Related Party Transactions - Additional Information (Detail) - Directors and Executive Officers [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) SecurityLoan	Dec. 31, 2019 USD ($)
Related Party Transaction [Line Items]
Granted loans to affiliate companies	$ 1,400	$ 1,300
Subsequent advances	9,400
Payment received	9,300
Difference in related borrowings amounts	124
Ownership interest amount	$ 38,300	$ 33,700
Number of new loans approved | SecurityLoan	1