BUSINESS COMBINATIONS - Narrative (Details) $ / shares in Units, $ in Thousands					1 Months Ended	3 Months Ended			6 Months Ended
	Jun. 29, 2018 USD ($) branch $ / shares shares	May 25, 2018 USD ($) branch $ / shares shares	Jan. 31, 2018 USD ($) shares	Jan. 03, 2018 USD ($)	Jan. 31, 2018 USD ($) transaction shares	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jan. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)
Business Acquisition [Line Items]
Issuance of common stock in acquisitions									$ 547,127	$ 0
Goodwill						$ 504,764		$ 125,532	504,764	125,532		$ 125,532
Liability for USPF acquisition contingent consideration						3,699			3,699
Amortization of intangible assets						2,252		1,013	3,186	2,049
Other noninterest income						5,230		$ 2,864	$ 8,810	$ 6,083
US Premium Financing Holding Company
Business Acquisition [Line Items]
Ameris Bancorp common shares issued (in shares) | shares			830,301
Consideration transferred			$ 8,900	$ 12,500
Ownership percentage											30.00%
Cost method investment											$ 23,900
Hamilton State Bancshares, Inc.
Business Acquisition [Line Items]
Number of bank branches | branch	28
Number of stock for each share of Ameris common stock converted | shares	0.16
Cash consideration distributed per share to shareholders of acquiree (USD per share) | $ / shares	$ 0.93
Ameris Bancorp common shares issued (in shares) | shares	6,548,385
Issuance of common stock in acquisitions	$ 349,356
Cash exchanged for shares	47,736
Goodwill	220,713
Loans	1,298,736
Loan discount	$ 15,500
Loan discount, percent	1.18%
Consideration transferred	$ 397,092
Purchased credit-impaired loans acquired	$ 18,800
Atlantic Coast Financial Corporation
Business Acquisition [Line Items]
Number of bank branches | branch		12
Number of stock for each share of Ameris common stock converted | shares		0.17
Cash consideration distributed per share to shareholders of acquiree (USD per share) | $ / shares		$ 1.39
Ameris Bancorp common shares issued (in shares) | shares		2,631,520
Issuance of common stock in acquisitions		$ 147,760
Cash exchanged for shares		21,527
Goodwill		91,360
Loans		758,182
Loan discount		$ 19,400
Loan discount, percent		2.50%
Consideration transferred		$ 169,287
Purchased credit-impaired loans acquired		$ 12,100
US Premium Financing Holding Company
Business Acquisition [Line Items]
Ameris Bancorp common shares issued (in shares) | shares			1,073,158		1,073,158
Issuance of common stock in acquisitions			$ 55,855		$ 55,900
Cash exchanged for shares			21,421		21,400
Goodwill			$ 67,159		$ 67,159
Percentage of voting interests acquired			70.00%		70.00%
Number of acquisition transactions | transaction					3
Contingent consideration, maximum			$ 5,800		$ 5,800
Liability for USPF acquisition contingent consideration			5,700		$ 5,700
Consideration transferred			$ 82,981
Amortization of intangible assets						1,300
Amortization expense not recorded due to allocation timing							$ 504
Other noninterest income						$ 2,000