Allowance for Doubtful Accounts - Age Analysis of Past-Due Note Receivable (Details) $ in Thousands	Sep. 30, 2020 USD ($)
Financing Receivable, Past Due [Line Items]
Notes Receivable	$ 16,522
0-90 Days
Financing Receivable, Past Due [Line Items]
Notes Receivable	4,592
91 - 180 Days
Financing Receivable, Past Due [Line Items]
Notes Receivable	1,641
Greater than 181 Days
Financing Receivable, Past Due [Line Items]
Notes Receivable	10,289
Standard notes receivable
Financing Receivable, Past Due [Line Items]
Notes Receivable	8,010
Standard notes receivable | 0-90 Days
Financing Receivable, Past Due [Line Items]
Notes Receivable	3,979
Standard notes receivable | 91 - 180 Days
Financing Receivable, Past Due [Line Items]
Notes Receivable	606
Standard notes receivable | Greater than 181 Days
Financing Receivable, Past Due [Line Items]
Notes Receivable	3,425
Elevated risk notes receivable
Financing Receivable, Past Due [Line Items]
Notes Receivable	8,512
Elevated risk notes receivable | 0-90 Days
Financing Receivable, Past Due [Line Items]
Notes Receivable	613
Elevated risk notes receivable | 91 - 180 Days
Financing Receivable, Past Due [Line Items]
Notes Receivable	1,035
Elevated risk notes receivable | Greater than 181 Days
Financing Receivable, Past Due [Line Items]
Notes Receivable	$ 6,864