Business Combinations - Narrative (Details) $ / shares in Units, $ in Thousands			12 Months Ended
	Aug. 01, 2021 USD ($) bank $ / shares shares	May 01, 2019 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Business Acquisition [Line Items]
Cash consideration paid			$ 4,210	$ 0
Goodwill			52,906	15,992
Change in goodwill			0	485
SouthCrest Financial Group, Inc.
Business Acquisition [Line Items]
Number of banking locations | bank	8
Cash paid in exchange for each share (in dollars per share) | $ / shares	$ 10.45
Shares exchanged for each share (in shares) | shares	0.7318
Shares of CBAN common stock issued to Southcrest shareholders (in shares) | shares	3,987,815
Fair value of shares issued	$ 71,400
Cash consideration paid	21,600
Goodwill	35,037
Revenue of acquiree since acquisition date, actual			7,900
Net income of acquiree since acquisition date, actual			6,000
Pro forma revenue			121,900	114,700
Pro forma net income (loss)			20,800	$ 11,600
Credit impaired loans acquired	306,302
Change in goodwill	$ 35,000
LBC Bancshares, Inc
Business Acquisition [Line Items]
Shares of CBAN common stock issued to Southcrest shareholders (in shares) | shares	3,987,815
Fair value of shares issued	$ 71,382
Cash consideration paid	21,620
Loans	307,456
Discount on loans purchased	$ 635
Discount on loans purchased, percentage of loan value	210.00%
Credit impaired loans acquired	$ 1,154
Change in goodwill		$ 15,700
Insurance Agencies
Business Acquisition [Line Items]
Change in goodwill			1,900
Insurance Agencies | Customer Deposits
Business Acquisition [Line Items]
Finite-lived intangible assets acquired			$ 2,300