Profit Sharing And Savings Plan (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended			48 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jun. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Required term of service to be eligible for plan match	6 months 500 hours			1 year 1000 hours
Profit Sharing and Savings Plan
Defined Benefit Plan Disclosure [Line Items]
Voluntary contribution, minimum percent of employee pay	2.00%
Voluntary contribution, maximum percent of employee pay	50.00%
Percentage of employee contribution matched by employer	50.00%
Percent of employee pay eligible for matching contributions	6.00%
Employer matching contribution percentage maximum of pay	3.00%
Employer Matching Contribution	$ 3.8	$ 2.7	$ 1.8
Discretionary Employer Contribution	$ 46.8	$ 56.8	$ 67.4