Commitments And Contingencies (Changes in Self-insurance Liability) (Details) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Write-off of insurance receivables		$ 12,600	$ 11,600
Insurance Settlements Receivable	$ 118,366				$ 118,366	$ 152,987
Insurance Related Expenses [Roll Forward]
Balance, beginning of period			$ 737,013		737,013	758,812	$ 831,058
Reserves provided					83,209	93,156	98,176
Adjustment to self insurance reserves	31,100	$ 12,800		$ 37,900	(49,437)	(35,873)	(97,789)
Payments					(60,987)	(79,082)	(72,633)
Balance, end of period	$ 709,798				$ 709,798	$ 737,013	$ 758,812