Loans and Allowance for Credit Losses - Age Analysis of Past Due Loans by Segment (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	$ 6,703,481
Loans	6,761,183	$ 6,189,148	$ 5,774,139
Financing Receivable, Past Due	57,702
Loans and Leases Receivable, Gross	6,761,183
Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	811,180
Loans	815,815	699,375
Financing Receivable, Past Due	4,635
Loans and Leases Receivable, Gross	815,815
Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	1,552,349
Loans	1,555,986	1,241,853
Financing Receivable, Past Due	3,637
Loans and Leases Receivable, Gross	1,555,986
Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	426,231
Loans	427,221	449,039
Financing Receivable, Past Due	990
Loans and Leases Receivable, Gross	427,221
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	1,737,624
Loans	1,750,592	1,681,362
Financing Receivable, Past Due	12,968
Loans and Leases Receivable, Gross	1,750,592
Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	2,176,097
Loans	2,211,569	2,117,519
Financing Receivable, Past Due	35,472
Loans and Leases Receivable, Gross	2,211,569
Time and demand loans | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	1,537,917
Loans	1,541,382
Financing Receivable, Past Due	3,465
Loans and Leases Receivable, Gross	1,541,382
Commercial credit cards | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	14,432
Loans	14,604
Financing Receivable, Past Due	172
Loans and Leases Receivable, Gross	14,604
Senior Lien | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,144,323
Senior Lien | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	1,138,132
Financing Receivable, Past Due	6,191
Loans and Leases Receivable, Gross	1,144,323
Junior Lien | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	606,269
Junior Lien | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	599,492
Financing Receivable, Past Due	6,777
Loans and Leases Receivable, Gross	606,269
Multifamily | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	371,239
Multifamily | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	370,779
Financing Receivable, Past Due	460
Loans and Leases Receivable, Gross	371,239
Nonowner Occupied Commercial Real Estate | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,421,151
Nonowner Occupied Commercial Real Estate | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	1,389,207
Financing Receivable, Past Due	31,944
Loans and Leases Receivable, Gross	1,421,151
Owner Occupied Commercial Real Estate | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	419,179
Owner Occupied Commercial Real Estate | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	416,111
Financing Receivable, Past Due	3,068
Loans and Leases Receivable, Gross	419,179
Automobile Loan | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	709,938
Financing Receivable, Past Due	2,862
Loans and Leases Receivable, Gross	712,800
Automobile Loan | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	712,800
Consumer Credit Cards | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	12,146
Financing Receivable, Past Due	214
Loans and Leases Receivable, Gross	12,360
Consumer Credit Cards | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	12,360
Other consumer loans | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	89,096
Financing Receivable, Past Due	1,559
Loans and Leases Receivable, Gross	90,655
Other consumer loans | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	90,655
Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		699,375	590,739
Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		449,039	358,978
Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		1,241,853	1,138,473
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		1,681,362	1,562,405
Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		2,117,519	$ 2,123,544
Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	8,072
Financial Asset, 30 to 59 Days Past Due [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	2,870
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	146
Financial Asset, 30 to 59 Days Past Due [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	936
Financial Asset, 30 to 59 Days Past Due [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	3,883
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	237
Financial Asset, 30 to 59 Days Past Due [Member] | Time and demand loans | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	97
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial credit cards | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	49
Financial Asset, 30 to 59 Days Past Due [Member] | Senior Lien | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	1,775
Financial Asset, 30 to 59 Days Past Due [Member] | Junior Lien | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	2,108
Financial Asset, 30 to 59 Days Past Due [Member] | Multifamily | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	0
Financial Asset, 30 to 59 Days Past Due [Member] | Nonowner Occupied Commercial Real Estate | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	18
Financial Asset, 30 to 59 Days Past Due [Member] | Owner Occupied Commercial Real Estate | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	219
Financial Asset, 30 to 59 Days Past Due [Member] | Automobile Loan | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	2,090
Financial Asset, 30 to 59 Days Past Due [Member] | Consumer Credit Cards | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	52
Financial Asset, 30 to 59 Days Past Due [Member] | Other consumer loans | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	728
Financial Asset, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	2,566
Financial Asset, 60 to 89 Days Past Due [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	852
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	62
Financial Asset, 60 to 89 Days Past Due [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	0
Financial Asset, 60 to 89 Days Past Due [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	1,492
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	160
Financial Asset, 60 to 89 Days Past Due [Member] | Time and demand loans | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	28
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial credit cards | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	34
Financial Asset, 60 to 89 Days Past Due [Member] | Senior Lien | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	660
Financial Asset, 60 to 89 Days Past Due [Member] | Junior Lien | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	832
Financial Asset, 60 to 89 Days Past Due [Member] | Multifamily | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	0
Financial Asset, 60 to 89 Days Past Due [Member] | Nonowner Occupied Commercial Real Estate | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	104
Financial Asset, 60 to 89 Days Past Due [Member] | Owner Occupied Commercial Real Estate | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	56
Financial Asset, 60 to 89 Days Past Due [Member] | Automobile Loan | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	417
Financial Asset, 60 to 89 Days Past Due [Member] | Consumer Credit Cards | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	39
Financial Asset, 60 to 89 Days Past Due [Member] | Other consumer loans | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	396
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	1,523
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	639
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	112
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	769
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	3
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Time and demand loans | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	23
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial credit cards | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	89
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Senior Lien | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	267
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Junior Lien | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	502
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Multifamily | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Nonowner Occupied Commercial Real Estate | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Owner Occupied Commercial Real Estate | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	3
