Condensed Financial Information of Ameris Bancorp (Parent Company Only) - Condensed Balance Sheets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Assets
Cash and due from banks	$ 80,256	$ 65,528	$ 74,326	$ 81,060
Other assets	24,409	24,889
Total assets	3,019,052	2,994,307
Liabilities
Other liabilities	22,983	9,037
Subordinated deferrable interest debentures	42,269	42,269
Total liabilities	2,740,035	2,700,537
Stockholders' equity	279,017	293,770	273,407
Total liabilities and stockholders' equity	3,019,052	2,994,307
Parent Company [Member]
Assets
Cash and due from banks	1,639	4,200	8,763	6,233
Investment in subsidiaries	319,364	331,946
Other assets	4,440	1,063
Total assets	325,443	337,209
Liabilities
Other liabilities	4,157	1,170
Subordinated deferrable interest debentures	42,269	42,269
Total liabilities	46,426	43,439
Stockholders' equity	279,017	293,770
Total liabilities and stockholders' equity	$ 325,443	$ 337,209