Allowance for Credit Losses - Analysis of Past Due and Nonaccrual Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Financing Receivable, Past Due [Line Items]
Financing receivable	$ 6,708,666	$ 6,450,447
Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	4,367,445	4,359,083
Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	1,288,810	1,240,743
Commercial and industrial
Financing Receivable, Past Due [Line Items]
Financing receivable	599,757	569,921
Construction
Financing Receivable, Past Due [Line Items]
Financing receivable	320,963	211,560
Agriculture production
Financing Receivable, Past Due [Line Items]
Financing receivable	123,472	61,414
Leases
Financing Receivable, Past Due [Line Items]
Financing receivable	8,219	7,726
CRE non-owner occupied | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	2,171,422	2,149,725
CRE owner occupied | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	958,054	984,807
Multifamily | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	959,361	944,537
Farmland | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	278,608	280,014
SFR 1-4 1st DT liens | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	870,209	790,349
SFR HELOCs and junior liens | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	352,798	393,666
Other | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	65,803	56,728
Financial Asset Originated
Financing Receivable, Past Due [Line Items]
Financing receivable	6,708,666	6,450,447
Financial Asset Originated | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	4,367,445	4,359,083
Financial Asset Originated | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	1,288,810	1,240,743
Financial Asset Originated | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Financing receivable	599,757	569,921
Financial Asset Originated | Construction
Financing Receivable, Past Due [Line Items]
Financing receivable	320,963	211,560
Financial Asset Originated | Agriculture production
Financing Receivable, Past Due [Line Items]
Financing receivable	123,472	61,414
Financial Asset Originated | Leases
Financing Receivable, Past Due [Line Items]
Financing receivable	8,219	7,726
Financial Asset Originated | CRE non-owner occupied | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	2,171,422	2,149,725
Financial Asset Originated | CRE owner occupied | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	958,054	984,807
Financial Asset Originated | Multifamily | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	959,361	944,537
Financial Asset Originated | Farmland | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	278,608	280,014
Financial Asset Originated | SFR 1-4 1st DT liens | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	870,209	790,349
Financial Asset Originated | SFR HELOCs and junior liens | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	352,798	393,666
Financial Asset Originated | Other | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	65,803	56,728
Total Past Due Loans | Financial Asset Originated
Financing Receivable, Past Due [Line Items]
Financing receivable	8,072	4,947
Total Past Due Loans | Financial Asset Originated | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	1,364	332
Total Past Due Loans | Financial Asset Originated | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	5,000	1,463
Total Past Due Loans | Financial Asset Originated | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Financing receivable	1,675	2,773
Total Past Due Loans | Financial Asset Originated | Construction
Financing Receivable, Past Due [Line Items]
Financing receivable	0	379
Total Past Due Loans | Financial Asset Originated | Agriculture production
Financing Receivable, Past Due [Line Items]
Financing receivable	33	0
Total Past Due Loans | Financial Asset Originated | Leases
Financing Receivable, Past Due [Line Items]
Financing receivable	0	0
Total Past Due Loans | Financial Asset Originated | CRE non-owner occupied | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	615	0
Total Past Due Loans | Financial Asset Originated | CRE owner occupied | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	485	173
Total Past Due Loans | Financial Asset Originated | Multifamily | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	0	159
Total Past Due Loans | Financial Asset Originated | Farmland | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	264	0
Total Past Due Loans | Financial Asset Originated | SFR 1-4 1st DT liens | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	1,530	303
Total Past Due Loans | Financial Asset Originated | SFR HELOCs and junior liens | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	3,255	1,045
Total Past Due Loans | Financial Asset Originated | Other | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	215	115
30-59 days | Financial Asset Originated
Financing Receivable, Past Due [Line Items]
Financing receivable	2,681	2,681
30-59 days | Financial Asset Originated | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	541	159
30-59 days | Financial Asset Originated | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	2,087	222
30-59 days | Financial Asset Originated | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Financing receivable	53	2,300
30-59 days | Financial Asset Originated | Construction
Financing Receivable, Past Due [Line Items]
Financing receivable	0	0
30-59 days | Financial Asset Originated | Agriculture production
Financing Receivable, Past Due [Line Items]
Financing receivable	0	0
30-59 days | Financial Asset Originated | Leases
Financing Receivable, Past Due [Line Items]
Financing receivable	0	0
30-59 days | Financial Asset Originated | CRE non-owner occupied | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	403	0
