Retirement Plans - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Employer contribution	6.00%
Employee contribution	80.00%
Plan expense	$ 3,900	$ 3,600	$ 3,200
Retirement Plan expense	$ 0	$ 0	$ 0
Minimum [Member]
Eligibility of participants	1.00%
Maximum [Member]
Eligibility of participants	25.00%