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Automobile Loan | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	94
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Credit Cards | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	123
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Other consumer loans | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	422
Nonaccrual Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	45,541
Nonaccrual Commercial Loans [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	274
Nonaccrual Commercial Loans [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	3,317
Nonaccrual Commercial Loans [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	54
Nonaccrual Commercial Loans [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	6,824
Nonaccrual Commercial Loans [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	35,072
Nonaccrual Commercial Loans [Member] | Time and demand loans | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	3,317
Nonaccrual Commercial Loans [Member] | Commercial credit cards | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	0
Nonaccrual Commercial Loans [Member] | Senior Lien | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	3,489
Nonaccrual Commercial Loans [Member] | Junior Lien | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	3,335
Nonaccrual Commercial Loans [Member] | Multifamily | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	460
Nonaccrual Commercial Loans [Member] | Nonowner Occupied Commercial Real Estate | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	31,822
Nonaccrual Commercial Loans [Member] | Owner Occupied Commercial Real Estate | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	2,790
Nonaccrual Commercial Loans [Member] | Automobile Loan | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	261
Nonaccrual Commercial Loans [Member] | Consumer Credit Cards | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	0
Nonaccrual Commercial Loans [Member] | Other consumer loans | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	$ 13
Originated Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		34,741
Current		5,679,632
Loans		5,714,373
Loans and Leases Receivable, Gross		5,714,373
Originated Loans [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		685,416
Loans and Leases Receivable, Gross		685,416
Originated Loans [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		1,212,026
Loans and Leases Receivable, Gross		1,212,026
Originated Loans [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		442,777
Loans and Leases Receivable, Gross		442,777
Originated Loans [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		1,415,808
Loans and Leases Receivable, Gross		1,415,808
Originated Loans [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		1,958,346
Loans and Leases Receivable, Gross		1,958,346
Originated Loans [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		6,328
Current		679,088
Loans		685,416
Originated Loans [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		207
Current		442,570
Loans		442,777
Originated Loans [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		9,368
Current		1,202,658
Loans		1,212,026
Originated Loans [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		11,888
Current		1,403,920
Loans		1,415,808
Originated Loans [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		6,950
Current		1,951,396
Loans		1,958,346
Originated Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		8,643
Originated Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		4,070
Originated Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		198
Originated Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		391
Originated Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		3,757
Originated Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		227
Originated Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		1,940
Originated Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		1,020
Originated Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		0
Originated Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		57
Originated Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		749
Originated Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		114
Originated Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		1,816
Originated Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		931
Originated Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		9
Originated Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		140
Originated Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		736
Originated Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		0
Originated Loans [Member] | Nonaccrual Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		22,342
Originated Loans [Member] | Nonaccrual Commercial Loans [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		307
Originated Loans [Member] | Nonaccrual Commercial Loans [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		0
Originated Loans [Member] | Nonaccrual Commercial Loans [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		8,780
Originated Loans [Member] | Nonaccrual Commercial Loans [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		6,646
Originated Loans [Member] | Nonaccrual Commercial Loans [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		6,609
Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		3,385
Current		471,390
Loans		474,775
Loans and Leases Receivable, Gross		474,775
Acquired Loans [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		13,959
Loans and Leases Receivable, Gross		13,959
Acquired Loans [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		29,827
Loans and Leases Receivable, Gross		29,827
Acquired Loans [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		6,262
Loans and Leases Receivable, Gross		6,262
Acquired Loans [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		265,554
Loans and Leases Receivable, Gross		265,554
Acquired Loans [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		159,173
Loans and Leases Receivable, Gross		159,173
Acquired Loans [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		223
Current		13,736
Loans		13,959
Acquired Loans [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		0
Current		6,262
Loans		6,262
Acquired Loans [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		76
Current		29,751
Loans		29,827
Acquired Loans [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		2,681
Current		262,873
Loans		265,554
Acquired Loans [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		405
Current		158,768
Loans		159,173
Acquired Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		392
Acquired Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		87
Acquired Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		0
Acquired Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		1
Acquired Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		304
Acquired Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		0
Acquired Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		403
Acquired Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		89
Acquired Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		0
Acquired Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		0
Acquired Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		207
Acquired Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		107
Acquired Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		257
Acquired Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		35
Acquired Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		0
Acquired Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		1
Acquired Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		221
Acquired Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		0
Acquired Loans [Member] | Nonaccrual Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		2,333
Acquired Loans [Member] | Nonaccrual Commercial Loans [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		12
Acquired Loans [Member] | Nonaccrual Commercial Loans [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		0
Acquired Loans [Member] | Nonaccrual Commercial Loans [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		74
Acquired Loans [Member] | Nonaccrual Commercial Loans [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		1,949
Acquired Loans [Member] | Nonaccrual Commercial Loans [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		$ 298