Allowance for Credit Losses (Portfolio Credit Quality) (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Loan portfolio by credit quality indicator
2022	$ 1,497,709
2021	2,731,390	$ 3,641,975
2020	1,228,614	1,540,327
2019	647,426	885,554
2018	529,733	616,037
2017/Prior	392,257	241,896
Prior		283,362
Total loans	7,027,129	7,209,151
Commercial, financial and agricultural
Loan portfolio by credit quality indicator
Total loans	4,252,063	4,497,444
Commercial, financial and agricultural | Domestic | Commercial.
Loan portfolio by credit quality indicator
2022	390,399
2021	823,937	1,154,047
2020	124,575	168,461
2019	54,040	78,434
2018	49,976	58,577
2017/Prior	32,437	37,178
Prior		5,155
Total loans	1,475,364	1,501,852
Commercial, financial and agricultural | Domestic | Commercial. | Pass
Loan portfolio by credit quality indicator
2022	357,293
2021	820,154	1,041,763
2020	124,285	167,691
2019	53,239	77,579
2018	49,922	58,439
2017/Prior	32,410	37,104
Prior		5,144
Total loans	1,437,303	1,387,720
Commercial, financial and agricultural | Domestic | Commercial. | Special Review
Loan portfolio by credit quality indicator
2022	81
2021	537	74,559
2020		497
2019	58	139
2018		81
Total loans	676	75,276
Commercial, financial and agricultural | Domestic | Commercial. | Watch List - Pass
Loan portfolio by credit quality indicator
2022	3,002
2021		33,920
2019	743
Prior		10
Total loans	3,745	33,930
Commercial, financial and agricultural | Domestic | Commercial. | Watch List - Substandard
Loan portfolio by credit quality indicator
2022	30,023
2021	3,067	3,581
2020	258	273
2019		716
2018	54	57
Prior		1
Total loans	33,402	4,628
Commercial, financial and agricultural | Domestic | Commercial. | Watch List - Doubtful
Loan portfolio by credit quality indicator
2021	179	224
2020	32
2017/Prior	27	74
Total loans	238	298
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial
Loan portfolio by credit quality indicator
2022	430,640
2021	694,148	1,021,054
2020	650,090	780,449
2019	262,696	292,569
2018	373,049	420,801
2017/Prior	132,131	98,606
Prior		97,577
Total loans	2,542,754	2,711,056
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Pass
Loan portfolio by credit quality indicator
2022	378,503
2021	693,221	1,001,335
2020	585,581	680,777
2019	258,592	288,333
2018	373,049	417,353
2017/Prior	129,821	96,096
Prior		97,119
Total loans	2,418,767	2,581,013
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Special Review
Loan portfolio by credit quality indicator
2022	233
2021	670	929
2020	863	1,292
2018		3,448
2017/Prior	1	61
Total loans	1,767	5,730
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Watch List - Pass
Loan portfolio by credit quality indicator
2022	17,242
2021	257	18,790
2020		44,059
2019	3,218
2017/Prior		94
Prior		1
Total loans	20,717	62,944
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Watch List - Substandard
Loan portfolio by credit quality indicator
2022	34,662
2020	63,646	54,097
2019	553	3,899
2017/Prior	2,309	2,355
Prior		456
Total loans	101,170	60,807
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Watch List - Doubtful
Loan portfolio by credit quality indicator
2020		224
2019	333	337
Prior		1
Total loans	333	562
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily
Loan portfolio by credit quality indicator
2022	46,317
2021	90,621	133,152
2020	60,528	40,897
2019	12,523	78,609
2018	6,529	10,632
2017/Prior	17,427	14,217
Prior		7,029
Total loans	233,945	284,536
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | Pass
Loan portfolio by credit quality indicator
2022	46,317
2021	90,621	133,152
2020	60,405	40,766
2019	12,523	78,609
2018	6,529	10,632
2017/Prior	17,427	14,217
Prior		7,029
Total loans	233,822	284,405
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | Watch List - Doubtful
Loan portfolio by credit quality indicator
