Loans and Leases - Credit Quality (Detail) $ in Thousands	Dec. 31, 2020 USD ($)
Financing Receivable, Credit Quality Indicator [Line Items]
2020	$ 2,001,595
2019	723,898
2018	395,275
2017	362,654
2016	205,604
Prior	254,149
Revolving Loans Amortized Cost Basis	516,936
Total	4,460,111
Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,966,242
2019	707,620
2018	390,152
2017	350,602
2016	201,130
Prior	238,726
Revolving Loans Amortized Cost Basis	499,565
Total	4,354,037
Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2020	31,522
2019	10,859
2018	4,002
2017	577
2016	2,202
Prior	7,144
Revolving Loans Amortized Cost Basis	9,565
Total	65,871
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2020	3,831
2019	5,419
2018	1,121
2017	11,475
2016	2,272
Prior	8,279
Revolving Loans Amortized Cost Basis	7,806
Total	40,203
Performing
Financing Receivable, Credit Quality Indicator [Line Items]
2020	267,150
2019	110,092
2018	88,792
2017	64,197
2016	43,329
Prior	89,160
Revolving Loans Amortized Cost Basis	180,220
Total	842,940
Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
2020	678
2019	182
2018	259
2017	205
2016	7
Prior	1,431
Revolving Loans Amortized Cost Basis	1,028
Total	3,790
Commercial, Financial and Agricultural [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020	165,270
2019	95,180
2018	75,400
2017	39,434
2016	18,148
Prior	57,824
Revolving Loans Amortized Cost Basis	441,409
Total	892,665
Commercial, Financial and Agricultural [Member] | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	162,547
2019	93,967
2018	74,722
2017	38,906
2016	17,371
Prior	56,053
Revolving Loans Amortized Cost Basis	427,336
Total	870,902
Commercial, Financial and Agricultural [Member] | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2020	2,723
2019	783
2018	316
2017	500
2016	777
Prior	1,144
Revolving Loans Amortized Cost Basis	8,318
Total	14,561
Commercial, Financial and Agricultural [Member] | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	430
2018	362
2017	28
2016	0
Prior	627
Revolving Loans Amortized Cost Basis	5,755
Total	7,202
Paycheck Protection Program Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020	483,773
2019	0
2018	0
2017	0
2016	0
Prior	0
Revolving Loans Amortized Cost Basis	0
Total	483,773
Paycheck Protection Program Loans [Member] | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	483,773
2019	0
2018	0
2017	0
2016	0
Prior	0
Revolving Loans Amortized Cost Basis	0
Total	483,773
Paycheck Protection Program Loans [Member] | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	0
Revolving Loans Amortized Cost Basis	0
Total	0
Paycheck Protection Program Loans [Member] | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	0
Revolving Loans Amortized Cost Basis	0
Total	0
Real Estate-Commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,094,180
2019	496,071
2018	227,853
2017	279,619
2016	145,498
Prior	170,063
Revolving Loans Amortized Cost Basis	45,588
Total	2,458,872
Real Estate-Commercial [Member] | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,084,157
2019	481,997
2018	223,646
2017	268,236
2016	143,041
Prior	157,503
Revolving Loans Amortized Cost Basis	43,008
Total	2,401,588
Real Estate-Commercial [Member] | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2020	6,220
2019	10,076
2018	3,498
2017	0
2016	1,250
Prior	5,870
Revolving Loans Amortized Cost Basis	1,247
Total	28,161
Real Estate-Commercial [Member] | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2020	3,803
2019	3,998
2018	709
2017	11,383
2016	1,207
Prior	6,690
Revolving Loans Amortized Cost Basis	1,333
Total	29,123
Real Estate-Construction [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020	138,065
2019	59,507
2018	39,009
2017	113
2016	2,950
Prior	0
Revolving Loans Amortized Cost Basis	3,711
Total	243,355
Real Estate-Construction [Member] | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	116,840
2019	59,507
2018	39,009
2017	113
2016	2,950
Prior	0
Revolving Loans Amortized Cost Basis	3,711
