Business Combinations - Estimated Fair Value of Assets Acquired and Liabilities Assumed (Detail) (USD $)	0 Months Ended
	Jan. 28, 2015	Jun. 30, 2014	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Assets
Cash value of bank owned life insurance			$ 59,212,000	$ 58,867,000	$ 49,738,000
Total assets				473,000,000
Deposits:
Federal funds purchased and securities sold under agreements to repurchase			16,100,000
Goodwill			63,547,000	63,547,000	35,049,000
Consideration:
Fair value of total consideration transferred	50,000,000
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