Allowance for Credit Losses (Aging By Loan Class) (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	$ 8,230	$ 8,642
Loans	7,027,129	7,209,151
Current
Financing receivable recorded investment
Loans	6,962,502	7,171,688
Total Past Due
Financing receivable recorded investment
Loans	64,627	37,463
30 to 59 Days
Financing receivable recorded investment
Loans	23,062	25,836
60 to 89 Days
Financing receivable recorded investment
Loans	32,360	2,456
90 Days or Greater
Financing receivable recorded investment
Loans	9,205	9,171
Commercial, financial and agricultural
Financing receivable recorded investment
Loans	4,252,063	4,497,444
Commercial, financial and agricultural | Domestic | Commercial.
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	68	577
Loans	1,475,364	1,501,852
Commercial, financial and agricultural | Domestic | Commercial. | Current
Financing receivable recorded investment
Loans	1,471,325	1,498,438
Commercial, financial and agricultural | Domestic | Commercial. | Total Past Due
Financing receivable recorded investment
Loans	4,039	3,414
Commercial, financial and agricultural | Domestic | Commercial. | 30 to 59 Days
Financing receivable recorded investment
Loans	3,498	2,534
Commercial, financial and agricultural | Domestic | Commercial. | 60 to 89 Days
Financing receivable recorded investment
Loans	440	303
Commercial, financial and agricultural | Domestic | Commercial. | 90 Days or Greater
Financing receivable recorded investment
Loans	101	577
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	1,314	307
Loans	2,542,754	2,711,056
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Current
Financing receivable recorded investment
Loans	2,532,434	2,692,076
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Total Past Due
Financing receivable recorded investment
Loans	10,320	18,980
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | 30 to 59 Days
Financing receivable recorded investment
Loans	8,253	18,164
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | 60 to 89 Days
Financing receivable recorded investment
Loans	420	172
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | 90 Days or Greater
Financing receivable recorded investment
Loans	1,647	644
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily
Financing receivable recorded investment
Loans	233,945	284,536
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | Current
Financing receivable recorded investment
Loans	233,750	284,536
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | Total Past Due
Financing receivable recorded investment
Loans	195
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | 30 to 59 Days
Financing receivable recorded investment
Loans	72
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | 60 to 89 Days
Financing receivable recorded investment
Loans	123
Obligations of states and political subdivisions
Financing receivable recorded investment
Loans	1,733,234	1,668,113
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	34	188
Loans	1,733,234	1,668,113
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | Current
Financing receivable recorded investment
Loans	1,694,399	1,667,092
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | Total Past Due
Financing receivable recorded investment
Loans	38,835	1,021
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | 30 to 59 Days
Financing receivable recorded investment
Loans	8,133	499
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | 60 to 89 Days
Financing receivable recorded investment
Loans	30,203	334
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | 90 Days or Greater
Financing receivable recorded investment
Loans	499	188
Real estate - mortgage
Financing receivable recorded investment
Loans	842,742	867,831
Real estate - mortgage | Domestic | Residential: first lien
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	5,452	4,937
Loans	405,386	403,658
Real estate - mortgage | Domestic | Residential: first lien | Current
Financing receivable recorded investment
Loans	397,059	394,975
Real estate - mortgage | Domestic | Residential: first lien | Total Past Due
Financing receivable recorded investment
Loans	8,327	8,683
Real estate - mortgage | Domestic | Residential: first lien | 30 to 59 Days
Financing receivable recorded investment
Loans	2,035	2,342
Real estate - mortgage | Domestic | Residential: first lien | 60 to 89 Days
Financing receivable recorded investment
Loans	696	1,212
Real estate - mortgage | Domestic | Residential: first lien | 90 Days or Greater
Financing receivable recorded investment
Loans	5,596	5,129
Real estate - mortgage | Domestic | Residential Junior Lien
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	1,328	1,055
Loans	437,356	464,173
Real estate - mortgage | Domestic | Residential Junior Lien | Current
Financing receivable recorded investment
Loans	435,226	462,256
Real estate - mortgage | Domestic | Residential Junior Lien | Total Past Due
Financing receivable recorded investment
Loans	2,130	1,917
Real estate - mortgage | Domestic | Residential Junior Lien | 30 to 59 Days
Financing receivable recorded investment
Loans	525	747
Real estate - mortgage | Domestic | Residential Junior Lien | 60 to 89 Days
Financing receivable recorded investment
Loans	277	115
Real estate - mortgage | Domestic | Residential Junior Lien | 90 Days or Greater
Financing receivable recorded investment
Loans	1,328	1,055
Consumer
Financing receivable recorded investment
Loans	40,815	40,966
Consumer | Domestic
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	18	4
Loans	40,815	40,966
Consumer | Domestic | Current
Financing receivable recorded investment
Loans	40,459	40,643
Consumer | Domestic | Total Past Due
Financing receivable recorded investment
Loans	356	323
Consumer | Domestic | 30 to 59 Days
Financing receivable recorded investment
Loans	260	231
Consumer | Domestic | 60 to 89 Days
Financing receivable recorded investment
Loans	78	88
Consumer | Domestic | 90 Days or Greater
Financing receivable recorded investment
Loans	18	4
Foreign.
Financing receivable recorded investment
Loans	158,275	134,797
Foreign. | Foreign
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	16	1,574
Loans	158,275	134,797
Foreign. | Foreign | Current
Financing receivable recorded investment
Loans	157,850	131,672
Foreign. | Foreign | Total Past Due
Financing receivable recorded investment
Loans	425	3,125
Foreign. | Foreign | 30 to 59 Days
Financing receivable recorded investment
Loans	286	1,319
Foreign. | Foreign | 60 to 89 Days
Financing receivable recorded investment
Loans	123	232
Foreign. | Foreign | 90 Days or Greater
Financing receivable recorded investment
Loans	$ 16	$ 1,574