Retirement Plans - Summary of 401(k) Contribution Plan (Detail) - 401(k) Plan - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
401(k) Plan benefits expense	$ 1,139	$ 1,119	$ 879
401(k) Plan contributions made by the Company	$ 202	$ 1,003	$ 872