SECURITIES - Investment Securities Available for Sale in Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Available-for-sale securities in a continuous unrealized loss position, fair value [Abstract]
Less than 12 months	$ 233,523	$ 259,567
12 months or longer	219	225
Total	233,742	259,792
Available-for-sale securities in a continuous unrealized loss position, unrealized losses [Abstract]
Less than 12 months	4,830	7,804
12 months or longer	1	1
Total	4,831	7,805
Mortgage-backed securities, residential
Available-for-sale securities in a continuous unrealized loss position, fair value [Abstract]
Less than 12 months	220,708	233,843
12 months or longer	0	0
Total	220,708	233,843
Available-for-sale securities in a continuous unrealized loss position, unrealized losses [Abstract]
Less than 12 months	4,690	7,492
12 months or longer	0	0
Total	4,690	7,492
Obligations of states and political subdivisions
Available-for-sale securities in a continuous unrealized loss position, fair value [Abstract]
Less than 12 months	12,815	25,724
12 months or longer	0	0
Total	12,815	25,724
Available-for-sale securities in a continuous unrealized loss position, unrealized losses [Abstract]
Less than 12 months	140	312
12 months or longer	0	0
Total	140	312
SBA loan pools
Available-for-sale securities in a continuous unrealized loss position, fair value [Abstract]
Less than 12 months	0	0
12 months or longer	219	225
Total	219	225
Available-for-sale securities in a continuous unrealized loss position, unrealized losses [Abstract]
Less than 12 months	0	0
12 months or longer	1	1
Total	$ 1	$ 1