ASSETS ACQUIRED IN FDIC-ASSISTED ACQUISITIONS - Components of Covered Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Covered Assets [Line Items]
Covered Loans	$ 33,396	$ 61,269
Less: Fair Value Adjustments	1,526	3,109
Total Covered Loans	31,870	58,160
OREO	242	1,212
Less: Fair Value Adjustments	0	4
Total Covered OREO	242	1,208
Total Covered Assets	32,112	59,368
FDIC loss- share receivable				$ 6,301
FDIC loss-share payable	(8,190)	(6,313)	$ (7,775)
American United Bank (“AUB”)
Covered Assets [Line Items]
Covered Loans	0	0
Less: Fair Value Adjustments	0	0
Total Covered Loans	0	0
OREO	0	0
Less: Fair Value Adjustments	0	0
Total Covered OREO	0	0
Total Covered Assets	0	0
FDIC loss- share receivable	0
FDIC loss-share payable		(27)
United Security Bank (“USB”)
Covered Assets [Line Items]
Covered Loans	2,763	3,199
Less: Fair Value Adjustments	12	13
Total Covered Loans	2,751	3,186
OREO	0	51
Less: Fair Value Adjustments	0	0
Total Covered OREO	0	51
Total Covered Assets	2,751	3,237
FDIC loss-share payable	(1,752)	(1,642)
Satilla Community Bank (“SCB”)
Covered Assets [Line Items]
Covered Loans	2,541	4,019
Less: Fair Value Adjustments	27	51
Total Covered Loans	2,514	3,968
OREO	0	0
Less: Fair Value Adjustments	0	0
Total Covered OREO	0	0
Total Covered Assets	2,514	3,968
FDIC loss-share payable	(169)	(32)
First Bank of Jacksonville (“FBJ”)
Covered Assets [Line Items]
Covered Loans	3,647	3,767
Less: Fair Value Adjustments	394	452
Total Covered Loans	3,253	3,315
OREO	0	0
Less: Fair Value Adjustments	0	0
Total Covered OREO	0	0
Total Covered Assets	3,253	3,315
FDIC loss-share payable	(312)	(234)
Darby Bank & Trust (“DBT”)
Covered Assets [Line Items]
Covered Loans	9,663	12,166
Less: Fair Value Adjustments	356	565
Total Covered Loans	9,307	11,601
OREO	81	0
Less: Fair Value Adjustments	0	0
Total Covered OREO	81	0
Total Covered Assets	9,388	11,601
FDIC loss-share payable	(4,442)	(4,591)
Tifton Banking Company (“TBC”)
Covered Assets [Line Items]
Covered Loans	1,667	1,679
Less: Fair Value Adjustments	0	0
Total Covered Loans	1,667	1,679
OREO	0	0
Less: Fair Value Adjustments	0	0
Total Covered OREO	0	0
Total Covered Assets	1,667	1,679
FDIC loss-share payable	(8)	(33)
High Trust Bank (“HTB”)
Covered Assets [Line Items]
Covered Loans	1,856	1,913
Less: Fair Value Adjustments	28	33
Total Covered Loans	1,828	1,880
OREO	0	0
Less: Fair Value Adjustments	0	0
Total Covered OREO	0	0
Total Covered Assets	1,828	1,880
FDIC loss- share receivable	27	734
One Georgia Bank (“OGB”)
Covered Assets [Line Items]
Covered Loans	930	1,077
Less: Fair Value Adjustments	31	32
Total Covered Loans	899	1,045
OREO	0	0
Less: Fair Value Adjustments	0	0
Total Covered OREO	0	0
Total Covered Assets	899	1,045
FDIC loss-share payable	(1,032)	(993)
Central Bank of Georgia (“CBG”)
Covered Assets [Line Items]
Covered Loans	10,329	33,449
Less: Fair Value Adjustments	678	1,963
Total Covered Loans	9,651	31,486
OREO	161	1,161
Less: Fair Value Adjustments	0	4
Total Covered OREO	161	1,157
Total Covered Assets	9,812	32,643
FDIC loss- share receivable		$ 505
FDIC loss-share payable	$ (502)