Loans and Allowance for Credit Losses - Summary of Information Related to Nonaccrual Loans (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Financing Receivable Impaired [Line Items]
With no related allowance recorded, Unpaid Principal Balance	$ 10,203		$ 10,203		$ 8,513
With no related allowance recorded, Recorded Investment	6,737		6,737		4,102
With related allowance recorded, Unpaid Principal Balance	24,531		24,531		30,712
With related allowance recorded, Recorded Investment	16,392		16,392		25,259
With an allowance recorded, Allowance for Loan Losses Allocated	4,609		4,609		7,338
Unpaid Principal Balance	34,734		34,734		39,225
Recorded nvestment	23,129		23,129		29,361
With no related allowance recorded, Average Recorded Investment	6,084	$ 3,906	4,963	$ 5,096
With no related allowance recorded, Interest Income Recognized	158		159	122
With an allowance recorded, Average Recorded Investment	14,911	56,989	18,048	50,650
With an allowance recorded, Interest Income Recognized	139	95	143	333
Average Recorded Investment	20,995	60,895	23,011	55,746
Interest Income Recognized	297	95	302	455
Commercial Real Estate [Member]
Financing Receivable Impaired [Line Items]
With no related allowance recorded, Unpaid Principal Balance	4,590		4,590
With no related allowance recorded, Recorded Investment	2,965		2,965
With related allowance recorded, Unpaid Principal Balance	2,574		2,574		7,690
With related allowance recorded, Recorded Investment	2,376		2,376		6,833
With an allowance recorded, Allowance for Loan Losses Allocated	775		775		1,632
With no related allowance recorded, Average Recorded Investment	2,646		1,528	421
With no related allowance recorded, Interest Income Recognized				3
With an allowance recorded, Average Recorded Investment	2,577	7,107	3,702	7,022
With an allowance recorded, Interest Income Recognized	20	1	20	19
Commercial and Industrial [Member]
Financing Receivable Impaired [Line Items]
With no related allowance recorded, Unpaid Principal Balance	2,745		2,745		6,060
With no related allowance recorded, Recorded Investment	1,995		1,995		1,964
With related allowance recorded, Unpaid Principal Balance	9,903		9,903		4,976
With related allowance recorded, Recorded Investment	5,541		5,541		4,593
With an allowance recorded, Allowance for Loan Losses Allocated	1,246		1,246		1,800
With no related allowance recorded, Average Recorded Investment	1,979		1,480	161
With no related allowance recorded, Interest Income Recognized	157		157	35
With an allowance recorded, Average Recorded Investment	3,464	36,720	3,808	31,203
With an allowance recorded, Interest Income Recognized	97		97	119
Residential Real Estate [Member]
Financing Receivable Impaired [Line Items]
With no related allowance recorded, Unpaid Principal Balance	30		30		609
With no related allowance recorded, Recorded Investment					429
With related allowance recorded, Unpaid Principal Balance	3,534		3,534		5,170
With related allowance recorded, Recorded Investment	3,269		3,269		4,646
With an allowance recorded, Allowance for Loan Losses Allocated	807		807		888
With no related allowance recorded, Average Recorded Investment			384	51
With no related allowance recorded, Interest Income Recognized			1	2
With an allowance recorded, Average Recorded Investment	3,086	2,870	3,559	2,843
With an allowance recorded, Interest Income Recognized	18	24	19	26
Agricultural Real Estate [Member]
Financing Receivable Impaired [Line Items]
With no related allowance recorded, Unpaid Principal Balance	2,812		2,812		1,795
With no related allowance recorded, Recorded Investment	1,758		1,758		1,660
With related allowance recorded, Unpaid Principal Balance	1,965		1,965		3,726
With related allowance recorded, Recorded Investment	1,510		1,510		2,738
With an allowance recorded, Allowance for Loan Losses Allocated	237		237		637
With no related allowance recorded, Average Recorded Investment	1,449	3,022	1,554	2,307
With no related allowance recorded, Interest Income Recognized				82
With an allowance recorded, Average Recorded Investment	1,924	2,501	2,251	3,346
With an allowance recorded, Interest Income Recognized	2		5	54
Agricultural [Member]
Financing Receivable Impaired [Line Items]
With no related allowance recorded, Unpaid Principal Balance	9		9
With no related allowance recorded, Recorded Investment	9		9
With related allowance recorded, Unpaid Principal Balance	6,231		6,231		8,836
With related allowance recorded, Recorded Investment	3,432		3,432		6,175
With an allowance recorded, Allowance for Loan Losses Allocated	1,478		1,478		2,307
With no related allowance recorded, Average Recorded Investment	5	884	2	2,156
With an allowance recorded, Average Recorded Investment	3,594	7,576	4,437	5,991
With an allowance recorded, Interest Income Recognized		69		113
Consumer [Member]
Financing Receivable Impaired [Line Items]
With no related allowance recorded, Unpaid Principal Balance	17		17		49
With no related allowance recorded, Recorded Investment	10		10		49
With related allowance recorded, Unpaid Principal Balance	324		324		314
With related allowance recorded, Recorded Investment	264		264		274
With an allowance recorded, Allowance for Loan Losses Allocated	66		66		$ 74
With no related allowance recorded, Average Recorded Investment	5		15
With no related allowance recorded, Interest Income Recognized	1		1
With an allowance recorded, Average Recorded Investment	266	215	291	245
With an allowance recorded, Interest Income Recognized	$ 2	$ 1	$ 2	$ 2