Consolidated Statements of Income - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest income:
Interest and fees on taxable loans	$ 62,502,000	$ 48,993,000	$ 40,827,000
Interest and fees on tax-exempt loans	1,543,000	1,101,000	960,000
Interest and dividends on taxable investment securities	26,677,000	19,643,000	11,264,000
Interest and dividends on tax-exempt investment securities	505,000	535,000	703,000
Interest on federal funds sold and other interest-earning assets	847,000	577,000	473,000
Total interest income	92,074,000	70,849,000	54,227,000
Interest expense:
Demand- interest bearing	7,946,000	3,020,000	2,088,000
Money market and savings	4,898,000	3,160,000	2,639,000
Time deposits	1,588,000	1,238,000	942,000
Other borrowings	1,738,000	1,366,000	1,194,000
Total interest expense	16,170,000	8,784,000	6,863,000
Net interest income	75,904,000	62,065,000	47,364,000
Provision for loan losses	2,300,000	900,000	1,557,000
Net interest income after provision for loan losses	73,604,000	61,165,000	45,807,000
Non-interest income:
Non-interest income	5,650,000	4,081,000	2,993,000
Gain on sales of SBA loans	3,105,000	3,378,000	4,981,000
Gain (loss) on sale of investment securities	(67,000)	(146,000)	656,000
Net securities impairment losses recognized in earnings			(7,000)
Other non-interest income	174,000	177,000	335,000
Total non-interest income	20,322,000	20,097,000	15,312,000
Non-interest expenses:
Salaries and employee benefits	44,082,000	37,959,000	28,602,000
Occupancy	8,046,000	7,156,000	6,109,000
Depreciation and amortization	5,447,000	4,618,000	3,518,000
Legal	985,000	984,000	459,000
Other real estate owned	1,588,000	4,092,000	2,182,000
Appraisal and other loan expenses	1,840,000	1,878,000	866,000
Advertising	1,211,000	1,279,000	811,000
Data processing	3,855,000	3,134,000	2,408,000
Insurance	996,000	982,000	962,000
Professional fees	2,048,000	1,893,000	1,580,000
Automated teller machine expenses	1,868,000	1,264,000	814,000
Regulatory assessments and costs	1,675,000	1,367,000	1,413,000
Taxes, other	796,000	817,000	366,000
Other operating expenses	9,284,000	7,853,000	6,203,000
Total non-interest expense	83,721,000	75,276,000	56,293,000
Income before benefit for income taxes	10,205,000	5,986,000	4,826,000
Provision (benefit) for income taxes	1,578,000	(2,919,000)	(119,000)
Net income	$ 8,627,000	$ 8,905,000	$ 4,945,000
Net income per share
Basic (in dollars per share)	$ 0.15	$ 0.16	$ 0.13
Diluted (in dollars per share)	$ 0.15	$ 0.15	$ 0.12
Loan and Servicing Fees [Member]
Non-interest income:
Non-interest income	$ 1,401,000	$ 1,614,000	$ 1,627,000
Mortgage Banking [Member]
Non-interest income:
Non-interest income	10,233,000	11,170,000	5,062,000
Deposit Account [Member]
Non-interest income:
Non-interest income	$ 5,476,000	$ 3,904,000	$ 2,658,000