Employee Benefits (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Defined contribution employee automatic contribution, percent			6.00%
Administrative expense			$ 0	$ 0
Contributions made to the defined contribution plan	$ 2,242,000	$ 1,820,000	$ 6,791,000	5,270,000
Profit sharing, percent of pre-tax profit paid to eligible employees on quarterly basis			10.00%
Profit sharing bonus plan expense	3,000,000	1,684,000	$ 8,691,000	4,948,000
Medical claim payments	2,985,000	1,650,000	6,843,000	4,500,000
Health saving account contributions	$ 890,000	$ 790,000	$ 2,663,000	$ 2,410,000
Effective January 1, 2016
Defined Benefit Plan Disclosure [Line Items]
Percent of match			175.00%
Defined contribution employer, maximum match percent			6.00%