Borrowings
	Federal Funds Purchased – We had unsecured lines of credit totaling $72.0 million with correspondent banks for overnight borrowings at March 31, 2015 and December 31, 2014.  In general, interest rates on these lines approximate the federal funds target rate. At March 31, 2015 and December 31, 2014, we had no overnight borrowings outstanding under these credit facilities.
	Federal Home Loan Bank Borrowings – As of March 31, 2015 and December 31, 2014, we had lines of credit with the FHLB totaling $446.7 million and $450.6 million, respectively, based on eligible collateral of certain loans.  At March 31, 2015 and December 31, 2014, we had no FHLB overnight borrowings.
	On February 5, 2008, we entered into a ten-year borrowing agreement under the same FHLB line of credit for $15.0 million at a fixed rate of 2.07%, which remained outstanding at March 31, 2015. Interest-only payments are required every three months until the entire principal is due on February 5, 2018. The FHLB has the unconditional right to accelerate the due date on May 5, 2015 and every three months thereafter (the “put dates”). If the FHLB exercises its right to accelerate the due date, the FHLB will offer replacement funding at the current market rate, subject to certain conditions. We must comply with the put date, but are not required to accept replacement funding.
	At March 31, 2015, $431.5 million was remaining as available for borrowing from the FHLB, net of the term borrowing and letters of credit acquired from NorCal totaling $241 thousand.
	Federal Reserve Line of Credit – We have a line of credit with the FRB secured by certain residential loans.  At March 31, 2015 and December 31, 2014, we had borrowing capacity under this line totaling $30.9 million and $27.7 million, respectively, and had no outstanding borrowings with the FRB.
	As part of the Acquisition, we assumed two subordinated debentures due to NorCal Community Bancorp Trusts I and II (the "Trusts"), established for the sole purpose of issuing trust preferred securities on September 22, 2003 and December 29, 2005, respectively. The subordinated debentures were recorded at fair values totaling $4.95 million at acquisition date with contractual values totaling $8.2 million. The difference between the contractual balance and the fair value at acquisition date is accreted into interest expense over the lives of the debentures. Accretion on the subordinated debentures totaled $53 thousand in the first three months of 2015 and $54 thousand in the first three months of 2014. We have the option to defer payment of the interest on the subordinated debentures for a period of up to five years, as long as there is no default on the subordinated debentures. In the event of interest deferral, dividends to Bank of Marin Bancorp common stockholders are prohibited. The trust preferred securities were sold and issued in private transactions pursuant to an exemption from registration under the Securities Act of 1933, as amended. Bancorp has guaranteed, on a subordinated basis, distributions and other payments due on trust preferred securities totaling $8.0 million issued by the Trusts which have identical maturity, repricing and payment terms as the subordinated debentures.
	The following is a summary of the contractual terms of the subordinated debentures due to the Trusts as of March 31, 2015:
	(in thousands; unaudited)
	Subordinated debentures due to NorCal Community Bancorp Trust I on October 7, 2033 with interest payable quarterly, based on 3-month LIBOR plus 3.05%, repricing quarterly (3.30% as of March 31, 2015), redeemable, in whole or in part, on any interest payment date	$	4,124
	Subordinated debentures due to NorCal Community Bancorp Trust II on March 15, 2036 with interest payable quarterly, based on 3-month LIBOR plus 1.40%, repricing quarterly (1.67% as of March 31, 2015), redeemable, in whole or in part, on any interest payment date	4,124
	Total	$	8,248

Stockholders_Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Stockholders' Equity	Stockholders' Equity
	Warrant
	Under the United States Department of the Treasury Capital Purchase Program (the “TCPP”), Bancorp issued to the U.S. Treasury a warrant to purchase 154,242 shares of common stock at a per share exercise price of $27.23. The warrant was immediately exercisable and expires on December 5, 2018. The warrant was subsequently auctioned to two institutional investors in November 2011 and remains outstanding. It is adjusted for cash dividend increases to represent a right to purchase 157,198 shares of common stock at $26.72 per share as of March 31, 2015 in accordance with Section 13(c) of the Form of Warrant to Purchase Common Stock.
	Dividends
	Presented below is a summary of cash dividends paid to common shareholders, recorded as a reduction of retained earnings.
		Three months ended
	(in thousands, except per share data; unaudited)	March 31, 2015		March 31, 2014
	Cash dividends to common stockholders	$	1,307	$	1,120
	Cash dividends per common share	$	0.22	$	0.19
	Share-Based Payments
	The fair value of stock options on the grant date is recorded as a stock-based compensation expense in the consolidated statements of comprehensive income over the requisite service period with a corresponding increase in common stock. Stock-based compensation also includes compensation expense related to the issuance of unvested restricted stock awards and performance-based stock awards pursuant to the 2007 Equity Plan. The grant-date fair value of the restricted stock awards and performance-based stock awards, which is equal to its intrinsic value on that date, is being recorded as compensation expense over the requisite service period with a corresponding increase in common stock as the shares vest.
	Starting in 2015, performance-based stock awards were issued to a selected group of employees. Stock award vesting is contingent upon the achievement of pre-established long-term performance goals set by the Compensation Committee of the Board of Directors. Performance is measured over a three-year period and cliff vested. These performance-based stock awards were granted at a maximum opportunity level, and based on the achievement of the pre-established goals, the actual payouts can range from 0% to 200% of the target award. For performance-based stock awards, an estimate is made of the number of shares expected to vest based on the probability that the performance criteria will be achieved to determine the amount of compensation expense to be recognized. The estimate is re-evaluated quarterly and total compensation expense is adjusted for any change in the current period.
	In addition, we record excess tax benefits on the exercise of non-qualified stock options, the disqualifying disposition of incentive stock options and vesting of restricted stock awards as an addition to common stock with a corresponding decrease in current taxes payable.
	The holders of unvested restricted stock awards and performance-based stock awards are entitled to dividends on the same per-share ratio as holders of common stock. Dividends paid on the portion of share-based awards not expected to vest are also included in stock-based compensation expense. Tax benefits on dividends paid on the portion of share-based awards expected to vest are recorded as an increase to common stock with a corresponding decrease in current taxes payable.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies
	Financial Instruments with Off-Balance Sheet Risk
	We make commitments to extend credit in the normal course of business to meet the financing needs of our customers. These financial instruments include commitments to extend credit in the form of loans or through standby letters of credit. Commitments to extend credit are agreements to lend to a customer as long as there is no violation of any condition established in the contract. Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. Since some of the commitments are expected to expire without being fully drawn upon, the total commitment amount does not necessarily represent future cash requirements.
	We are exposed to credit loss equal to the contract amount of the commitment in the event of nonperformance by the borrower. We use the same credit policies in making commitments as we do for on-balance-sheet instruments and we evaluate each customer’s creditworthiness on a case-by-case basis. The amount of collateral obtained, if deemed necessary by us, is based on Management's credit evaluation of the borrower. Collateral held varies, but may include accounts receivable, inventory, property, plant and equipment, and real property.
	The contractual amount of loan commitments and standby letters of credit not reflected on the consolidated statements of condition was $343.7 million at March 31, 2015. This amount included $177.2 million under commercial lines of credit (these commitments are contingent upon customers maintaining specific credit standards), $118.3 million under revolving home equity lines, $34.5 million under undisbursed construction loans, $2.3 million under standby letters of credit, and a remaining $11.4 million under personal and other lines of credit. We record an allowance for losses on these off-balance sheet commitments based on an estimate of probabilities of these commitments being drawn upon according to our historical utilization experience on different types of commitments and expected loss severity. We have set aside an allowance for losses in the amount of $811 thousand and $1.0 million for these commitments as of March 31, 2015 and December 31, 2014, respectively, which is recorded in interest payable and other liabilities on the consolidated statements of condition. A reduction in reserve requirements for off-balance sheet commitments due to the reduced effect of historical charge-offs resulted in the decline in the allowance for losses in the first quarter of 2015.
	Operating Leases
	We rent certain premises and equipment under long-term, non-cancelable operating leases expiring at various dates through the year 2028. Most of the leases contain certain renewal options and escalation clauses. At March 31, 2015, the approximate minimum future commitments payable under non-cancelable contracts for leased premises are as follows:
	(in thousands; unaudited)	2015		2016		2017		2018		2019		Thereafter		Total
	Operating leases	$	2,822	$	3,788	$	3,781	$	3,810	$	3,553	$	6,786	$	24,540
	Litigation Matters
	We may be party to legal actions which arise from time to time as part of the normal course of our business.  We believe, after consultation with legal counsel, that we have meritorious defenses in these actions, and that litigation contingent liability, if any, will not have a material adverse effect on our financial position, results of operations, or cash flows.
	We are responsible for our proportionate share of certain litigation indemnifications provided to Visa U.S.A. ("Visa") by its member banks in connection with lawsuits related to anti-trust charges and interchange fees ("Covered Litigation"). Visa Inc. maintains an escrow account from which settlements of, or judgments in, the covered litigation are paid. According to the latest SEC filing by VISA, Inc. dated April 30, 2015, at March 31, 2015, the balance of escrow account was $1.2 billion. On January 14, 2015, following a Court-approved process to give class members who previously opted out of the damages portion of the class settlement an option to rejoin it, the class administrator submitted a report stating that it had received 1,179 requests by merchants to rejoin the cash settlement class, some of which may include multiple merchants. The conversion rate of Visa Class B common stock held by us to Class A common stock (as discussed in Note 4) may reduce if Visa makes more Covered Litigation settlement payments in the future and the full impact to member banks is still uncertain. However, we are not aware of significant future cash settlement payments required by us on the Covered Litigation.

Derivative_Financial_Instrumen

Derivative Financial Instruments and Hedging Activities	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments and Hedging Activities	Derivative Financial Instruments and Hedging Activities
	We have entered into interest rate swap agreements, primarily as an asset/liability management strategy, in order to mitigate the changes in the fair value of specified long-term fixed-rate loans (or firm commitments to enter into long-term fixed-rate loans) caused by changes in interest rates. These hedges allow us to offer long-term fixed rate loans to customers without assuming the interest rate risk of a long-term asset. Converting our fixed-rate interest payments to floating-rate interest payments, generally benchmarked to the one-month U.S. dollar LIBOR index, protects us against changes in the fair value of our loans associated with fluctuating interest rates.
	The fixed-rate payment features of the interest rate swap agreements are generally structured at inception to mirror substantially all of the provisions of the hedged loan agreements. These interest rate swaps, designated and qualified as fair value hedges, are carried on the consolidated statements of condition at their fair value in other assets (when the fair value is positive) or in other liabilities (when the fair value is negative). One of our interest rate swap agreements qualifies for shortcut hedge accounting treatment. The change in fair value of the swap using the shortcut accounting treatment is recorded in other non-interest income, while the change in fair value of swaps using non-shortcut accounting is recorded in interest income. The unrealized gain or loss in fair value of the hedged fixed-rate loan due to LIBOR interest rate movements is recorded as an adjustment to the hedged loan and offset in other non-interest income (for shortcut accounting treatment) or interest income (for non-shortcut accounting treatment).
	From time to time, we make firm commitments to enter into long-term fixed-rate loans with borrowers backed by yield maintenance agreements and simultaneously enter into forward interest rate swap agreements with correspondent banks to mitigate the change in fair value of the yield maintenance agreement. Prior to loan funding, yield maintenance agreements with net settlement features that meet the definition of a derivative are considered as non-designated hedges and are carried on the consolidated statements of condition at their fair value in other assets (when the fair value is positive) or in other liabilities (when the fair value is negative). The offsetting changes in the fair value of the forward swap and the yield maintenance agreement are recorded in interest income. When the fixed-rate loans are originated, the forward swaps are designated to offset the change in fair value in the loans. Subsequent to the point of the swap designations, the related yield maintenance agreements are no longer considered derivatives. Their fair value at the designation date is recorded in other assets and is amortized using the effective yield method over the life of the respective designated loans.
	The net effect of the change in fair value of interest rate swaps, the amortization of the yield maintenance agreement and the change in the fair value of the hedged loans result in an insignificant amount of hedge ineffectiveness recognized in interest income.
	Our credit exposure, if any, on interest rate swaps is limited to the favorable value (net of any collateral pledged to us) and interest payments of all swaps by each counterparty. Conversely, when an interest rate swap is in a liability position exceeding a certain threshold, we may be required to post collateral to the counterparty in an amount determined by the agreements (generally when our derivative liability position is greater than $100 thousand or $250 thousand, depending upon the counterparty). Collateral levels are monitored and adjusted on a regular basis for changes in interest rate swap values.
	As of March 31, 2015, we have eight interest rate swap agreements, which are scheduled to mature in September 2018, June 2020, August 2020, June 2031, October 2031, July 2032, August 2037 and October 2037. All of our derivatives are accounted for as fair value hedges. Our interest rate swaps are settled monthly with counterparties. Accrued interest on the swaps totaled $40 thousand and $41 thousand as of March 31, 2015 and December 31, 2014, respectively. Information on our derivatives follows:
			Asset derivatives							Liability derivatives
	(in thousands; 2015 unaudited)		March 31, 2015				December 31, 2014			March 31, 2015				31-Dec-14
	Fair value hedges:
	Interest rate contracts notional amount		$	—			$	4,589		$	30,992			$	26,899
	Interest rate contracts fair value1		$	—			$	61		$	2,481			$	1,996
		Three months ended
	(in thousands; unaudited)	March 31, 2015					31-Mar-14
	(Decrease) increase in value of designated interest rate swaps recognized in interest income	$	(546	)			$	736
	Payment on interest rate swaps recorded in interest income	(235		)			(253		)
	Increase (decrease) in value of hedged loans recognized in interest income	571					(531		)
	Decrease in value of yield maintenance agreement recognized against interest income	(14		)			(47		)
	Net loss on derivatives recognized against interest income 2	$	(224	)			$	(95	)
	1 See Note 3 for valuation methodology.
	2 Includes hedge ineffectiveness gain of $11 thousand and gain of $158 thousand for the quarters ended March 31, 2015 and March 31, 2014, respectively. Changes in value of swaps were included in the assessment of hedge effectiveness.
	Our derivative transactions with counterparties are under International Swaps and Derivative Association (“ISDA”) master agreements that include “right of set-off” provisions. “Right of set-off” provisions are legally enforceable rights to offset recognized amounts and there may be an intention to settle such amounts on a net basis. We do not offset such financial instruments for financial reporting purposes.
	Information on financial instruments that are eligible for offset in the consolidated statements of condition follows:
	Offsetting of Financial Assets and Derivative Assets
	(in thousands; 2015 unaudited)									Gross Amounts Not Offset in the Statements of Condition
					Gross Amounts			Net Amounts
		Gross Amounts			Offset in the			of Assets Presented
		of Recognized			Statements of			in the Statements		Financial			Cash Collateral
		Assets1			Condition			of Condition1		Instruments			Received			Net Amount
	As of March 31, 2015
	Derivatives by Counterparty
	Counterparty A	$	—		$	—		$	—	$	—		$	—		$	—
	Counterparty B	—			—			—		—			—			—
	Total	$	—		$	—		$	—	$	—		$	—		$	—
	As of December 31, 2014
	Derivatives by Counterparty
	Counterparty A	$	61		$	—		$	61	$	(61	)	$	—		$	—
	Counterparty B	—			—			—		—			—			—
	Total	$	61		$	—		$	61	$	(61	)	$	—		$	—
	1 Amounts exclude accrued interest totaling zero and $1 thousand at March 31, 2015 and December 31, 2014, respectively.
	Offsetting of Financial Liabilities and Derivative Liabilities
	(in thousands; 2015 unaudited)									Gross Amounts Not Offset in the Statements of Condition
					Gross Amounts			Net Amounts of
		Gross Amounts			Offset in the			Liabilities Presented
		of Recognized			Statements of			in the Statements of		Financial			Cash Collateral
		Liabilities2			Condition			Condition2		Instruments			Pledged			Net Amount
	As of March 31, 2015
	Derivatives by Counterparty
	Counterparty A	$	2,107		$	—		$	2,107	$	—		$	(2,107	)	$	—
	Counterparty B	374			—			374		—			(374		)	—
	Total	$	2,481		$	—		$	2,481	$	—		$	(2,481	)	$	—
	As of December 31, 2014
	Derivatives by Counterparty
	Counterparty A	$	1,616		$	—		$	1,616	$	(61	)	$	(1,360	)	$	195
	Counterparty B	380			—			380		—			(380		)	—
	Total	$	1,996		$	—		$	1,996	$	(61	)	$	(1,740	)	$	195
	2 Amounts exclude accrued interest totaling $40 thousand and $39 thousand at March 31, 2015 and December 31, 2014, respectively.

