Fair Value - Schedule of Quantitative Information about Nonrecurring Level 3 Fair Value Measurements (Detail)	12 Months Ended
	Dec. 31, 2020 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans
Rate lock commitments	354,000
Mortgage servicing rights	1,806,000
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cost of Goods and Services Sold	84,000
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cost of Goods and Services Sold	$ 85,000
Measurement Input, Discount Rate [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates	10.0
Measurement Input, Discount Rate [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates	13.5
Interest Rate Lock Commitments [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates	75.0
Interest Rate Lock Commitments [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates	100.0
Measurement Input, Prepayment Rate [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates	18.0
Measurement Input, Prepayment Rate [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates	46.2
Appraisals [Member] | Measurement Input, Discount Rate [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates	1,000
Appraisals [Member] | Measurement Input, Discount Rate [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates	2,000