BUSINESS COMBINATIONS - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ / shares in Units, $ in Thousands							12 Months Ended
	Jun. 29, 2018	May 25, 2018	Jan. 31, 2018	Jan. 03, 2018	Jan. 18, 2017	Mar. 11, 2016	Dec. 31, 2018	Jan. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2018
Deposits:
Goodwill							$ 503,434		$ 125,532	$ 125,532
Consideration:
Company common stock issued							547,127		$ 0	$ 72,455
Hamilton State Bancshares, Inc.
Assets
Cash and cash equivalents							13,927
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							1,298,040
Less allowance for loan losses							0
Loans, net							1,298,040
Other real estate owned							847
Premises and equipment							26,760
Intangible assets							23,610
Cash value of bank owned life insurance							4,454
Deferred income taxes, net							6,480
Other assets							13,036
Total assets							1,788,792
Deposits:
Noninterest-bearing							381,039
Interest-bearing							1,204,211
Total deposits							1,585,250
Other borrowings							10,907
Subordinated deferrable interest debenture							2,292
Other liabilities							12,851
Total liabilities							1,611,300
Net identifiable assets acquired over (under) liabilities assumed							177,492
Goodwill							219,643
Net assets acquired over (under) liabilities assumed							397,135
Consideration:
Ameris Bancorp common shares issued	6,548,385
Share price (in dollars per share)	$ 53.35
Company common stock issued	$ 349,400
Company common stock issued	349,356
Cash exchanged for shares	47,779
Fair value of total consideration transferred	397,135
Hamilton State Bancshares, Inc. | Initial Fair Value Adjustments
Assets
Cash and cash equivalents	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)
Deposits:
Noninterest-bearing	0
Interest-bearing	(1,896)
Total deposits	(1,896)
Other borrowings	(66)
Subordinated deferrable interest debenture	(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 (under) liabilities assumed	205,158
Hamilton State Bancshares, Inc. | Subsequent Fair Value Adjustments
Assets
Cash and cash equivalents							(478)
Federal funds sold and interest-bearing deposits in banks							0
Time deposits in other banks							0
Investment securities							0
Other investments							0
Loans							(696)
Less allowance for loan losses							0
Loans, net							(696)
Other real estate owned							0
Premises and equipment							(723)
Intangible assets							7,610
Cash value of bank owned life insurance							0
Deferred income taxes, net							343
Other assets							(17)
Total assets							6,039
Deposits:
Noninterest-bearing							0
Interest-bearing							4,783
Total deposits							4,783
Other borrowings							286
Subordinated deferrable interest debenture							(143)
Other liabilities							0
Total liabilities							4,926
Net identifiable assets acquired over (under) liabilities assumed							1,113
Goodwill							(1,070)
Net assets acquired over (under) liabilities assumed							43
Atlantic Coast Financial Corporation
Assets
Cash and cash equivalents							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							755,704				$ 755,700
Less allowance for loan losses							0
Loans, net							755,704
Other real estate owned							1,041
Premises and equipment							10,896
Intangible assets							7,488
Cash value of bank owned life insurance							18,182
Deferred income taxes, net							6,833
Other assets							2,970
Total assets							874,313
Deposits:
Noninterest-bearing							69,761
Interest-bearing							515,406
Total deposits							585,167
Other borrowings							204,475
Other liabilities							8,354
Total liabilities							797,996
Net identifiable assets acquired over (under) liabilities assumed							76,317
Goodwill							92,970				$ 93,000
Net assets acquired over (under) liabilities assumed							169,287
Consideration:
Ameris Bancorp common shares issued		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 cash equivalents		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)
Deposits:
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 (under) liabilities assumed		84,538
Atlantic Coast Financial Corporation | Subsequent Fair Value Adjustments
Assets
Cash and cash equivalents							0
Federal funds sold and interest-bearing deposits in banks							0
Investment securities							0
Other investments							0
Loans held for sale							0
Loans							(2,478)
Less allowance for loan losses							0
Loans, net							(2,478)
Other real estate owned							0
Premises and equipment							0
Intangible assets							1,551
Cash value of bank owned life insurance							0
Deferred income taxes, net							342
Other assets							0
Total assets							(585)