Basis_of_Presentation_Policies

Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	The consolidated financial statements include the accounts of Bank of Marin Bancorp (“Bancorp”), a bank holding company, and its wholly-owned bank subsidiary, Bank of Marin (the “Bank”), a California state-chartered commercial bank. References to “we,” “our,” “us” mean the holding company and the Bank that are consolidated for financial reporting purposes. The accompanying unaudited consolidated interim financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission ("SEC"). Certain information and note disclosures normally included in annual financial statements prepared in accordance with generally accepted accounting principles ("GAAP") have been condensed or omitted pursuant to those rules and regulations. Although we believe that the disclosures made are adequate to make the information not misleading, we suggest that these interim financial statements be read in conjunction with the financial statements and the notes thereto included in our 2014 Annual Report on Form 10-K.  In the opinion of Management, the unaudited consolidated financial statements reflect all adjustments which are necessary for a fair presentation of the consolidated financial position, the results of operations, changes in comprehensive income, changes in stockholders’ equity, and cash flows for the periods presented. All material intercompany transactions have been eliminated. The results of these interim periods may not be indicative of the results for the full year or for any other period. We have evaluated subsequent events through the date of filing with the SEC and have determined that there are no subsequent events that require additional recognition or disclosure.
	On November 29, 2013, we completed the merger of NorCal Community Bancorp ("NorCal"), parent company of Bank of Alameda, to enhance our market presence (the “Acquisition”). On the date of acquisition, Bancorp assumed ownership of NorCal Community Bancorp Trusts I and II, respectively (the "Trusts"), which were formed for the sole purpose of issuing trust preferred securities. Bancorp is not considered the primary beneficiary of the Trusts (variable interest entities), therefore the Trusts are not consolidated in our consolidated financial statements, but rather the subordinated debentures are shown as a liability on our consolidated statements of condition. Bancorp's investment in the common stock of the Trusts is accounted for under the equity method and is included in interest receivable and other assets on the consolidated statements of condition.
Earnings Per Share	Basic earnings per share (“EPS”) are calculated by dividing net income by the weighted average number of common shares outstanding during each period, excluding unvested restricted stock awards. Diluted EPS are calculated using the weighted average diluted shares. The number of potentially dilutive common shares included in quarterly diluted EPS is computed using the average market prices during the three months included in the reporting period under the treasury stock method. The number of potentially dilutive common shares included in year-to-date diluted EPS is a year-to-date weighted average of potentially dilutive common shares included in each quarterly diluted EPS computation. We have two forms of outstanding stock: common stock and unvested restricted stock awards. Holders of unvested restricted stock awards receive non-forfeitable dividends at the same rate as common shareholders and they both share equally in undistributed earnings. Therefore, under the two-class method, the difference in EPS is not significant for these participating securities.
Recently Issued Accounting Standards	In January 2014, the FASB issued ASU No. 2014-04, Receivables - Troubled Debt Restructurings by Creditors (Subtopic 310-40) Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure. Current accounting literature on troubled debt restructurings includes guidance on the receipt of one or more collateral assets in satisfaction of all or part of a receivable. The accounting literature indicates that a creditor should reclassify a collateralized mortgage loan such that the loan should be de-recognized and the collateral asset recognized when it is determined that there has been in substance a repossession or foreclosure by the creditor. However, in substance repossession or foreclosure and physical possession were not defined, leaving uncertainty about when a creditor should de-recognize the loan receivable and recognize the real estate property. This ASU clarifies when an in substance repossession or foreclosure occurs. ASU 2014-04 is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2014 for public entities. Since we currently do not hold any in substance foreclosures, the adoption of this ASU has not had any impact on our financial condition or results of operations.
	In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). The ASU is a converged standard involving FASB and International Financial Reporting Standards that provides a single comprehensive revenue recognition model for all contracts with customers across transactions and industries. The guidance in this ASU affects any entity that either enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of nonfinancial assets unless those contracts are within the scope of other standards. The core principal of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. For public entities, the ASU is effective on a retrospective basis for annual reporting periods, and interim periods within those annual periods, beginning after December 15, 2016. Since this ASU does not apply to financial instruments and we do not have a significant source of non-interest income subject to this ASU, we do not expect it to have a significant impact on our financial condition or results of operations.
	In June 2014, the FASB issued ASU No. 2014-12, Compensation - Stock Compensation (Topic 718) Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period. This ASU provides guidance for entities that grant their employees share-based payment awards where a performance target that affects vesting could be achieved after the requisite service period. That is the case when an employee is eligible to retire or otherwise terminate employment before the end of the period in which a performance target could be achieved and still be eligible to vest in the award if and when the performance target is achieved. This ASU stipulates that compensation expense should be recognized in the period where the performance target becomes probable of being achieved as opposed to the date that the award was granted. ASU 2014-12 is effective for annual periods and interim periods within those annual periods beginning after December 15, 2015. As of March 31, 2015 we have not granted share-based payment awards where a performance target that affects vesting could be achieved after the requisite service period. We do not expect this ASU to have a material impact on our financial condition or results of operations.

Basis_of_Presentation_Tables

Basis of Presentation (Tables)	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Earnings Per Share Reconciliation	The following table shows: 1) weighted average basic shares, 2) potentially dilutive common shares related to stock options, unvested restricted stock awards and stock warrant, and 3) weighted average diluted shares. Basic earnings per share (“EPS”) are calculated by dividing net income by the weighted average number of common shares outstanding during each period, excluding unvested restricted stock awards. Diluted EPS are calculated using the weighted average diluted shares. The number of potentially dilutive common shares included in quarterly diluted EPS is computed using the average market prices during the three months included in the reporting period under the treasury stock method. The number of potentially dilutive common shares included in year-to-date diluted EPS is a year-to-date weighted average of potentially dilutive common shares included in each quarterly diluted EPS computation. We have two forms of outstanding stock: common stock and unvested restricted stock awards. Holders of unvested restricted stock awards receive non-forfeitable dividends at the same rate as common shareholders and they both share equally in undistributed earnings. Therefore, under the two-class method, the difference in EPS is not significant for these participating securities.
		Three months ended
	(in thousands, except per share data; unaudited)	March 31, 2015		March 31, 2014
	Weighted average basic shares outstanding	5,921		5,870
	Add: Potentially dilutive common shares related to stock options	47		43
	Potentially dilutive common shares related to unvested restricted stock	6		6
	Potentially dilutive common shares related to the warrant	74		61
	Weighted average diluted shares outstanding	6,048		5,980
	Net income	$	4,457	$	4,533
	Basic EPS	$	0.75	$	0.77
	Diluted EPS	$	0.74	$	0.76
	Weighted average anti-dilutive shares not included in the calculation of diluted EPS	24		44

Fair_Value_of_Assets_and_Liabi1

Fair Value of Assets and Liabilities (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following table summarizes our assets and liabilities that were required to be recorded at fair value on a recurring basis.
	(in thousands)	Carrying Value			Quoted Prices in Active Markets for Identical Assets (Level 1)			Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
	Description of Financial Instruments
	At March 31, 2015 (unaudited):
	Securities available-for-sale:
	Mortgage-backed securities and collateralized mortgage obligations issued by U.S. government-sponsored agencies	$	152,142		$	—		$	149,472		$	2,670
	Debentures of government-sponsored agencies	$	26,174		$	—		$	26,174		$	—
	Privately-issued collateralized mortgage obligations	$	5,493		$	—		$	5,493		$	—
	Obligations of state and political subdivisions	$	15,850		$	—		$	15,850		$	—
	Corporate bonds	$	5,021		$	—		5,021			$	—
	Derivative financial assets (interest rate contracts)	$	—		$	—		$	—		$	—
	Derivative financial liabilities (interest rate contracts)	$	2,481		$	—		$	2,481		$	—
	At December 31, 2014:
	Securities available-for-sale:
	Mortgage-backed securities and collateralized mortgage obligations issued by U.S. government-sponsored agencies	$	158,119		$	—		$	155,421		$	2,698
	Debentures of government-sponsored agencies	$	14,557		$	—		$	14,557		$	—
	Privately-issued collateralized mortgage obligations	$	7,294		$	—		$	7,294		$	—
	Obligations of state and political subdivisions	$	15,880		$	—		$	15,771		$	—
	Corporate bonds	$	4,998		$	—		$	5,437		$	—
	Derivative financial assets (interest rate contracts)	$	61		$	—		$	61		$	—
	Derivative financial liabilities (interest rate contracts)	$	1,996		$	—		$	1,996		$	—
Fair Value Measurements, Nonrecurring	The following table presents the carrying value of financial instruments that were measured at fair value on a non-recurring basis and that were still held in the consolidated statements of condition at each respective period end, by level within the fair value hierarchy as of March 31, 2015 and December 31, 2014.
	(in thousands)	Carrying Value1			Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs			Significant Unobservable Inputs
	Description of Financial Instruments				(Level 1)			(Level 2)			(Level 3) 1
	At March 31, 2015 (unaudited):
	Impaired loans carried at fair value:
	Installment and other consumer	13			—			—			13
	Total	$	13		$	—		$	—		$	13
	At December 31, 2014:
	Impaired loans carried at fair value:
	Installment and other consumer	77			—			—			77
	Total	$	77		$	—		$	—		$	77
	1 Represents collateral-dependent loan principal balances that had been generally written down to the values of the underlying collateral, net of specific valuation allowances of $10 thousand and $26 thousand at March 31, 2015 and December 31, 2014, respectively. The carrying value of loans fully charged-off, which includes unsecured lines of credit, overdrafts and all other loans, is zero.
Fair Value, by Balance Sheet Grouping	The table below is a summary of fair value estimates for financial instruments as of March 31, 2015 and December 31, 2014, excluding financial instruments recorded at fair value on a recurring basis (summarized in the first table in this note). The carrying amounts in the following table are recorded in the consolidated statements of condition under the indicated captions. We have excluded non-financial assets and non-financial liabilities defined by the Codification (ASC 820-10-15-1A), such as Bank premises and equipment, deferred taxes and other liabilities.  In addition, we have not disclosed the fair value of financial instruments specifically excluded from disclosure requirements of the Financial Instruments Topic of the Codification (ASC 825-10-50-8), such as Bank-owned life insurance policies.
		March 31, 2015						December 31, 2014
	(in thousands; 2015 unaudited)	Carrying Amounts		Fair Value			Fair Value Hierarchy	Carrying Amounts		Fair Value			Fair Value Hierarchy
	Financial assets
	Cash and cash equivalents	$	103,164	$	103,164		Level 1	$	41,367	$	41,367		Level 1
	Investment securities held-to-maturity	107,476		109,785			Level 2	116,437		118,643			Level 2
	Loans, net	1,331,328		1,341,118			Level 3	1,348,252		1,361,244			Level 3
	Interest receivable	5,453		5,453			Level 2	5,909		5,909			Level 2
	Financial liabilities
	Deposits	1,585,120		1,585,907			Level 2	1,551,619		1,552,446			Level 2
	Federal Home Loan Bank borrowings	15,000		15,514			Level 2	15,000		15,484			Level 2
	Subordinated debentures	5,238		5,274			Level 3	5,185		5,290			Level 3
	Interest payable	208		208			Level 2	213		213			Level 2

