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Securities (Schedule of Contractual Maturities of Securities) (Details) - USD ($) $ in Thousands | Mar. 31, 2019 | Dec. 31, 2018
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Available for Sale, Fair Value |  |
Debt Securities, Available-for-sale, Amortized Cost | $ 439,307 | $ 450,548
Debt Securities, Available-for-sale | 437,689 | 442,752
Held to Maturity, Amortized Cost |  |
Held to maturity Securities, Amortized Cost | 623,243 | 611,490
Held to Maturity, Fair Value |  |
Held to Maturity, Fair Value, Total | 623,156 | 603,640
Available for Sale Securities and Held to Maturity Securities Amortized Cost | 1,062,550 | 1,062,038
Debt Securities, Available-for-sale and Held-to-maturity | 1,060,845 | 1,046,392
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost | 10,012 |
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value | 9,972 |
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost | 75,869 |
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value | 75,666 |
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost | 137,678 |
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value | 137,965 |
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Ten Years, Amortized Cost | 838,991 |
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Ten Years, Fair Value | 837,242 |
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 | 10,005 |
Available for Sale, Amortized Cost, Due after one year to five years | 10,003 |
Available for Sale, Amortized Cost, Due after five to ten years | 12,469 |
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 | 9,965 |
Available for Sale, Fair Value, Due after one year to five years | 10,028 |
Available for Sale, Fair Value, Due after five to ten years | 12,462 |
Available for Sale, Fair Value, Due after ten years | 0 |
Debt Securities, Available-for-sale, Amortized Cost | 32,477 | 32,477
Debt Securities, Available-for-sale | 32,455 | 32,038
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 | 52,549 |
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 | 52,134 |
Debt Securities, Available-for-sale, Amortized Cost | 52,549 | 53,317
Debt Securities, Available-for-sale | 52,134 | 51,927
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 | 23,336 |
Held to maturity Securities, Amortized Cost | 23,336 | 23,727
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 | 23,062 |
Held to Maturity, Fair Value, Total | 23,062 | 23,483
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 | 10,012 |
Available for Sale, Amortized Cost, Due after one year to five years | 63,079 |
Available for Sale, Amortized Cost, Due after five to ten years | 101,498 |
Available for Sale, Amortized Cost, Due after ten years | 264,718 |
Available for Sale, Fair Value |  |
Available for Sale, Fair Value, Due in one year or less | 9,972 |
Available for Sale, Fair Value, Due after one year to five years | 62,925 |
Available for Sale, Fair Value, Due after five to ten years | 101,880 |
Available for Sale, Fair Value, Due after ten years | 262,912 |
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 | 12,790 |
Held to Maturity, Amortized Cost, Due after five to ten years | 36,180 |
Held to Maturity, Amortized Cost, Due after ten years | 574,273 |
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 | 12,741 |
Held to Maturity, Fair Value, Due after five to ten years | 36,085 |
Held to Maturity, Fair Value, Due after ten years | 574,330 |
Held to Maturity, Fair Value, Total | 623,156 |
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 | 1,660 |
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 | 1,314 |
Debt Securities, Available-for-sale, Amortized Cost | 1,660 | 1,678
Debt Securities, Available-for-sale | 1,314 | 1,329
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 | 717 |
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 | 721 |
Debt Securities, Available-for-sale, Amortized Cost | 717 | 717
Debt Securities, Available-for-sale | 721 | 707
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 Securities, Amortized Cost | 1,500 | 1,500
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 |
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 | 0 |
Available for Sale, Amortized Cost, Due after one year to five years | 1,022 |
Available for Sale, Amortized Cost, Due after five to ten years | 694 |
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 | 1,026 |
Available for Sale, Fair Value, Due after five to ten years | 713 |
Available for Sale, Fair Value, Due after ten years | 0 |
Debt Securities, Available-for-sale, Amortized Cost | 1,716 | 1,719
Debt Securities, Available-for-sale | 1,739 | 1,735
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 | 133,025 |
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 | 131,531 |
Debt Securities, Available-for-sale, Amortized Cost | 133,025 | 138,149
Debt Securities, Available-for-sale | 131,531 | 134,911
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 | 553 |
Held to Maturity, Amortized Cost, Due after ten years | 337,251 |
Held to maturity Securities, Amortized Cost | 337,804 | 332,775
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 | 551 |
Held to Maturity, Fair Value, Due after ten years | 335,154 |
Held to Maturity, Fair Value, Total | 335,705 | 326,724
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 | 7 |
Available for Sale, Amortized Cost, Due after one year to five years | 52,054 |
Available for Sale, Amortized Cost, Due after five to ten years | 88,335 |
Available for Sale, Amortized Cost, Due after ten years | 76,767 |
Available for Sale, Fair Value |  |
Available for Sale, Fair Value, Due in one year or less | 7 |
Available for Sale, Fair Value, Due after one year to five years | 51,871 |
Available for Sale, Fair Value, Due after five to ten years | 88,705 |
Available for Sale, Fair Value, Due after ten years | 77,212 |
Debt Securities, Available-for-sale, Amortized Cost | 217,163 | 222,491
Debt Securities, Available-for-sale | 217,795 | 220,105
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 | 11,786 |
Held to Maturity, Amortized Cost, Due after five to ten years | 34,127 |
Held to Maturity, Amortized Cost, Due after ten years | 213,686 |
Held to maturity Securities, Amortized Cost | 259,599 | 252,484
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 | 11,724 |
Held to Maturity, Fair Value, Due after five to ten years | 34,044 |
Held to Maturity, Fair Value, Due after ten years | 216,114 |
Held to Maturity, Fair Value, Total | 261,882 | 250,928
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 | 1,004 |
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 Securities, Amortized Cost | 1,004 | 1,004
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 | 1,017 |
Held to Maturity, Fair Value, Due after five to ten years | 0 |
Held to Maturity, Fair Value, Due after ten years | 0 |
Held to Maturity, Fair Value, Total | $ 1,017 | $ 1,015

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