Purchased Receivables - Allowance on Net Purchase Receivables (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Purchased Receivable Allowance for Loan Loss Reserve [Roll Forward]
Balance, beginning of period			$ 200
Charge-offs	$ (9)	$ (1,203)	(1,213)	$ (1,689)
Balance, end of period	196		196
Purchased Receivable
Purchased Receivable Allowance for Loan Loss Reserve [Roll Forward]
Balance, beginning of period	201	194	200	171
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Charge-offs net of recoveries	0	0	0	0
(Benefit) reserve for purchased receivables	(5)	6	(4)	29
Balance, end of period	$ 196	$ 200	$ 196	$ 200