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Securities (Schedule of Contractual Maturities of Securities) (Details) - USD ($) $ in Thousands | Mar. 31, 2020 | Dec. 31, 2019
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Available for Sale, Fair Value |  |
Debt Securities, Available-for-sale, Amortized Cost | $ 419,452 | $ 420,703
Debt Securities, Available-for-sale | 437,296 | 426,424
Held to Maturity, Fair Value |  |
Debt Securities, Held-to-maturity | 777,798 | 740,806
Held to Maturity, Fair Value, Total | 809,355 | 753,263
Available for Sale Securities and Held to Maturity Securities Amortized Cost | 1,197,250 |
Debt Securities, Available-for-sale and Held-to-maturity | 1,246,651 |
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost | 8,869 |
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value | 8,965 |
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost | 88,712 |
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value | 92,400 |
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost | 104,169 |
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value | 110,586 |
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Ten Years, Amortized Cost | 995,500 |
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Ten Years, Fair Value | 1,034,700 |
U.S. government agency securities |  |
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items] |  |
Available for Sale, Amortized Cost, Due in one year or less | 0 |
Available for Sale, Amortized Cost, Due after one year to five years | 10,002 |
Available for Sale, Amortized Cost, Due after five to ten years | 12,472 |
Available for Sale, Amortized Cost, Due after ten years | 0 |
Available for Sale, Fair Value |  |
Available for Sale, Fair Value, Due in one year or less | 0 |
Available for Sale, Fair Value, Due after one year to five years | 10,351 |
Available for Sale, Fair Value, Due after five to ten years | 13,941 |
Available for Sale, Fair Value, Due after ten years | 0 |
Debt Securities, Available-for-sale, Amortized Cost | 22,474 | 32,473
Debt Securities, Available-for-sale | 24,292 | 33,115
Held to Maturity, Fair Value |  |
Debt Securities, Held-to-maturity | 0 | 12,874
Held to Maturity, Fair Value, Total | 0 | 12,997
Small Business Administration Pooled Securities [Member] |  |
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items] |  |
Available for Sale, Amortized Cost, Due in one year or less | 0 |
Available for Sale, Amortized Cost, Due after one year to five years | 0 |
Available for Sale, Amortized Cost, Due after five to ten years | 0 |
Available for Sale, Amortized Cost, Due after ten years | 63,062 |
Available for Sale, Fair Value |  |
Available for Sale, Fair Value, Due in one year or less | 0 |
Available for Sale, Fair Value, Due after one year to five years | 0 |
Available for Sale, Fair Value, Due after five to ten years | 0 |
Available for Sale, Fair Value, Due after ten years | 64,421 |
Debt Securities, Available-for-sale, Amortized Cost | 63,062 | 54,024
Debt Securities, Available-for-sale | 64,421 | 54,795
Held to Maturity, Amortized Cost |  |
Held to Maturity, Amortized Cost, Due in one year or less | 0 |
Held to Maturity, Amortized Cost, Due after one year to five years | 0 |
Held to Maturity, Amortized Cost, Due after five to ten years | 0 |
Held to Maturity, Amortized Cost, Due after ten years | 30,716 |
Held to Maturity, Fair Value |  |
Held to Maturity, Fair Value, Due in one year or less | 0 |
Held to Maturity, Fair Value, Due after one year to five years | 0 |
Held to Maturity, Fair Value, Due after five to ten years | 0 |
Held to Maturity, Fair Value, Due after ten years | 31,461 |
Debt Securities, Held-to-maturity | 30,716 | 31,324
Held to Maturity, Fair Value, Total | 31,461 | 31,607
Debt Securities [Member] |  |
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items] |  |
Available for Sale, Amortized Cost, Due in one year or less | 250 |
Available for Sale, Amortized Cost, Due after one year to five years | 82,781 |
Available for Sale, Amortized Cost, Due after five to ten years | 54,546 |
