Purchased Receivables - Summary of Components of Net Purchased Receivables (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Purchased Receivables [Abstract]
Purchased receivables	$ 13,760	$ 14,596
Reserve for purchased receivable losses	(87)	(190)
Total	$ 13,673	$ 14,406