Deposits:
Noninterest-bearing							0
Interest-bearing							1,025
Total deposits							1,025
Other borrowings							0
Other liabilities							0
Total liabilities							1,025
Net identifiable assets acquired over (under) liabilities assumed							(1,610)
Goodwill							1,610
Net assets acquired over (under) liabilities assumed							0
US Premium Financing Holding Company
Assets
Total assets							23,607
Deposits:
Deferred tax liability							5,916
Total liabilities							5,916
Net identifiable assets acquired over (under) liabilities assumed							17,691
Goodwill							65,290
Net assets acquired over (under) liabilities assumed							82,981
Consideration:
Ameris Bancorp common shares issued			830,301					1,073,158
Share price (in dollars per share)			$ 53.55					$ 53.55
Company common stock issued			$ 44,500	$ 5,500	$ 5,800
Price per share of the Company's common stock (in dollars per share)				$ 48.55	$ 45.45
Company common stock issued								$ 55,855
Cash exchanged for shares								21,421
Present value of contingent earn-out consideration expected to be paid								5,705
Fair value of total consideration transferred			8,900	$ 12,500				82,981
US Premium Financing Holding Company | Initial Fair Value Adjustments
Assets
Total assets			21,314					21,314
Deposits:
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 (under) liabilities assumed			82,981					82,981
US Premium Financing Holding Company | Subsequent Fair Value Adjustments
Assets
Total assets							2,293
Deposits:
Deferred tax liability							424
Total liabilities							424
Net identifiable assets acquired over (under) liabilities assumed							1,869
Goodwill							(1,869)
Net assets acquired over (under) liabilities assumed							0
Jacksonville Bancorp, Inc
Assets
Cash and cash equivalents						$ 9,704
Federal funds sold and interest-bearing deposits in banks						7,027
Investment securities						59,894
Other investments						2,458
Loans						401,638
Less allowance for loan losses						0
Loans, net						401,638
Other real estate owned						1,926
Premises and equipment						4,679
Intangible assets						4,746
Other assets						33,883
Total assets						525,955
Deposits:
Noninterest-bearing						123,399
Interest-bearing						277,960
Total deposits						401,359
Other borrowings						48,434
Subordinated deferrable interest debenture						12,901
Other liabilities						2,354
Total liabilities						465,048
Net identifiable assets acquired over (under) liabilities assumed						60,907
Goodwill						35,485
Net assets acquired over (under) liabilities assumed						$ 96,392
Consideration:
Ameris Bancorp common shares issued						2,549,469
Share price (in dollars per share)						$ 16.50
Price per share of the Company's common stock (in dollars per share)						$ 28.42
Company common stock issued						$ 72,455
Cash exchanged for shares						23,937
Fair value of total consideration transferred						96,392
Jacksonville Bancorp, Inc | Initial Fair Value Adjustments
Assets
Cash and cash equivalents						0
Federal funds sold and interest-bearing deposits in banks						0
Investment securities						(942)
Other investments						0
Loans						(15,746)
Less allowance for loan losses						12,613
Loans, net						(3,133)
Other real estate owned						(1,035)
Premises and equipment						0
Intangible assets						5,566
Other assets						23,266
Total assets						23,722
Deposits:
Noninterest-bearing						0
Interest-bearing						421
Total deposits						421
Other borrowings						84
Subordinated deferrable interest debenture						(3,393)
Other liabilities						0
Total liabilities						(2,888)
Net identifiable assets acquired over (under) liabilities assumed						26,610
Goodwill						31,375
Net assets acquired over (under) liabilities assumed						57,985
Jacksonville Bancorp, Inc | Subsequent Fair Value Adjustments
Assets
Cash and cash equivalents						0
Federal funds sold and interest-bearing deposits in banks						0
Investment securities						0
Other investments						0
Loans						553
Less allowance for loan losses						0
Loans, net						553
Other real estate owned						88
Premises and equipment						(119)
Intangible assets						(1,108)
Other assets						(3,524)
Total assets						(4,110)
Deposits:
Noninterest-bearing						0
Interest-bearing						0
Total deposits						0
Other borrowings						0
Subordinated deferrable interest debenture						0
Other liabilities						0
Total liabilities						0
Net identifiable assets acquired over (under) liabilities assumed						(4,110)
Goodwill						4,110
Net assets acquired over (under) liabilities assumed						0
As Previously Reported | Hamilton State Bancshares, Inc.
