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SECURITIES AVAILABLE FOR SALE, HELD TO MATURITY, AND MARKETABLE EQUITY SECURITIES - Narrative (Details) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2019 USD ($) security | Jun. 30, 2019 USD ($) security | Jun. 30, 2018 USD ($)
Investment Holdings [Line Items] |  |  |
Purchases of securities available for sale | $ |  | $ 15,180 | $ 165,312
Proceeds from sale of available-for-sale securities | $ | $ 80,400 | 82,978 | $ 0
Debt securities, available-for-sale, realized gain | $ | 5 | 11 |
Debt securities, available-for-sale, realized loss | $ | $ 7 | $ 7 |
Municipal bonds and obligations |  |  |
Investment Holdings [Line Items] |  |  |
Available-for-sale, securities in unrealized loss positions | 2 | 2 |
Available for sale securities portfolio, number of securities |  | 246 |
Available for sale securities, continuous unrealized loss position, aggregate losses |  | 0.40% |
Agency collateralized mortgage obligations |  |  |
Investment Holdings [Line Items] |  |  |
Available-for-sale, securities in unrealized loss positions | 59 | 59 |
Available for sale securities portfolio, number of securities |  | 253 |
Available for sale securities, continuous unrealized loss position, aggregate losses |  | 0.40% |
Held-to-maturity, securities in unrealized loss positions | 1 | 1 |
Held-to-maturity securities portfolio, number of securities | 9 | 9 |
Held to maturity securities, continuous unrealized loss position, aggregate losses |  | 0.80% |
Mortgage-backed securities |  |  |
Investment Holdings [Line Items] |  |  |
Available-for-sale, securities in unrealized loss positions | 45 | 45 |
Available for sale securities portfolio, number of securities |  | 97 |
Available for sale securities, continuous unrealized loss position, aggregate losses |  | 1.40% |
Held-to-maturity, securities in unrealized loss positions | 1 | 1 |
Held-to-maturity securities portfolio, number of securities | 2 | 2 |
Held to maturity securities, continuous unrealized loss position, aggregate losses |  | 0.80% |
Corporate bonds |  |  |
Investment Holdings [Line Items] |  |  |
Available-for-sale, securities in unrealized loss positions | 11 | 11 |
Available for sale securities portfolio, number of securities |  | 23 |
Available for sale securities, continuous unrealized loss position, aggregate losses |  | 1.50% |
Trust preferred securities |  |  |
Investment Holdings [Line Items] |  |  |
Available-for-sale, securities in unrealized loss positions | 1 | 1 |
Available for sale securities portfolio, number of securities |  | 2 |
Available for sale securities, continuous unrealized loss position, aggregate losses |  | 0.10% |
Other bonds and obligations |  |  |
Investment Holdings [Line Items] |  |  |
Available-for-sale, securities in unrealized loss positions | 6 | 6 |
Available for sale securities portfolio, number of securities |  | 10 |
Available for sale securities, continuous unrealized loss position, aggregate losses |  | 0.20% |
Tax advantaged economic development bonds |  |  |
Investment Holdings [Line Items] |  |  |
Held-to-maturity, securities in unrealized loss positions | 1 | 1 |
Held-to-maturity securities portfolio, number of securities | 5 | 5 |
Held to maturity securities, continuous unrealized loss position, aggregate losses |  | 15.80% |

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