BUSINESS COMBINATIONS - Narrative (Details)		12 Months Ended
	Jul. 01, 2019 USD ($) branch shares	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 13, 2021 USD ($)
Business Acquisition [Line Items]
Goodwill		$ 1,012,620,000	$ 928,005,000	$ 931,637,000
Issuance of common stock in acquisition		0	$ 0	$ 869,294,000
Fidelity Southern Corporation
Business Acquisition [Line Items]
Goodwill		426,865,000
Other intangible assets, net		50,610,000
Number of bank branches | branch	62
Number of stock for each share of Ameris common stock converted (in shares) | shares	0.80
Common shares issued in a business combination (in shares) | shares	22,181,522
Issuance of common stock in acquisition	$ 869,300,000
Loans	3,510,000,000	$ 3,512,262,000
Loan discount	$ 75,200,000
Loan discount, percent	2.09%
Accretable yield	$ 121,300,000
Fidelity Southern Corporation | Georgia
Business Acquisition [Line Items]
Number of bank branches | branch	46
Fidelity Southern Corporation | Florida
Business Acquisition [Line Items]
Number of bank branches | branch	16
Balboa Capital Corporation
Business Acquisition [Line Items]
Goodwill					$ 84,600,000
Other intangible assets, net					68,900,000
Goodwill expected to be deductible for tax purposes					$ 0