Selected Condensed Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Summary of selected quarterly financial information
Interest income									$ 94,818	$ 92,652	$ 76,657
Interest expense									15,008	25,383	16,505
Net interest income									79,810	67,269	60,152
Provision for loan losses									29,600	2,300	1,900
Noninterest income									27,353	14,983	10,201
Noninterest expenses									53,744	44,473	39,763
Income before income tax expense									23,819	35,479	28,690
Income tax expense									5,491	7,621	6,401
Net income available to common shareholders									$ 18,328	$ 27,858	$ 22,289
Earnings per common share
Basic									$ 2.37	$ 3.70	$ 3.02
Diluted									$ 2.34	$ 3.58	$ 2.88
Weighted average common shares outstanding
Basic									7,718,615	7,528,283	7,384,200
Diluted									7,824,214	7,772,544	7,737,495
Quarterly Financial Information [Member]
Summary of selected quarterly financial information
Interest income	$ 23,547	$ 23,415	$ 23,991	$ 23,866	$ 23,896	$ 24,056	$ 23,088	$ 21,612
Interest expense	2,244	2,778	4,217	5,768	6,263	6,777	6,549	5,794
Net interest income	21,303	20,637	19,774	18,098	17,633	17,279	16,539	15,818
Provision for loan losses	2,300	11,100	10,200	6,000	1,050	650	300	300
Noninterest income	6,644	7,584	9,207	3,916	3,503	4,396	4,090	2,994
Noninterest expenses	14,544	14,183	12,644	12,372	10,973	11,484	11,368	10,648
Income before income tax expense	11,103	2,938	6,137	3,642	9,113	9,541	8,961	7,864
Income tax expense	2,502	721	1,459	810	1,915	2,129	1,722	1,855
Net income available to common shareholders	$ 8,601	$ 2,217	$ 4,678	$ 2,832	$ 7,198	$ 7,412	$ 7,239	$ 6,009
Earnings per common share
Basic	$ 1.11	$ 0.29	$ 0.61	$ 0.37	$ 0.94	$ 0.98	$ 0.97	$ 0.81
Diluted	$ 1.10	$ 0.28	$ 0.60	$ 0.36	$ 0.92	$ 0.95	$ 0.93	$ 0.78
Weighted average common shares outstanding
Basic	7,740,755	7,732,293	7,722,419	7,678,598	7,608,241	7,548,184	7,495,508	7,459,342
Diluted	7,835,739	7,815,265	7,818,651	7,827,173	7,810,922	7,780,504	7,756,044	7,741,860