Purchased Receivables - Allowance on Net Purchase Receivables (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Purchased Receivable Allowance for Loan Loss Reserve [Roll Forward]
Balance, beginning of period	$ 190
Charge-offs	(109)	$ (1,104)
Balance, end of period	141
Purchased Receivable
Purchased Receivable Allowance for Loan Loss Reserve [Roll Forward]
Balance, beginning of period	190	200
Charge-offs	0	0
Recoveries	0	0
Charge-offs net of recoveries	0	0
(Benefit) reserve for purchased receivables	(49)	9
Balance, end of period	$ 141	$ 209