Securities (Schedule of Contractual Maturities of Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Available for Sale, Fair Value
Debt Securities, Available-for-sale, Amortized Cost	$ 1,425,392	$ 395,453
Debt Securities, Available-for-sale	1,427,210	412,860
Held to Maturity, Fair Value
Debt Securities, Held-to-maturity	865,249	724,512
Held to Maturity, Fair Value, Total	875,306	752,177
Available for Sale Securities and Held to Maturity Securities Amortized Cost	2,290,641
Debt Securities, Available-for-sale and Held-to-maturity	2,302,516
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost	15,365
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	15,467
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost	690,802
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value	690,436
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost	624,951
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value	621,521
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Ten Years, Amortized Cost	959,523
Debt Securities, Available-for-sale and Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Ten Years, Fair Value	975,092
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	10,000
Available for Sale, Amortized Cost, Due after one year to five years	31,422
Available for Sale, Amortized Cost, Due after five to ten years	176,191
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	10,066
Available for Sale, Fair Value, Due after one year to five years	31,275
Available for Sale, Fair Value, Due after five to ten years	176,004
Available for Sale, Fair Value, Due after ten years	0
Debt Securities, Available-for-sale, Amortized Cost	217,613	22,476
Debt Securities, Available-for-sale	217,345	24,116
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	33,422
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	33,295
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	33,422	0
Held to Maturity, Fair Value, Total	33,295	0
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	51,718
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	54,368
Debt Securities, Available-for-sale, Amortized Cost	51,718	57,289
Debt Securities, Available-for-sale	54,368	61,081
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	23,686
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	24,828
Debt Securities, Held-to-maturity	23,686	26,917
Held to Maturity, Fair Value, Total	24,828	28,362
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	12,358
Available for Sale, Amortized Cost, Due after one year to five years	653,898
Available for Sale, Amortized Cost, Due after five to ten years	498,247
Available for Sale, Amortized Cost, Due after ten years	260,889
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	12,443
Available for Sale, Fair Value, Due after one year to five years	653,464
Available for Sale, Fair Value, Due after five to ten years	494,606
Available for Sale, Fair Value, Due after ten years	266,697
Held to Maturity, Amortized Cost
Held to Maturity, Amortized Cost, Due in one year or less	3,007
Held to Maturity, Amortized Cost, Due after one year to five years	36,904
Held to Maturity, Amortized Cost, Due after five to ten years	126,704
Held to Maturity, Amortized Cost, Due after ten years	698,634
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Due in one year or less	3,024
Held to Maturity, Fair Value, Due after one year to five years	36,972
Held to Maturity, Fair Value, Due after five to ten years	126,915
Held to Maturity, Fair Value, Due after ten years	708,395
Held to Maturity, Fair Value, Total	875,306
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	1,341
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	1,010
Debt Securities, Available-for-sale, Amortized Cost	1,341	1,429
Debt Securities, Available-for-sale	1,010	1,056
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	491
Debt Securities, Available-for-sale, Amortized Cost	489	489
Debt Securities, Available-for-sale	491	488
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	1,508
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	1,508	1,498
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	85
Available for Sale, Amortized Cost, Due after one year to five years	0
Available for Sale, Amortized Cost, Due after five to ten years	191
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	85
Available for Sale, Fair Value, Due after one year to five years	0
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	276	790
Debt Securities, Available-for-sale	288	807
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	85,076
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	86,487
Debt Securities, Available-for-sale, Amortized Cost	85,076	88,687
Debt Securities, Available-for-sale	86,487	91,683
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	451,151
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	452,038
Debt Securities, Held-to-maturity	451,151	335,993
Held to Maturity, Fair Value, Total	452,038	344,119
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	2,273
Available for Sale, Amortized Cost, Due after one year to five years	81,194
Available for Sale, Amortized Cost, Due after five to ten years	88,655
Available for Sale, Amortized Cost, Due after ten years	122,265
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	2,292
Available for Sale, Fair Value, Due after one year to five years	83,434
Available for Sale, Fair Value, Due after five to ten years	87,152
Available for Sale, Fair Value, Due after ten years	124,341
Debt Securities, Available-for-sale, Amortized Cost	294,387	224,293
Debt Securities, Available-for-sale	297,219	233,629
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	3,482
Held to Maturity, Amortized Cost, Due after five to ten years	125,204
Held to Maturity, Amortized Cost, Due after ten years	223,797
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	3,677
Held to Maturity, Fair Value, Due after five to ten years	125,407
Held to Maturity, Fair Value, Due after ten years	231,529
Debt Securities, Held-to-maturity	352,483	356,085
Held to Maturity, Fair Value, Total	360,613	374,121
US Treasury 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	541,282
Available for Sale, Amortized Cost, Due after five to ten years	233,210
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	538,755
Available for Sale, Fair Value, Due after five to ten years	231,247
Available for Sale, Fair Value, Due after ten years	0
Debt Securities, Available-for-sale, Amortized Cost	774,492	0
Debt Securities, Available-for-sale	770,002
Held to Maturity, Amortized Cost
Held to Maturity, Amortized Cost, Due in one year or less	3,007
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	0
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Due in one year or less	3,024
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	0
Debt Securities, Held-to-maturity	3,007	4,017
Held to Maturity, Fair Value, Total	$ 3,024	$ 4,077