Loans Receivable - Credit Loss Roll Forward (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 68,372	$ 68,372	$ 68,372
Provision for loan losses	11,351	18,690
Loan write-offs	0	(18,690)
Foreign currency translation	(40)	0
Balance at end of period	$ 84,895	68,372	$ 68,372
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member		us-gaap:AccountingStandardsUpdate201613Member
Accounting Standards Update 2016-13 | Cumulative effect, period of adoption, adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 5,212	$ 0	$ 0
Balance at end of period			$ 5,212