Consolidated Statements of Income - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Interest income:
Interest and fees on taxable loans	$ 48,993,000	$ 40,827,000	$ 37,241,000
Interest and fees on tax-exempt loans	1,101,000	960,000	540,000
Interest and dividends on taxable investment securities	19,643,000	11,264,000	6,792,000
Interest and dividends on tax-exempt investment securities	535,000	703,000	585,000
Interest on federal funds sold and other interest-earning assets	577,000	473,000	278,000
Total interest income	70,849,000	54,227,000	45,436,000
Interest expense:
Demand- interest bearing	3,020,000	2,088,000	1,401,000
Money market and savings	3,160,000	2,639,000	2,170,000
Time deposits	1,238,000	942,000	695,000
Other borrowings	1,366,000	1,194,000	1,115,000
Total interest expense	8,784,000	6,863,000	5,381,000
Net interest income	62,065,000	47,364,000	40,055,000
Provision for loan losses	900,000	1,557,000	500,000
Net interest income after provision for loan losses	61,165,000	45,807,000	39,555,000
Non-interest income:
Loan and servicing fees	1,614,000	1,627,000	2,226,000
Mortgage banking income	11,170,000	5,062,000
Gain on sales of SBA loans	3,378,000	4,981,000	3,139,000
Service fees on deposit accounts	3,904,000	2,658,000	1,720,000
Legal settlements			2,550,000
Gain (loss) on sale of investment securities	(146,000)	656,000	108,000
Net securities impairment losses recognized in earnings	0	(7,000)	(3,000)
Other non-interest income	(177,000)	(335,000)	(203,000)
Total non-interest income	20,097,000	15,312,000	9,943,000
Non-interest expenses:
Salaries and employee benefits	37,959,000	28,602,000	22,488,000
Occupancy	7,156,000	6,109,000	4,929,000
Depreciation and amortization	4,618,000	3,518,000	3,080,000
Legal	984,000	459,000	915,000
Other real estate owned	4,092,000	2,182,000	4,239,000
Appraisal and other loan expenses	1,878,000	866,000	280,000
Advertising	1,279,000	811,000	627,000
Data processing	3,134,000	2,408,000	1,593,000
Insurance	982,000	962,000	720,000
Professional fees	1,893,000	1,580,000	1,268,000
Regulatory assessments and costs	1,367,000	1,413,000	1,248,000
Taxes, other	817,000	366,000	689,000
Other operating expenses	9,117,000	7,017,000	5,015,000
Total non-interest expense	75,276,000	56,293,000	47,091,000
Income before benefit for income taxes	5,986,000	4,826,000	2,407,000
Benefit for income taxes	(2,919,000)	(119,000)	(26,000)
Net income	$ 8,905,000	$ 4,945,000	$ 2,433,000
Net income per share
Basic (in dollars per share)	$ 0.16	$ 0.13	$ 0.06
Diluted (in dollars per share)	$ 0.15	$ 0.12	$ 0.06