Loans, Allowance for Credit Losses, and Asset Quality Information (Schedule of Recorded Investment in Loans by Credit Quality Indicators) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020
Financing Receivable, Credit Quality Indicator [Line Items]
2021	$ 469,566
2020	1,538,808
2019	723,742
2018	522,342
2017	354,333
Prior	603,029
Revolving	418,777
Total	4,630,597	$ 4,735,013	$ 4,550,996
Unamortized net deferred loan costs (fees)	(6,543)	(3,698)	1,712
Total loans	4,624,054	4,731,315	4,552,708
Commercial, financial, and agricultural
Financing Receivable, Credit Quality Indicator [Line Items]
Total	768,318	782,549	521,470
Commercial, financial, and agricultural | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	768,318	782,412
Consumer loans
Financing Receivable, Credit Quality Indicator [Line Items]
2021	4,696
2020	26,657
2019	5,720
2018	2,900
2017	1,281
Prior	1,377
Revolving	10,853
Total	53,484	53,955	54,133
Consumer loans | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	53,484	53,917
Commercial, financial, and agricultural
Financing Receivable, Credit Quality Indicator [Line Items]
2021	148,041
2020	298,069
2019	112,596
2018	93,143
2017	21,564
Prior	27,510
Revolving	67,395
Total	768,318
Real estate – construction, land development & other land loans | Real estate, commercial
Financing Receivable, Credit Quality Indicator [Line Items]
2021	104,847
2020	316,288
2019	70,999
2018	13,049
2017	12,781
Prior	12,011
Revolving	18,533
Total	548,508	570,672	590,485
Real estate – construction, land development & other land loans | Real estate, commercial | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	548,508	570,522
Real estate – mortgage – residential (1-4 family) first mortgages | Real estate, mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
2021	27,373
2020	175,672
2019	173,790
2018	183,417
2017	121,092
Prior	227,039
Revolving	7,786
Total	916,169	972,378	1,083,022
Real estate – mortgage – residential (1-4 family) first mortgages | Real estate, mortgage | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	916,169	968,151
Real estate – mortgage – home equity loans / lines of credit | Real estate, mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
2021	175
2020	693
2019	1,294
2018	1,827
2017	1,810
Prior	2,146
Revolving	286,666
Total	294,611	306,256	331,170
Real estate – mortgage – home equity loans / lines of credit | Real estate, mortgage | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	294,611	306,156
Real estate – mortgage – commercial and other | Real estate, commercial
Financing Receivable, Credit Quality Indicator [Line Items]
2021	184,434
2020	721,429
2019	359,343
2018	228,006
2017	195,805
Prior	332,946
Revolving	27,544
Total	2,049,507	2,049,203	$ 1,970,716
Real estate – mortgage – commercial and other | Real estate, commercial | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,049,507	2,045,264
Purchased credit impaired
Financing Receivable, Credit Quality Indicator [Line Items]
Total		8,591
Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total		4,613,259
Pass | Commercial, financial, and agricultural | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		762,091
Pass | Consumer loans
Financing Receivable, Credit Quality Indicator [Line Items]
2021	4,696
2020	26,569
2019	5,675
2018	2,872
2017	1,281
Prior	1,293
Revolving	10,626
Total	53,012
Pass | Consumer loans | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		53,488
Pass | Commercial, financial, and agricultural
Financing Receivable, Credit Quality Indicator [Line Items]
2021	147,842
2020	293,349
2019	105,182
2018	87,514
2017	21,260
Prior	27,420
Revolving	66,442
Total	749,009
Pass | Real estate – construction, land development & other land loans | Real estate, commercial
Financing Receivable, Credit Quality Indicator [Line Items]
2021	104,771
2020	311,765
2019	70,727
2018	12,754
2017	12,577
Prior	11,343
Revolving	18,161
Total	542,098
Pass | Real estate – construction, land development & other land loans | Real estate, commercial | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		560,845
Pass | Real estate – mortgage – residential (1-4 family) first mortgages | Real estate, mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
2021	26,304
2020	172,807
2019	170,991
2018	180,894
2017	119,528
Prior	213,166
Revolving	7,325
Total	891,015
Pass | Real estate – mortgage – residential (1-4 family) first mortgages | Real estate, mortgage | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		943,455
Pass | Real estate – mortgage – home equity loans / lines of credit | Real estate, mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
2021	175
2020	531
2019	1,139
2018	1,827
2017	1,810
Prior	1,388
Revolving	279,116
Total	285,986
Pass | Real estate – mortgage – home equity loans / lines of credit | Real estate, mortgage | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		297,795
Pass | Real estate – mortgage – commercial and other | Real estate, commercial
Financing Receivable, Credit Quality Indicator [Line Items]
2021	180,222
2020	699,117
2019	349,785
2018	222,224
2017	189,511
Prior	326,685
Revolving	26,465
Total	1,994,009
Pass | Real estate – mortgage – commercial and other | Real estate, commercial | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		1,988,684
Pass | Purchased credit impaired
Financing Receivable, Credit Quality Indicator [Line Items]
Total		6,901
Special Mention Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		61,260
Special Mention Loans | Commercial, financial, and agricultural | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		9,553
Special Mention Loans | Consumer loans
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving	76
Total	76