Investment_Securities_Tables

Investment Securities (Tables)	3 Months Ended
	Mar. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Schedule of Available-for-sale Securities and Held-to-maturity Securities Reconciliation	Our investment securities portfolio consists of obligations of state and political subdivisions, corporate bonds, U.S. government agency securities, including mortgage-backed securities (“MBS”) and collateralized mortgage obligations (“CMOs”) issued or guaranteed by Federal National Mortgage Association ("FNMA"), Federal Home Loan Mortgage Corporation ("FHLMC"), or Government National Mortgage Association ("GNMA"), debentures issued by government-sponsored agencies such as FNMA and FHLMC, as well as privately issued CMOs, as reflected in the table below:
		31-Mar-15													31-Dec-14
		Amortized			Fair			Gross Unrealized							Amortized			Fair			Gross Unrealized
	(in thousands; 2015 unaudited)	Cost			Value			Gains			(Losses)				Cost			Value			Gains			(Losses)
	Held-to-maturity
	Obligations of state and	$	60,529		$	62,257		$	1,741		$	(13	)		$	63,425		$	65,121		$	1,736		$	(40	)
	political subdivisions
	Corporate bonds	32,175			32,345			173			(3		)		40,257			40,448			216			(25		)
	MBS pass-through securities issued by FHLMC and FNMA	14,772			15,183			411			—				12,755			13,074			319			—
	Total held-to-maturity	107,476			109,785			2,325			(16		)		116,437			118,643			2,271			(65		)
	Available-for-sale
	Securities of U.S. government agencies:
	MBS pass-through securities issued by FHLMC and FNMA	90,215			92,057			1,842			—				92,963			94,214			1,262			(11		)
	CMOs issued by FNMA	13,896			14,055			197			(38		)		14,771			14,790			77			(58		)
	CMOs issued by FHLMC	29,482			29,799			339			(22		)		31,238			31,260			109			(87		)
	CMOs issued by GNMA	15,933			16,231			308			(10		)		17,573			17,855			298			(16		)
	Debentures of government- sponsored agencies	26,154			26,174			119			(99		)		14,694			14,557			95			(232		)
	Privately issued CMOs	5,353			5,493			142			(2		)		7,137			7,294			172			(15		)
	Obligations of state and	15,596			15,850			256			(2		)		15,733			15,880			155			(8		)
	political subdivisions
	Corporate bonds	4,939			5,021			82			—				4,936			4,998			66			(4		)
	Total available-for-sale	201,568			204,680			3,285			(173		)		199,045			200,848			2,234			(431		)
	Total investment securities	$	309,044		$	314,465		$	5,610		$	(189	)		$	315,482		$	319,491		$	4,505		$	(496	)
Investments Classified by Contractual Maturity Date	The amortized cost and fair value of investment debt securities by contractual maturity at March 31, 2015 are shown below. Expected maturities will differ from contractual maturities because the issuers of the securities may have the right to call or prepay obligations with or without call or prepayment penalties.
		March 31, 2015																31-Dec-14
		Held-to-Maturity								Available-for-Sale								Held-to-Maturity								Available-for-Sale
	(in thousands; 2015 unaudited)	Amortized Cost				Fair Value				Amortized Cost				Fair Value				Amortized Cost				Fair Value				Amortized Cost		Fair Value
	Within one year	$	36,925			$	37,015			$	5,769			$	5,816			$	39,778			$	39,913			$	2,378	$	2,388
	After one year but within five years	44,701				45,804				50,411				50,686				50,983				51,953				43,866		43,919
	After five years through ten years	12,216				12,871				9,312				9,471				11,679				12,426				9,644		9,749
	After ten years	13,634				14,095				136,076				138,707				13,997				14,351				143,157		144,792
	Total	$	107,476			$	109,785			$	201,568			$	204,680			$	116,437			$	118,643			$	199,045	$	200,848
Schedule of Unrealized Loss on Investments	Those securities are summarized and classified according to the duration of the loss period in the table below:
	March 31, 2015		< 12 continuous months								> 12 continuous months								Total securities
																			in a loss position
	(in thousands; unaudited)		Fair value				Unrealized loss				Fair value				Unrealized loss				Fair value				Unrealized loss
	Held-to-maturity
	Obligations of state & political subdivisions		$	2,556			$	(3	)		361				(10		)		$	2,917			$	(13	)
	Corporate bonds		1,997				(3		)		—				—				1,997				(3		)
	Total held-to-maturity		4,553				(6		)		361				(10		)		4,914				(16		)
	Available-for-sale
	CMOs issued by FNMA		—				—				3,918				(38		)		3,918				(38		)
	CMOs issued by FHLMC		—				—				2,232				(22		)		2,232				(22		)
	CMOs issued by GNMA		3,074				(10		)		—				—				3,074				(10		)
	Debentures of government- sponsored agencies		—				—				9,901				(99		)		9,901				(99		)
	Privately issued CMOs		458				(2		)		—				—				458				(2		)
	Obligations of state & political subdivisions		—				—				588				(2		)		588				(2		)
	Total available-for-sale		3,532				(12		)		16,639				(161		)		20,171				(173		)
	Total temporarily impaired securities		$	8,085			$	(18	)		$	17,000			$	(171	)		$	25,085			$	(189	)
	31-Dec-14		< 12 continuous months								> 12 continuous months								Total securities
																			in a loss position
	(dollars in thousands)		Fair value				Unrealized loss				Fair value				Unrealized loss				Fair value				Unrealized loss
	Held-to-maturity
	Obligations of state & political subdivisions		$	5,830			$	(27	)		$	359			$	(13	)		$	6,189			$	(40	)
	Corporate bonds		3,009				(1		)		3,533				(24		)		6,542				(25		)
	Total held-to-maturity		8,839				(28		)		3,892				(37		)		12,731				(65		)
	Available-for-sale
	MBS pass-through securities issued by FNMA and FHLMC		1,960				(11		)		—				—				1,960				(11		)
	CMOs issued by FNMA		—				—				4,115				(58		)		4,115				(58		)
	CMOs issued by FHLMC		17,157				(44		)		2,291				(43		)		19,448				(87		)
	CMOs issued by GNMA		3,262				(16		)		—				—				3,262				(16		)
	Debentures of government- sponsored agencies		494				(1		)		9,769				(231		)		10,263				(232		)
	Privately issued CMOs		817				(15		)		—				—				817				(15		)
	Obligations of state & political subdivisions		2,695				(3		)		1,112				(5		)		3,807				(8		)
	Corporate bonds		1,002				(1		)		990				(3		)		1,992				(4		)
	Total available-for-sale		27,387				(91		)		18,277				(340		)		45,664				(431		)
	Total temporarily impaired securities		$	36,226			$	(119	)		$	22,169			$	(377	)		$	58,395			$	(496	)

Loans_and_Allowance_for_Loan_L1

Loans and Allowance for Loan Losses (Tables)	3 Months Ended
	Mar. 31, 2015
Receivables [Abstract]
Past Due Financing Receivables	Outstanding loans by class and payment aging as of March 31, 2015 and December 31, 2014 are as follows:
	Loan Aging Analysis by Class as of March 31, 2015 and December 31, 2014
	(dollars in thousands; 2015 unaudited)	Commercial and industrial				Commercial real estate, owner-occupied				Commercial real estate, investor				Construction				Home equity				Other residential 1				Installment and other consumer				Total
	31-Mar-15
	30-59 days past due	$	13			$	—			$	—			$	—			$	295			$	161			$	184			$	653
	60-89 days past due	296				—				—				—				—				—				—				296
	Greater than 90 days past due (non-accrual) 2	373				1,403				2,354				5,107				166				—				79				9,482
	Total past due	682				1,403				2,354				5,107				461				161				263				10,431
	Current	195,760				233,934				651,494				51,943				112,816				73,214				16,892				1,336,053
	Total loans 3	$	196,442			$	235,337			$	653,848			$	57,050			$	113,277			$	73,375			$	17,155			$	1,346,484
	Non-accrual loans to total loans	0.2		%		0.6		%		0.4		%		9		%		0.1		%		—		%		0.5		%		0.7		%
	December 31, 2014
	30-59 days past due	$	183			$	—			$	—			$	—			$	646			$	—			$	180			$	1,009
	60-89 days past due	—				—				—				—				—				—				—				—
	Greater than 90 days past due (non-accrual) 2	—				1,403				2,429				5,134				280				—				104				9,350
	Total past due	183				1,403				2,429				5,134				926				—				284				10,359
	Current	210,040				229,202				671,070				43,279				109,862				73,035				16,504				1,352,992
	Total loans 3	$	210,223			$	230,605			$	673,499			$	48,413			$	110,788			$	73,035			$	16,788			$	1,363,351
	Non-accrual loans to total loans	—		%		0.6		%		0.4		%		10.6		%		0.3		%		—		%		0.6		%		0.7		%
	1 Our residential loan portfolio does not include sub-prime loans, nor is it our practice to underwrite loans commonly referred to as "Alt-A mortgages", the characteristics of which are loans lacking full documentation, borrowers having low FICO scores or higher loan-to-value ratios.
	2 Amounts include $1.4 million of Purchased Credit Impaired ("PCI") loans that have stopped accreting interest at both March 31, 2015 and December 31, 2014. Amounts exclude accreting PCI loans of $3.7 million and $3.8 million at March 31, 2015 and December 31, 2014, respectively, as we have a reasonable expectation about future cash flows to be collected and we continue to recognize accretable yield on these loans in interest income. There were no accruing loans past due more than ninety days at March 31, 2015 or December 31, 2014.
	3 Amounts include net deferred loan costs of $651 thousand and $487 thousand at March 31, 2015 and December 31, 2014, respectively. Amounts are also net of unaccreted purchase discounts on non-PCI loans of $4.2 million and $4.4 million at March 31, 2015 and December 31, 2014, respectively.
Financing Receivable Credit Quality Indicators	The following table represents an analysis of loans by internally assigned grades, including the PCI loans, at March 31, 2015 and December 31, 2014:
	(in thousands; 2015 unaudited)	Commercial and industrial				Commercial real estate, owner-occupied				Commercial real estate, investor				Construction				Home equity				Other residential				Installment and other consumer				Purchased credit-impaired			Total
	Credit Risk Profile by Internally Assigned Grade:
	31-Mar-15
	Pass	$	181,842			$	211,551			$	640,656			$	50,305			$	111,227			$	71,768			$	16,816			$	2,202		$	1,286,367
	Special Mention	9,424				10,281				3,853				1,078				321				—				—				1,031			25,988
	Substandard	4,974				10,876				7,175				5,657				1,662				1,607				339				1,839			34,129
	Total loans	$	196,240			$	232,708			$	651,684			$	57,040			$	113,210			$	73,375			$	17,155			$	5,072		$	1,346,484
	December 31, 2014
	Pass	$	197,659			$	205,820			$	651,548			$	41,710			$	107,933			$	70,987			$	16,101			$	2,210		$	1,293,968
	Special Mention	6,776				10,406				13,304				1,008				322				—				190				1,140			33,146
	Substandard	5,464				11,763				6,473				5,684				2,466				2,048				497				1,842			36,237
	Total loans	$	209,899			$	227,989			$	671,325			$	48,402			$	110,721			$	73,035			$	16,788			$	5,192		$	1,363,351
Troubled Debt Restructurings on Financing Receivables	The table below summarizes outstanding TDR loans by loan class as of March 31, 2015 and December 31, 2014. The summary includes both TDRs that are on non-accrual status and those that continue to accrue interest.
	(in thousands; 2015 unaudited)		As of
	Recorded investment in Troubled Debt Restructurings 1		March 31, 2015				December 31, 2014
	Commercial and industrial		$	3,477			$	3,584
	Commercial real estate, owner-occupied		8,427				8,459
	Commercial real estate, investor		522				524
	Construction		5,657				5,684
	Home equity		561				694
	Other residential		2,037				2,045
	Installment and other consumer		1,636				1,713
	Total		$	22,317			$	22,703
	1 Includes $15.6 million and $15.9 million of TDR loans that were accruing interest as of March 31, 2015 and December 31, 2014, respectively. Includes $1.6 million and $1.8 million of acquired loans at March 31, 2015 and December 31, 2014, respectively.
	The table below presents the following information for loans modified in a TDR during the quarter ended March 31, 2014: number of contracts modified, the recorded investment in the loans prior to modification, and the recorded investment in the loans after the loans were restructured. The table below excludes fully paid-off and fully charged-off TDR loans. There were no loans modified in a TDR during 2015.
	(dollars in thousands; unaudited)	Number of Contracts Modified			Pre-Modification Outstanding Recorded Investment				Post-Modification Outstanding Recorded Investment				Post-Modification Outstanding Recorded Investment at period end
	Troubled Debt Restructurings during the three months ended March 31, 2014:
	Commercial and industrial	3			$	1,420			$	1,405			$	1,405
	Home equity	1			150				150				150
	Installment and other consumer	3			170				168				169
	Total	7			$	1,740			$	1,723			$	1,724
Impaired Financing Receivables	The tables below summarize information on impaired loans and their related allowance. Total impaired loans include non-accrual loans, accruing TDR loans and accreting PCI loans that have experienced post-acquisition declines in cash flows expected to be collected.
	(in thousands; unaudited)		Commercial and industrial				Commercial real estate, owner-occupied				Commercial real estate, investor				Construction				Home equity				Other residential				Installment and other consumer				Total
	31-Mar-15
	Recorded investment in impaired loans:
	With no specific allowance recorded		$	1,318			$	5,545			$	2,875			$	5,107			$	263			$	1,024			$	295			$	16,427
	With a specific allowance recorded		2,533				2,882				—				560				298				1,012				1,398				8,683
	Total recorded investment in impaired loans		$	3,851			$	8,427			$	2,875			$	5,667			$	561			$	2,036			$	1,693			$	25,110
	Unpaid principal balance of impaired loans:
	With no specific allowance recorded		$	1,315			$	6,545			$	4,867			$	7,797			$	263			$	1,024			$	295			$	22,106
	With a specific allowance recorded		2,604				2,882				—				745				298				1,012				1,398				8,939
	Total unpaid principal balance of impaired loans		$	3,919			$	9,427			$	4,867			$	8,542			$	561			$	2,036			$	1,693			$	31,045
	Specific allowance		$	652			$	32			$	—			$	3			$	1			$	85			$	188			$	961
	Average recorded investment in impaired loans during the quarter ended March 31, 2015		$	3,718			$	8,443			$	2,915			$	5,681			$	627			$	2,041			$	1,743			$	25,168
	Interest income recognized on impaired loans during the quarter ended March 31, 2015		$	62			$	66			$	6			$	9			$	5			$	23			$	19			$	190
	Average recorded investment in impaired loans during the quarter ended March 31, 2014		$	5,945			$	5,484			$	3,283			$	6,524			$	577			$	2,054			$	1,884			$	25,751
	Interest income recognized on impaired loans during the quarter ended March 31, 2014		$	118			$	83			$	7			$	21			$	4			$	23			$	18			$	274
	(in thousands)		Commercial and industrial				Commercial real estate, owner-occupied				Commercial real estate, investor				Construction				Home equity				Other residential				Installment and other consumer				Total
	31-Dec-14
	Recorded investment in impaired loans:
	With no specific allowance recorded		$	1,141			$	5,577			$	2,954			$	5,134			$	393			$	1,026			$	239			$	16,464
	With a specific allowance recorded		2,443				2,882				—				561				300				1,019				1,554				$	8,759
	Total recorded investment in impaired loans		$	3,584			$	8,459			$	2,954			$	5,695			$	693			$	2,045			$	1,793			$	25,223
	Unpaid principal balance of impaired loans:
	With no specific allowance recorded		$	1,186			$	6,577			$	4,945			$	7,824			$	880			$	1,026			$	239			$	22,677
	With a specific allowance recorded		2,524				2,882				—				749				300				1,019				1,554				9,028
	Total recorded investment in impaired loans		$	3,710			$	9,459			$	4,945			$	8,573			$	1,180			$	2,045			$	1,793			$	31,705
	Specific allowance		$	694			$	65			$	—			$	3			$	—			$	92			$	284			$	1,138
	Average recorded investment in impaired loans during 2014		5,354				6,604				3,138				6,471				741				1,744				1,857				25,909
	Interest income recognized on impaired loans during 2014		378				288				28				85				19				74				76				948
Allowance for Credit Losses on Financing Receivables	The following tables disclose loans by major portfolio category and activity in the ALLL, as well as the related ALLL disaggregated by impairment evaluation method.
	Allowance for Loan Losses Rollforward for the Period
	(in thousands; unaudited)		Commercial and industrial				Commercial real estate, owner-occupied				Commercial real estate, investor				Construction				Home equity				Other residential				Installment and other consumer				Unallocated			Total
	For the three months ended March 31, 2015
	Allowance for loan losses:
	Beginning balance		$	2,837			$	1,924			$	6,672			$	839			$	859			$	433			$	566			$	969		$	15,099
	Provision (reversal)		(275		)		170				(383		)		(61		)		63				(3		)		(99		)		588			—
	Charge-offs		(2		)		—				—				—				—				—				(6		)		—			(8		)
	Recoveries		60				—				3				—				1				—				1				—			65
	Ending balance		$	2,620			$	2,094			$	6,292			$	778			$	923			$	430			$	462			$	1,557		$	15,156
	For the three months ended March 31, 2014
	Allowance for loan losses:
	Beginning balance		$	3,056			$	2,012			$	6,196			$	633			$	875			$	317			$	629			$	506		$	14,224
	Provision (reversal)		(255		)		(27		)		268				100				11				92				(142		)		103			150
	Charge-offs		(61		)		—				—				(197		)		—				—				(3		)		—			(261		)
	Recoveries		32				—				5				—				1				—				81				—			119
	Ending balance		$	2,772			$	1,985			$	6,469			$	536			$	887			$	409			$	565			$	609		$	14,232
	Allowance for Loan Losses and Recorded Investment in Loans
	(dollars in thousands; unaudited)		Commercial and industrial				Commercial real estate, owner-occupied				Commercial real estate, investor				Construction				Home equity				Other residential				Installment and other consumer				Unallocated			Total
	As of March 31, 2015:
	Ending ALLL related to loans collectively evaluated for impairment		$	1,968			$	2,062			$	6,292			$	775			$	922			$	345			$	274			$	1,557		$	14,195
	Ending ALLL related to loans  individually evaluated for impairment		$	648			$	32			$	—			$	—			$	1			$	85			$	188			$	—		$	954
	Ending ALLL related to purchased  credit-impaired loans		$	4			$	—			$	—			$	3			$	—			$	—			$	—			$	—		$	7
	Loans outstanding:
	Collectively evaluated for impairment		$	192,557			$	225,684			$	648,809			$	51,383			$	112,649			$	71,339			$	15,462			$	—		$	1,317,883
	Individually evaluated for impairment1		3,683				7,024				2,875				5,657				561				2,036				1,693				—			23,529
	Purchased credit-impaired		202				2,629				2,164				10				67				—				—				—			5,072
	Total		$	196,442			$	235,337			$	653,848			$	57,050			$	113,277			$	73,375			$	17,155			$	—		$	1,346,484
	Ratio of allowance for loan losses to total loans		1.33		%		0.89		%		0.96		%		1.36		%		0.81		%		0.59		%		2.69		%		NM			1.13		%
	Allowance for loan losses to non-accrual loans		702		%		149		%		267		%		15		%		556		%		NM				585		%		NM			160		%
	1 Total excludes $1.6 million of PCI loans that have experienced post-acquisition declines in cash flows expected to be collected. These loans are included in the "purchased credit-impaired" amount in the next line below.
	NM - Not Meaningful
	Allowance for Loan Losses and Recorded Investment in Loans
	(dollars in thousands)		Commercial and industrial				Commercial real estate, owner-occupied				Commercial real estate, investor				Construction				Home equity				Other residential				Installment and other consumer				Unallocated			Total
	As of December 31, 2014:
	Ending ALLL related to loans collectively evaluated for impairment		$	2,143			$	1,859			$	6,672			$	836			$	859			$	341			$	282			$	969		$	13,961
	Ending ALLL related to loans  individually evaluated for impairment		$	690			$	65			$	—			$	—			$	—			$	92			$	284			$	—		$	1,131
	Ending ALLL related to purchased  credit-impaired loans		$	4			$	—			$	—			$	3			$	—			$	—			$	—			$	—		$	7
	Loans outstanding:
	Collectively evaluated for impairment		$	206,603			$	220,933			$	668,371			$	42,718			$	110,028			$	70,990			$	14,995			$	—		$	1,334,638
	Individually evaluated for impairment1		3,296				7,056				2,954				5,684				693				2,045				1,793				—			23,521
	Purchased credit-impaired		324				2,616				2,174				11				67				—				—				—			5,192
	Total		$	210,223			$	230,605			$	673,499			$	48,413			$	110,788			$	73,035			$	16,788			$	—		$	1,363,351
	Ratio of allowance for loan losses to total loans		1.35		%		0.83		%		0.99		%		1.73		%		0.78		%		0.59		%		3.37		%		NM			1.11		%
	Allowance for loan losses to non-accrual loans		NM				137		%		275		%		16		%		307		%		NM				544		%		NM			161		%
	1 Total excludes $1.7 million PCI loans that have experienced credit deterioration post-acquisition, which are included in the "purchased credit-impaired" amount in the next line below.
	NM - Not Meaningful
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period	The following table reflects the outstanding balance and related carrying value of PCI loans as of March 31, 2015 and December 31, 2014.
		31-Mar-15								31-Dec-14
	PCI Loans	Unpaid principal balance				Carrying value				Unpaid principal balance				Carrying value
	(in thousands; 2015 unaudited)
	Commercial and industrial	$	301			$	202			$	479			$	324
	Commercial real estate	6,806				4,793				6,831				4,790
	Construction	132				10				136				11
	Home equity	230				67				232				67
	Total purchased credit-impaired loans	$	7,469			$	5,072			$	7,678			$	5,192
Accretable Yield Activity	The activities in the accretable yield, or income expected to be earned, for PCI loans were as follows:
	Accretable Yield	Three months ended
	(dollars in thousands, unaudited)	March 31, 2015				March 31, 2014
	Balance at beginning of period	$	4,027			$	3,649
	Removals 1	(77		)		—
	Accretion	(119		)		(180		)
	Reclassifications from nonaccretable difference 2	—				1,832
	Balance at end of period	$	3,831			$	5,301
	1 Represents the accretable difference that is relieved when a loan exits the PCI population due to payoff, full charge-off, or transfer to repossessed assets, etc.
	2 Primarily relates to changes in expected credit performance and changes in expected timing of cash flows.

