Investments - Schedule of Amortized Cost and Estimated Fair Value of Investment Securities by Contractual Maturities (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Available-for-sale, Amortized cost
Available for sale securities, Amortized cost, Due in one year or less	$ 13,456
Available for sale securities, Amortized cost, Due after one year through five years	105,969
Available for sale securities, Amortized cost, Due after five years through ten years	23,056
Available for sale securities, Amortized cost, Due after ten years	29,840
Available for sale securities, Amortized cost, Amortized cost	172,321
Available-for-sale, Fair value
Available for sale securities, Estimated fair value, Due in one year or less	13,613
Available for sale securities, Estimated fair value, Due after one year through five years	107,783
Available for sale securities, Estimated fair value, Due after five years through ten years	23,813
Available for sale securities, Estimated fair value, Due after ten years	32,382
Fair value	177,591	$ 132,981
Held-to-maturity, Amortized cost
Held to maturity securities, Amortized cost, Due in one year or less	867
Held to maturity securities, Amortized cost, Due after one year through five years	24,732
Held to maturity securities, Amortized cost, Due after five years through ten years	1,023
Held to maturity securities, Amortized cost, Due after ten years	19,178
Held to maturity securities, Amortized cost, Mortgage-backed securities	315,135
Held-to-maturity Securities, Total	360,935	366,041
Held-to-maturity, Fair value
Held to maturity securities, Estimated fair value, Due in one year or less	867
Held to maturity securities, Estimated fair value, Due after one year through five years	24,978
Held to maturity securities, Estimated fair value, Due after five years through ten years	1,049
Held to maturity securities, Estimated fair value, Due after ten years	19,359
Held to maturity securities, Estimated fair value, Mortgage-backed securities	314,127
Fair value	$ 360,380	$ 363,178