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SECURITIES - Investment Securities Available for Sale in Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands | Mar. 31, 2018 | Dec. 31, 2017 | Mar. 31, 2017
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Available-for-sale securities in a continuous unrealized loss position, fair value [Abstract] |  |  |
Less than 12 months | $ 132,542 | $ 123,007 |
12 months or longer | 134,138 | 131,436 |
Total | 266,680 | 254,443 |
Available-for-sale securities in a continuous unrealized loss position, unrealized losses [Abstract] |  |  |
Less than 12 months | 2,746 | 1,199 |
12 months or longer | 6,696 | 4,171 |
Total | 9,442 | 5,370 |
Obligations of U.S. Government and U.S. Government sponsored enterprises |  |  |
Available-for-sale securities in a continuous unrealized loss position, fair value [Abstract] |  |  |
Less than 12 months |  | 14,982 | $ 14,947
12 months or longer |  | 0 | 0
Total |  | 14,982 | 14,947
Available-for-sale securities in a continuous unrealized loss position, unrealized losses [Abstract] |  |  |
Less than 12 months |  | 21 | 54
12 months or longer |  | 0 | 0
Total |  | 21 | $ 54
Mortgage-backed securities, residential |  |  |
Available-for-sale securities in a continuous unrealized loss position, fair value [Abstract] |  |  |
Less than 12 months | 73,034 | 83,562 |
12 months or longer | 132,122 | 131,165 |
Total | 205,156 | 214,727 |
Available-for-sale securities in a continuous unrealized loss position, unrealized losses [Abstract] |  |  |
Less than 12 months | 2,093 | 1,013 |
12 months or longer | 6,664 | 4,153 |
Total | 8,757 | 5,166 |
Obligations of states and political subdivisions |  |  |
Available-for-sale securities in a continuous unrealized loss position, fair value [Abstract] |  |  |
Less than 12 months | 42,728 | 20,526 |
12 months or longer | 260 | 271 |
Total | 42,988 | 20,797 |
Available-for-sale securities in a continuous unrealized loss position, unrealized losses [Abstract] |  |  |
Less than 12 months | 574 | 133 |
12 months or longer | 30 | 18 |
Total | 604 | 151 |
SBA loan pools |  |  |
Available-for-sale securities in a continuous unrealized loss position, fair value [Abstract] |  |  |
Less than 12 months | 1,833 | 3,937 |
12 months or longer | 1,756 | 0 |
Total | 3,589 | 3,937 |
Available-for-sale securities in a continuous unrealized loss position, unrealized losses [Abstract] |  |  |
Less than 12 months | 25 | 32 |
12 months or longer | 2 | 0 |
Total | $ 27 | $ 32 |

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- Definition Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563 + Details
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- Definition Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563 + Details
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- Definition This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563 + Details
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- Definition Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for less than twelve months. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563 + Details
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