Subsequent Events - Notes Receivable (Details) - USD ($) $ in Thousands		12 Months Ended
	Feb. 19, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Subsequent Events
Principal payments received on notes receivable		$ 5,275	$ 3,503	$ 3,848
Notes Receivable
Subsequent Events
Principal payments received on notes receivable		$ 900
Subsequent Event | Notes Receivable
Subsequent Events
Principal payments received on notes receivable	$ 900