Fair Value - Fair Value on Recurring Basis - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	$ 52,246	$ 40,568
Percentage of portfolio in residential mortgage backed securities	63.00%
Residential mortgage backed securities guaranteed by Government National Mortgage Association or Federal National Mortgage Association or Federal Home Loan Mortgage Corporation	$ 32,100
Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	$ 32,794	$ 21,631