Loans and Finance Receivables and Allowance for Credit Losses (Loans) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	$ 1,238,409	$ 1,144,954
Net deferred origination costs	26,903	24,453
Total loans and finance receivables	1,265,312	1,169,407
Term loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	946,322	956,755
Lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	277,843	188,199
Other loans and finance receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	$ 14,244	$ 0