Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Interest income:
Interest and fees on loans		$ 39,112	$ 35,435	$ 32,871
Interest on taxable securities		3,921	2,986	3,284
Interest on tax-exempt securities		2,144	2,256	2,392
Interest on interest-bearing deposits in other banks		772	332	206
Total interest income		45,949	41,009	38,753
Interest expense:
Interest on demand deposits		744	523	460
Interest on savings deposits		200	174	213
Interest on certificates of deposit		2,188	2,179	2,356
Interest on term debt		1,168	1,667	1,759
Interest on junior subordinated debentures		287	235	195
Total interest expense		4,587	4,778	4,983
Net interest income		41,362	36,231	33,770
Provision for loan and lease losses		950
Net interest income after provision for loan and lease losses		40,412	36,231	33,770
Noninterest income:
Service charges on deposit accounts		542	413	204
ATM and point of sale fees		1,093	995	383
Fees on payroll and benefit processing		658	593	555
Life insurance		1,050	613	641
Gain on sale of investment securities, net		137	244	443
Impairment losses on investment securities		0	(546)
Federal Home Loan Bank of San Francisco dividends		318	644	630
Gain (loss) on sale of OREO		368	(109)	13
Insured cash sweep fees		197	3
Other income		461	636	314
Total noninterest income		4,824	3,486	3,183
Noninterest expense:
Salaries and related benefits		17,819	16,425	14,303
Premises and equipment		4,242	3,869	2,894
Federal Deposit Insurance Corporation insurance premium		318	615	717
Data processing fees		1,749	1,675	1,016
Professional service fees		1,398	1,690	1,628
Telecommunications		879	751	449
Branch acquisition costs			580	347
Loss on cancellation of interest rate swap			2,325
Other expenses		4,559	4,570	3,551
Total noninterest expense		30,964	32,500	24,905
Income before provision for income taxes		14,272	7,217	12,048
Provision for income taxes		6,928	1,958	3,462
Net income		7,344	5,259	8,586
Less: Preferred stock extinguishment costs				102
Less: Preferred stock dividends				189
Income available to common shareholders		$ 7,344	$ 5,259	$ 8,295
Earnings per share - basic (in dollars per share)		$ 0.48	$ 0.39	$ 0.62
Weighted average shares - basic (in shares)	[1]	15,207	13,367	13,331
Earnings per share - diluted (in dollars per share)		$ 0.48	$ 0.39	$ 0.62
Weighted average shares - diluted (in shares)		15,310	13,425	13,365

[1] Excludes unvested restricted shares because they do not have dividend or voting rights.