SECURITIES (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Available for sale:
Amortized Cost	$ 834,564	$ 808,168
Gross Unrealized Gains	383	1,193
Gross Unrealized Losses	(15,225)	(9,158)
Estimated Fair Value	819,722	800,203
Held to maturity:
Held-to-maturity Securities	223,237	208,351
Gross Unrealized Gains	1,692	2,867
Gross Unrealized Losses	(2,051)	(1,215)
Estimated Fair Value	222,878	210,003
Total securities
Amortized Cost	1,057,801	1,016,519
Gross Unrealized Gains	2,075	4,060
Gross Unrealized Losses	(17,276)	(10,373)
Investments, Fair Value Disclosure	1,042,600	1,010,206
U.S. GSE securities
Available for sale:
Amortized Cost	64,993	63,238
Gross Unrealized Gains
Gross Unrealized Losses	(1,344)	(564)
Estimated Fair Value	63,649	62,674
Held to maturity:
Held-to-maturity Securities		7,466
Gross Unrealized Gains		1
Gross Unrealized Losses
Estimated Fair Value		7,467
State and municipal obligations
Available for sale:
Amortized Cost	117,292	87,830
Gross Unrealized Gains	212	427
Gross Unrealized Losses	(1,339)	(322)
Estimated Fair Value	116,165	87,935
Held to maturity:
Held-to-maturity Securities	66,666	64,878
Gross Unrealized Gains	1,085	1,715
Gross Unrealized Losses	(130)	(113)
Estimated Fair Value	67,621	66,480
U.S. GSE residential mortgage-backed securities
Available for sale:
Amortized Cost	160,446	201,297
Gross Unrealized Gains	16	237
Gross Unrealized Losses	(2,414)	(1,270)
Estimated Fair Value	158,048	200,264
Held to maturity:
Held-to-maturity Securities	13,443	7,609
Gross Unrealized Gains
Gross Unrealized Losses	(287)	(106)
Estimated Fair Value	13,156	7,503
U.S. GSE residential collateralized mortgage Obligations
Available for sale:
Amortized Cost	373,098	321,253
Gross Unrealized Gains	149	513
Gross Unrealized Losses	(5,736)	(3,888)
Estimated Fair Value	367,511	317,878
Held to maturity:
Held-to-maturity Securities	61,639	60,933
Gross Unrealized Gains	352	617
Gross Unrealized Losses	(552)	(498)
Estimated Fair Value	61,439	61,052
U.S. GSE commercial mortgage-backed securities
Available for sale:
Amortized Cost	6,337	12,491
Gross Unrealized Gains	6	7
Gross Unrealized Losses	(36)	(80)
Estimated Fair Value	6,307	12,418
Held to maturity:
Held-to-maturity Securities	28,772	23,056
Gross Unrealized Gains	136	210
Gross Unrealized Losses	(509)	(313)
Estimated Fair Value	28,399	22,953
U.S. GSE commercial collateralized mortgage Obligations
Available for sale:
Amortized Cost	56,148	64,809
Gross Unrealized Gains		9
Gross Unrealized Losses	(956)	(620)
Estimated Fair Value	55,192	64,198
Held to maturity:
Held-to-maturity Securities	41,717	33,409
Gross Unrealized Gains	93	282
Gross Unrealized Losses	(573)	(185)
Estimated Fair Value	41,237	33,506
Other asset backed securities
Available for sale:
Amortized Cost	24,250	24,250
Gross Unrealized Gains
Gross Unrealized Losses	(1,697)	(1,879)
Estimated Fair Value	22,553	22,371
Corporate bonds
Available for sale:
Amortized Cost	32,000	33,000
Gross Unrealized Gains
Gross Unrealized Losses	(1,703)	(535)
Estimated Fair Value	30,297	32,465
Held to maturity:
Held-to-maturity Securities	11,000	11,000
Gross Unrealized Gains	26	42
Gross Unrealized Losses
Estimated Fair Value	$ 11,026	$ 11,042