Current Expected Credit Losses - Schedule of Aging Analysis for Net Investment in Leases and Financed Sale Receivables (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable Recorded Investment Current And Past Due [Line Items]
Billed	$ 18,703		$ 10,245
Unbilled	113,184		118,863
Financed sales receivables, Total	131,887		129,108
Allowance for Credit Losses	(5,147)		(1,070)
Total financing receivables	126,740		128,038
Net Investment in Leases [Member]
Financing Receivable Recorded Investment Current And Past Due [Line Items]
Billed	1,346		349
Unbilled	16,253		15,412
Financed sales receivables, Total	17,599		15,761
Allowance for Credit Losses	(504)	$ (459)	(155)	$ (155)	$ (155)	$ (155)
Total financing receivables	17,095		15,606
Net Financed Sales Receivables [Member]
Financing Receivable Recorded Investment Current And Past Due [Line Items]
Billed	17,357		9,896
Unbilled	96,931		103,451
Financed sales receivables, Total	114,288		113,347
Allowance for Credit Losses	(4,643)	$ (3,709)	(915)	$ (915)	$ (839)	$ (839)
Total financing receivables	109,645		112,432
Accrued and Current [Member]
Financing Receivable Recorded Investment Current And Past Due [Line Items]
Billed	1,818		1,708
Accrued and Current [Member] | Net Investment in Leases [Member]
Financing Receivable Recorded Investment Current And Past Due [Line Items]
Billed	132		30
Accrued and Current [Member] | Net Financed Sales Receivables [Member]
Financing Receivable Recorded Investment Current And Past Due [Line Items]
Billed	1,686		1,678
30 to 89 Days Past Due [Member]
Financing Receivable Recorded Investment Current And Past Due [Line Items]
Billed	2,520		2,840
30 to 89 Days Past Due [Member] | Net Investment in Leases [Member]
Financing Receivable Recorded Investment Current And Past Due [Line Items]
Billed	161		68
30 to 89 Days Past Due [Member] | Net Financed Sales Receivables [Member]
Financing Receivable Recorded Investment Current And Past Due [Line Items]
Billed	2,359		2,772
Equal To Greater Than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Current And Past Due [Line Items]
Billed	14,365		5,697
Equal To Greater Than 90 Days Past Due [Member] | Net Investment in Leases [Member]
Financing Receivable Recorded Investment Current And Past Due [Line Items]
Billed	1,053		251
Equal To Greater Than 90 Days Past Due [Member] | Net Financed Sales Receivables [Member]
Financing Receivable Recorded Investment Current And Past Due [Line Items]
Billed	$ 13,312		$ 5,446