Assets
Cash and cash equivalents	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
Deposits:
Noninterest-bearing	381,039
Interest-bearing	1,201,324
Total deposits	1,582,363
Other borrowings	10,687
Subordinated deferrable interest debenture	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 (under) liabilities assumed	$ 191,934
As Previously Reported | Atlantic Coast Financial Corporation
Assets
Cash and cash equivalents		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
Deposits:
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 (under) liabilities assumed		$ 84,749
As Previously Reported | US Premium Financing Holding Company
Assets
Total assets			0					0
Deposits:
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 (under) liabilities assumed			0					0
As Previously Reported | Jacksonville Bancorp, Inc
Assets
Cash and cash equivalents						9,704
Federal funds sold and interest-bearing deposits in banks						7,027
Investment securities						60,836
Other investments						2,458
Loans						416,831
Less allowance for loan losses						(12,613)
Loans, net						404,218
Other real estate owned						2,873
Premises and equipment						4,798
Intangible assets						288
Other assets						14,141
Total assets						506,343
Deposits:
Noninterest-bearing						123,399
Interest-bearing						277,539
Total deposits						400,938
Other borrowings						48,350
Subordinated deferrable interest debenture						16,294
Other liabilities						2,354
Total liabilities						467,936
Net identifiable assets acquired over (under) liabilities assumed						38,407
Goodwill						0
Net assets acquired over (under) liabilities assumed						$ 38,407
Insurance agent relationships | US Premium Financing Holding Company
Assets
Intangible assets							22,351
Insurance agent relationships | US Premium Financing Holding Company | Initial Fair Value Adjustments
Assets
Intangible assets			20,000					20,000
Insurance agent relationships | US Premium Financing Holding Company | Subsequent Fair Value Adjustments
Assets
Intangible assets							2,351
Insurance agent relationships | As Previously Reported | US Premium Financing Holding Company
Assets
Intangible assets			0					0
US Premium Finance trade name | US Premium Financing Holding Company
Assets
Intangible assets							1,094
US Premium Finance trade name | US Premium Financing Holding Company | Initial Fair Value Adjustments
Assets
Intangible assets			1,136					1,136
US Premium Finance trade name | US Premium Financing Holding Company | Subsequent Fair Value Adjustments
Assets
Intangible assets							(42)
US Premium Finance trade name | As Previously Reported | US Premium Financing Holding Company
Assets
Intangible assets			0					0
Non-compete agreement | US Premium Financing Holding Company
Assets
Intangible assets							162
Non-compete agreement | US Premium Financing Holding Company | Initial Fair Value Adjustments
Assets
Intangible assets			178					178
Non-compete agreement | US Premium Financing Holding Company | Subsequent Fair Value Adjustments
Assets
Intangible assets							$ (16)
Non-compete agreement | As Previously Reported | US Premium Financing Holding Company
Assets
Intangible assets			$ 0					$ 0
Weighted Average | US Premium Financing Holding Company
Consideration:
Share price (in dollars per share)			$ 52.047					$ 52.047