Securities (Schedule of Contractual Maturities of Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Available for Sale, Fair Value
Debt Securities, Available-for-sale, Amortized Cost	$ 404,159	$ 420,703
Debt Securities, Available-for-sale	423,478	426,424
Held to Maturity, Fair Value
Debt Securities, Held-to-maturity	659,573	740,806
Held to Maturity, Fair Value, Total	690,467	753,263
Available for Sale Securities and Held to Maturity Securities Amortized Cost	1,063,732
Debt Securities, Available-for-sale and Held-to-maturity	1,113,945
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost	10,026
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	10,109
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost	86,523
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value	89,073
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost	106,650
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value	113,935
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Ten Years, Amortized Cost	860,533
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Ten Years, Fair Value	900,828
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	10,001
Available for Sale, Amortized Cost, Due after five to ten years	12,474
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	10,288
Available for Sale, Fair Value, Due after five to ten years	13,985
Available for Sale, Fair Value, Due after ten years	0
Debt Securities, Available-for-sale, Amortized Cost	22,475	32,473
Debt Securities, Available-for-sale	24,273	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	59,830
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	63,873
Debt Securities, Available-for-sale, Amortized Cost	59,830	54,024
Debt Securities, Available-for-sale	63,873	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	28,566
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	30,139
Debt Securities, Held-to-maturity	28,566	31,324
Held to Maturity, Fair Value, Total	30,139	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	515
Available for Sale, Amortized Cost, Due after one year to five years	82,045
Available for Sale, Amortized Cost, Due after five to ten years	51,620
Available for Sale, Amortized Cost, Due after ten years	269,979
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	516
Available for Sale, Fair Value, Due after one year to five years	84,483
Available for Sale, Fair Value, Due after five to ten years	56,148
Available for Sale, Fair Value, Due after ten years	282,331
Held to Maturity, Amortized Cost
Held to Maturity, Amortized Cost, Due in one year or less	9,511
Held to Maturity, Amortized Cost, Due after one year to five years	4,478
Held to Maturity, Amortized Cost, Due after five to ten years	55,030
Held to Maturity, Amortized Cost, Due after ten years	590,554
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Due in one year or less	9,593
Held to Maturity, Fair Value, Due after one year to five years	4,590
Held to Maturity, Fair Value, Due after five to ten years	57,787
Held to Maturity, Fair Value, Due after ten years	618,497
Held to Maturity, Fair Value, Total	690,467
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	1,433
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	1,021
Debt Securities, Available-for-sale, Amortized Cost	1,433	1,488
Debt Securities, Available-for-sale	1,021	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	469
Debt Securities, Available-for-sale, Amortized Cost	489	488
Debt Securities, Available-for-sale	469	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	1,498
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	1,498	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	515
Available for Sale, Amortized Cost, Due after one year to five years	420
Available for Sale, Amortized Cost, Due after five to ten years	190
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	516
Available for Sale, Fair Value, Due after one year to five years	422
Available for Sale, Fair Value, Due after five to ten years	207
Available for Sale, Fair Value, Due after ten years	0
Debt Securities, Available-for-sale, Amortized Cost	1,125	1,377
Debt Securities, Available-for-sale	1,145	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	98,657
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	102,077
Debt Securities, Available-for-sale, Amortized Cost	98,657	87,305
Debt Securities, Available-for-sale	102,077	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	237,380
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	246,937
Debt Securities, Held-to-maturity	237,380	293,662
Held to Maturity, Fair Value, Total	246,937	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	71,624
Available for Sale, Amortized Cost, Due after five to ten years	38,956
Available for Sale, Amortized Cost, Due after ten years	109,570
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	73,773
Available for Sale, Fair Value, Due after five to ten years	41,956
Available for Sale, Fair Value, Due after ten years	114,891
Debt Securities, Available-for-sale, Amortized Cost	220,150	243,548
Debt Securities, Available-for-sale	230,620	247,000
Held to Maturity, Amortized Cost
Held to Maturity, Amortized Cost, Due in one year or less	8,510
Held to Maturity, Amortized Cost, Due after one year to five years	1,458
Held to Maturity, Amortized Cost, Due after five to ten years	53,530
Held to Maturity, Amortized Cost, Due after ten years	324,608
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Due in one year or less	8,574
Held to Maturity, Fair Value, Due after one year to five years	1,509
Held to Maturity, Fair Value, Due after five to ten years	56,289
Held to Maturity, Fair Value, Due after ten years	341,421
Debt Securities, Held-to-maturity	388,106	397,414
Held to Maturity, Fair Value, Total	407,793	405,802
US Treasury Securities [Member]
Held to Maturity, Amortized Cost
Held to Maturity, Amortized Cost, Due in one year or less	1,001
Held to Maturity, Amortized Cost, Due after one year to five years	3,020
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	1,019
Held to Maturity, Fair Value, Due after one year to five years	3,081
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	4,021	4,032
Held to Maturity, Fair Value, Total	$ 4,100	$ 4,053