Total	222,130
Real Estate-Construction [Member] | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2020	21,225
2019	0
2018	0
2017	0
2016	0
Prior	0
Revolving Loans Amortized Cost Basis	0
Total	21,225
Real Estate-Construction [Member] | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	0
Revolving Loans Amortized Cost Basis	0
Total	0
Real Estate-Residential Secured for Business Purpose [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020	120,307
2019	73,140
2018	53,013
2017	43,488
2016	39,008
Prior	26,262
Revolving Loans Amortized Cost Basis	26,228
Total	381,446
Real Estate-Residential Secured for Business Purpose [Member] | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	118,925
2019	72,149
2018	52,775
2017	43,347
2016	37,768
Prior	25,170
Revolving Loans Amortized Cost Basis	25,510
Total	375,644
Real Estate-Residential Secured for Business Purpose [Member] | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,354
2019	0
2018	188
2017	77
2016	175
Prior	130
Revolving Loans Amortized Cost Basis	0
Total	1,924
Real Estate-Residential Secured for Business Purpose [Member] | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2020	28
2019	991
2018	50
2017	64
2016	1,065
Prior	962
Revolving Loans Amortized Cost Basis	718
Total	3,878
Real Estate-Residential Secured for Personal Purpose [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020	192,653
2019	61,880
2018	56,370
2017	50,983
2016	38,975
Prior	85,502
Revolving Loans Amortized Cost Basis	1,237
Total	487,600
Real Estate-Residential Secured for Personal Purpose [Member] | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
2020	191,987
2019	61,880
2018	56,314
2017	50,983
2016	38,975
Prior	84,138
Revolving Loans Amortized Cost Basis	1,237
Total	485,514
Real Estate-Residential Secured for Personal Purpose [Member] | Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
2020	666
2019	0
2018	56
2017	0
2016	0
Prior	1,364
Revolving Loans Amortized Cost Basis	0
Total	2,086
Real Estate-Home Equity Secured for Personal Purpose [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,195
2019	815
2018	1,027
2017	1,160
2016	518
Prior	2,225
Revolving Loans Amortized Cost Basis	159,669
Total	166,609
Real Estate-Home Equity Secured for Personal Purpose [Member] | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,195
2019	815
2018	829
2017	1,160
2016	518
Prior	2,189
Revolving Loans Amortized Cost Basis	158,803
Total	165,509
Real Estate-Home Equity Secured for Personal Purpose [Member] | Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	198
2017	0
2016	0
Prior	36
Revolving Loans Amortized Cost Basis	866
Total	1,100
Loans to Individuals [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,795
2019	1,425
2018	970
2017	441
2016	220
Prior	2,289
Revolving Loans Amortized Cost Basis	20,342
Total	27,482
Loans to Individuals [Member] | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,795
2019	1,425
2018	970
2017	441
2016	220
Prior	2,266
Revolving Loans Amortized Cost Basis	20,180
Total	27,297
Loans to Individuals [Member] | Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	23
Revolving Loans Amortized Cost Basis	162
Total	185
Lease Financings [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020	72,185
2019	46,154
2018	30,684
2017	11,818
2016	3,623
Prior	575
Revolving Loans Amortized Cost Basis	0
Total	165,039
Lease Financings [Member] | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
2020	72,173
2019	45,972
2018	30,679
2017	11,613
2016	3,616
Prior	567
Revolving Loans Amortized Cost Basis	0
Total	164,620
Lease Financings [Member] | Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
2020	12
2019	182
2018	5
2017	205
2016	7
Prior	8
Revolving Loans Amortized Cost Basis	0
Total	419
Financing Receivable
Financing Receivable, Credit Quality Indicator [Line Items]
2020	267,828
2019	110,274
2018	89,051
2017	64,402
2016	43,336
Prior	90,591
Revolving Loans Amortized Cost Basis	181,248
Total	$ 846,730