Benefit Plans - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Postemployment Benefits Disclosure [Line Items]
Expense for the period	$ 755	$ 687	$ 621
Employee Contribution Up to First 2%
Postemployment Benefits Disclosure [Line Items]
Contribution equivalent to the company's common stock	100.00%
Employee Contribution on Next 4%
Postemployment Benefits Disclosure [Line Items]
Contribution equivalent to the company's common stock	50.00%