INVESTMENT SECURITIES, Investment Securities in a Continuous Unrealized Loss Position (Details) $ in Thousands	Sep. 30, 2016 USD ($) Position	Dec. 31, 2015 USD ($) Position
Available-for-Sale Portfolio in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months | Position	13	46
12 months or longer | Position	18	24
Total | Position	31	70
Available-for-Sale Portfolio in Unrealized Loss Positions, Fair Value [Abstract]
Less than 12 months	$ 12,103	$ 389,937
12 months or longer	23,312	33,551
Total	35,415	423,488
Available-for-Sale Portfolio, Debt Maturities, Gross Unrealized Losses [Abstract]
Less than 12 months	41	2,236
12 months or longer	221	1,183
Total	$ 262	$ 3,419
U.S. Treasury and Agency Obligations [Member]
Available-for-Sale Portfolio in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months | Position		9
12 months or longer | Position		0
Total | Position		9
Available-for-Sale Portfolio in Unrealized Loss Positions, Fair Value [Abstract]
Less than 12 months		$ 353,844
12 months or longer		0
Total		353,844
Available-for-Sale Portfolio, Debt Maturities, Gross Unrealized Losses [Abstract]
Less than 12 months		2,027
12 months or longer		0
Total		$ 2,027
Obligations of State and Political Subdivisions [Member]
Available-for-Sale Portfolio in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months | Position	4	18
12 months or longer | Position	0	2
Total | Position	4	20
Available-for-Sale Portfolio in Unrealized Loss Positions, Fair Value [Abstract]
Less than 12 months	$ 1,987	$ 8,804
12 months or longer	0	735
Total	1,987	9,539
Available-for-Sale Portfolio, Debt Maturities, Gross Unrealized Losses [Abstract]
Less than 12 months	1	34
12 months or longer	0	25
Total	$ 1	$ 59
Government Agency Mortgage-Backed Securities [Member]
Available-for-Sale Portfolio in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months | Position	9	17
12 months or longer | Position	15	19
Total | Position	24	36
Available-for-Sale Portfolio in Unrealized Loss Positions, Fair Value [Abstract]
Less than 12 months	$ 10,116	$ 24,178
12 months or longer	23,228	30,103
Total	33,344	54,281
Available-for-Sale Portfolio, Debt Maturities, Gross Unrealized Losses [Abstract]
Less than 12 months	40	161
12 months or longer	202	1,100
Total	$ 242	$ 1,261
Corporate Debt Securities [Member]
Available-for-Sale Portfolio in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months | Position		1
12 months or longer | Position		1
Total | Position		2
Available-for-Sale Portfolio in Unrealized Loss Positions, Fair Value [Abstract]
Less than 12 months		$ 3,024
12 months or longer		2,710
Total		5,734
Available-for-Sale Portfolio, Debt Maturities, Gross Unrealized Losses [Abstract]
Less than 12 months		0
12 months or longer		58
Total		$ 58
Government Agency Collateralized Mortgage Obligations [Member]
Available-for-Sale Portfolio 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 Portfolio in Unrealized Loss Positions, Fair Value [Abstract]
Less than 12 months	$ 0	$ 0
12 months or longer	2	3
Total	2	3
Available-for-Sale Portfolio, Debt Maturities, Gross Unrealized Losses [Abstract]
Less than 12 months	0	0
12 months or longer	0	0
Total	$ 0	$ 0
Marketable Equity Securities [Member]
Available-for-Sale Portfolio in Unrealized Loss Positions, Number of Positions [Abstract]
Less than 12 months | Position	0	1
12 months or longer | Position	1	0
Total | Position	1	1
Available-for-Sale Portfolio in Unrealized Loss Positions, Fair Value [Abstract]
Less than 12 months	$ 0	$ 87
12 months or longer	82	0
Total	82	87
Available-for-Sale Portfolio, Debt Maturities, Gross Unrealized Losses [Abstract]
Less than 12 months	0	14
12 months or longer	19	0
Total	$ 19	$ 14