Available for Sale, Amortized Cost, Due after ten years | 281,875 |
Available for Sale, Fair Value |  |
Available for Sale, Fair Value, Due in one year or less | 250 |
Available for Sale, Fair Value, Due after one year to five years | 86,310 |
Available for Sale, Fair Value, Due after five to ten years | 58,751 |
Available for Sale, Fair Value, Due after ten years | 291,985 |
Held to Maturity, Amortized Cost |  |
Held to Maturity, Amortized Cost, Due in one year or less | 8,619 |
Held to Maturity, Amortized Cost, Due after one year to five years | 5,931 |
Held to Maturity, Amortized Cost, Due after five to ten years | 49,623 |
Held to Maturity, Amortized Cost, Due after ten years | 713,625 |
Held to Maturity, Fair Value |  |
Held to Maturity, Fair Value, Due in one year or less | 8,715 |
Held to Maturity, Fair Value, Due after one year to five years | 6,090 |
Held to Maturity, Fair Value, Due after five to ten years | 51,835 |
Held to Maturity, Fair Value, Due after ten years | 742,715 |
Held to Maturity, Fair Value, Total | 809,355 |
Pooled trust preferred securities issued by banks and insurers |  |
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items] |  |
Available for Sale, Amortized Cost, Due in one year or less | 0 |
Available for Sale, Amortized Cost, Due after one year to five years | 0 |
Available for Sale, Amortized Cost, Due after five to ten years | 0 |
Available for Sale, Amortized Cost, Due after ten years | 1,443 |
Available for Sale, Fair Value |  |
Available for Sale, Fair Value, Due in one year or less | 0 |
Available for Sale, Fair Value, Due after one year to five years | 0 |
Available for Sale, Fair Value, Due after five to ten years | 0 |
Available for Sale, Fair Value, Due after ten years | 1,009 |
Debt Securities, Available-for-sale, Amortized Cost | 1,443 | 1,488
Debt Securities, Available-for-sale | 1,009 | 1,114
Single Issuer Trust Preferred Securities Issued by Banks and Insurers [Member] |  |
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items] |  |
Available for Sale, Amortized Cost, Due in one year or less | 0 |
Available for Sale, Amortized Cost, Due after one year to five years | 0 |
Available for Sale, Amortized Cost, Due after five to ten years | 0 |
Available for Sale, Amortized Cost, Due after ten years | 489 |
Available for Sale, Fair Value |  |
Available for Sale, Fair Value, Due in one year or less | 0 |
Available for Sale, Fair Value, Due after one year to five years | 0 |
Available for Sale, Fair Value, Due after five to ten years | 0 |
Available for Sale, Fair Value, Due after ten years | 436 |
Debt Securities, Available-for-sale, Amortized Cost | 489 | 488
Debt Securities, Available-for-sale | 436 | 493
Held to Maturity, Amortized Cost |  |
Held to Maturity, Amortized Cost, Due in one year or less | 0 |
Held to Maturity, Amortized Cost, Due after one year to five years | 0 |
Held to Maturity, Amortized Cost, Due after five to ten years | 1,500 |
Held to Maturity, Amortized Cost, Due after ten years | 0 |
Held to Maturity, Fair Value |  |
Held to Maturity, Fair Value, Due in one year or less | 0 |
Held to Maturity, Fair Value, Due after one year to five years | 0 |
Held to Maturity, Fair Value, Due after five to ten years | 1,490 |
Held to Maturity, Fair Value, Due after ten years | 0 |
Debt Securities, Held-to-maturity | 1,500 | 1,500
Held to Maturity, Fair Value, Total | 1,490 | 1,490
US States and Political Subdivisions Debt Securities [Member] |  |
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items] |  |
Available for Sale, Amortized Cost, Due in one year or less | 250 |
Available for Sale, Amortized Cost, Due after one year to five years | 687 |
Available for Sale, Amortized Cost, Due after five to ten years | 189 |
Available for Sale, Amortized Cost, Due after ten years | 0 |
Available for Sale, Fair Value |  |
Available for Sale, Fair Value, Due in one year or less | 250 |
Available for Sale, Fair Value, Due after one year to five years | 691 |
Available for Sale, Fair Value, Due after five to ten years | 203 |
