Financial Instruments - Credit Losses - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Notes receivable, net	$ 53,983	$ 46,161
Uncollected balance of defaulted notes	7,087
Allowance for credit losses	$ 4,923	$ 4,234	$ 3,673
Uncollectible balance reserved (as a percent)	100.00%
Uncollectible balance period	5 years
Minimum | Notes Receivable
Financing Receivable, Credit Quality Indicator [Line Items]
Service period	3 years
Maximum | Notes Receivable
Financing Receivable, Credit Quality Indicator [Line Items]
Service period	10 years
Notes Receivable, Five years and Older
Financing Receivable, Credit Quality Indicator [Line Items]
Allowance for credit losses	$ 3,300
Notes Receivable, Under Five Years
Financing Receivable, Credit Quality Indicator [Line Items]
Allowance for credit losses	$ 1,600