Purchased Receivables - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($) segment purchased_receivable	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) segment purchased_receivable	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($) purchased_receivable
Purchased Receivables [Abstract]
Term of purchased receivables (less than)			1 year
Number of classes of purchased receivables | segment	1		1
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$ 25,968,000		$ 25,968,000		$ 16,200,000
Charge-offs	$ 1,203,000	$ 22,000	$ 1,689,000	$ 891,000
Purchased Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of purchased receivables past due | purchased_receivable	0		0		0
Total	$ 0		$ 0		$ 0
Charge-offs	$ 0	$ 0	$ 0	$ 0