Investment Securities - Amortization Cost and Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Available-for-sale
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Total Amortized Cost	$ 119,503	$ 143,194
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Total Fair Value	120,121	144,310
Available-for-sale | Obligations of U.S. Government sponsored enterprises
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Amortized Cost Due after one year through five years	21,179	15,001
Amortized Cost Due five year through ten years	1,003	7,217
Total Amortized Cost	22,182	22,218
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Fair Value Due after one year through five years	21,160	15,112
Fair Value Due five years through ten years	1,065	7,293
Total Fair Value	22,225	22,405
Available-for-sale | Municipal securities
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Amortized Cost Due after one year through five years	1,503	431
Amortized Cost Due five year through ten years	2,753	3,961
Amortized Cost Due after ten years	5,062	7,314
Total Amortized Cost	9,318	11,706
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Fair Value Due after one year through five years	1,488	448
Fair Value Due five years through ten years	2,877	4,070
Fair Value Due after ten years	5,270	7,463
Total Fair Value	9,635	11,981
Available-for-sale | SBA pool securities
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Amortized Cost Due five year through ten years	7,967	8,407
Amortized Cost Due after ten years	5,064	5,735
Total Amortized Cost	13,031	14,142
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Fair Value Due five years through ten years	7,931	8,325
Fair Value Due after ten years	4,979	5,587
Total Fair Value	12,910	13,912
Available-for-sale | Residential mortgage-backed securities issued by GSE's
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Total Amortized Cost	50,251	64,141
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Total Fair Value	50,978	65,630
Available-for-sale | Commercial mortgage-backed securities
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Total Amortized Cost	24,721	30,987
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Total Fair Value	24,373	30,382
Held-to-maturity
Held-to-maturity Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Amortized Cost	21,689	16,583
Held-to-maturity Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Fair Value	21,685	16,534
Held-to-maturity | Municipal securities
Held-to-maturity Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Amortized Cost due after ten years	1,588	0
Amortized Cost due after yen years	7,000	1,588
Amortized Cost	8,588	1,588
Held-to-maturity Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Fair Value due after five years through ten years	1,641	0
Fair Value due after ten years	7,000	1,536
Fair Value	8,641	1,536
Held-to-maturity | Residential mortgage-backed securities issued by GSE's
Held-to-maturity Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Amortized Cost	9,100	10,899
Held-to-maturity Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Fair Value	9,043	10,902
Held-to-maturity | Commercial mortgage-backed securities
Held-to-maturity Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Amortized Cost	4,001	4,096
Held-to-maturity Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Fair Value	$ 4,001	$ 4,096