SECURITIES (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Available for sale:
Amortized Cost	$ 836,741	$ 834,564
Gross Unrealized Gains	755	383
Gross Unrealized Losses	(13,981)	(15,225)
Estimated Fair Value	823,515	819,722
Held to maturity:
Amortized Cost	214,961	223,237
Gross Unrealized Gains	1,773	1,692
Gross Unrealized Losses	(2,112)	(2,051)
Estimated Fair Value	214,622	222,878
Total securities
Amortized Cost	1,051,702	1,057,801
Gross Unrealized Gains	2,528	2,075
Gross Unrealized Losses	(16,093)	(17,276)
Total securities	1,038,137	1,042,600
U.S. GSE securities
Available for sale:
Amortized Cost	64,993	64,993
Gross Unrealized Gains
Gross Unrealized Losses	(1,160)	(1,344)
Estimated Fair Value	63,833	63,649
State and municipal obligations
Available for sale:
Amortized Cost	116,222	117,292
Gross Unrealized Gains	469	212
Gross Unrealized Losses	(960)	(1,339)
Estimated Fair Value	115,731	116,165
Held to maturity:
Amortized Cost	65,064	66,666
Gross Unrealized Gains	1,274	1,085
Gross Unrealized Losses	(87)	(130)
Estimated Fair Value	66,251	67,621
U.S. GSE residential mortgage-backed securities
Available for sale:
Amortized Cost	182,139	160,446
Gross Unrealized Gains	41	16
Gross Unrealized Losses	(2,358)	(2,414)
Estimated Fair Value	179,822	158,048
Held to maturity:
Amortized Cost	12,973	13,443
Gross Unrealized Gains
Gross Unrealized Losses	(285)	(287)
Estimated Fair Value	12,688	13,156
U.S. GSE residential collateralized mortgage obligations
Available for sale:
Amortized Cost	356,471	373,098
Gross Unrealized Gains	217	149
Gross Unrealized Losses	(5,200)	(5,736)
Estimated Fair Value	351,488	367,511
Held to maturity:
Amortized Cost	59,590	61,639
Gross Unrealized Gains	338	352
Gross Unrealized Losses	(586)	(552)
Estimated Fair Value	59,342	61,439
U.S. GSE commercial mortgage-backed securities
Available for sale:
Amortized Cost	6,296	6,337
Gross Unrealized Gains	25	6
Gross Unrealized Losses	(37)	(36)
Estimated Fair Value	6,284	6,307
Held to maturity:
Amortized Cost	28,595	28,772
Gross Unrealized Gains	98	136
Gross Unrealized Losses	(495)	(509)
Estimated Fair Value	28,198	28,399
U.S. GSE commercial collateralized mortgage obligations
Available for sale:
Amortized Cost	54,370	56,148
Gross Unrealized Gains	3
Gross Unrealized Losses	(1,028)	(956)
Estimated Fair Value	53,345	55,192
Held to maturity:
Amortized Cost	37,739	41,717
Gross Unrealized Gains	30	93
Gross Unrealized Losses	(659)	(573)
Estimated Fair Value	37,110	41,237
Other asset backed securities
Available for sale:
Amortized Cost	24,250	24,250
Gross Unrealized Gains
Gross Unrealized Losses	(1,455)	(1,697)
Estimated Fair Value	22,795	22,553
Corporate bonds
Available for sale:
Amortized Cost	32,000	32,000
Gross Unrealized Gains
Gross Unrealized Losses	(1,783)	(1,703)
Estimated Fair Value	30,217	30,297
Held to maturity:
Amortized Cost	11,000	11,000
Gross Unrealized Gains	33	26
Gross Unrealized Losses
Estimated Fair Value	$ 11,033	$ 11,026