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SECURITIES (Details) - USD ($) $ in Thousands | Dec. 31, 2016 | Dec. 31, 2015
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Available-for-sale Debt Securities, Amortized Cost Basis [Abstract] |  |
Available-for-sale debt securities, amortized cost basis | $ 1,145,448 | $ 1,118,572
Available-for-sale debt securities, accumulated gross unrealized gain, before tax | 7,234 | 10,444
Available-for-sale debt securities, accumulated gross unrealized loss, before tax | (8,686) | (8,526)
Available-for-sale securities, debt securities | 1,143,996 | 1,120,490
Available-for-sale Equity Securities, Amortized Cost Basis [Abstract] |  |
Available-for-sale equity securities, amortized cost basis | 47,858 | 30,522
Available-for-sale equity securities, accumulated gross unrealized gain, before tax | 19,296 | 5,331
Available-for-sale equity securities, accumulated gross unrealized loss, before tax | (1,613) | (1,886)
Available-for-sale securities, equity securities | 65,541 | 33,967
Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract] |  |
Available-for-sale securities, amortized cost basis | 1,193,306 | 1,149,094
Available-for-sale securities, accumulated gross unrealized gain, before tax | 26,530 | 15,775
Available-for-sale securities, accumulated gross unrealized loss, before tax | (10,299) | (10,412)
Available-for-securities | 1,209,537 | 1,154,457
Held-to-maturity Securities, Unclassified [Abstract] |  |
Held-to-maturity securities | 334,368 | 131,652
Held-to-maturity securities, accumulated unrecognized holding gain | 6,816 | 5,286
Held-to-maturity securities, accumulated unrecognized holding loss | (3,504) | (34)
Held-to-maturity securities, fair value | 337,680 | 136,904
Available-for-sale Securities and Held-to-maturity Securities [Abstract] |  |
Held to maturity and available for sale securities amortized cost | 1,527,674 | 1,280,746
Held to maturity and available for sale securities, gross unrealized gain | 33,346 | 21,061
Held to maturity and available for sale securities, gross unrealized losses | (13,803) | (10,446)
Available for sale securities and held to maturity securities | 1,547,217 | 1,291,361
Municipal bonds and obligations |  |
Held-to-maturity Securities, Unclassified [Abstract] |  |
Held-to-maturity securities | 203,463 | 94,642
Held-to-maturity securities, accumulated unrecognized holding gain | 3,939 | 3,359
Held-to-maturity securities, accumulated unrecognized holding loss | (2,416) | (34)
Held-to-maturity securities, fair value | 204,986 | 97,967
Agency collateralized mortgage obligations |  |
Held-to-maturity Securities, Unclassified [Abstract] |  |
Held-to-maturity securities | 75,655 | 68
Held-to-maturity securities, accumulated unrecognized holding gain | 1,281 | 3
Held-to-maturity securities, accumulated unrecognized holding loss | (411) | 0
Held-to-maturity securities, fair value | 76,525 | 71
Tax advantaged economic development bonds |  |
Held-to-maturity Securities, Unclassified [Abstract] |  |
Held-to-maturity securities | 35,278 | 36,613
Held-to-maturity securities, accumulated unrecognized holding gain | 1,596 | 1,924
Held-to-maturity securities, accumulated unrecognized holding loss | 0 | 0
Held-to-maturity securities, fair value | 36,874 | 38,537
Other bonds and obligations |  |
Held-to-maturity Securities, Unclassified [Abstract] |  |
Held-to-maturity securities | 325 | 329
Held-to-maturity securities, accumulated unrecognized holding gain | 0 | 0
Held-to-maturity securities, accumulated unrecognized holding loss | 0 | 0
Held-to-maturity securities, fair value | 325 | 329
Municipal bonds and obligations |  |
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract] |  |
Available-for-sale debt securities, amortized cost basis | 117,910 | 99,922
Available-for-sale debt securities, accumulated gross unrealized gain, before tax | 2,955 | 4,763
Available-for-sale debt securities, accumulated gross unrealized loss, before tax | (1,049) | (124)
Available-for-sale securities, debt securities | 119,816 | 104,561
Agency collateralized mortgage obligations |  |
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract] |  |
Available-for-sale debt securities, amortized cost basis | 652,680 | 833,633
Available-for-sale debt securities, accumulated gross unrealized gain, before tax | 2,522 | 4,957
Available-for-sale debt securities, accumulated gross unrealized loss, before tax | (3,291) | (5,554)
Available-for-sale securities, debt securities | 651,911 | 833,036
Agency mortgage-backed securities |  |
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract] |  |
Available-for-sale debt securities, amortized cost basis | 230,308 | 127,274
Available-for-sale debt securities, accumulated gross unrealized gain, before tax | 557 | 542
Available-for-sale debt securities, accumulated gross unrealized loss, before tax | (2,181) | (987)
Available-for-sale securities, debt securities | 228,684 | 126,829
Held-to-maturity Securities, Unclassified [Abstract] |  |
Held-to-maturity securities | 9,102 |
Held-to-maturity securities, accumulated unrecognized holding gain | 0 |
Held-to-maturity securities, accumulated unrecognized holding loss | (243) |
Held-to-maturity securities, fair value | 8,859 |
Agency commercial mortgage-backed securities |  |
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract] |  |
Available-for-sale debt securities, amortized cost basis | 65,673 | 0
Available-for-sale debt securities, accumulated gross unrealized gain, before tax | 229 | 0
Available-for-sale debt securities, accumulated gross unrealized loss, before tax | (1,368) | 0
Available-for-sale securities, debt securities | 64,534 | 0
Held-to-maturity Securities, Unclassified [Abstract] |  |
Held-to-maturity securities | 10,545 |
Held-to-maturity securities, accumulated unrecognized holding gain | 0 |
Held-to-maturity securities, accumulated unrecognized holding loss | (434) |
Held-to-maturity securities, fair value | 10,111 |
Corporate bonds |  |
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract] |  |
Available-for-sale debt securities, amortized cost basis | 56,320 | 42,849
Available-for-sale debt securities, accumulated gross unrealized gain, before tax | 408 | 0
Available-for-sale debt securities, accumulated gross unrealized loss, before tax | (722) | (1,826)
Available-for-sale securities, debt securities | 56,006 | 41,023
Trust preferred securities |  |
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract] |  |
Available-for-sale debt securities, amortized cost basis | 11,578 | 11,719
Available-for-sale debt securities, accumulated gross unrealized gain, before tax | 368 | 182
Available-for-sale debt securities, accumulated gross unrealized loss, before tax | (59) | (1)
Available-for-sale securities, debt securities | 11,887 | 11,900
Other bonds and obligations |  |
Available-for-sale Debt Securities, Amortized Cost Basis [Abstract] |  |
Available-for-sale debt securities, amortized cost basis | 10,979 | 3,175
Available-for-sale debt securities, accumulated gross unrealized gain, before tax | 195 | 0
Available-for-sale debt securities, accumulated gross unrealized loss, before tax | (16) | (34)
Available-for-sale securities, debt securities | $ 11,158 | $ 3,141

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