Employee Benefit Plans - Narrative (Detail)	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 USD ($) year	Dec. 31, 2019 USD ($) SERP_retirement_age	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Retirement Benefits [Abstract]
Employers matching contribution		50.00%
Employees first contribution		6.00%
401(k) profit sharing plan, employers matching contribution amount					$ 2,200,000	$ 2,100,000	$ 1,900,000
SERP annual retirement benefits period (years)	15 years
SERP retirement age			65	65
SERP target annual retirement benefit	$ 300,000	$ 300,000	$ 300,000	$ 300,000	300,000
SERP annual rate of return		7.00%
SERP present value of the amount owed	$ 5,500,000	$ 5,500,000	$ 5,500,000	$ 5,500,000	$ 5,500,000	$ 4,300,000