Loans and Allowance for Credit Losses - Credit Risk Profile by Creditworthiness (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	$ 6,839,230	$ 6,761,183
Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	6,641,104	6,458,370
Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	120,563	226,634
Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	77,563	76,179
Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	198,126	302,813
Unlikely to be Collected Financing Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Commercial, financial, agricultural and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,173,452	1,555,986
Commercial, financial, agricultural and other [Member] | Commercial credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	13,928	14,604
Commercial, financial, agricultural and other [Member] | Time and demand loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,159,524	1,541,382
Commercial, financial, agricultural and other [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,121,234	1,491,916
Commercial, financial, agricultural and other [Member] | Pass [Member] | Commercial credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	13,928	14,604
Commercial, financial, agricultural and other [Member] | Pass [Member] | Time and demand loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,107,306	1,477,312
Commercial, financial, agricultural and other [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	33,765	48,233
Commercial, financial, agricultural and other [Member] | Special Mention [Member] | Commercial credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Commercial, financial, agricultural and other [Member] | Special Mention [Member] | Time and demand loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	33,765	48,233
Commercial, financial, agricultural and other [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	18,453	15,837
Commercial, financial, agricultural and other [Member] | Substandard [Member] | Commercial credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Commercial, financial, agricultural and other [Member] | Substandard [Member] | Time and demand loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	18,453	15,837
Commercial, financial, agricultural and other [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Commercial, financial, agricultural and other [Member] | Doubtful [Member] | Commercial credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Commercial, financial, agricultural and other [Member] | Doubtful [Member] | Time and demand loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Commercial, financial, agricultural and other [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	52,218	64,070
Commercial, financial, agricultural and other [Member] | Total Non-Pass [Member] | Commercial credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Commercial, financial, agricultural and other [Member] | Total Non-Pass [Member] | Time and demand loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	52,218	64,070
Commercial, financial, agricultural and other [Member] | Unlikely to be Collected Financing Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Commercial, financial, agricultural and other [Member] | Unlikely to be Collected Financing Receivable | Commercial credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Commercial, financial, agricultural and other [Member] | Unlikely to be Collected Financing Receivable | Time and demand loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	494,456	427,221
Real Estate Construction [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	493,913	426,663
Real Estate Construction [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	498	504
Real Estate Construction [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	45	54
Real Estate Construction [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Real Estate Construction [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	543	558
Real Estate Construction [Member] | Unlikely to be Collected Financing Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,920,250	1,750,592
Residential Real Estate [Member] | Senior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,299,534	1,144,323
Residential Real Estate [Member] | Junior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	620,716	606,269
Residential Real Estate [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,913,064	1,740,992
Residential Real Estate [Member] | Pass [Member] | Senior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,295,524	1,138,409
Residential Real Estate [Member] | Pass [Member] | Junior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	617,540	602,583
Residential Real Estate [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	976	1,902
Residential Real Estate [Member] | Special Mention [Member] | Senior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	905	1,780
Residential Real Estate [Member] | Special Mention [Member] | Junior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	71	122
Residential Real Estate [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	6,210	7,698
Residential Real Estate [Member] | Substandard [Member] | Senior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	3,105	4,134
Residential Real Estate [Member] | Substandard [Member] | Junior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	3,105	3,564
Residential Real Estate [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Residential Real Estate [Member] | Doubtful [Member] | Senior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Residential Real Estate [Member] | Doubtful [Member] | Junior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Residential Real Estate [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	7,186	9,600
Residential Real Estate [Member] | Total Non-Pass [Member] | Senior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	4,010	5,914
Residential Real Estate [Member] | Total Non-Pass [Member] | Junior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	3,176	3,686
Residential Real Estate [Member] | Unlikely to be Collected Financing Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Residential Real Estate [Member] | Unlikely to be Collected Financing Receivable | Senior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Residential Real Estate [Member] | Unlikely to be Collected Financing Receivable | Junior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	2,251,097	2,211,569
Commercial real estate [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	385,432	371,239
Commercial real estate [Member] | Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,465,247	1,421,151
Commercial real estate [Member] | Owner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	400,418	419,179
Commercial real estate [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	2,113,123	1,983,258
Commercial real estate [Member] | Pass [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	355,702	369,883
Commercial real estate [Member] | Pass [Member] | Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,368,922	1,216,252
Commercial real estate [Member] | Pass [Member] | Owner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	388,499	397,123
Commercial real estate [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	85,324	175,995
Commercial real estate [Member] | Special Mention [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	14,565	131
Commercial real estate [Member] | Special Mention [Member] | Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	63,783	161,336
Commercial real estate [Member] | Special Mention [Member] | Owner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	6,976	14,528
Commercial real estate [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	52,650	52,316
Commercial real estate [Member] | Substandard [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	15,165	1,225
Commercial real estate [Member] | Substandard [Member] | Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	32,542	43,563
Commercial real estate [Member] | Substandard [Member] | Owner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	4,943	7,528
Commercial real estate [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Commercial real estate [Member] | Doubtful [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Commercial real estate [Member] | Doubtful [Member] | Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Commercial real estate [Member] | Doubtful [Member] | Owner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Commercial real estate [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	137,974	228,311
Commercial real estate [Member] | Total Non-Pass [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	29,730	1,356
Commercial real estate [Member] | Total Non-Pass [Member] | Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	96,325	204,899
Commercial real estate [Member] | Total Non-Pass [Member] | Owner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	11,919	22,056
Commercial real estate [Member] | Unlikely to be Collected Financing Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Commercial real estate [Member] | Unlikely to be Collected Financing Receivable | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Commercial real estate [Member] | Unlikely to be Collected Financing Receivable | Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Commercial real estate [Member] | Unlikely to be Collected Financing Receivable | Owner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	999,975	815,815
Loans To Individuals [Member] | Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	901,280	712,800
Loans To Individuals [Member] | Consumer Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	11,151	12,360
Loans To Individuals [Member] | Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	87,544	90,655
Loans To Individuals [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	999,770	815,541
Loans To Individuals [Member] | Pass [Member] | Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	901,132	712,539
Loans To Individuals [Member] | Pass [Member] | Consumer Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	11,151	12,360
Loans To Individuals [Member] | Pass [Member] | Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	87,487	90,642
Loans To Individuals [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Loans To Individuals [Member] | Special Mention [Member] | Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Loans To Individuals [Member] | Special Mention [Member] | Consumer Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Loans To Individuals [Member] | Special Mention [Member] | Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Loans To Individuals [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	205	274
Loans To Individuals [Member] | Substandard [Member] | Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	148	261
Loans To Individuals [Member] | Substandard [Member] | Consumer Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Loans To Individuals [Member] | Substandard [Member] | Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	57	13
Loans To Individuals [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Loans To Individuals [Member] | Doubtful [Member] | Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Loans To Individuals [Member] | Doubtful [Member] | Consumer Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Loans To Individuals [Member] | Doubtful [Member] | Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Loans To Individuals [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	205	274
Loans To Individuals [Member] | Total Non-Pass [Member] | Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	148	261
Loans To Individuals [Member] | Total Non-Pass [Member] | Consumer Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Loans To Individuals [Member] | Total Non-Pass [Member] | Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	57	13
Loans To Individuals [Member] | Unlikely to be Collected Financing Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Loans To Individuals [Member] | Unlikely to be Collected Financing Receivable | Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Loans To Individuals [Member] | Unlikely to be Collected Financing Receivable | Consumer Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Loans To Individuals [Member] | Unlikely to be Collected Financing Receivable | Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	$ 0	$ 0