30-59 days | Financial Asset Originated | CRE owner occupied | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	138	0
30-59 days | Financial Asset Originated | Multifamily | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	0	159
30-59 days | Financial Asset Originated | Farmland | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	0	0
30-59 days | Financial Asset Originated | SFR 1-4 1st DT liens | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	398	24
30-59 days | Financial Asset Originated | SFR HELOCs and junior liens | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	1,570	172
30-59 days | Financial Asset Originated | Other | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	119	26
60-89 days | Financial Asset Originated
Financing Receivable, Past Due [Line Items]
Financing receivable	2,197	488
60-89 days | Financial Asset Originated | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	117	98
60-89 days | Financial Asset Originated | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	1,972	200
60-89 days | Financial Asset Originated | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Financing receivable	108	190
60-89 days | Financial Asset Originated | Construction
Financing Receivable, Past Due [Line Items]
Financing receivable	0	0
60-89 days | Financial Asset Originated | Agriculture production
Financing Receivable, Past Due [Line Items]
Financing receivable	0	0
60-89 days | Financial Asset Originated | Leases
Financing Receivable, Past Due [Line Items]
Financing receivable	0	0
60-89 days | Financial Asset Originated | CRE non-owner occupied | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	0	0
60-89 days | Financial Asset Originated | CRE owner occupied | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	117	98
60-89 days | Financial Asset Originated | Multifamily | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	0	0
60-89 days | Financial Asset Originated | Farmland | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	0	0
60-89 days | Financial Asset Originated | SFR 1-4 1st DT liens | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	560	0
60-89 days | Financial Asset Originated | SFR HELOCs and junior liens | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	1,391	166
60-89 days | Financial Asset Originated | Other | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	21	34
> 90 days | Financial Asset Originated
Financing Receivable, Past Due [Line Items]
Financing receivable	3,194	1,778
> 90 days | Financial Asset Originated | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	706	75
> 90 days | Financial Asset Originated | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	941	1,041
> 90 days | Financial Asset Originated | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Financing receivable	1,514	283
> 90 days | Financial Asset Originated | Construction
Financing Receivable, Past Due [Line Items]
Financing receivable	0	379
> 90 days | Financial Asset Originated | Agriculture production
Financing Receivable, Past Due [Line Items]
Financing receivable	33	0
> 90 days | Financial Asset Originated | Leases
Financing Receivable, Past Due [Line Items]
Financing receivable	0	0
> 90 days | Financial Asset Originated | CRE non-owner occupied | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	212	0
> 90 days | Financial Asset Originated | CRE owner occupied | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	230	75
> 90 days | Financial Asset Originated | Multifamily | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	0	0
> 90 days | Financial Asset Originated | Farmland | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	264	0
> 90 days | Financial Asset Originated | SFR 1-4 1st DT liens | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	572	279
> 90 days | Financial Asset Originated | SFR HELOCs and junior liens | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	294	707
> 90 days | Financial Asset Originated | Other | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	75	55
Current | Financial Asset Originated
Financing Receivable, Past Due [Line Items]
Financing receivable	6,700,594	6,445,500
Current | Financial Asset Originated | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	4,366,081	4,358,751
Current | Financial Asset Originated | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	1,283,810	1,239,280
Current | Financial Asset Originated | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Financing receivable	598,082	567,148
Current | Financial Asset Originated | Construction
Financing Receivable, Past Due [Line Items]
Financing receivable	320,963	211,181
Current | Financial Asset Originated | Agriculture production
Financing Receivable, Past Due [Line Items]
Financing receivable	123,439	61,414
Current | Financial Asset Originated | Leases
Financing Receivable, Past Due [Line Items]
Financing receivable	8,219	7,726
Current | Financial Asset Originated | CRE non-owner occupied | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	2,170,807	2,149,725
Current | Financial Asset Originated | CRE owner occupied | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	957,569	984,634
Current | Financial Asset Originated | Multifamily | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	959,361	944,378
Current | Financial Asset Originated | Farmland | Commercial Real Estate
Financing Receivable, Past Due [Line Items]
Financing receivable	278,344	280,014
Current | Financial Asset Originated | SFR 1-4 1st DT liens | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	868,679	790,046
Current | Financial Asset Originated | SFR HELOCs and junior liens | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	349,543	392,621
Current | Financial Asset Originated | Other | Consumer
Financing Receivable, Past Due [Line Items]
Financing receivable	$ 65,588	$ 56,613