BUSINESS COMBINATIONS - Schedule of Assets And Liabilities Acquired (Details) - USD ($) $ / shares in Units, $ in Thousands				1 Months Ended	6 Months Ended
	Jun. 29, 2018	May 25, 2018	Jan. 31, 2018	Jan. 31, 2018	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Liabilities
Goodwill					$ 504,764	$ 125,532	$ 125,532
Company common stock issued					$ 547,127	$ 0
Hamilton State Bancshares, Inc.
Assets
Cash and due from banks	$ 14,405
Federal funds sold and interest-bearing deposits in banks	102,156
Time deposits in other banks	11,558
Investment securities	285,830
Other investments	2,094
Loans	1,298,736
Less allowance for loan losses	0
Loans, net	1,298,736
Other real estate owned	847
Premises and equipment	27,483
Intangible assets	16,000
Cash value of bank owned life insurance	4,454
Deferred income taxes, net	6,137
Other assets	13,053
Total assets	1,782,753
Liabilities
Noninterest-bearing	381,039
Interest-bearing	1,199,428
Total deposits	1,580,467
Other borrowings	10,621
Subordinated deferrable interest debentures	2,435
Other liabilities	12,851
Total liabilities	1,606,374
Net identifiable assets acquired over (under) liabilities assumed	176,379
Goodwill	220,713
Net assets acquired over liabilities assumed	$ 397,092
Ameris Bancorp common shares issued (in shares)	6,548,385
Share price (in dollars per share)	$ 53.35
Company common stock issued	$ 349,356
Cash exchanged for shares	47,736
Fair value of total consideration transferred	397,092
Hamilton State Bancshares, Inc. | Initial Fair Value Adjustments
Assets
Cash and due from banks	0
Federal funds sold and interest-bearing deposits in banks	0
Time deposits in other banks	0
Investment securities	(2,376)
Other investments	0
Loans	(15,528)
Less allowance for loan losses	11,183
Loans, net	(4,345)
Other real estate owned	0
Premises and equipment	0
Intangible assets	(2,755)
Cash value of bank owned life insurance	0
Deferred income taxes, net	(6,308)
Other assets	0
Total assets	(15,784)
Liabilities
Noninterest-bearing	0
Interest-bearing	(1,896)
Total deposits	(1,896)
Other borrowings	(66)
Subordinated deferrable interest debentures	(658)
Other liabilities	2,391
Total liabilities	(229)
Net identifiable assets acquired over (under) liabilities assumed	(15,555)
Goodwill	220,713
Net assets acquired over liabilities assumed	205,158
Hamilton State Bancshares, Inc. | Scenario, Previously Reported
Assets
Cash and due from banks	14,405
Federal funds sold and interest-bearing deposits in banks	102,156
Time deposits in other banks	11,558
Investment securities	288,206
Other investments	2,094
Loans	1,314,264
Less allowance for loan losses	(11,183)
Loans, net	1,303,081
Other real estate owned	847
Premises and equipment	27,483
Intangible assets	18,755
Cash value of bank owned life insurance	4,454
Deferred income taxes, net	12,445
Other assets	13,053
Total assets	1,798,537
Liabilities
Noninterest-bearing	381,039
Interest-bearing	1,201,324
Total deposits	1,582,363
Other borrowings	10,687
Subordinated deferrable interest debentures	3,093
Other liabilities	10,460
Total liabilities	1,606,603
Net identifiable assets acquired over (under) liabilities assumed	191,934
Goodwill	0
Net assets acquired over liabilities assumed	$ 191,934
Atlantic Coast Financial Corporation
Assets
Cash and due from banks		$ 3,990
Federal funds sold and interest-bearing deposits in banks		22,149
Investment securities		35,126
Other investments		9,576
Loans held for sale		358
Loans		758,182
Less allowance for loan losses		0
Loans, net		758,182
Other real estate owned		1,041
Premises and equipment		10,896
Intangible assets		5,937
Cash value of bank owned life insurance		18,182
Deferred income taxes, net		6,491
Other assets		2,970
Total assets		874,898
Liabilities
Noninterest-bearing		69,761
Interest-bearing		514,381
Total deposits		584,142
Other borrowings		204,475
Other liabilities		8,354
Total liabilities		796,971
Net identifiable assets acquired over (under) liabilities assumed		77,927
Goodwill		91,360
Net assets acquired over liabilities assumed		$ 169,287
Ameris Bancorp common shares issued (in shares)		2,631,520
Share price (in dollars per share)		$ 56.15
Company common stock issued		$ 147,760
