Quarterly Results of Operations (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
Quarterly Financial Information Disclosure [Abstract]
Interest income	$ 39,142	$ 38,667	$ 39,178	$ 40,213	$ 41,552	$ 42,520	$ 42,437	$ 42,009	$ 157,200	$ 168,518	$ 151,377
Interest expense	3,681	4,186	4,639	8,387	9,313	10,597	10,864	10,114	20,893	40,888	30,984
Net interest income	35,461	34,481	34,539	31,826	32,239	31,923	31,573	31,895	136,307	127,630	120,393
Provision for credit losses	258	987	9,398	1,775	214	730	1,173	744	12,418	2,861	847
Non-interest income	14,331	12,696	12,060	11,403	11,948	10,739	10,037	9,389	50,490	42,113	38,176
Non-interest expense	26,692	25,221	23,509	24,561	24,814	23,748	23,958	22,783	99,983	95,303	91,945
Income before income tax expense	22,842	20,969	13,692	16,893	19,159	18,184	16,479	17,757	74,396	71,579	65,777
Income tax expense	4,564	4,194	2,752	3,400	3,921	3,696	3,275	3,484	14,910	14,376	12,706
Net income	$ 18,278	$ 16,775	$ 10,940	$ 13,493	$ 15,238	$ 14,488	$ 13,204	$ 14,273	$ 59,486	$ 57,203	$ 53,071
Per common share:
Basic earnings per share	$ 1.22	$ 1.12	$ 0.73	$ 0.89	$ 1.00	$ 0.94	$ 0.85	$ 0.91	$ 3.96	$ 3.70	$ 3.40
Diluted earnings per share	$ 1.22	$ 1.11	$ 0.73	$ 0.89	$ 0.99	$ 0.94	$ 0.85	$ 0.91	$ 3.95	$ 3.69	$ 3.39