Available for Sale, Fair Value, Due after ten years | 0 |
Debt Securities, Available-for-sale, Amortized Cost | 1,126 | 1,377
Debt Securities, Available-for-sale | 1,144 | 1,396
Agency Collateralized Mortgage Obligations [Member] |  |
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items] |  |
Available for Sale, Amortized Cost, Due in one year or less | 0 |
Available for Sale, Amortized Cost, Due after one year to five years | 0 |
Available for Sale, Amortized Cost, Due after five to ten years | 0 |
Available for Sale, Amortized Cost, Due after ten years | 83,183 |
Available for Sale, Fair Value |  |
Available for Sale, Fair Value, Due in one year or less | 0 |
Available for Sale, Fair Value, Due after one year to five years | 0 |
Available for Sale, Fair Value, Due after five to ten years | 0 |
Available for Sale, Fair Value, Due after ten years | 87,210 |
Debt Securities, Available-for-sale, Amortized Cost | 83,183 | 87,305
Debt Securities, Available-for-sale | 87,210 | 88,511
Held to Maturity, Amortized Cost |  |
Held to Maturity, Amortized Cost, Due in one year or less | 0 |
Held to Maturity, Amortized Cost, Due after one year to five years | 0 |
Held to Maturity, Amortized Cost, Due after five to ten years | 0 |
Held to Maturity, Amortized Cost, Due after ten years | 277,921 |
Held to Maturity, Fair Value |  |
Held to Maturity, Fair Value, Due in one year or less | 0 |
Held to Maturity, Fair Value, Due after one year to five years | 0 |
Held to Maturity, Fair Value, Due after five to ten years | 0 |
Held to Maturity, Fair Value, Due after ten years | 289,902 |
Debt Securities, Held-to-maturity | 277,921 | 293,662
Held to Maturity, Fair Value, Total | 289,902 | 297,314
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] |  |
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items] |  |
Available for Sale, Amortized Cost, Due in one year or less | 0 |
Available for Sale, Amortized Cost, Due after one year to five years | 72,092 |
Available for Sale, Amortized Cost, Due after five to ten years | 41,885 |
Available for Sale, Amortized Cost, Due after ten years | 133,698 |
Available for Sale, Fair Value |  |
Available for Sale, Fair Value, Due in one year or less | 0 |
Available for Sale, Fair Value, Due after one year to five years | 75,268 |
Available for Sale, Fair Value, Due after five to ten years | 44,607 |
Available for Sale, Fair Value, Due after ten years | 138,909 |
Debt Securities, Available-for-sale, Amortized Cost | 247,675 | 243,548
Debt Securities, Available-for-sale | 258,784 | 247,000
Held to Maturity, Amortized Cost |  |
Held to Maturity, Amortized Cost, Due in one year or less | 8,619 |
Held to Maturity, Amortized Cost, Due after one year to five years | 1,902 |
Held to Maturity, Amortized Cost, Due after five to ten years | 48,123 |
Held to Maturity, Amortized Cost, Due after ten years | 404,988 |
Held to Maturity, Fair Value |  |
Held to Maturity, Fair Value, Due in one year or less | 8,715 |
Held to Maturity, Fair Value, Due after one year to five years | 1,951 |
Held to Maturity, Fair Value, Due after five to ten years | 50,345 |
Held to Maturity, Fair Value, Due after ten years | 421,352 |
Debt Securities, Held-to-maturity | 463,632 | 397,414
Held to Maturity, Fair Value, Total | 482,363 | 405,802
US Treasury Securities [Member] |  |
Held to Maturity, Amortized Cost |  |
Held to Maturity, Amortized Cost, Due in one year or less | 0 |
Held to Maturity, Amortized Cost, Due after one year to five years | 4,029 |
Held to Maturity, Amortized Cost, Due after five to ten years | 0 |
Held to Maturity, Amortized Cost, Due after ten years | 0 |
Held to Maturity, Fair Value |  |
Held to Maturity, Fair Value, Due in one year or less | 0 |
Held to Maturity, Fair Value, Due after one year to five years | 4,139 |
Held to Maturity, Fair Value, Due after five to ten years | 0 |
Held to Maturity, Fair Value, Due after ten years | 0 |
Debt Securities, Held-to-maturity | 4,029 | 4,032
Held to Maturity, Fair Value, Total | $ 4,139 | $ 4,053

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