Borrowings_Tables

Borrowings (Tables)	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	The following is a summary of the contractual terms of the subordinated debentures due to the Trusts as of March 31, 2015:
	(in thousands; unaudited)
	Subordinated debentures due to NorCal Community Bancorp Trust I on October 7, 2033 with interest payable quarterly, based on 3-month LIBOR plus 3.05%, repricing quarterly (3.30% as of March 31, 2015), redeemable, in whole or in part, on any interest payment date	$	4,124
	Subordinated debentures due to NorCal Community Bancorp Trust II on March 15, 2036 with interest payable quarterly, based on 3-month LIBOR plus 1.40%, repricing quarterly (1.67% as of March 31, 2015), redeemable, in whole or in part, on any interest payment date	4,124
	Total	$	8,248

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Dividends Declared	Presented below is a summary of cash dividends paid to common shareholders, recorded as a reduction of retained earnings.
		Three months ended
	(in thousands, except per share data; unaudited)	March 31, 2015		March 31, 2014
	Cash dividends to common stockholders	$	1,307	$	1,120
	Cash dividends per common share	$	0.22	$	0.19

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	At March 31, 2015, the approximate minimum future commitments payable under non-cancelable contracts for leased premises are as follows:
	(in thousands; unaudited)	2015		2016		2017		2018		2019		Thereafter		Total
	Operating leases	$	2,822	$	3,788	$	3,781	$	3,810	$	3,553	$	6,786	$	24,540

Derivative_Financial_Instrumen1

Derivative Financial Instruments and Hedging Activities (Tables)	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	Information on our derivatives follows:
			Asset derivatives							Liability derivatives
	(in thousands; 2015 unaudited)		March 31, 2015				December 31, 2014			March 31, 2015				31-Dec-14
	Fair value hedges:
	Interest rate contracts notional amount		$	—			$	4,589		$	30,992			$	26,899
	Interest rate contracts fair value1		$	—			$	61		$	2,481			$	1,996
Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance
		Three months ended
	(in thousands; unaudited)	March 31, 2015					31-Mar-14
	(Decrease) increase in value of designated interest rate swaps recognized in interest income	$	(546	)			$	736
	Payment on interest rate swaps recorded in interest income	(235		)			(253		)
	Increase (decrease) in value of hedged loans recognized in interest income	571					(531		)
	Decrease in value of yield maintenance agreement recognized against interest income	(14		)			(47		)
	Net loss on derivatives recognized against interest income 2	$	(224	)			$	(95	)
	1 See Note 3 for valuation methodology.
	2 Includes hedge ineffectiveness gain of $11 thousand and gain of $158 thousand for the quarters ended March 31, 2015 and March 31, 2014, respectively. Changes in value of swaps were included in the assessment of hedge effectiveness.
Offsetting Assets	Information on financial instruments that are eligible for offset in the consolidated statements of condition follows:
	Offsetting of Financial Assets and Derivative Assets
	(in thousands; 2015 unaudited)									Gross Amounts Not Offset in the Statements of Condition
					Gross Amounts			Net Amounts
		Gross Amounts			Offset in the			of Assets Presented
		of Recognized			Statements of			in the Statements		Financial			Cash Collateral
		Assets1			Condition			of Condition1		Instruments			Received			Net Amount
	As of March 31, 2015
	Derivatives by Counterparty
	Counterparty A	$	—		$	—		$	—	$	—		$	—		$	—
	Counterparty B	—			—			—		—			—			—
	Total	$	—		$	—		$	—	$	—		$	—		$	—
	As of December 31, 2014
	Derivatives by Counterparty
	Counterparty A	$	61		$	—		$	61	$	(61	)	$	—		$	—
	Counterparty B	—			—			—		—			—			—
	Total	$	61		$	—		$	61	$	(61	)	$	—		$	—
	1 Amounts exclude accrued interest totaling zero and $1 thousand at March 31, 2015 and December 31, 2014, respectively.
Offsetting Liabilities
	Offsetting of Financial Liabilities and Derivative Liabilities
	(in thousands; 2015 unaudited)									Gross Amounts Not Offset in the Statements of Condition
					Gross Amounts			Net Amounts of
		Gross Amounts			Offset in the			Liabilities Presented
		of Recognized			Statements of			in the Statements of		Financial			Cash Collateral
		Liabilities2			Condition			Condition2		Instruments			Pledged			Net Amount
	As of March 31, 2015
	Derivatives by Counterparty
	Counterparty A	$	2,107		$	—		$	2,107	$	—		$	(2,107	)	$	—
	Counterparty B	374			—			374		—			(374		)	—
	Total	$	2,481		$	—		$	2,481	$	—		$	(2,481	)	$	—
	As of December 31, 2014
	Derivatives by Counterparty
	Counterparty A	$	1,616		$	—		$	1,616	$	(61	)	$	(1,360	)	$	195
	Counterparty B	380			—			380		—			(380		)	—
	Total	$	1,996		$	—		$	1,996	$	(61	)	$	(1,740	)	$	195
	2 Amounts exclude accrued interest totaling $40 thousand and $39 thousand at March 31, 2015 and December 31, 2014, respectively.

Basis_of_Presentation_Details

Basis of Presentation (Details) (USD $)	3 Months Ended		12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Weighted average basic shares outstanding	5,921	5,870
Add: Potential common shares related to stock options	47	43
Potential common shares related to unvested restricted stock	6	6
Potential common shares related to warrants	74	61
Weighted average diluted shares outstanding	6,048	5,980
Net income	$4,457	$4,533	$19,771
Basic EPS (usd per share)	$0.75	$0.77
Diluted EPS (usd per share)	$0.74	$0.76
Weighted average anti-dilutive shares not included in the calculation of diluted EPS	24	44

Fair_Value_of_Assets_and_Liabi2

Fair Value of Assets and Liabilities - Recorded on a Recurring Basis (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	$204,680	$200,848
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of securities	0	0
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of securities	1
Mortgage-backed securities and collateralized mortgage obligations issued by U.S. government-sponsored agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	92,057	94,214
Increase in unrealized gain due to transfers to Level 3	10
Debentures of government sponsored agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	26,174	14,557
Privately-issued collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	5,493	7,294
Obligations of state and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	15,850	15,880
Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	5,021	4,998
Assets and liabilities at fair value measured on a recurring basis | Carrying Value | Interest rate contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets (interest rate contracts)	0	61
Derivative financial liabilities (interest rate contracts)	2,481	1,996
Assets and liabilities at fair value measured on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Interest rate contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets (interest rate contracts)	0	0
Derivative financial liabilities (interest rate contracts)	0	0
Assets and liabilities at fair value measured on a recurring basis | Significant Other Observable Inputs (Level 2) | Interest rate contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets (interest rate contracts)	0	61
Derivative financial liabilities (interest rate contracts)	2,481	1,996
Assets and liabilities at fair value measured on a recurring basis | Significant Unobservable Inputs (Level 3) | Interest rate contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets (interest rate contracts)	0	0
Derivative financial liabilities (interest rate contracts)	0	0
Assets and liabilities at fair value measured on a recurring basis | Mortgage-backed securities and collateralized mortgage obligations issued by U.S. government-sponsored agencies | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	152,142	158,119
Assets and liabilities at fair value measured on a recurring basis | Mortgage-backed securities and collateralized mortgage obligations issued by U.S. government-sponsored agencies | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	0	0
Assets and liabilities at fair value measured on a recurring basis | Mortgage-backed securities and collateralized mortgage obligations issued by U.S. government-sponsored agencies | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	149,472	155,421
Assets and liabilities at fair value measured on a recurring basis | Mortgage-backed securities and collateralized mortgage obligations issued by U.S. government-sponsored agencies | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	2,670	2,698
Assets and liabilities at fair value measured on a recurring basis | Debentures of government sponsored agencies | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	26,174	14,557
Assets and liabilities at fair value measured on a recurring basis | Debentures of government sponsored agencies | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	0	0
Assets and liabilities at fair value measured on a recurring basis | Debentures of government sponsored agencies | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	26,174	14,557
Assets and liabilities at fair value measured on a recurring basis | Debentures of government sponsored agencies | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	0	0
Assets and liabilities at fair value measured on a recurring basis | Privately-issued collateralized mortgage obligations | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	5,493	7,294
Assets and liabilities at fair value measured on a recurring basis | Privately-issued collateralized mortgage obligations | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	0	0
Assets and liabilities at fair value measured on a recurring basis | Privately-issued collateralized mortgage obligations | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	5,493	7,294
Assets and liabilities at fair value measured on a recurring basis | Privately-issued collateralized mortgage obligations | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	0	0
Assets and liabilities at fair value measured on a recurring basis | Obligations of state and political subdivisions | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	15,850	15,880
Assets and liabilities at fair value measured on a recurring basis | Obligations of state and political subdivisions | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	0	0
Assets and liabilities at fair value measured on a recurring basis | Obligations of state and political subdivisions | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	15,850	15,771
Assets and liabilities at fair value measured on a recurring basis | Obligations of state and political subdivisions | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	0	0
Assets and liabilities at fair value measured on a recurring basis | Corporate bonds | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	5,021	4,998
Assets and liabilities at fair value measured on a recurring basis | Corporate bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	0	0
Assets and liabilities at fair value measured on a recurring basis | Corporate bonds | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	5,021	5,437
Assets and liabilities at fair value measured on a recurring basis | Corporate bonds | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale, Fair Value	$0	$0

