Loans - Summary of Deferral Activity Related to Loan Modification Programs to Customers (Detail) - Covid-19 [Member] $ in Thousands	6 Months Ended
	Jun. 30, 2020 USD ($) Loan
Loan Modification Programs to Customer [Line Items]
Deferred of loans | Loan	212
Outstanding, portfolio	$ 638,860
Outstanding, deferred	$ 66,758
Outstanding, percentage	10.00%
Commercial [Member]
Loan Modification Programs to Customer [Line Items]
Deferred of loans | Loan	72
Outstanding, portfolio	$ 215,139
Outstanding, deferred	$ 10,450
Outstanding, percentage	5.00%
Commercial Real Estate [Member]
Loan Modification Programs to Customer [Line Items]
Deferred of loans | Loan	77
Outstanding, portfolio	$ 198,948
Outstanding, deferred	$ 51,645
Outstanding, percentage	26.00%
Construction [Member]
Loan Modification Programs to Customer [Line Items]
Deferred of loans | Loan	3
Outstanding, portfolio	$ 28,123
Outstanding, deferred	$ 535
Outstanding, percentage	2.00%
Total Commercial [Member]
Loan Modification Programs to Customer [Line Items]
Deferred of loans | Loan	152
Outstanding, portfolio	$ 442,210
Outstanding, deferred	$ 62,630
Outstanding, percentage	14.00%
Residential Real Estate [Member]
Loan Modification Programs to Customer [Line Items]
Deferred of loans | Loan	33
Outstanding, portfolio	$ 177,799
Outstanding, deferred	$ 3,663
Outstanding, percentage	2.00%
RV [Member]
Loan Modification Programs to Customer [Line Items]
Deferred of loans | Loan	12
Outstanding, portfolio	$ 9,271
Outstanding, deferred	$ 254
Outstanding, percentage	3.00%
Other consumer [Member]
Loan Modification Programs to Customer [Line Items]
Deferred of loans | Loan	15
Outstanding, portfolio	$ 9,580
Outstanding, deferred	$ 211
Outstanding, percentage	2.00%
Total Consumer [Member]
Loan Modification Programs to Customer [Line Items]
Deferred of loans | Loan	60
Outstanding, portfolio	$ 196,650
Outstanding, deferred	$ 4,128
Outstanding, percentage	2.00%