Consolidated Statements of Cash Flows $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Cash flows from operating activities:
Net income	$ 7,344	$ 5,259	$ 8,586
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan and lease losses	950
Provision for depreciation and amortization	2,061	1,908	1,524
Amortization of core deposit intangible	221	185
Amortization of debt issuance costs	45	40	4
Compensation expense associated with stock options	23	24	42
Compensation expense associated with restricted stock	196	215	89
Tax benefits from vesting of restricted stock	(53)
Net gain on sale or call of securities	(137)	(244)	(443)
Other-than-temporary impairment on investment securities	0	546
Amortization of investment premiums and accretion of discounts, net	2,031	1,715	1,876
Accretion of held-to-maturity fair value adjustments	(56)	(97)	(144)
Loss on cancellation of interest rate swap		2,325
Write-down of fixed assets			238
Write-down of other real estate owned	52	66
(Gain) loss on sale of other real estate owned	(368)	109	(13)
Increase in cash surrender value of life insurance	(548)	(613)	(641)
Life insurance death benefit	(502)
Increase (decrease) in deferred compensation and salary continuation plans	18	(19)	28
Increase in deferred loan fees and costs	(386)	(454)	(713)
Decrease in deferred income taxes	271	132	584
Deferred tax asset write down	2,490	363
Decrease in other assets	863	118	538
(Decrease) increase in other liabilities	(961)	306	(1,219)
Net cash provided by operating activities	13,554	11,884	10,336
Cash flows from investing activities:
Proceeds from maturities and payments of available-for-sale securities	23,551	31,685	23,426
Proceeds from sale of available-for-sale securities	64,349	51,025	71,277
Purchases of available-for-sale securities	(150,888)	(104,134)	(69,362)
Proceeds from maturities and payments of held-to-maturity securities	1,098	4,963	1,099
Investment in Qualified Zone Academy Bonds	(1,000)	(2,000)
Investment in qualified affordable housing partnerships	(124)	(697)	(1,133)
Net (purchase) redemption of Federal Home Loan Bank of San Francisco stock	(72)		1,263
Loan (originations), net of principal repayments	(76,016)	(105,892)	(46,554)
Net (purchase of) repayment on purchased loans	(1,158)	18,666	(12,715)
Purchase of premises and equipment	(584)	(2,873)	(705)
Proceeds from the sale of other real estate owned	2,111	636	3,111
Proceeds from life insurance policy	2,249
Payments to derivative counterparties for the termination of interest rate swaps		(2,578)
Acquisition of branches, net of cash paid		142,411
Net cash (used) provided by investing activities	(136,484)	31,212	(30,293)
Cash flows from financing activities:
Net increase in demand deposits and savings accounts	124,201	84,722	35,382
Net decrease in certificates of deposit	(26,135)	(32,838)	(20,682)
Advances on term debt	30,260	55,000	260,000
Repayment of term debt	(32,080)	(131,172)	(240,083)
Debt issuance costs paid			(223)
Proceeds from stock options exercised	245	10	156
Net proceeds from issuance of common stock	26,778
Redemption of preferred stock			(20,000)
Preferred stock extinguishment costs			(33)
Cash dividends paid on preferred stock			(189)
Cash dividends paid on common stock	(1,776)	(1,603)	(1,601)
Net cash provided by (used in) financing activities	121,493	(25,881)	12,727
Net increase (decrease) cash and cash equivalents	(1,437)	17,215	(7,230)
Cash and cash equivalents at the beginning of year	68,407	51,192	58,422
Cash and cash equivalents at the end of year	66,970	68,407	51,192
Supplemental disclosures of cash flow activity:
Income taxes	3,846	2,705	4,123
Interest	4,581	5,142	4,628
Supplemental disclosures of non cash investing activities:
Transfer of loans to other real estate owned	981	147	3,888
Transfer of fixed asset to other real estate owned			170
Changes in unrealized gain (loss) on investment securities available-for-sale	892	(2,964)	(985)
Changes in net deferred tax asset related to changes in unrealized (loss) gain on investment securities available-for-sale	(368)	1,220	402
Changes in accumulated other comprehensive income (loss) due to changes in unrealized gain (loss) on investment securities available-for-sale	524	(1,744)	(583)
Accretion of held-to-maturity fair value adjustment from other comprehensive income to interest income	(56)	(97)	(144)
Changes in deferred tax related to accretion of held-to-maturity investment securities	23
Changes in accumulated other comprehensive income (loss) due to accretion of held-to-maturity investment securities	(33)	(97)	(144)
Fair value adjustment for held-to-maturity securities transferred to available-for-sale	(167)
Changes in deferred tax related to transfer of held-to-maturity investment securities to available-for-sale	69
Net fair value adjustment for held-to-maturity securities transferred to available-for-sale	(98)
Changes in accumulated other comprehensive income (loss) related held-to-maturity investment securities	(131)	(97)	(144)
Changes in unrealized loss on derivatives		(348)	(584)
Changes in net deferred tax asset related to changes in unrealized loss on derivatives		143	242
Changes in accumulated other comprehensive income (loss) due to changes in unrealized loss on derivatives		(205)	(342)
Reclassification of losses on derivatives		2,721	1,435
Changes in net deferred tax asset related to reclassification of losses on derivatives		(1,120)	(592)
Changes in accumulated other comprehensive income (loss) due to reclassification of losses on derivatives		1,601	843
Supplemental disclosures of non cash financing activities:
Vested and granted restricted stock issued under employee plans		84	36
Stock compensation grants for the 2016 compensation plan	41
Preferred stock accretion
Transfer of HTM to AFS	30,330
Cash dividend declared on common stock and payable after period-end	486	401	400
Transactions Related to Acquisition:
Assets acquired - fair value		155,230
Goodwill		665
Liabilities assumed - fair value		149,239
Preferred Stock [Member]
Supplemental disclosures of non cash financing activities:
Preferred stock accretion			$ 69