Basis and Summary of Significant Accounting Policies - Credit Quality Indicators (Details)	Mar. 31, 2017	Dec. 31, 2016
FICO Score, 600 or Less
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable (net of allowances and unamortized fees of $14,646 in 2017 and $13,830 in 2016)	1.80%	1.80%
FICO Score, Between 600 and 700
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable (net of allowances and unamortized fees of $14,646 in 2017 and $13,830 in 2016)	77.40%	78.10%
FICO Score, 700 or Greater
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable (net of allowances and unamortized fees of $14,646 in 2017 and $13,830 in 2016)	20.80%	20.10%