Notes Receivable and Allowance for Credit Losses - Schedule Of Notes Receivable (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Notes Receivable and Allowance for Losses [Line Items]
Notes receivable	$ 143,699	$ 133,014
Total allowance for notes receivable losses	15,850	4,556	$ 4,685
Total notes receivable, net of allowance	127,849	128,458
Current portion, net of allowance	29,914	25,404
Long-term portion, net of allowance	97,935	103,054
Senior
Notes Receivable and Allowance for Losses [Line Items]
Notes receivable	107,968	98,545
Subordinated
Notes Receivable and Allowance for Losses [Line Items]
Notes receivable	33,284	32,153
Unsecured
Notes Receivable and Allowance for Losses [Line Items]
Notes receivable	$ 2,447	$ 2,316