INVESTMENT SECURITIES, Investment Securities in a Continuous Unrealized Loss Position (Details) $ in Thousands	Dec. 31, 2016 USD ($) Position	Dec. 31, 2015 USD ($) Position
Available-for-Sale Securities in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months | Position	268	46
12 months or longer | Position	17	24
Total | Position	285	70
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 637,887	$ 389,937
12 months or longer	21,790	33,551
Total	659,677	423,488
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses [Abstract]
Less than 12 months	4,840	2,236
12 months or longer	830	1,183
Total	$ 5,670	$ 3,419
U.S. Treasury and Agency Securities [Member]
Available-for-Sale Securities in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months | Position	13	9
12 months or longer | Position	0	0
Total | Position	13	9
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 449,242	$ 353,844
12 months or longer	0	0
Total	449,242	353,844
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses [Abstract]
Less than 12 months	2,118	2,027
12 months or longer	0	0
Total	$ 2,118	$ 2,027
Obligations of State and Political Subdivisions [Member]
Available-for-Sale Securities in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months | Position	197	18
12 months or longer | Position	0	2
Total | Position	197	20
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 102,106	$ 8,804
12 months or longer	0	735
Total	102,106	9,539
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses [Abstract]
Less than 12 months	1,054	34
12 months or longer	0	25
Total	$ 1,054	$ 59
Government Agency Mortgage-Backed Securities [Member]
Available-for-Sale Securities in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months | Position	57	17
12 months or longer | Position	15	19
Total | Position	72	36
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 83,862	$ 24,178
12 months or longer	21,788	30,103
Total	105,650	54,281
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses [Abstract]
Less than 12 months	1,637	161
12 months or longer	830	1,100
Total	$ 2,467	$ 1,261
Corporate Debt Securities [Member]
Available-for-Sale Securities in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months | Position	1	1
12 months or longer | Position	0	1
Total | Position	1	2
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 2,677	$ 3,024
12 months or longer	0	2,710
Total	2,677	5,734
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses [Abstract]
Less than 12 months	31	0
12 months or longer	0	58
Total	$ 31	$ 58
Government Agency Collateralized Mortgage Obligations [Member]
Available-for-Sale Securities in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months | Position	0	0
12 months or longer | Position	2	2
Total | Position	2	2
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 0	$ 0
12 months or longer	2	3
Total	2	3
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses [Abstract]
Less than 12 months	0	0
12 months or longer	0	0
Total	$ 0	$ 0
Marketable Equity Security [Member]
Available-for-Sale Securities in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months | Position		1
12 months or longer | Position		0
Total | Position		1
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months		$ 87
12 months or longer		0
Total		87
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses [Abstract]
Less than 12 months		14
12 months or longer		0
Total		$ 14