Employee Benefit Plans (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) Contribution shares	Dec. 31, 2019 USD ($) shares	Dec. 31, 2018 USD ($)
Executive Retirement Plan, Life Insurance Arrangements and Senior Management Retention Plan [Abstract]
Net gains on deferred compensation plan investments	$ 1,777	$ 2,625	$ 1,088
Tax-exempt interest earned on the life insurance policies	2,088	2,031	1,900
Executive Officers [Member]
Executive Retirement Plan, Life Insurance Arrangements and Senior Management Retention Plan [Abstract]
Employer contribution	6,800	6,600	6,200
Carrying value of liability	$ 56,700	$ 50,500
Common stock held as investments in Rabbi Trust of ERP (in shares) | shares	52,980	48,133
Common stock held as investments in Rabbi Trust of ERP, historical cost basis amount	$ 31,200	$ 29,100
Net gains on deferred compensation plan investments	1,800	2,600
Tax-exempt interest earned on the life insurance policies	2,100	2,000	1,900
Cash surrender value of life insurance policies	69,200	67,100
Senior Level Employees [Member] | Senior Management Retention Plan [Member]
Executive Retirement Plan, Life Insurance Arrangements and Senior Management Retention Plan [Abstract]
Employer contribution	2,300	1,300	1,500
Carrying value of liability	$ 8,600	$ 6,300
Common stock held as investments in Rabbi Trust of ERP (in shares) | shares	12,548	9,822
Common stock held as investments in Rabbi Trust of ERP, historical cost basis amount	$ 7,900	$ 5,800
Net gains on deferred compensation plan investments	$ 100	0
Profit Sharing Plan [Member]
Profit Sharing Plan [Abstract]
Minimum requisite service period	1 year
Number of annual employer contribution | Contribution	2
Employer discretionary contribution amount	$ 1,500	1,400	1,200
Employer mandatory contributions amount	$ 1,700	$ 1,600	$ 1,400
Annual vesting percentage, first year	0.00%
Annual vesting percentage, full year thereafter	25.00%
Benefit vesting period	5 years