Description of Business and Basis of Presentation (Accounting Pronouncements) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Mar. 31, 2020	Sep. 30, 2020	Sep. 30, 2019	Jan. 01, 2020	Dec. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts and other receivables		$ 348,565			$ 373,471
Allowance for credit losses		38,068	$ 20,124		19,651	$ 20,222
Retained earnings		(5,190,914)			(5,438,930)
Provision for credit losses	$ 11,000	35,000	22,000
Allowance for credit losses
Balance at December 31, 2019	17,830	17,830
Amounts charged to expense		35,400	$ 22,131
Balance at September 30, 2020		29,669
Cumulative Effect
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses					$ 9,503
ASU 2016-13
Allowance for credit losses
Balance at December 31, 2019	17,830	17,830
Amounts charged to expense		16,856
Write-offs, recoveries and currency impact		(20,353)
Balance at September 30, 2020		29,669
ASU 2016-13 | Adjusted Balance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts and other receivables				$ 15,000
Allowance for credit losses				10,000
Retained earnings				$ 22,000
ASU 2016-13 | Cumulative Effect
Allowance for credit losses
Balance at December 31, 2019	$ 15,336	$ 15,336