Special Mention Loans | Consumer loans | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		80
Special Mention Loans | Commercial, financial, and agricultural
Financing Receivable, Credit Quality Indicator [Line Items]
2021	22
2020	653
2019	3,690
2018	2,900
2017	49
Prior	42
Revolving	452
Total	7,808
Special Mention Loans | Real estate – construction, land development & other land loans | Real estate, commercial
Financing Receivable, Credit Quality Indicator [Line Items]
2021	48
2020	4,037
2019	55
2018	3
2017	116
Prior	254
Revolving	109
Total	4,622
Special Mention Loans | Real estate – construction, land development & other land loans | Real estate, commercial | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		7,877
Special Mention Loans | Real estate – mortgage – residential (1-4 family) first mortgages | Real estate, mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
2021	638
2020	1,459
2019	291
2018	313
2017	384
Prior	3,963
Revolving	23
Total	7,071
Special Mention Loans | Real estate – mortgage – residential (1-4 family) first mortgages | Real estate, mortgage | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		7,609
Special Mention Loans | Real estate – mortgage – home equity loans / lines of credit | Real estate, mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	0
2019	18
2018	0
2017	0
Prior	20
Revolving	1,298
Total	1,336
Special Mention Loans | Real estate – mortgage – home equity loans / lines of credit | Real estate, mortgage | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		1,468
Special Mention Loans | Real estate – mortgage – commercial and other | Real estate, commercial
Financing Receivable, Credit Quality Indicator [Line Items]
2021	3,833
2020	15,743
2019	2,775
2018	2,940
2017	3,394
Prior	1,915
Revolving	817
Total	31,417
Special Mention Loans | Real estate – mortgage – commercial and other | Real estate, commercial | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		34,588
Special Mention Loans | Purchased credit impaired
Financing Receivable, Credit Quality Indicator [Line Items]
Total		85
Classified | Consumer loans
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	88
2019	45
2018	28
2017	0
Prior	84
Revolving	151
Total	396
Classified | Commercial, financial, and agricultural
Financing Receivable, Credit Quality Indicator [Line Items]
2021	177
2020	4,067
2019	3,724
2018	2,729
2017	255
Prior	48
Revolving	501
Total	11,501
Classified | Real estate – construction, land development & other land loans | Real estate, commercial
Financing Receivable, Credit Quality Indicator [Line Items]
2021	28
2020	486
2019	217
2018	292
2017	88
Prior	414
Revolving	263
Total	1,788
Classified | Real estate – mortgage – residential (1-4 family) first mortgages | Real estate, mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
2021	431
2020	1,406
2019	2,508
2018	2,210
2017	1,180
Prior	9,910
Revolving	438
Total	18,083
Classified | Real estate – mortgage – home equity loans / lines of credit | Real estate, mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	162
2019	137
2018	0
2017	0
Prior	738
Revolving	6,252
Total	7,289
Classified | Real estate – mortgage – commercial and other | Real estate, commercial
Financing Receivable, Credit Quality Indicator [Line Items]
2021	379
2020	6,569
2019	6,783
2018	2,842
2017	2,900
Prior	4,346
Revolving	262
Total	$ 24,081
Classified Accruing Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		25,418
Classified Accruing Loans | Commercial, financial, and agricultural | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		1,087
Classified Accruing Loans | Consumer loans | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		169
Classified Accruing Loans | Real estate – construction, land development & other land loans | Real estate, commercial | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		1,157
Classified Accruing Loans | Real estate – mortgage – residential (1-4 family) first mortgages | Real estate, mortgage | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		11,039
Classified Accruing Loans | Real estate – mortgage – home equity loans / lines of credit | Real estate, mortgage | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		5,560
Classified Accruing Loans | Real estate – mortgage – commercial and other | Real estate, commercial | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		4,801
Classified Accruing Loans | Purchased credit impaired
Financing Receivable, Credit Quality Indicator [Line Items]
Total		1,605
Classified Nonaccrual Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		35,076
Classified Nonaccrual Loans | Commercial, financial, and agricultural | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		9,681
Classified Nonaccrual Loans | Consumer loans | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		180
Classified Nonaccrual Loans | Real estate – construction, land development & other land loans | Real estate, commercial | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		643
Classified Nonaccrual Loans | Real estate – mortgage – residential (1-4 family) first mortgages | Real estate, mortgage | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		6,048
Classified Nonaccrual Loans | Real estate – mortgage – home equity loans / lines of credit | Real estate, mortgage | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		1,333
Classified Nonaccrual Loans | Real estate – mortgage – commercial and other | Real estate, commercial | Loans, Excluding Purchased Credit Impaired Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total		17,191
Classified Nonaccrual Loans | Purchased credit impaired
Financing Receivable, Credit Quality Indicator [Line Items]
Total		$ 0