Commitments And Contingencies (Changes in Self-insurance Liability) (Details) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Write-off of insurance receivables			$ 12,600	$ 11,600		$ 22,600
Insurance Settlements Receivable	$ 69,491		118,366		$ 69,491	118,366
Insurance Related Expenses [Roll Forward]
Balance, beginning of period					709,798	737,013	$ 758,812
Reserves provided					83,912	83,209	93,156
Adjustment to self insurance reserves	34,100	$ 60,700			(93,431)	(49,437)	(35,873)
Payments					(58,500)	(60,987)	(79,082)
Balance, end of period	$ 641,779		$ 709,798		$ 641,779	$ 709,798	$ 737,013