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Investment Securities Held to Maturity Securities by Type (Details) - USD ($) $ in Thousands | Sep. 30, 2019 | Dec. 31, 2018
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Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities, Held-to-maturity | $ 357,890 | $ 393,855
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain | 2,741 | 387
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss | (407) | (10,249)
Securities held to maturity, fair value | 360,224 | 383,993
US Government Agencies Residential Mortgage-backed Securities [Member] |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities, Held-to-maturity | 3,549 | 3,635
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain | 57 | 0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss | 0 | (97)
Securities held to maturity, fair value | 3,606 | 3,538
US Government Agency Debt Securities Commercial [Domain] |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities, Held-to-maturity | 54,244 | 55,221
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain | 173 | 0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss | (106) | (2,327)
Securities held to maturity, fair value | 54,311 | 52,894
Residential Mortgage Backed Securities [Member] |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities, Held-to-maturity | 245,238 | 279,109
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain | 1,762 | 212
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss | (297) | (7,254)
Securities held to maturity, fair value | 246,703 | 272,067
Obligations of U.S. Government-Sponsored Enterprises - Mortgage-Backed Securities - Commercial [Member] |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities, Held-to-maturity | 12,361 | 13,159
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain | 123 | 0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss | 0 | (258)
Securities held to maturity, fair value | 12,484 | 12,901
Obligations of States and Political Subdivisions [Member] |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities, Held-to-maturity | 41,898 | 42,331
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain | 626 | 175
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss | 0 | (313)
Securities held to maturity, fair value | 42,524 | 42,193
Debt Security, Government, Non-US [Member] |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities, Held-to-maturity | 600 | 400
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain | 0 | 0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss | (4) | 0
Securities held to maturity, fair value | $ 596 | $ 400

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- Definition Amount of investment in debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118954083&loc=d3e26610-111562 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27232-111563 + Details
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- Definition Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27232-111563 + Details
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- Definition Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27232-111563 + Details
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