SECURITIES - Investment Securities Available for Sale in Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Available-for-sale securities in a continuous unrealized loss position, fair value [Abstract]
Less than 12 months	$ 117,756	$ 123,007
12 months or longer	135,840	131,436
Total	253,596	254,443
Available-for-sale securities in a continuous unrealized loss position, unrealized losses [Abstract]
Less than 12 months	2,732	1,199
12 months or longer	7,081	4,171
Total	9,813	5,370
Obligations of U.S. Government and U.S. Government sponsored enterprises
Available-for-sale securities in a continuous unrealized loss position, fair value [Abstract]
Less than 12 months	14,948	14,982
12 months or longer	0	0
Total	14,948	14,982
Available-for-sale securities in a continuous unrealized loss position, unrealized losses [Abstract]
Less than 12 months	50	21
12 months or longer	0	0
Total	50	21
Mortgage-backed securities, residential
Available-for-sale securities in a continuous unrealized loss position, fair value [Abstract]
Less than 12 months	65,746	83,562
12 months or longer	130,586	131,165
Total	196,332	214,727
Available-for-sale securities in a continuous unrealized loss position, unrealized losses [Abstract]
Less than 12 months	2,193	1,013
12 months or longer	6,944	4,153
Total	9,137	5,166
Obligations of states and political subdivisions
Available-for-sale securities in a continuous unrealized loss position, fair value [Abstract]
Less than 12 months	36,819	20,526
12 months or longer	1,709	271
Total	38,528	20,797
Available-for-sale securities in a continuous unrealized loss position, unrealized losses [Abstract]
Less than 12 months	488	133
12 months or longer	94	18
Total	582	151
SBA loan pools
Available-for-sale securities in a continuous unrealized loss position, fair value [Abstract]
Less than 12 months	243	3,937
12 months or longer	3,545	0
Total	3,788	3,937
Available-for-sale securities in a continuous unrealized loss position, unrealized losses [Abstract]
Less than 12 months	1	32
12 months or longer	43	0
Total	$ 44	$ 32