SECURITIES (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Available for sale:
Amortized Cost	$ 881,917	$ 808,168
Gross Unrealized Gains	5,642	1,193
Gross Unrealized Losses	(3,933)	(9,158)
Estimated Fair Value	883,626	800,203
Held to maturity:
Amortized Cost	218,278	208,351
Gross Unrealized Gains	5,564	2,867
Gross Unrealized Losses	(307)	(1,215)
Estimated Fair Value	223,535	210,003
Total securities
Amortized Cost	1,100,195	1,016,519
Gross Unrealized Gains	11,206	4,060
Gross Unrealized Losses	(4,240)	(10,373)
Total securities	1,107,161	1,010,206
U.S. GSE securities
Available for sale:
Amortized Cost	67,242	$ 63,238
Gross Unrealized Gains	82
Gross Unrealized Losses	(18)	$ (564)
Estimated Fair Value	$ 67,306	62,674
Held to maturity:
Amortized Cost		7,466
Gross Unrealized Gains		$ 1
Gross Unrealized Losses
Estimated Fair Value		$ 7,467
State and municipal obligations
Available for sale:
Amortized Cost	$ 102,417	87,830
Gross Unrealized Gains	1,346	427
Gross Unrealized Losses	(84)	(322)
Estimated Fair Value	103,679	87,935
Held to maturity:
Amortized Cost	63,326	64,878
Gross Unrealized Gains	$ 2,620	1,715
Gross Unrealized Losses		(113)
Estimated Fair Value	$ 65,946	66,480
U.S. GSE residential mortgage-backed securities
Available for sale:
Amortized Cost	214,827	201,297
Gross Unrealized Gains	1,775	237
Gross Unrealized Losses	(78)	(1,270)
Estimated Fair Value	216,524	200,264
Held to maturity:
Amortized Cost	12,393	$ 7,609
Gross Unrealized Gains	34
Gross Unrealized Losses	(13)	$ (106)
Estimated Fair Value	12,414	7,503
U.S. GSE residential collateralized mortgage obligations
Available for sale:
Amortized Cost	360,008	321,253
Gross Unrealized Gains	1,663	513
Gross Unrealized Losses	(808)	(3,888)
Estimated Fair Value	360,863	317,878
Held to maturity:
Amortized Cost	63,969	60,933
Gross Unrealized Gains	1,544	617
Gross Unrealized Losses	(66)	(498)
Estimated Fair Value	65,447	61,052
U.S. GSE commercial mortgage-backed securities
Available for sale:
Amortized Cost	12,432	12,491
Gross Unrealized Gains	$ 224	7
Gross Unrealized Losses		(80)
Estimated Fair Value	$ 12,656	12,418
Held to maturity:
Amortized Cost	29,291	23,056
Gross Unrealized Gains	512	210
Gross Unrealized Losses	(81)	(313)
Estimated Fair Value	29,722	22,953
U.S. GSE commercial collateralized mortgage obligations
Available for sale:
Amortized Cost	68,741	64,809
Gross Unrealized Gains	449	9
Gross Unrealized Losses	(129)	(620)
Estimated Fair Value	69,061	64,198
Held to maturity:
Amortized Cost	38,299	33,409
Gross Unrealized Gains	821	282
Gross Unrealized Losses	(147)	(185)
Estimated Fair Value	38,973	33,506
Other asset backed securities
Available for sale:
Amortized Cost	$ 24,250	$ 24,250
Gross Unrealized Gains
Gross Unrealized Losses	$ (1,940)	$ (1,879)
Estimated Fair Value	22,310	22,371
Corporate bonds
Available for sale:
Amortized Cost	32,000	$ 33,000
Gross Unrealized Gains	103
Gross Unrealized Losses	(876)	$ (535)
Estimated Fair Value	31,227	32,465
Held to maturity:
Amortized Cost	11,000	11,000
Gross Unrealized Gains	$ 33	$ 42
Gross Unrealized Losses
Estimated Fair Value	$ 11,033	$ 11,042