Cash exchanged for shares		21,527
Fair value of total consideration transferred		169,287
Atlantic Coast Financial Corporation | Initial Fair Value Adjustments
Assets
Cash and due from banks		0
Federal funds sold and interest-bearing deposits in banks		0
Investment securities		(60)
Other investments		0
Loans held for sale		0
Loans		(19,423)
Less allowance for loan losses		8,573
Loans, net		(10,850)
Other real estate owned		(796)
Premises and equipment		(1,695)
Intangible assets		5,937
Cash value of bank owned life insurance		0
Deferred income taxes, net		709
Other assets		(634)
Total assets		(7,389)
Liabilities
Noninterest-bearing		0
Interest-bearing		(554)
Total deposits		(554)
Other borrowings		0
Other liabilities		(13)
Total liabilities		(567)
Net identifiable assets acquired over (under) liabilities assumed		(6,822)
Goodwill		91,360
Net assets acquired over liabilities assumed		84,538
Atlantic Coast Financial Corporation | Scenario, Previously Reported
Assets
Cash and due from banks		3,990
Federal funds sold and interest-bearing deposits in banks		22,149
Investment securities		35,186
Other investments		9,576
Loans held for sale		358
Loans		777,605
Less allowance for loan losses		(8,573)
Loans, net		769,032
Other real estate owned		1,837
Premises and equipment		12,591
Intangible assets		0
Cash value of bank owned life insurance		18,182
Deferred income taxes, net		5,782
Other assets		3,604
Total assets		882,287
Liabilities
Noninterest-bearing		69,761
Interest-bearing		514,935
Total deposits		584,696
Other borrowings		204,475
Other liabilities		8,367
Total liabilities		797,538
Net identifiable assets acquired over (under) liabilities assumed		84,749
Goodwill		0
Net assets acquired over liabilities assumed		$ 84,749
US Premium Financing Holding Company
Assets
Total assets			$ 21,314	$ 21,314
Liabilities
Deferred tax liability			5,492	5,492
Total liabilities			5,492	5,492
Net identifiable assets acquired over (under) liabilities assumed			15,822	15,822
Goodwill			67,159	67,159
Net assets acquired over liabilities assumed			$ 82,981	$ 82,981
Ameris Bancorp common shares issued (in shares)			1,073,158	1,073,158
Share price (in dollars per share)			$ 52.05	$ 52.05
Company common stock issued			$ 55,855	$ 55,900
Cash exchanged for shares			21,421	21,400
Present value of contingent earn-out consideration expected to be paid			5,705
Fair value of total consideration transferred			82,981
US Premium Financing Holding Company | Insurance Agent Relationships
Assets
Intangible assets			20,000	20,000
US Premium Financing Holding Company | Trade Names
Assets
Intangible assets			1,136	1,136
US Premium Financing Holding Company | Noncompete Agreements
Assets
Intangible assets			178	178
US Premium Financing Holding Company | Initial Fair Value Adjustments
Assets
Total assets			21,314	21,314
Liabilities
Deferred tax liability			5,492	5,492
Total liabilities			5,492	5,492
Net identifiable assets acquired over (under) liabilities assumed			15,822	15,822
Goodwill			67,159	67,159
Net assets acquired over liabilities assumed			82,981	82,981
US Premium Financing Holding Company | Initial Fair Value Adjustments | Insurance Agent Relationships
Assets
Intangible assets			20,000	20,000
US Premium Financing Holding Company | Initial Fair Value Adjustments | Trade Names
Assets
Intangible assets			1,136	1,136
US Premium Financing Holding Company | Initial Fair Value Adjustments | Noncompete Agreements
Assets
Intangible assets			178	178
US Premium Financing Holding Company | Scenario, Previously Reported
Assets
Total assets			0	0
Liabilities
Deferred tax liability			0	0
Total liabilities			0	0
Net identifiable assets acquired over (under) liabilities assumed			0	0
Goodwill			0	0
Net assets acquired over liabilities assumed			0	0
US Premium Financing Holding Company | Scenario, Previously Reported | Insurance Agent Relationships
Assets
Intangible assets			0	0
US Premium Financing Holding Company | Scenario, Previously Reported | Trade Names
Assets
Intangible assets			0	0
US Premium Financing Holding Company | Scenario, Previously Reported | Noncompete Agreements
Assets
Intangible assets			$ 0	$ 0