INVESTMENT SECURITIES (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 826,527	$ 778,261	$ 600,744
Gross Unrealized Gains	12,120	8,136	11,250
Gross Unrealized Losses	(1,544)	(3,212)	(1,664)
Fair Value	837,103	783,185	610,330
U.S. government sponsored agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	7,592	14,959	14,954
Gross Unrealized Gains	45	0	72
Gross Unrealized Losses	(9)	(69)	(42)
Fair Value	7,628	14,890	14,984
State, county and municipal securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	152,764	157,681	154,499
Gross Unrealized Gains	4,894	4,046	4,800
Gross Unrealized Losses	(125)	(411)	(235)
Fair Value	157,533	161,316	159,064
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	8,407	5,900	10,794
Gross Unrealized Gains	139	145	193
Gross Unrealized Losses	(24)	(28)	(52)
Fair Value	8,522	6,017	10,935
Mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	657,764	599,721	420,497
Gross Unrealized Gains	7,042	3,945	6,185
Gross Unrealized Losses	(1,386)	(2,704)	(1,335)
Fair Value	$ 663,420	$ 600,962	$ 425,347