Employee Benefits (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Definedcontributionemployeeautomaticcontributionpercentag	6.00%
Administrative expenses	$ 0	$ 0	$ 0
Contributions, net of forfeitures, made to the defined contribution plan	$ 9,091,000	7,034,000	8,127,000
Profits sharing, percent of pre-tax profit paid to eligible employees on quarterly basis	10.00%
Employee profit sharing bonus plan	$ 11,593,000	7,448,000	6,165,000
Medical claim payments	9,060,000	5,898,000	5,915,000
Health saving account payments	$ 3,476,000	$ 3,265,000	$ 2,948,000
Effective January 1, 2016
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution, percent of match	175.00%
Maximum annual contributions per employee, percent	6.00%