BUSINESS COMBINATIONS - Narrative (Details) $ in Thousands	Jul. 01, 2019 USD ($) branch shares	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jun. 30, 2019 USD ($)
Business Acquisition [Line Items]
Goodwill		$ 928,005	$ 931,637	$ 501,140
Fidelity Southern Corporation
Business Acquisition [Line Items]
Number of bank branches | branch	62
Number of stock for each share of Ameris common stock converted (in shares) | shares	0.80
Ameris Bancorp common shares issued (in shares) | shares	22,181,522
Issuance of common stock in acquisitions	$ 869,294
Goodwill	426,900	426,865
Loans	3,510,000	$ 3,512,262
Loan discount	$ 75,200
Loan discount, percent	2.09%
Purchased credit-impaired loans acquired	$ 121,300
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