Fair_Value_of_Assets_and_Liabi3

Fair Value of Assets and Liabilities - Recorded on Nonrecurring Basis (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans carried at fair value, carrying value	$25,110		$25,223
Specific valuation allowance for impaired loans	961		1,138
Discount rate for selling costs applied to all properties	6.00%
OREO acquired	421		461
Changed in estimated value of OREO	40
Impaired loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Specific valuation allowance for impaired loans	10		26
Financial instruments at fair value measured on a nonrecurring basis | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans carried at fair value, carrying value	13	[1]	77	[1]
Financial instruments at fair value measured on a nonrecurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans carried at fair value, carrying value	0		0
Financial instruments at fair value measured on a nonrecurring basis | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans carried at fair value, carrying value	0		0
Financial instruments at fair value measured on a nonrecurring basis | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans carried at fair value, carrying value	13		77
Installment and other consumer
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans carried at fair value, carrying value	1,693		1,793
Specific valuation allowance for impaired loans	188		284
Installment and other consumer | Financial instruments at fair value measured on a nonrecurring basis | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans carried at fair value, carrying value	13	[1]	77	[1]
Installment and other consumer | Financial instruments at fair value measured on a nonrecurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans carried at fair value, carrying value	0		0
Installment and other consumer | Financial instruments at fair value measured on a nonrecurring basis | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans carried at fair value, carrying value	0		0
Installment and other consumer | Financial instruments at fair value measured on a nonrecurring basis | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans carried at fair value, carrying value	$13		$77
[1]	Represents collateral-dependent loan principal balances that had been generally written down to the values of the underlying collateral, net of specific valuation allowances of $10 thousand and $26 thousand at March 31, 2015 and December 31, 2014, respectively. The carrying value of loans fully charged-off, which includes unsecured lines of credit, overdrafts and all other loans, is zero.

Fair_Value_of_Assets_and_Liabi4

Fair Value of Assets and Liabilities - Fair Value of Financial Instruments (Details) (USD $)	0 Months Ended	3 Months Ended
In Thousands, unless otherwise specified	Nov. 29, 2013	Mar. 31, 2015	Dec. 31, 2014
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Investment securities held to maturity		109,785	$118,643
Subordinated Debt [Abstract]
Number of subordinated debentures acquired	2
Fair value of loan commitments and standby letters of credit		811	1,000
Subordinated debenture
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Subordinated debentures	4,950
Subordinated Debt [Abstract]
Number of subordinated debentures acquired	2
NorCal Community Bancorp Trust I | Subordinated debenture
Subordinated Debt [Abstract]
Basis spread on subordinated debentures	3.05%	3.05%
NorCal Community Bancorp Trust II | Subordinated debenture
Subordinated Debt [Abstract]
Basis spread on subordinated debentures	1.40%	1.40%
Carrying Value | Fair Value Hierarchy, Level 1
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Cash and cash equivalents		103,164	41,367
Carrying Value | Fair Value Hierarchy, Level 2
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Investment securities held to maturity		107,476	116,437
Interest receivable		5,453	5,909
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Deposits		1,585,120	1,551,619
Federal Home Loan Bank borrowings		15,000	15,000
Interest payable		208	213
Carrying Value | Fair Value Hierarchy, Level 3
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Loans, net		1,331,328	1,348,252
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Subordinated debentures		5,238	5,185
Fair Value | Fair Value Hierarchy, Level 1
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Cash and cash equivalents		103,164	41,367
Fair Value | Fair Value Hierarchy, Level 2
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Investment securities held to maturity		109,785	118,643
Interest receivable		5,453	5,909
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Deposits		1,585,907	1,552,446
Federal Home Loan Bank borrowings		15,514	15,484
Interest payable		208	213
Fair Value | Fair Value Hierarchy, Level 3
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Loans, net		1,341,118	1,361,244
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Subordinated debentures		5,274	$5,290

Investment_Securities_Amortize

Investment Securities - Amortized Cost and Fair Value (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	$107,476	$116,437
Held to maturity, Fair Value	109,785	118,643
Held-to-maturity, Gross Unrealized Gains	2,325	2,271
Held-to-maturity, Gross Unrealized Losses	-16	-65
Available-for-sale, Amortized Cost	201,568	199,045
Available-for-sale, Fair Value	204,680	200,848
Available-for-sale, Gross Unrealized Gains	3,285	2,234
Available-for-sale, Gross Unrealized Losses	-173	-431
Total investment securities, Amortized Cost	309,044	315,482
Total investment securities, Fair Value	314,465	319,491
Total investment securities, Gross Unrealized Gains	5,610	4,505
Total investment securities, Gross Unrealized Losses	-189	-496
MBS pass-through securities issued by FNMA and FHLMC
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, Amortized Cost	90,215	92,963
Available-for-sale, Fair Value	92,057	94,214
Available-for-sale, Gross Unrealized Gains	1,842	1,262
Available-for-sale, Gross Unrealized Losses	0	-11
CMOs issued by FNMA
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, Amortized Cost	13,896	14,771
Available-for-sale, Fair Value	14,055	14,790
Available-for-sale, Gross Unrealized Gains	197	77
Available-for-sale, Gross Unrealized Losses	-38	-58
CMOs issued by FHLMC
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, Amortized Cost	29,482	31,238
Available-for-sale, Fair Value	29,799	31,260
Available-for-sale, Gross Unrealized Gains	339	109
Available-for-sale, Gross Unrealized Losses	-22	-87
CMOs issued by GNMA
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, Amortized Cost	15,933	17,573
Available-for-sale, Fair Value	16,231	17,855
Available-for-sale, Gross Unrealized Gains	308	298
Available-for-sale, Gross Unrealized Losses	-10	-16
Debentures of government sponsored agencies
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, Amortized Cost	26,154	14,694
Available-for-sale, Fair Value	26,174	14,557
Available-for-sale, Gross Unrealized Gains	119	95
Available-for-sale, Gross Unrealized Losses	-99	-232
Privately-issued CMOs
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, Amortized Cost	5,353	7,137
Available-for-sale, Fair Value	5,493	7,294
Available-for-sale, Gross Unrealized Gains	142	172
Available-for-sale, Gross Unrealized Losses	-2	-15
Obligations of state and political subdivisions
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, Amortized Cost	15,596	15,733
Available-for-sale, Fair Value	15,850	15,880
Available-for-sale, Gross Unrealized Gains	256	155
Available-for-sale, Gross Unrealized Losses	-2	-8
Corporate bonds
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, Amortized Cost	4,939	4,936
Available-for-sale, Fair Value	5,021	4,998
Available-for-sale, Gross Unrealized Gains	82	66
Available-for-sale, Gross Unrealized Losses	0	-4
Obligations of state and political subdivisions
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	60,529	63,425
Held to maturity, Fair Value	62,257	65,121
Held-to-maturity, Gross Unrealized Gains	1,741	1,736
Held-to-maturity, Gross Unrealized Losses	-13	-40
Corporate bonds
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	32,175	40,257
Held to maturity, Fair Value	32,345	40,448
Held-to-maturity, Gross Unrealized Gains	173	216
Held-to-maturity, Gross Unrealized Losses	-3	-25
MBS pass-through securities issued by FNMA and FHLMC
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	14,772	12,755
Held to maturity, Fair Value	15,183	13,074
Held-to-maturity, Gross Unrealized Gains	411	319
Held-to-maturity, Gross Unrealized Losses	$0	$0

Investment_Securities_Maturiti

Investment Securities - Maturities (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Investments, Debt and Equity Securities [Abstract]
Held to Maturity, Amortized Cost, Within one year	$36,925	$39,778
Held to Maturity, Amortized Cost, After one but within five years	44,701	50,983
Held to Maturity, Amortized Cost, After five years through ten years	12,216	11,679
Held to Maturity, Amortized Cost, After ten years	13,634	13,997
Held to Maturity, Amortized Cost, Total	107,476	116,437
Available for Sale Securities, Amortized Cost, Within one year	5,769	2,378
Available for Sale, Amortized Cost, After one but within five years	50,411	43,866
Available for Sale, Amortized Cost, After five years through ten years	9,312	9,644
Available for Sale, Amortized Cost, After ten years	136,076	143,157
Available for Sale, Amortized Cost, Total	201,568	199,045
Held to Maturity, Fair Value, Within one year	37,015	39,913
Held to Maturity, Fair Value, After one but within five years	45,804	51,953
Held to Maturity, Fair Value, After five years through ten years	12,871	12,426
Held to Maturity, Fair Value, After ten years	14,095	14,351
Held to maturity, Fair Value	109,785	118,643
Available for Sale, Fair Value, Within one year	5,816	2,388
Available for Sale, Fair Value, After one but within five years	50,686	43,919
Available for Sale, Fair Value, After five years through ten years	9,471	9,749
Available for Sale, Fair Value, After ten years	138,707	144,792
Available for Sale, Fair Value, Total	$204,680	$200,848

Investment_Securities_Securiti

Investment Securities - Securities Sold and Pledged as Collateral (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Financial Instruments Owned and Pledged as Collateral [Line Items]
Proceeds from sale of available-for-sale securities	$1,559	$2,023
Gain on sale of held-to-maturity securities	8	7
Proceeds from sale of held-to-maturity securities	0	725
Loss on sale of available-for-sale securities sold		15
State of California
Financial Instruments Owned and Pledged as Collateral [Line Items]
Available-for-sale securities pledged as collateral	69,200		74,700
Public Deposits
Financial Instruments Owned and Pledged as Collateral [Line Items]
Available-for-sale securities pledged as collateral	68,400		73,800
Trust Deposits
Financial Instruments Owned and Pledged as Collateral [Line Items]
Available-for-sale securities pledged as collateral	852		856
Internal checking account
Financial Instruments Owned and Pledged as Collateral [Line Items]
Available-for-sale securities pledged as collateral	$1,100		$1,100
Available-for-sale Securities
Financial Instruments Owned and Pledged as Collateral [Line Items]
Number of securities sold during period	2	1
Held-to-maturity Securities
Financial Instruments Owned and Pledged as Collateral [Line Items]
Number of securities sold during period		3

