Supplemental Financial Statement Information (Allowance for Credit on Losses for Accounts and Other Reveivables) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for doubtful accounts	$ 20,480		$ 18,899
Allowance for credit losses	3,992	$ 15,926
Accounts and other receivables	20,480	29,444
Other assets	16,561	0
ASU 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for doubtful accounts	35,344	17,830	$ 37,041	$ 29,444
Allowance for credit losses	3,011	3,280
Write-offs, recoveries and other	(1,314)	(7,002)
ASU 2016-13 | Cumulative Effect
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for doubtful accounts	$ 0	$ 15,336