Loans Receivable - Aging of the Loans Receivable Balance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans receivable (percentage)	14.60%	14.80%
Current loans receivable (percentage)	85.40%	85.20%
Balance of Loans Receivable on Nonaccrual Status	$ 2,110	$ 2,016
30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans receivable (percentage)	6.90%	7.10%
60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans receivable (percentage)	3.40%	3.60%
90 or more Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans receivable (percentage)	4.30%	4.10%
Balance of Loans Receivable Greater Than 90 Days Past Due and Still Accruing Interest and Fees	$ 0	$ 0