Ownership, Nature of Business, and Significant Accounting Policies - Estimated fair values of financial instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Financial assets:
Restricted cash	$ 4,040	$ 6,090	$ 4,145	$ 4,175
Level 1 | Carrying Amount
Financial assets:
Cash and cash equivalents	60,991	49,016
Restricted cash	4,040	6,090
Level 1 | Fair Value
Financial assets:
Cash and cash equivalents	60,991	49,016
Restricted cash	4,040	6,090
Level 3 | Carrying Amount
Financial assets:
Finance receivables	60,367	81,995
Level 3 | Fair Value
Financial assets:
Finance receivables	60,367	81,995
Senior PIK notes payable | Level 3 | Carrying Amount
Financial liabilities:
Financial liabilities debt instrument	36,670	74,243
Senior PIK notes payable | Level 3 | Fair Value
Financial liabilities:
Financial liabilities debt instrument	36,670	74,243
Secured notes payable | Level 2 | Carrying Amount
Financial liabilities:
Financial liabilities debt instrument	40,000	40,000
Secured notes payable | Level 2 | Fair Value
Financial liabilities:
Financial liabilities debt instrument	40,000	40,000
Subsidiary notes payable | Level 2 | Carrying Amount
Financial liabilities:
Financial liabilities debt instrument	74,699	74,731
Subsidiary notes payable | Level 2 | Fair Value
Financial liabilities:
Financial liabilities debt instrument	$ 74,699	$ 74,731