Investment_Securities_Investme

Investment Securities - Investment Securities in Unrealized Loss Positions (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified	security	security
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Number of investment securities other-than-temporarily impaired	0
Number of investment securities in unrealized loss position	12	28
Held-to-maturity, less than 12 continuous months, Fair value	$4,553	$8,839
Held-to-maturity, less than 12 continuous months, Unrealized loss	-6	-28
Held-to-maturity, greater than 12 continuous months, Fair value	361	3,892
Held-to-maturity, greater than 12 continuous months, Unrealized loss	-10	-37
Held-to-maturity, Total Securities in a loss position, Fair value	4,914	12,731
Held-to-maturity, Gross Unrealized Losses	-16	-65
Available-for-sale, less than 12 continuous months, Fair value	3,532	27,387
Available-for-sale, less than 12 continuous months, Unrealized loss	-12	-91
Available-for-sale, greater than 12 continuous months, Fair value	16,639	18,277
Available-for-sale, greater than 12 continuous months, Unrealized loss	-161	-340
Available-for-sale, Total Securities in a loss position, Fair Value	20,171	45,664
Available-for-sale, Total Securities in a loss position, Unrealized loss	-173	-431
Marketable securities, less than 12 continuous months, Fair value	8,085	36,226
Marketable securities, less than 12 continuous months, Unrealized loss	-18	-119
Marketable securities, greater than 12 continuous months, Fair value	17,000	22,169
Marketable securities, greater than 12 continuous months, Unrealized loss	-171	-377
Marketable securities, Total Securities in a loss position, Fair value	25,085	58,395
Marketable securities, Total Securities in a loss position, Unrealized loss	-189	-496
Number of investment securities in unrealized loss position longer than 12 months	6
Number of investment securities in unrealized loss position less than 12 months	6
MBS pass-through securities issued by FNMA and FHLMC
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, less than 12 continuous months, Fair value		1,960
Available-for-sale, less than 12 continuous months, Unrealized loss		-11
Available-for-sale, greater than 12 continuous months, Fair value		0
Available-for-sale, greater than 12 continuous months, Unrealized loss		0
Available-for-sale, Total Securities in a loss position, Fair Value		1,960
Available-for-sale, Total Securities in a loss position, Unrealized loss		-11
CMOs issued by FNMA
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, less than 12 continuous months, Fair value	0	0
Available-for-sale, less than 12 continuous months, Unrealized loss	0	0
Available-for-sale, greater than 12 continuous months, Fair value	3,918	4,115
Available-for-sale, greater than 12 continuous months, Unrealized loss	-38	-58
Available-for-sale, Total Securities in a loss position, Fair Value	3,918	4,115
Available-for-sale, Total Securities in a loss position, Unrealized loss	-38	-58
CMOs issued by FHLMC
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, less than 12 continuous months, Fair value	0	17,157
Available-for-sale, less than 12 continuous months, Unrealized loss	0	-44
Available-for-sale, greater than 12 continuous months, Fair value	2,232	2,291
Available-for-sale, greater than 12 continuous months, Unrealized loss	-22	-43
Available-for-sale, Total Securities in a loss position, Fair Value	2,232	19,448
Available-for-sale, Total Securities in a loss position, Unrealized loss	-22	-87
CMOs issued by GNMA
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, less than 12 continuous months, Fair value	3,074	3,262
Available-for-sale, less than 12 continuous months, Unrealized loss	-10	-16
Available-for-sale, greater than 12 continuous months, Fair value	0	0
Available-for-sale, greater than 12 continuous months, Unrealized loss	0	0
Available-for-sale, Total Securities in a loss position, Fair Value	3,074	3,262
Available-for-sale, Total Securities in a loss position, Unrealized loss	-10	-16
Debentures of government-sponsored agencies
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, less than 12 continuous months, Fair value	0	494
Available-for-sale, less than 12 continuous months, Unrealized loss	0	-1
Available-for-sale, greater than 12 continuous months, Fair value	9,901	9,769
Available-for-sale, greater than 12 continuous months, Unrealized loss	-99	-231
Available-for-sale, Total Securities in a loss position, Fair Value	9,901	10,263
Available-for-sale, Total Securities in a loss position, Unrealized loss	-99	-232
Privately-issued CMOs
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, less than 12 continuous months, Fair value	458	817
Available-for-sale, less than 12 continuous months, Unrealized loss	-2	-15
Available-for-sale, greater than 12 continuous months, Fair value	0	0
Available-for-sale, greater than 12 continuous months, Unrealized loss	0	0
Available-for-sale, Total Securities in a loss position, Fair Value	458	817
Available-for-sale, Total Securities in a loss position, Unrealized loss	-2	-15
Obligations of state and political subdivisions
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Available-for-sale, less than 12 continuous months, Fair value	0
Available-for-sale, less than 12 continuous months, Unrealized loss	0
Available-for-sale, greater than 12 continuous months, Fair value	588
Available-for-sale, greater than 12 continuous months, Unrealized loss	-2
Available-for-sale, Total Securities in a loss position, Fair Value	588
Available-for-sale, Total Securities in a loss position, Unrealized loss	-2
Obligations of state and political subdivisions
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Held-to-maturity, less than 12 continuous months, Fair value	2,556	5,830
Held-to-maturity, less than 12 continuous months, Unrealized loss	-3	-27
Held-to-maturity, greater than 12 continuous months, Fair value	361	359
Held-to-maturity, greater than 12 continuous months, Unrealized loss	-10	-13
Held-to-maturity, Total Securities in a loss position, Fair value	2,917	6,189
Held-to-maturity, Gross Unrealized Losses	-13	-40
Available-for-sale, less than 12 continuous months, Fair value		2,695
Available-for-sale, less than 12 continuous months, Unrealized loss		-3
Available-for-sale, greater than 12 continuous months, Fair value		1,112
Available-for-sale, greater than 12 continuous months, Unrealized loss		-5
Available-for-sale, Total Securities in a loss position, Fair Value		3,807
Available-for-sale, Total Securities in a loss position, Unrealized loss		-8
Corporate bonds
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Held-to-maturity, less than 12 continuous months, Fair value	1,997	3,009
Held-to-maturity, less than 12 continuous months, Unrealized loss	-3	-1
Held-to-maturity, greater than 12 continuous months, Fair value	0	3,533
Held-to-maturity, greater than 12 continuous months, Unrealized loss	0	-24
Held-to-maturity, Total Securities in a loss position, Fair value	1,997	6,542
Held-to-maturity, Gross Unrealized Losses	-3	-25
Available-for-sale, less than 12 continuous months, Fair value		1,002
Available-for-sale, less than 12 continuous months, Unrealized loss		-1
Available-for-sale, greater than 12 continuous months, Fair value		990
Available-for-sale, greater than 12 continuous months, Unrealized loss		-3
Available-for-sale, Total Securities in a loss position, Fair Value		1,992
Available-for-sale, Total Securities in a loss position, Unrealized loss		($4)

Investment_Securities_NonMarke

Investment Securities - Non-Marketable Securities (Details) (USD $)	3 Months Ended	0 Months Ended
	Mar. 31, 2015	Jan. 28, 2015	Dec. 31, 2014	Apr. 29, 2015
Schedule of Cost-method Investments [Line Items]
Federal Home Loan Bank stock, par value	$100
Investments in low income housing tax credit funds	$2,800,000		$1,800,000
Low income housing tax credits and other tax benefits	72,000
Low income housing amortization expense	56,000
Unfunded commitments for low income housing tax credit funds	2,200,000
Visa Inc. | Visa Inc. Class A common stock
Schedule of Cost-method Investments [Line Items]
Stockholders' Equity Note, Stock Split, Conversion Ratio		4
Visa Inc. | Visa Inc. Class B common stock
Schedule of Cost-method Investments [Line Items]
Stockholders' Equity Note, Stock Split, Conversion Ratio	1.6483
Visa Inc. Class B common stock
Schedule of Cost-method Investments [Line Items]
Number of shares of securities carried at cost	16,939
Carrying value of securities carried at cost	0
Fair value of Class B common stock	1,800,000		1,800,000
Subsequent event
Schedule of Cost-method Investments [Line Items]
Federal Home Loan Bank, dividend rate percentage				7.67%
Other assets
Schedule of Cost-method Investments [Line Items]
Federal Home Loan Bank stock	$8,200,000		$8,200,000

Loans_and_Allowance_for_Loan_L2

Loans and Allowance for Loan Losses - Loans Outstanding and Aging Analysis (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
	loans		loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	$10,431,000		$10,359,000
Current	1,336,053,000		1,352,992,000
Total loans	1,346,484,000	[1]	1,363,351,000	[1]
Non-accrual loans to total loans	0.70%		0.70%
Purchased Credit Impaired (PCI) loans no longer accreting interest	1,400,000		1,400,000
Purchased Credit-impaired (PCI) loans accreting interest	3,700,000		3,800,000
Number of accruing loans past due more than ninety days	0		0
Deferred loan fees	651,000		487,000
Unaccreted purchase discounts on non-PCI loans	4,200,000		4,400,000
30-59 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	653,000		1,009,000
60-89 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	296,000		0
Greater than 90 days past due (non-accrual) 2
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	9,482,000	[2]	9,350,000	[2]
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	682,000		183,000
Current	195,760,000		210,040,000
Total loans	196,442,000	[1]	210,223,000	[1]
Non-accrual loans to total loans	0.20%		0.00%
Commercial and industrial | 30-59 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	13,000		183,000
Commercial and industrial | 60-89 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	296,000		0
Commercial and industrial | Greater than 90 days past due (non-accrual) 2
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	373,000	[2]	0	[2]
Commercial real estate, owner-occupied
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	1,403,000		1,403,000
Current	233,934,000		229,202,000
Total loans	235,337,000	[1]	230,605,000	[1]
Non-accrual loans to total loans	0.60%		0.60%
Commercial real estate, owner-occupied | 30-59 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	0		0
Commercial real estate, owner-occupied | 60-89 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	0		0
Commercial real estate, owner-occupied | Greater than 90 days past due (non-accrual) 2
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	1,403,000	[2]	1,403,000	[2]
Commercial real estate, investor
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	2,354,000		2,429,000
Current	651,494,000		671,070,000
Total loans	653,848,000	[1]	673,499,000	[1]
Non-accrual loans to total loans	0.40%		0.40%
Commercial real estate, investor | 30-59 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	0		0
Commercial real estate, investor | 60-89 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	0		0
Commercial real estate, investor | Greater than 90 days past due (non-accrual) 2
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	2,354,000	[2]	2,429,000	[2]
Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	5,107,000		5,134,000
Current	51,943,000		43,279,000
Total loans	57,050,000	[1]	48,413,000	[1]
Non-accrual loans to total loans	9.00%		10.60%
Construction | 30-59 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	0		0
Construction | 60-89 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	0		0
Construction | Greater than 90 days past due (non-accrual) 2
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	5,107,000	[2]	5,134,000	[2]
Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	461,000		926,000
Current	112,816,000		109,862,000
Total loans	113,277,000	[1]	110,788,000	[1]
Non-accrual loans to total loans	0.10%		0.30%
Home equity | 30-59 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	295,000		646,000
Home equity | 60-89 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	0		0
Home equity | Greater than 90 days past due (non-accrual) 2
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	166,000	[2]	280,000	[2]
Other residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	161,000	[3]	0	[3]
Current	73,214,000	[3]	73,035,000	[3]
Total loans	73,375,000	[1],[3]	73,035,000	[1],[3]
Non-accrual loans to total loans	0.00%	[3]	0.00%	[3]
Other residential | 30-59 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	161,000	[3]	0	[3]
Other residential | 60-89 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	0	[3]	0	[3]
Other residential | Greater than 90 days past due (non-accrual) 2
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	0	[2],[3]	0	[2],[3]
Installment and other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	263,000		284,000
Current	16,892,000		16,504,000
Total loans	17,155,000	[1]	16,788,000	[1]
Non-accrual loans to total loans	0.50%		0.60%
Installment and other consumer | 30-59 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	184,000		180,000
Installment and other consumer | 60-89 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	0		0
Installment and other consumer | Greater than 90 days past due (non-accrual) 2
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans past due	$79,000	[2]	$104,000	[2]
[1]	Amounts include net deferred loan costs of $651 thousand and $487 thousand at March 31, 2015 and December 31, 2014, respectively. Amounts are also net of unaccreted purchase discounts on non-PCI loans of $4.2 million and $4.4 million at March 31, 2015 and December 31, 2014, respectively.
[2]	Amounts include $1.4 million of Purchased Credit Impaired ("PCI") loans that have stopped accreting interest at both March 31, 2015 and December 31, 2014. Amounts exclude accreting PCI loans of $3.7 million and $3.8 million at March 31, 2015 and December 31, 2014, respectively, as we have a reasonable expectation about future cash flows to be collected and we continue to recognize accretable yield on these loans in interest income. There were no accruing loans past due more than ninety days at March 31, 2015 or December 31, 2014.
[3]	Our residential loan portfolio does not include sub-prime loans, nor is it our practice to underwrite loans commonly referred to as "Alt-A mortgages", the characteristics of which are loans lacking full documentation, borrowers having low FICO scores or higher loan-to-value ratios.

Loans_and_Allowance_for_Loan_L3

Loans and Allowance for Loan Losses - Credit Quality of Loans (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Thousands, unless otherwise specified
Financing Receivable, Recorded Investment [Line Items]
Total loans	$1,346,484	[1]	$1,363,351	[1]
Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment [Line Items]
Purchase credit-impaired	5,072		5,192
Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,286,367		1,293,968
Pass | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment [Line Items]
Purchase credit-impaired	2,202		2,210
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	25,988		33,146
Special Mention | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment [Line Items]
Purchase credit-impaired	1,031		1,140
Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	34,129		36,237
Substandard | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment [Line Items]
Purchase credit-impaired	1,839		1,842
Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Loans excluding purchased credit-impaired loans	196,240		209,899
Total loans	196,442	[1]	210,223	[1]
Commercial and industrial | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment [Line Items]
Purchase credit-impaired	202		324
Commercial and industrial | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans excluding purchased credit-impaired loans	181,842		197,659
Commercial and industrial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans excluding purchased credit-impaired loans	9,424		6,776
Commercial and industrial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans excluding purchased credit-impaired loans	4,974		5,464
Commercial real estate, owner-occupied
Financing Receivable, Recorded Investment [Line Items]
Loans excluding purchased credit-impaired loans	232,708		227,989
Total loans	235,337	[1]	230,605	[1]
Commercial real estate, owner-occupied | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment [Line Items]
Purchase credit-impaired	2,629		2,616
Commercial real estate, owner-occupied | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans excluding purchased credit-impaired loans	211,551		205,820
Commercial real estate, owner-occupied | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans excluding purchased credit-impaired loans	10,281		10,406
Commercial real estate, owner-occupied | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans excluding purchased credit-impaired loans	10,876		11,763
Commercial real estate, investor
Financing Receivable, Recorded Investment [Line Items]
Loans excluding purchased credit-impaired loans	651,684		671,325
Total loans	653,848	[1]	673,499	[1]
Commercial real estate, investor | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment [Line Items]
Purchase credit-impaired	2,164		2,174
Commercial real estate, investor | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans excluding purchased credit-impaired loans	640,656		651,548
Commercial real estate, investor | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans excluding purchased credit-impaired loans	3,853		13,304
Commercial real estate, investor | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans excluding purchased credit-impaired loans	7,175		6,473
Construction
Financing Receivable, Recorded Investment [Line Items]
Loans excluding purchased credit-impaired loans	57,040		48,402
Total loans	57,050	[1]	48,413	[1]
Construction | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment [Line Items]
Purchase credit-impaired	10		11
Construction | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans excluding purchased credit-impaired loans	50,305		41,710
Construction | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans excluding purchased credit-impaired loans	1,078		1,008
Construction | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans excluding purchased credit-impaired loans	5,657		5,684
Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans excluding purchased credit-impaired loans	113,210		110,721
Total loans	113,277	[1]	110,788	[1]
Home equity | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment [Line Items]
Purchase credit-impaired	67		67
Home equity | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans excluding purchased credit-impaired loans	111,227		107,933
Home equity | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans excluding purchased credit-impaired loans	321		322
Home equity | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans excluding purchased credit-impaired loans	1,662		2,466
Other residential
Financing Receivable, Recorded Investment [Line Items]
Total loans	73,375	[1],[2]	73,035	[1],[2]
Other residential | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment [Line Items]
Purchase credit-impaired	0		0
Other residential | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	71,768		70,987
Other residential | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	0		0
Other residential | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,607		2,048
Installment and other consumer
Financing Receivable, Recorded Investment [Line Items]
Total loans	17,155	[1]	16,788	[1]
Installment and other consumer | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment [Line Items]
Purchase credit-impaired	0		0
Installment and other consumer | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	16,816		16,101
Installment and other consumer | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	0		190
Installment and other consumer | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	$339		$497
[1]	Amounts include net deferred loan costs of $651 thousand and $487 thousand at March 31, 2015 and December 31, 2014, respectively. Amounts are also net of unaccreted purchase discounts on non-PCI loans of $4.2 million and $4.4 million at March 31, 2015 and December 31, 2014, respectively.
[2]	Our residential loan portfolio does not include sub-prime loans, nor is it our practice to underwrite loans commonly referred to as "Alt-A mortgages", the characteristics of which are loans lacking full documentation, borrowers having low FICO scores or higher loan-to-value ratios.

