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Investment (Held-to-Maturity) Securities (Details) $ in Thousands | 6 Months Ended |
--- | --- | ---
Jun. 30, 2020 USD ($) | Dec. 31, 2019 USD ($)
Schedule of Investment (Held-to-Maturity) Securities [Line Items] |  |  |  |
Investment Securities, Gross Amortized Cost |  | $ 269,616 |  | $ 293,418
Investment securities, Allowance for Credit Loss |  | (1,628) | [1] | 0
Investments securities, Amortized Cost, Net of Allowance |  | 267,988 |  | 293,418
Investment Securities, Fair Value |  | 299,126 |  | 314,402
Investment Securities, Gross Unrealized Gain |  | 29,541 |  | 21,285
Investment Securities, Gross Unrealized Loss |  | $ (31) |  | $ (301)
Investment Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract] |  |  |  |
Investment Securities, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions |  | 4 |  | 17
Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract] |  |  |  |
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value |  | $ 0 |  | $ 1,276
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value |  | 2,142 |  | 9,747
Investment Securities, Continuous Unrealized Loss Position, Fair Value |  | 2,142 |  | 11,023
Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract] |  |  |  |
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss |  | 0 |  | 2
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss |  | 31 |  | 299
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss |  | 31 |  | 301
Fixed Maturity Securities [Member] |  |  |  |
Investment Securities, Debt Maturities, Net Carrying Value [Abstract] |  |  |  |
Investment Securities, Debt Maturities, Less than One Year, Net Carrying Value |  | 39,734 |  |
Investment Securities, Debt Maturities, One to Five Years, Net Carrying Value |  | 87,863 |  |
Investment Securities, Debt Maturities, Six to Ten Years, Net Carrying Value |  | 122,309 |  |
Investment Securities, Debt Maturities, Over Ten Years, Net Carrying Value |  | 9,898 |  |
Investment Securities, Debt Maturities, Single Maturity Date, Net Carrying Value |  | 259,804 |  |
Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract] |  |  |  |
Investment Securities, Debt Maturities, Less Than One Year, Fair Value |  | 40,151 |  |
Investment Securities, Debt Maturities, One to Five Years, Fair Value |  | 96,615 |  |
Investment Securities, Debt Maturities, Six to Ten Years, Fair Value |  | 141,378 |  |
Investment Securities, Debt Maturities, Over Ten Years, Fair Value |  | 10,248 |  |
Investment Securities, Debt Maturities, Single Maturity Date, Fair Value |  | $ 288,392 |  |
Investment Securities, Debt Maturities, Weighted Average Maturity | [2] | 4.95 |  |
Municipal and other tax-exempt securities [Member] |  |  |  |
Schedule of Investment (Held-to-Maturity) Securities [Line Items] |  |  |  |
Investment Securities, Gross Amortized Cost |  | $ 84,239 |  | 93,653
Investment Securities, Fair Value |  | 88,623 |  | 96,897
Investment Securities, Gross Unrealized Gain |  | 4,384 |  | 3,250
Investment Securities, Gross Unrealized Loss |  | 0 |  | $ (6)
Investment Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract] |  |  |  |
Investment Securities, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions |  |  |  | 4
Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract] |  |  |  |
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value |  |  |  | $ 1,001
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value |  |  |  | 1,706
Investment Securities, Continuous Unrealized Loss Position, Fair Value |  |  |  | 2,707
Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract] |  |  |  |
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss |  |  |  | 1
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss |  |  |  | 5
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss |  |  |  | 6
Other debt securities [Member] |  |  |  |
Schedule of Investment (Held-to-Maturity) Securities [Line Items] |  |  |  |
Investment Securities, Gross Amortized Cost |  | 175,565 |  | 189,089
Investment Securities, Fair Value |  | 199,769 |  | 206,341
Investment Securities, Gross Unrealized Gain |  | 24,235 |  | 17,547
Investment Securities, Gross Unrealized Loss |  | $ (31) |  | $ (295)
Investment Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract] |  |  |  |
Investment Securities, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions |  | 4 |  | 13
Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract] |  |  |  |
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value |  | $ 0 |  | $ 275
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value |  | 2,142 |  | 8,041
Investment Securities, Continuous Unrealized Loss Position, Fair Value |  | 2,142 |  | 8,316
Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract] |  |  |  |
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss |  | 0 |  | 1
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss |  | 31 |  | 294
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss |  | 31 |  | 295
Residential agency mortgage-backed securities [Member] |  |  |  |
Schedule of Investment (Held-to-Maturity) Securities [Line Items] |  |  |  |
Investment Securities, Gross Amortized Cost |  | 9,812 |  | 10,676
Investment Securities, Fair Value |  | 10,734 |  | 11,164
Investment Securities, Gross Unrealized Gain |  | 922 |  | 488
Investment Securities, Gross Unrealized Loss |  | 0 |  | $ 0
Investment Securities, Debt Maturities, Net Carrying Value [Abstract] |  |  |  |
Investment Securities, Debt Maturities, without Single Maturity Date, Net Carrying Value | [3] | 9,812 |  |
Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract] |  |  |  |
Investment Securities, Debt Maturities, without Single Maturity Date, Fair Value |  | $ 10,734 |  |
Investment Securities, Debt Maturities, Average Expected Life of Mortgage-backed Securities |  | 4.6 years |  |
[1] | Effective with the adoption of FASB ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326) on January 1, 2020.
[2] | Expected maturities may differ from contractual maturities, because borrowers may have the right to call or prepay obligations with or without penalty.
[3] | The average expected lives of residential mortgage-backed securities were 4.6 years based upon current prepayment assumptions.

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- Definition Amount of investment in debt security measured at amortized cost (held-to-maturity), with single maturity date and allocated without single maturity date, maturing after rolling tenth fiscal year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date. + References No definition available. + Details
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- Definition Amount of investment in debt security measured at amortized cost (held-to-maturity), with single maturity date and allocated without single maturity date, maturing in sixth through tenth rolling fiscal year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date. + References No definition available. + Details
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- Definition Amount of investment in debt security measured at amortized cost (held-to-maturity), with single maturity date and allocated without single maturity date, maturing in second through fifth rolling fiscal year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date. + References No definition available. + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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