2020	123	131
Total loans	123	131
Obligations of states and political subdivisions
Loan portfolio by credit quality indicator
Total loans	1,733,234	1,668,113
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development
Loan portfolio by credit quality indicator
2022	388,540
2021	848,151	967,431
2020	227,758	335,593
2019	221,558	308,884
2018	33,028	37,124
2017/Prior	14,199	16,642
Prior		2,439
Total loans	1,733,234	1,668,113
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | Pass
Loan portfolio by credit quality indicator
2022	388,540
2021	847,686	966,946
2020	204,559	312,389
2019	221,348	308,673
2018	33,028	37,124
2017/Prior	14,199	16,642
Prior		2,439
Total loans	1,709,360	1,644,213
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | Special Review
Loan portfolio by credit quality indicator
2019	210	211
Total loans	210	211
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | Watch List - Pass
Loan portfolio by credit quality indicator
2020		23,100
Total loans		23,100
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | Watch List - Substandard
Loan portfolio by credit quality indicator
2020	23,100
Total loans	23,100
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | Watch List - Doubtful
Loan portfolio by credit quality indicator
2021	465	485
2020	99	104
Total loans	564	589
Real estate - mortgage
Loan portfolio by credit quality indicator
Total loans	842,742	867,831
Real estate - mortgage | Domestic | Residential: first lien
Loan portfolio by credit quality indicator
2022	88,620
2021	87,351	128,798
2020	54,478	52,812
2019	44,902	57,352
2018	37,259	49,259
2017/Prior	92,776	29,599
Prior		85,838
Total loans	405,386	403,658
Real estate - mortgage | Domestic | Residential: first lien | Pass
Loan portfolio by credit quality indicator
2022	88,520
2021	86,918	128,742
2020	54,395	52,725
2019	44,902	57,249
2018	37,259	49,259
2017/Prior	92,776	29,477
Prior		85,838
Total loans	404,770	403,290
Real estate - mortgage | Domestic | Residential: first lien | Watch List - Substandard
Loan portfolio by credit quality indicator
2022	100
2021	433	56
2019		103
2017/Prior		122
Total loans	533	281
Real estate - mortgage | Domestic | Residential: first lien | Watch List - Doubtful
Loan portfolio by credit quality indicator
2020	83	87
Total loans	83	87
Real estate - mortgage | Domestic | Residential Junior Lien
Loan portfolio by credit quality indicator
2022	48,374
2021	119,846	130,629
2020	102,124	123,062
2019	45,454	59,113
2018	24,213	30,603
2017/Prior	97,345	40,855
Prior		79,911
Total loans	437,356	464,173
Real estate - mortgage | Domestic | Residential Junior Lien | Pass
Loan portfolio by credit quality indicator
2022	48,374
2021	119,846	130,629
2020	102,124	123,062
2019	45,454	59,113
2018	24,213	30,603
2017/Prior	97,345	40,855
Prior		79,911
Total loans	437,356	464,173
Consumer
Loan portfolio by credit quality indicator
Total loans	40,815	40,966
Consumer | Domestic
Loan portfolio by credit quality indicator
2022	19,081
2021	17,005	32,053
2020	2,274	5,693
2019	740	1,370
2018	65	189
2017/Prior	1,650	9
Prior		1,652
Total loans	40,815	40,966
Consumer | Domestic | Pass
Loan portfolio by credit quality indicator
2022	19,081
2021	17,005	32,053
2020	2,274	5,693
2019	740	1,370
2018	65	189
2017/Prior	1,650	9
Prior		1,652
Total loans	40,815	40,966
Foreign.
Loan portfolio by credit quality indicator
Total loans	158,275	134,797
Foreign. | Foreign
Loan portfolio by credit quality indicator
2022	85,738
2021	50,331	74,811
2020	6,787	33,360
2019	5,513	9,223
2018	5,614	8,852
2017/Prior	4,292	4,790
Prior		3,761
Total loans	158,275	134,797
Foreign. | Foreign | Pass
Loan portfolio by credit quality indicator
2022	85,738
2021	50,331	74,811
2020	6,787	33,360
2019	5,513	9,223
2018	5,614	8,852
2017/Prior	4,292	4,790
Prior		3,761
Total loans	$ 158,275	$ 134,797