Loans_and_Allowance_for_Loan_L4

Loans and Allowance for Loan Losses - Troubled Debt Restructuring by Class (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2015		Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Modifications, Recorded Investment, Removal From Troubled Debt Restructuring	$108,000		$0
Recorded investment in Troubled Debt Restructurings	22,317,000	[1]	22,703,000	[1]
TDR loans accruing interest as of period end	15,600,000		15,900,000
TDR loans acquired	1,600,000		1,800,000
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in Troubled Debt Restructurings	3,477,000	[1]	3,584,000	[1]
Commercial real estate, owner-occupied
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in Troubled Debt Restructurings	8,427,000	[1]	8,459,000	[1]
Commercial real estate, investor
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in Troubled Debt Restructurings	522,000	[1]	524,000	[1]
Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in Troubled Debt Restructurings	5,657,000	[1]	5,684,000	[1]
Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in Troubled Debt Restructurings	561,000	[1]	694,000	[1]
Other residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in Troubled Debt Restructurings	2,037,000	[1]	2,045,000	[1]
Installment and other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in Troubled Debt Restructurings	$1,636,000	[1]	$1,713,000	[1]
[1]	Includes $15.6 million and $15.9 million of TDR loans that were accruing interest as of March 31, 2015 and December 31, 2014, respectively. Includes $1.6 million and $1.8 million of acquired loans at March 31, 2015 and December 31, 2014, respectively.

Loans_and_Allowance_for_Loan_L5

Loans and Allowance for Loan Losses - Troubled Debt Restructuring Modifications (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
	loans	contract
		loans
Financing Receivable, Modifications [Line Items]
Number of Contracts Modified		7
Pre-Modification Outstanding Recorded Investment		$1,740
Post-Modification Outstanding Recorded Investment		1,723
Post-Modification Outstanding Recorded Investment at period end		1,724
Number of troubled debt restructurings	0	0
Commercial and industrial
Financing Receivable, Modifications [Line Items]
Number of Contracts Modified		3
Pre-Modification Outstanding Recorded Investment		1,420
Post-Modification Outstanding Recorded Investment		1,405
Post-Modification Outstanding Recorded Investment at period end		1,405
Home equity
Financing Receivable, Modifications [Line Items]
Number of Contracts Modified		1
Pre-Modification Outstanding Recorded Investment		150
Post-Modification Outstanding Recorded Investment		150
Post-Modification Outstanding Recorded Investment at period end		150
Installment and other consumer
Financing Receivable, Modifications [Line Items]
Number of Contracts Modified		3
Pre-Modification Outstanding Recorded Investment		170
Post-Modification Outstanding Recorded Investment		168
Post-Modification Outstanding Recorded Investment at period end		$169

Loans_and_Allowance_for_Loan_L6

Loans and Allowance for Loan Losses - Impaired Loans and Related Allowance (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Recorded investment in impaired loans:
With no specific allowance recorded	$16,427,000		$16,464,000
With a specific allowance recorded	8,683,000		8,759,000
Total recorded investment in impaired loans	25,110,000		25,223,000
Unpaid principal balance of impaired loans:
With no specific allowance recorded	22,106,000		22,677,000
With a specific allowance recorded	8,939,000		9,028,000
Total unpaid principal balance of impaired loans	31,045,000		31,705,000
Specific valuation	961,000		1,138,000
Average recorded investment in impaired loans during the period	25,168,000	25,751,000	25,909,000
Interest income recognized on impaired loans during the period ended	190,000	274,000	948,000
Gross interest income that would have been recorded had nonaccrual loans been current	231,000	205,000
Charged-off portion of impaired loans	5,400,000
Outstanding commitments to extend credit on impaired loans	1,200,000
Commercial and industrial
Recorded investment in impaired loans:
With no specific allowance recorded	1,318,000		1,141,000
With a specific allowance recorded	2,533,000		2,443,000
Total recorded investment in impaired loans	3,851,000		3,584,000
Unpaid principal balance of impaired loans:
With no specific allowance recorded	1,315,000		1,186,000
With a specific allowance recorded	2,604,000		2,524,000
Total unpaid principal balance of impaired loans	3,919,000		3,710,000
Specific valuation	652,000		694,000
Average recorded investment in impaired loans during the period	3,718,000	5,945,000	5,354,000
Interest income recognized on impaired loans during the period ended	62,000	118,000	378,000
Commercial real estate, owner-occupied
Recorded investment in impaired loans:
With no specific allowance recorded	5,545,000		5,577,000
With a specific allowance recorded	2,882,000		2,882,000
Total recorded investment in impaired loans	8,427,000		8,459,000
Unpaid principal balance of impaired loans:
With no specific allowance recorded	6,545,000		6,577,000
With a specific allowance recorded	2,882,000		2,882,000
Total unpaid principal balance of impaired loans	9,427,000		9,459,000
Specific valuation	32,000		65,000
Average recorded investment in impaired loans during the period	8,443,000	5,484,000	6,604,000
Interest income recognized on impaired loans during the period ended	66,000	83,000	288,000
Commercial real estate, investor
Recorded investment in impaired loans:
With no specific allowance recorded	2,875,000		2,954,000
With a specific allowance recorded	0		0
Total recorded investment in impaired loans	2,875,000		2,954,000
Unpaid principal balance of impaired loans:
With no specific allowance recorded	4,867,000		4,945,000
With a specific allowance recorded	0		0
Total unpaid principal balance of impaired loans	4,867,000		4,945,000
Specific valuation	0		0
Average recorded investment in impaired loans during the period	2,915,000	3,283,000	3,138,000
Interest income recognized on impaired loans during the period ended	6,000	7,000	28,000
Construction
Recorded investment in impaired loans:
With no specific allowance recorded	5,107,000		5,134,000
With a specific allowance recorded	560,000		561,000
Total recorded investment in impaired loans	5,667,000		5,695,000
Unpaid principal balance of impaired loans:
With no specific allowance recorded	7,797,000		7,824,000
With a specific allowance recorded	745,000		749,000
Total unpaid principal balance of impaired loans	8,542,000		8,573,000
Specific valuation	3,000		3,000
Average recorded investment in impaired loans during the period	5,681,000	6,524,000	6,471,000
Interest income recognized on impaired loans during the period ended	9,000	21,000	85,000
Home equity
Recorded investment in impaired loans:
With no specific allowance recorded	263,000		393,000
With a specific allowance recorded	298,000		300,000
Total recorded investment in impaired loans	561,000		693,000
Unpaid principal balance of impaired loans:
With no specific allowance recorded	263,000		880,000
With a specific allowance recorded	298,000		300,000
Total unpaid principal balance of impaired loans	561,000		1,180,000
Specific valuation	1,000		0
Average recorded investment in impaired loans during the period	627,000	577,000	741,000
Interest income recognized on impaired loans during the period ended	5,000	4,000	19,000
Other residential
Recorded investment in impaired loans:
With no specific allowance recorded	1,024,000		1,026,000
With a specific allowance recorded	1,012,000		1,019,000
Total recorded investment in impaired loans	2,036,000		2,045,000
Unpaid principal balance of impaired loans:
With no specific allowance recorded	1,024,000		1,026,000
With a specific allowance recorded	1,012,000		1,019,000
Total unpaid principal balance of impaired loans	2,036,000		2,045,000
Specific valuation	85,000		92,000
Average recorded investment in impaired loans during the period	2,041,000	2,054,000	1,744,000
Interest income recognized on impaired loans during the period ended	23,000	23,000	74,000
Installment and other consumer
Recorded investment in impaired loans:
With no specific allowance recorded	295,000		239,000
With a specific allowance recorded	1,398,000		1,554,000
Total recorded investment in impaired loans	1,693,000		1,793,000
Unpaid principal balance of impaired loans:
With no specific allowance recorded	295,000		239,000
With a specific allowance recorded	1,398,000		1,554,000
Total unpaid principal balance of impaired loans	1,693,000		1,793,000
Specific valuation	188,000		284,000
Average recorded investment in impaired loans during the period	1,743,000	1,884,000	1,857,000
Interest income recognized on impaired loans during the period ended	$19,000	$18,000	$76,000

Loans_and_Allowance_for_Loan_L7

Loans and Allowance for Loan Losses - Allowance for Loan Losses (Details) (USD $)	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014	Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	$15,099,000		$14,224,000
Provision for loan losses	0		150,000
Charge-offs	-8,000		-261,000
Recoveries	65,000		119,000
Ending balance	15,156,000		14,232,000
Ending ALLL related to loans collectively evaluated for impairment	14,195,000			13,961,000
Ending ALLL related to loans individually evaluated for impairment	954,000			1,131,000
Collectively evaluated for impairment	1,317,883,000			1,334,638,000
Individually evaluated for impairment	23,529,000	[1]		23,521,000	[2]
Total loans	1,346,484,000	[3]		1,363,351,000	[3]
Ratio of allowance for loan losses to total loans	1.13%			1.11%
Allowance for loan losses to non-accrual loans	160.00%			161.00%
PCI loans impaired post-acquisition	1,600,000			1,700,000
Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending ALLL related to purchased credit-impaired loans	7,000			7,000
Purchase credit-impaired	5,072,000			5,192,000
Commercial and industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	2,837,000		3,056,000
Provision for loan losses	-275,000		-255,000
Charge-offs	-2,000		-61,000
Recoveries	60,000		32,000
Ending balance	2,620,000		2,772,000
Ending ALLL related to loans collectively evaluated for impairment	1,968,000			2,143,000
Ending ALLL related to loans individually evaluated for impairment	648,000			690,000
Collectively evaluated for impairment	192,557,000			206,603,000
Individually evaluated for impairment	3,683,000	[1]		3,296,000	[2]
Total loans	196,442,000	[3]		210,223,000	[3]
Ratio of allowance for loan losses to total loans	1.33%			1.35%
Allowance for loan losses to non-accrual loans	702.00%
Commercial and industrial | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending ALLL related to purchased credit-impaired loans	4,000			4,000
Purchase credit-impaired	202,000			324,000
Commercial real estate, owner-occupied
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	1,924,000		2,012,000
Provision for loan losses	170,000		-27,000
Charge-offs	0		0
Recoveries	0		0
Ending balance	2,094,000		1,985,000
Ending ALLL related to loans collectively evaluated for impairment	2,062,000			1,859,000
Ending ALLL related to loans individually evaluated for impairment	32,000			65,000
Collectively evaluated for impairment	225,684,000			220,933,000
Individually evaluated for impairment	7,024,000	[1]		7,056,000	[2]
Total loans	235,337,000	[3]		230,605,000	[3]
Ratio of allowance for loan losses to total loans	0.89%			0.83%
Allowance for loan losses to non-accrual loans	149.00%			137.00%
Commercial real estate, owner-occupied | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending ALLL related to purchased credit-impaired loans	0			0
Purchase credit-impaired	2,629,000			2,616,000
Commercial real estate, investor
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	6,672,000		6,196,000
Provision for loan losses	-383,000		268,000
Charge-offs	0		0
Recoveries	3,000		5,000
Ending balance	6,292,000		6,469,000
Ending ALLL related to loans collectively evaluated for impairment	6,292,000			6,672,000
Ending ALLL related to loans individually evaluated for impairment	0			0
Collectively evaluated for impairment	648,809,000			668,371,000
Individually evaluated for impairment	2,875,000	[1]		2,954,000	[2]
Total loans	653,848,000	[3]		673,499,000	[3]
Ratio of allowance for loan losses to total loans	0.96%			0.99%
Allowance for loan losses to non-accrual loans	267.00%			275.00%
Commercial real estate, investor | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending ALLL related to purchased credit-impaired loans	0			0
Purchase credit-impaired	2,164,000			2,174,000
Construction
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	839,000		633,000
Provision for loan losses	-61,000		100,000
Charge-offs	0		-197,000
Recoveries	0		0
Ending balance	778,000		536,000
Ending ALLL related to loans collectively evaluated for impairment	775,000			836,000
Ending ALLL related to loans individually evaluated for impairment	0			0
Collectively evaluated for impairment	51,383,000			42,718,000
Individually evaluated for impairment	5,657,000	[1]		5,684,000	[2]
Total loans	57,050,000	[3]		48,413,000	[3]
Ratio of allowance for loan losses to total loans	1.36%			1.73%
Allowance for loan losses to non-accrual loans	15.00%			16.00%
Construction | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending ALLL related to purchased credit-impaired loans	3,000			3,000
Purchase credit-impaired	10,000			11,000
Home equity
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	859,000		875,000
Provision for loan losses	63,000		11,000
Charge-offs	0		0
Recoveries	1,000		1,000
Ending balance	923,000		887,000
Ending ALLL related to loans collectively evaluated for impairment	922,000			859,000
Ending ALLL related to loans individually evaluated for impairment	1,000			0
Collectively evaluated for impairment	112,649,000			110,028,000
Individually evaluated for impairment	561,000	[1]		693,000	[2]
Total loans	113,277,000	[3]		110,788,000	[3]
Ratio of allowance for loan losses to total loans	0.81%			0.78%
Allowance for loan losses to non-accrual loans	556.00%			307.00%
Home equity | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending ALLL related to purchased credit-impaired loans	0			0
Purchase credit-impaired	67,000			67,000
Other residential
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	433,000		317,000
Provision for loan losses	-3,000		92,000
Charge-offs	0		0
Recoveries	0		0
Ending balance	430,000		409,000
Ending ALLL related to loans collectively evaluated for impairment	345,000			341,000
Ending ALLL related to loans individually evaluated for impairment	85,000			92,000
Collectively evaluated for impairment	71,339,000			70,990,000
Individually evaluated for impairment	2,036,000	[1]		2,045,000	[2]
Total loans	73,375,000	[3],[4]		73,035,000	[3],[4]
Ratio of allowance for loan losses to total loans	0.59%			0.59%
Other residential | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending ALLL related to purchased credit-impaired loans	0			0
Purchase credit-impaired	0			0
Installment and other consumer
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	566,000		629,000
Provision for loan losses	-99,000		-142,000
Charge-offs	-6,000		-3,000
Recoveries	1,000		81,000
Ending balance	462,000		565,000
Ending ALLL related to loans collectively evaluated for impairment	274,000			282,000
Ending ALLL related to loans individually evaluated for impairment	188,000			284,000
Collectively evaluated for impairment	15,462,000			14,995,000
Individually evaluated for impairment	1,693,000	[1]		1,793,000	[2]
Total loans	17,155,000	[3]		16,788,000	[3]
Ratio of allowance for loan losses to total loans	2.69%			3.37%
Allowance for loan losses to non-accrual loans	585.00%			544.00%
Installment and other consumer | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending ALLL related to purchased credit-impaired loans	0			0
Purchase credit-impaired	0			0
Unallocated
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	969,000		506,000
Provision for loan losses	588,000		103,000
Charge-offs	0		0
Recoveries	0		0
Ending balance	1,557,000		609,000
Ending ALLL related to loans collectively evaluated for impairment	1,557,000			969,000
Ending ALLL related to loans individually evaluated for impairment	0			0
Collectively evaluated for impairment	0			0
Individually evaluated for impairment	0	[1]		0	[2]
Total loans	0			0
Unallocated | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending ALLL related to purchased credit-impaired loans	0			0
Purchase credit-impaired	$0			$0
[1]	Total excludes $1.6 million of PCI loans that have experienced post-acquisition declines in cash flows expected to be collected. These loans are included in the "purchased credit-impaired" amount in the next line below.
[2]	Total excludes $1.7 million PCI loans that have experienced credit deterioration post-acquisition, which are included in the "purchased credit-impaired" amount in the next line below.
[3]	Amounts include net deferred loan costs of $651 thousand and $487 thousand at March 31, 2015 and December 31, 2014, respectively. Amounts are also net of unaccreted purchase discounts on non-PCI loans of $4.2 million and $4.4 million at March 31, 2015 and December 31, 2014, respectively.
[4]	Our residential loan portfolio does not include sub-prime loans, nor is it our practice to underwrite loans commonly referred to as "Alt-A mortgages", the characteristics of which are loans lacking full documentation, borrowers having low FICO scores or higher loan-to-value ratios.

