Investor Notes Payable (Schedule of Investor Notes Payable) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Amount	$ 72,821	$ 73,101
Weighted Average Interest Rate	3.53%	4.06%
Public Offerings [Member]
Debt Instrument [Line Items]
Amount	$ 56,825	$ 55,317
Weighted Average Interest Rate	3.21%	3.82%
Public Offerings [Member] | Class A [Member]
Debt Instrument [Line Items]
Amount	$ 305	$ 487
Weighted Average Interest Rate	2.22%	3.97%
Public Offerings [Member] | Class 1 [Member]
Debt Instrument [Line Items]
Amount	$ 15,482	$ 22,098
Weighted Average Interest Rate	3.78%	4.01%
Public Offerings [Member] | Class 1A [Member]
Debt Instrument [Line Items]
Amount	$ 41,038	$ 32,732
Weighted Average Interest Rate	3.00%	3.70%
Private Offerings [Member]
Debt Instrument [Line Items]
Amount	$ 15,996	$ 17,784
Weighted Average Interest Rate	4.69%	4.78%
Private Offerings [Member] | Subordinated Notes [Member]
Debt Instrument [Line Items]
Amount	$ 9,546	$ 11,317
Weighted Average Interest Rate	5.15%	5.24%
Private Offerings [Member] | Secured Notes [Member]
Debt Instrument [Line Items]
Amount	$ 6,450	$ 6,467
Weighted Average Interest Rate	3.99%	3.98%
Unsecured [Member]
Debt Instrument [Line Items]
Amount	$ 66,371	$ 66,634
Weighted Average Interest Rate	3.49%	4.06%
Secured [Member]
Debt Instrument [Line Items]
Amount	$ 6,450	$ 6,467
Weighted Average Interest Rate	3.99%	3.98%