Fair Value Disclosures - Additional Information (Detail)	3 Months Ended		12 Months Ended
	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets transfer between Level 2 and Level 3	$ 0	$ 0	$ 0
Impaired loans carrying value, recorded investment with allowance	28,106,000	15,729,000	16,213,000
Impaired loans valuation reserves	3,386,000	4,472,000	3,228,000
Impaired loans net fair value	24,720,000
Other real estate owned, total	$ 982,000	$ 612,000	$ 982,000
Minimum [Member] | Measurement Input, Discount Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt discounts, percentage	5
Maximum [Member] | Measurement Input, Discount Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt discounts, percentage	25