Business Combinations - Estimated Fair Value of Assets Acquired and Liabilities Assumed (Detail) (USD $)	0 Months Ended
	Dec. 23, 2013	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2013
Assets
Cash value of bank owned life insurance			$ 58,867,000	$ 49,432,000
Deposits:
Goodwill			63,547,000	35,049,000
Prosperity Banking Company [Member]
Assets
Cash and cash equivalents	4,285,000
Federal funds sold and interest-bearing balances	21,687,000
Investment securities	152,274,000
Other investments	8,727,000
Loans	449,696,000
Loans, net	449,696,000
Other real estate owned	5,623,000
Premises and equipment	36,293,000
Intangible assets	4,557,000
Other assets	26,732,000
Total assets	709,874,000
Deposits:
Noninterest-bearing	149,242,000
Interest-bearing	324,441,000
Total deposits	473,683,000
Federal funds purchased and securities sold under agreements to repurchase	21,530,000
Other borrowings	197,313,000
Other liabilities	14,513,000
Subordinated deferrable interest debentures	13,197,000
Total liabilities	720,236,000
Net identifiable assets acquired over (under) liabilities assumed	(10,362,000)
Goodwill	35,153,000		35,200,000
Net assets acquired over (under) liabilities assumed	24,791,000
Consideration:
Ameris Bancorp common shares issued	1,168,918
Prosperity Banking Company [Member] | As Recorded by Acquired Bank [Member]
Assets
Cash and cash equivalents	4,285,000
Federal funds sold and interest-bearing balances	21,687,000
Investment securities	151,863,000
Other investments	8,727,000
Loans	487,358,000
Less allowance for loan losses	(6,811,000)
Loans, net	480,547,000
Other real estate owned	6,883,000
Premises and equipment	36,293,000
Intangible assets	174,000
Other assets	26,600,000
Total assets	737,059,000
Deposits:
Noninterest-bearing	149,242,000
Interest-bearing	324,441,000
Total deposits	473,683,000
Federal funds purchased and securities sold under agreements to repurchase	21,530,000
Other borrowings	185,000,000
Other liabilities	14,058,000
Subordinated deferrable interest debentures	29,500,000
Total liabilities	723,771,000
Net identifiable assets acquired over (under) liabilities assumed	13,288,000
Net assets acquired over (under) liabilities assumed	13,288,000
Consideration:
Ameris Bancorp common shares issued	1,168,918
Purchase price per share of the Company's common stock	$ 21.07
Company common stock issued	24,629,000
Cash exchanged for shares	162,000
Fair value of total consideration transferred	24,791,000
Prosperity Banking Company [Member] | Initial Fair Value Adjustments [Member]
Assets
Investment securities	411,000
Loans	(37,662,000)
Less allowance for loan losses	6,811,000
Loans, net	(30,851,000)
Other real estate owned	(1,260,000)
Intangible assets	4,383,000
Other assets	1,192,000
Total assets	(26,125,000)
Deposits:
Other borrowings	12,313,000
Other liabilities	455,000
Subordinated deferrable interest debentures	(16,303,000)
Total liabilities	(3,535,000)
Net identifiable assets acquired over (under) liabilities assumed	(22,590,000)
Goodwill	34,093,000
Net assets acquired over (under) liabilities assumed	11,503,000
Prosperity Banking Company [Member] | Subsequent Fair Value Adjustments [Member]
Assets
Other assets	(1,060,000)
Total assets	(1,060,000)
Deposits:
Net identifiable assets acquired over (under) liabilities assumed	(1,060,000)
Goodwill	1,060,000
Coastal Bankshares, Inc. [Member]
Assets
Cash and cash equivalents		3,895,000
Federal funds sold and interest-bearing balances		15,923,000
Investment securities		66,766,000
Other investments		975,000
Mortgage loans held for sale		7,288,000
Loans		279,441,000
Loans, net		279,441,000
Other real estate owned		8,864,000
Premises and equipment		11,882,000
Intangible assets		4,542,000
Cash value of bank owned life insurance		7,812,000
Other assets		14,146,000
Total assets		421,534,000
Deposits:
Noninterest-bearing		80,012,000
Interest-bearing		289,012,000
Total deposits		369,024,000
Federal funds purchased and securities sold under agreements to repurchase		5,428,000
Other borrowings		22,005,000
Other liabilities		6,192,000
Subordinated deferrable interest debentures		9,052,000
Total liabilities		411,701,000
Net identifiable assets acquired over (under) liabilities assumed		9,833,000
Goodwill		27,437,000	27,400,000
Net assets acquired over (under) liabilities assumed		37,270,000
Consideration:
Ameris Bancorp common shares issued		1,598,998
Coastal Bankshares, Inc. [Member] | As Recorded by Acquired Bank [Member]
Assets
Cash and cash equivalents		3,895,000
Federal funds sold and interest-bearing balances		15,923,000
Investment securities		67,266,000
Other investments		975,000
Mortgage loans held for sale		7,288,000
Loans		296,141,000
Less allowance for loan losses		(3,218,000)
Loans, net		292,923,000
Other real estate owned		14,992,000
Premises and equipment		11,882,000
Intangible assets		507,000
Cash value of bank owned life insurance		7,812,000
Other assets		14,898,000
Total assets		438,361,000
Deposits:
Noninterest-bearing		80,012,000
Interest-bearing		289,012,000
Total deposits		369,024,000
Federal funds purchased and securities sold under agreements to repurchase		5,428,000
Other borrowings		22,005,000
Other liabilities		6,192,000
Subordinated deferrable interest debentures		15,465,000
Total liabilities		418,114,000
Net identifiable assets acquired over (under) liabilities assumed		20,247,000
Net assets acquired over (under) liabilities assumed		20,247,000
Consideration:
Ameris Bancorp common shares issued		1,598,998
Purchase price per share of the Company's common stock		$ 21.56
Company common stock issued		34,474,000
Cash exchanged for shares		2,796,000
Fair value of total consideration transferred		37,270,000
Coastal Bankshares, Inc. [Member] | Initial Fair Value Adjustments [Member]
Assets
Investment securities		(500,000)
Loans		(16,700,000)
Less allowance for loan losses		3,218,000
Loans, net		(13,482,000)
Other real estate owned		(3,528,000)
Intangible assets		4,266,000
Total assets		(13,244,000)
Deposits:
Subordinated deferrable interest debentures		(6,413,000)
Total liabilities		(6,413,000)
Net identifiable assets acquired over (under) liabilities assumed		(6,831,000)
Goodwill		23,854,000
Net assets acquired over (under) liabilities assumed		17,023,000
Coastal Bankshares, Inc. [Member] | Subsequent Fair Value Adjustments [Member]
Assets
Other real estate owned		(2,600,000)
Intangible assets		(231,000)
Other assets		(752,000)
Total assets		(3,583,000)
Deposits:
Net identifiable assets acquired over (under) liabilities assumed		(3,583,000)
Goodwill		$ 3,583,000