Loans_and_Allowance_for_Loan_L8

Loans and Allowance for Loan Losses - Purchased Credit-Impaired Loans (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014
PCI Loans, Carrying Value [Abstract]
Unpaid principal balance	$7,469				$7,678
Carrying value	5,072				5,192
Accretable Yield [Roll Forward]
Balance at beginning of period	4,027		3,649
Removals	-77	[1]	0	[1]
Accretion	-119		-180
Reclassifications (to) from nonaccretable difference	0	[2]	1,832	[2]
Balance at end of period	3,831		5,301
Commercial and industrial
PCI Loans, Carrying Value [Abstract]
Unpaid principal balance	301				479
Carrying value	202				324
Commercial real estate loans
PCI Loans, Carrying Value [Abstract]
Unpaid principal balance	6,806				6,831
Carrying value	4,793				4,790
Construction
PCI Loans, Carrying Value [Abstract]
Unpaid principal balance	132				136
Carrying value	10				11
Home equity
PCI Loans, Carrying Value [Abstract]
Unpaid principal balance	230				232
Carrying value	$67				$67
[1]	Represents the accretable difference that is relieved when a loan exits the PCI population due to payoff, full charge-off, or transfer to repossessed assets, etc.
[2]	Primarily relates to changes in expected credit performance and changes in expected timing of cash flows.

Loans_and_Allowance_for_Loan_L9

Loans and Allowance for Loan Losses - Pledged Loans (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Financial Instruments Owned and Pledged as Collateral [Line Items]
Residential loans pledged for FRB borrowings	$863.60	$868.10
Other residential
Financial Instruments Owned and Pledged as Collateral [Line Items]
Pledged residential loan portfolio to secure borrowing with FRB	30.9	27.7
Line of credit | Federal Home Loan Bank Borrowings
Financial Instruments Owned and Pledged as Collateral [Line Items]
Lines of credit	$446.70	$450.60

Borrowings_Lines_of_Credit_Det

Borrowings - Lines of Credit (Details) (USD $)	0 Months Ended	3 Months Ended
	Feb. 05, 2008	Mar. 31, 2015	Dec. 31, 2014
Line of Credit Facility [Line Items]
Periodic term lender may accelerate due date		3 months
Federal Funds Purchased | Line of credit
Line of Credit Facility [Line Items]
Amount of borrowings outstanding		$0	$0
Federal Home Loan Bank Borrowings | Line of credit
Line of Credit Facility [Line Items]
Lines of credit		446,700,000	450,600,000
Term of FHLB borrowing agreements	10 years
Principal amount of borrowing agreements with FHLB		15,000,000
Fixed interest rate of FHLB borrowing agreement	2.07%
Periodic term interest-only payments are due		3 months
Remaining available line of credit from FHLB		431,500,000
Federal Home Loan Bank Borrowings | Letters of credit
Line of Credit Facility [Line Items]
Amount of borrowings outstanding		241,000
Federal Home Loan Bank Overnight Borrowings | Line of credit
Line of Credit Facility [Line Items]
Amount of borrowings outstanding		0	0
Federal Reserve Line of Credit | Line of credit
Line of Credit Facility [Line Items]
Lines of credit		30,900,000	27,700,000
Amount of borrowings outstanding		0
Unsecured Debt | Federal Funds Purchased | Line of credit
Line of Credit Facility [Line Items]
Lines of credit		$72,000,000	$72,000,000

Borrowings_Subordinated_Debt_D

Borrowings - Subordinated Debt (Details) (USD $)	0 Months Ended	3 Months Ended
	Nov. 29, 2013	Mar. 31, 2015	Mar. 31, 2014	Nov. 29, 2013
				debenture
Debt Instrument [Line Items]
Number of subordinated debentures acquired	2			2
Accretion of discount on subordinated debentures		$53,000	$54,000
Amount guaranteed, on subordinated basis, distributions and other payments on trust preferred securities		8,000,000
Subordinated debenture
Debt Instrument [Line Items]
Number of subordinated debentures acquired	2			2
Subordinated debentures	4,950,000			4,950,000
Contractual value of subordinated debt	8,200,000	8,248,000		8,200,000
Accretion of discount on subordinated debentures		53,000	54,000
Debenture distribution deferral period (up to number of years)	5 years
Subordinated debenture | NorCal Community Bancorp Trust I
Debt Instrument [Line Items]
Contractual value of subordinated debt		4,124,000
Effective interest rate		3.30%
Basis spread on subordinated debentures	3.05%	3.05%
Subordinated debenture | NorCal Community Bancorp Trust II
Debt Instrument [Line Items]
Contractual value of subordinated debt		$4,124,000
Effective interest rate		1.67%
Basis spread on subordinated debentures	1.40%	1.40%

Stockholders_Equity_Details

Stockholders' Equity (Details) (USD $)	1 Months Ended	3 Months Ended		12 Months Ended
In Thousands, except Share data, unless otherwise specified	Nov. 30, 2011	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Dec. 05, 2008
	investor
Class of Stock [Line Items]
Number of institutional investors that purchased warrant	2
Cash dividends to common stockholders		$1,307	$1,120	$4,733
Cash dividends paid per common share		$0.22	$0.19
Performance Shares [Member]
Class of Stock [Line Items]
Vesting period of performance-based stock awards		3 years
Performance Shares [Member] | Minimum [Member]
Class of Stock [Line Items]
Vesting percentage of performance-based awards		0.00%
Performance Shares [Member] | Maximum [Member]
Class of Stock [Line Items]
Vesting percentage of performance-based awards		200.00%
Common stock
Class of Stock [Line Items]
Number of common stock shares authorized to be purchased by warrant		157,198
Exercise price of warrant to purchase common stock (usd per share)		$26.72
U.S. Treasury Capital Purchase Program (TCPP) | Common stock
Class of Stock [Line Items]
Number of common stock shares authorized to be purchased by warrant					154,242
Exercise price of warrant to purchase common stock (usd per share)					$27.23

Commitments_and_Contingencies_1

Commitments and Contingencies (Details) (USD $)	0 Months Ended
	Jan. 14, 2015	Mar. 31, 2015	Dec. 31, 2014
	request
Operating Leases
2015		$2,822,000
2016		3,788,000
2017		3,781,000
2018		3,810,000
2019		3,553,000
Thereafter		6,786,000
Total		24,540,000
Visa Inc.
Litigation Matters
Number of requests by merchants rejoining class settlement	1,179
Loan commitments and standby letters of credit, unused
Loss Contingencies [Line Items]
Loan commitments and standby letters of credit, off-balance sheet		343,700,000
Loan commitments and standby letters of credit, unused | Interest payable and other liabilities
Loss Contingencies [Line Items]
Allowance for off balance sheet commitments		811,000	1,000,000
Commercial lines of credit
Loss Contingencies [Line Items]
Loan commitments and standby letters of credit, off-balance sheet		177,200,000
Revolving home equity lines
Loss Contingencies [Line Items]
Loan commitments and standby letters of credit, off-balance sheet		118,300,000
Undisbursed construction loans
Loss Contingencies [Line Items]
Loan commitments and standby letters of credit, off-balance sheet		34,500,000
Standby letters of credit
Loss Contingencies [Line Items]
Loan commitments and standby letters of credit, off-balance sheet		2,300,000
Personal and other lines of credit
Loss Contingencies [Line Items]
Loan commitments and standby letters of credit, off-balance sheet		$11,400,000

Derivative_Financial_Instrumen2

Derivative Financial Instruments and Hedging Activities (Details) (USD $)	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014	Jun. 30, 2011	Aug. 31, 2010
						derivative	derivative
Derivatives, Fair Value [Line Items]
Lower threshold requiring collateral to be posted, liabilities	$100,000
Higher threshold requiring collateral to be posted, liabilities	250,000
Fair value hedge
Derivatives, Fair Value [Line Items]
Net hedge ineffectiveness, derivatives	11,000		158,000
Designated as hedging instrument | Fair value hedge
Derivatives, Fair Value [Line Items]
Accrued interest on swaps	40,000				41,000
Interest rate swap | Not Designated as Hedging Instrument | Fair value hedge | Forward swap
Derivatives, Fair Value [Line Items]
Number of derivative instruments						1	1
Interest rate swap | Designated as hedging instrument | Fair value hedge
Derivatives, Fair Value [Line Items]
Number of derivative instruments qualifying for short-cut hedge treatment	1
Number of derivative instruments	8
Interest rate swap | Designated as hedging instrument | Fair value hedge | Other assets
Derivatives, Fair Value [Line Items]
Interest rate contracts notional amount, Asset derivatives	0				4,589,000
Interest rate swap | Designated as hedging instrument | Fair value hedge | Other liabilities
Derivatives, Fair Value [Line Items]
Interest rate contracts notional amount, Liability derivatives	30,992,000				26,899,000
Interest rate swap | Designated as hedging instrument | Fair value hedge | Forward swap
Derivatives, Fair Value [Line Items]
Number of derivative instruments						1	1
Interest income | Fair value hedge
Derivatives, Fair Value [Line Items]
(Decrease) increase in value of designated interest rate swaps recognized in interest income	-546,000		736,000
Payment on interest rate swaps recorded in interest income	-235,000		-253,000
Increase (decrease) in value of hedged loans recognized in interest income	571,000		-531,000
Decrease in value of yield maintenance agreement recognized against interest income	-14,000		-47,000
Net loss on derivatives recognized against interest income	-224,000	[1]	-95,000	[1]
Assets and liabilities at fair value measured on a recurring basis | Interest rate contract | Designated as hedging instrument | Fair value hedge | Other assets
Derivatives, Fair Value [Line Items]
Interest rate contracts fair value, Asset derivatives	0				61,000
Assets and liabilities at fair value measured on a recurring basis | Interest rate contract | Designated as hedging instrument | Fair value hedge | Other liabilities
Derivatives, Fair Value [Line Items]
Interest rate contracts fair value, Liability derivatives	$2,481,000				$1,996,000
[1]	Includes hedge ineffectiveness gain of $11 thousand and gain of $158 thousand for the quarters ended March 31, 2015 and March 31, 2014, respectively. Changes in value of swaps were included in the assessment of hedge effectiveness.

Derivative_Financial_Instrumen3

Derivative Financial Instruments and Hedging Activities - Offsetting of Assets (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
Offsetting Assets [Line Items]
Gross Amounts of Recognized Assets	$0	[1]	$61,000	[1]
Gross Amounts Offset in the Statements of Condition	0		0
Net Amounts of Assets Presented in the Statements of Condition	0	[1]	61,000	[1]
Gross Amounts Not Offset in the Statements of Condition, Financial Instruments	0		-61,000
Gross Amounts Not Offset in the Statements of Condition, Cash Collateral Received	0		0
Net Amount	0		0
Counterparty A
Offsetting Assets [Line Items]
Gross Amounts of Recognized Assets	0	[1]	61,000	[1]
Gross Amounts Offset in the Statements of Condition	0		0
Net Amounts of Assets Presented in the Statements of Condition	0	[1]	61,000	[1]
Gross Amounts Not Offset in the Statements of Condition, Financial Instruments	0		-61,000
Gross Amounts Not Offset in the Statements of Condition, Cash Collateral Received	0		0
Net Amount	0		0
Counterparty B
Offsetting Assets [Line Items]
Gross Amounts of Recognized Assets	0	[1]	0	[1]
Gross Amounts Offset in the Statements of Condition	0		0
Net Amounts of Assets Presented in the Statements of Condition	0	[1]	0	[1]
Gross Amounts Not Offset in the Statements of Condition, Financial Instruments	0		0
Gross Amounts Not Offset in the Statements of Condition, Cash Collateral Received	0		0
Net Amount	0		0
Other assets | Interest rate swap
Offsetting Assets [Line Items]
Accrued interest on derivative asset interest rate swaps	$0		$1,000
[1]	Amounts exclude accrued interest totaling zero and $1 thousand at March 31, 2015 and December 31, 2014, respectively.

Derivative_Financial_Instrumen4

Derivative Financial Instruments and Hedging Activities - Offsetting of Liabilities (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Thousands, unless otherwise specified
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	$2,481	[1]	$1,996	[1]
Gross Amounts Offset in the Statements of Condition	0		0
Net Amounts of Liabilities Presented in the Statements of Condition	2,481	[1]	1,996	[1]
Gross Amounts Not Offset in the Statements of Condition, Financial Instruments	0		-61
Gross Amounts Not Offset in the Statements of Condition, Cash Collateral Pledged	-2,481		-1,740
Net Amount	0		195
Counterparty A
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	2,107	[1]	1,616	[1]
Gross Amounts Offset in the Statements of Condition	0		0
Net Amounts of Liabilities Presented in the Statements of Condition	2,107	[1]	1,616	[1]
Gross Amounts Not Offset in the Statements of Condition, Financial Instruments	0		-61
Gross Amounts Not Offset in the Statements of Condition, Cash Collateral Pledged	-2,107		-1,360
Net Amount	0		195
Counterparty B
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	374	[1]	380	[1]
Gross Amounts Offset in the Statements of Condition	0		0
Net Amounts of Liabilities Presented in the Statements of Condition	374	[1]	380	[1]
Gross Amounts Not Offset in the Statements of Condition, Financial Instruments	0		0
Gross Amounts Not Offset in the Statements of Condition, Cash Collateral Pledged	-374		-380
Net Amount	0		0
Other liabilities | Interest rate swap
Offsetting Liabilities [Line Items]
Accrued interest on derivative liability interest swaps	$40		$39
[1]	Amounts exclude accrued interest totaling $40 thousand and $39 thousand at March 31, 2015 and December 31, 2014, respectively.