SECURITIES (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Available for sale:
Amortized Cost	$ 802,432	$ 834,564
Gross Unrealized Gains	658	383
Gross Unrealized Losses	(11,032)	(15,225)
Estimated Fair Value	792,058	819,722
Held to maturity:
Amortized Cost	189,603	223,237
Gross Unrealized Gains	2,006	1,692
Gross Unrealized Losses	(1,504)	(2,051)
Estimated Fair Value	190,105	222,878
Total securities
Amortized Cost	992,035	1,057,801
Gross Unrealized Gains	2,664	2,075
Gross Unrealized Losses	(12,536)	(17,276)
Total securities	982,163	1,042,600
U.S. GSE securities
Available for sale:
Amortized Cost	64,994	64,993
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(766)	(1,344)
Estimated Fair Value	64,228	63,649
State and municipal obligations
Available for sale:
Amortized Cost	91,359	117,292
Gross Unrealized Gains	430	212
Gross Unrealized Losses	(469)	(1,339)
Estimated Fair Value	91,320	116,165
Held to maturity:
Amortized Cost	60,616	66,666
Gross Unrealized Gains	1,446	1,085
Gross Unrealized Losses	(36)	(130)
Estimated Fair Value	62,026	67,621
U.S. GSE residential mortgage-backed securities
Available for sale:
Amortized Cost	195,062	160,446
Gross Unrealized Gains	112	16
Gross Unrealized Losses	(1,770)	(2,414)
Estimated Fair Value	193,404	158,048
Held to maturity:
Amortized Cost	11,905	13,443
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(175)	(287)
Estimated Fair Value	11,730	13,156
U.S. GSE residential collateralized mortgage obligations
Available for sale:
Amortized Cost	323,427	373,098
Gross Unrealized Gains	75	149
Gross Unrealized Losses	(4,300)	(5,736)
Estimated Fair Value	319,202	367,511
Held to maturity:
Amortized Cost	55,871	61,639
Gross Unrealized Gains	389	352
Gross Unrealized Losses	(348)	(552)
Estimated Fair Value	55,912	61,439
U.S. GSE commercial mortgage-backed securities
Available for sale:
Amortized Cost	6,129	6,337
Gross Unrealized Gains	41	6
Gross Unrealized Losses	(17)	(36)
Estimated Fair Value	6,153	6,307
Held to maturity:
Amortized Cost	28,202	28,772
Gross Unrealized Gains	158	136
Gross Unrealized Losses	(350)	(509)
Estimated Fair Value	28,010	28,399
U.S. GSE commercial collateralized mortgage obligations
Available for sale:
Amortized Cost	51,211	56,148
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(825)	(956)
Estimated Fair Value	50,386	55,192
Held to maturity:
Amortized Cost	33,009	41,717
Gross Unrealized Gains	13	93
Gross Unrealized Losses	(595)	(573)
Estimated Fair Value	32,427	41,237
Other asset backed securities
Available for sale:
Amortized Cost	24,250	24,250
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1,213)	(1,697)
Estimated Fair Value	23,037	22,553
Corporate bonds
Available for sale:
Amortized Cost	46,000	32,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1,672)	(1,703)
Estimated Fair Value	$ 44,328	30,297
Held to maturity:
Amortized Cost		11,000
Gross Unrealized Gains		26
Gross Unrealized Losses		0
Estimated Fair Value		$ 11,026