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Investment Securities - Amortized Cost and Fair Value (Details) - USD ($) $ in Thousands | Mar. 31, 2019 | Dec. 31, 2018
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Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items] |  |
Held to maturity, Amortized Cost | $ 152,845 | $ 157,206
Held to maturity, Fair Value | 151,254 | 153,894
Held-to-maturity, Gross Unrealized Gains | 300 | 210
Held-to-maturity, Gross Unrealized Losses | (1,891) | (3,522)
Total | 442,386 | 465,910
Available-for-sale, at fair value | 442,885 | 462,464
Available-for-sale, Gross Unrealized Gains | 3,272 | 1,748
Available-for-sale, Gross Unrealized Losses | (2,773) | (5,194)
Total investment securities, Amortized Cost | 595,231 | 623,116
Total investment securities, Fair Value | 594,139 | 616,358
Total investment securities, Gross Unrealized Gains | 3,572 | 1,958
Total investment securities, Gross Unrealized Losses | (4,664) | (8,716)
MBS pass-through securities issued by FHLMC and FNMA |  |
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items] |  |
Held to maturity, Amortized Cost | 86,117 | 88,606
Held to maturity, Fair Value | 84,588 | 85,804
Held-to-maturity, Gross Unrealized Gains | 44 | 7
Held-to-maturity, Gross Unrealized Losses | (1,573) | (2,809)
Total | 91,714 | 95,339
Available-for-sale, at fair value | 91,771 | 94,467
Available-for-sale, Gross Unrealized Gains | 617 | 358
Available-for-sale, Gross Unrealized Losses | (560) | (1,230)
SBA-backed securities |  |
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items] |  |
Held to maturity, Amortized Cost | 8,403 | 8,720
Held to maturity, Fair Value | 8,483 | 8,757
Held-to-maturity, Gross Unrealized Gains | 80 | 37
Held-to-maturity, Gross Unrealized Losses | 0 | 0
Total | 48,441 | 50,722
Available-for-sale, at fair value | 48,798 | 50,781
Available-for-sale, Gross Unrealized Gains | 582 | 465
Available-for-sale, Gross Unrealized Losses | (225) | (406)
CMOs issued by FNMA |  |
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items] |  |
Held to maturity, Amortized Cost | 11,166 | 11,447
Held to maturity, Fair Value | 11,165 | 11,327
Held-to-maturity, Gross Unrealized Gains | 0 | 0
Held-to-maturity, Gross Unrealized Losses | (1) | (120)
Total | 27,192 | 28,275
Available-for-sale, at fair value | 27,037 | 28,079
Available-for-sale, Gross Unrealized Gains | 127 | 134
Available-for-sale, Gross Unrealized Losses | (282) | (330)
CMOs issued by FHLMC |  |
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items] |  |
Held to maturity, Amortized Cost | 33,375 | 33,583
Held to maturity, Fair Value | 33,148 | 33,021
Held-to-maturity, Gross Unrealized Gains | 65 | 8
Held-to-maturity, Gross Unrealized Losses | (292) | (570)
Total | 145,917 | 145,979
Available-for-sale, at fair value | 146,237 | 144,836
Available-for-sale, Gross Unrealized Gains | 1,112 | 454
Available-for-sale, Gross Unrealized Losses | (792) | (1,597)
CMOs issued by GNMA |  |
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items] |  |
Held to maturity, Amortized Cost | 3,746 | 3,739
Held to maturity, Fair Value | 3,733 | 3,769
Held-to-maturity, Gross Unrealized Gains | 0 | 30
Held-to-maturity, Gross Unrealized Losses | (13) | 0
Total | 13,983 | 11,294
Available-for-sale, at fair value | 13,681 | 11,021
Available-for-sale, Gross Unrealized Gains | 0 | 1
Available-for-sale, Gross Unrealized Losses | (302) | (274)
Debentures of government- sponsored agencies |  |
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items] |  |
Total | 37,984 | 52,956
Available-for-sale, at fair value | 38,245 | 53,018
Available-for-sale, Gross Unrealized Gains | 344 | 185
Available-for-sale, Gross Unrealized Losses | (83) | (123)
Privately issued CMOs |  |
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items] |  |
Total | 251 | 295
Available-for-sale, at fair value | 252 | 297
Available-for-sale, Gross Unrealized Gains | 1 | 2
Available-for-sale, Gross Unrealized Losses | 0 | 0
Obligations of state and political subdivisions |  |
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items] |  |
Held to maturity, Amortized Cost | 10,038 | 11,111
Held to maturity, Fair Value | 10,137 | 11,216
Held-to-maturity, Gross Unrealized Gains | 111 | 128
Held-to-maturity, Gross Unrealized Losses | (12) | (23)
Total | 74,902 | 79,046
Available-for-sale, at fair value | 74,855 | 77,960
Available-for-sale, Gross Unrealized Gains | 477 | 134
Available-for-sale, Gross Unrealized Losses | (524) | (1,220)
Corporate bonds |  |
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items] |  |
Total | 2,002 | 2,004
Available-for-sale, at fair value | 2,009 | 2,005
Available-for-sale, Gross Unrealized Gains | 12 | 15
Available-for-sale, Gross Unrealized Losses | $ (5) | $ (14)

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