Investment Securities - Amortized Cost and Estimated Fair Value of Debt Investments by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Available-for-sale securities, debt maturities, amortized cost [Abstract]
Due in one year or less	$ 17,110
Due after one year through five years	15,004
Due after five years through ten years	12,357
Due after ten years	9,722
Sub-total	54,193
Amortized cost	139,489
Available-for-sale securities, debt maturities, Estimated Fair Value [Abstract]
Due in one year or less	17,083
Due after one year through five years	14,968
Due after five years through ten years	12,457
Due after ten years	9,460
Sub-total	53,968
Available-for-sale securities, debt maturities, fair value, totals	138,605
Held-to-maturity Securities, debt maturities, amortized cost [Abstract]
Due in one year or less	1,676
Due after one year through five years	9,796
Due after five years through ten years	17,373
Due after ten years	19,324
Sub-total	48,169
Held-to-maturity securities, at amortized cost (fair value of $68,041 and $54,429, respectively)	67,193	$ 54,645
Held-to-maturity Securities, debt maturities, Estimated Fair Value [Abstract]
Due in one year or less	1,674
Due after one year through five years	9,991
Due after five years through ten years	17,978
Due after ten years	19,155
Sub-total	48,798
Held-to-maturity securities at fair value	68,041	54,429
Residential Mortgage-Backed - US Agency [Member]
Available-for-sale securities, debt maturities, amortized cost [Abstract]
Amortized cost	30,722	31,204
Available-for-sale securities, debt maturities, Estimated Fair Value [Abstract]
Available-for-sale securities, debt maturities, fair value, totals	30,578
Held-to-maturity Securities, debt maturities, amortized cost [Abstract]
Held-to-maturity securities, at amortized cost (fair value of $68,041 and $54,429, respectively)	7,379	6,386
Held-to-maturity Securities, debt maturities, Estimated Fair Value [Abstract]
Held-to-maturity securities at fair value	7,549	6,397
Collateralized Mortgage Obligations - US Agency [Member]
Available-for-sale securities, debt maturities, amortized cost [Abstract]
Amortized cost	46,102	42,124
Available-for-sale securities, debt maturities, Estimated Fair Value [Abstract]
Available-for-sale securities, debt maturities, fair value, totals	45,642
Held-to-maturity Securities, debt maturities, amortized cost [Abstract]
Held-to-maturity securities, at amortized cost (fair value of $68,041 and $54,429, respectively)	7,843	2,927
Held-to-maturity Securities, debt maturities, Estimated Fair Value [Abstract]
Held-to-maturity securities at fair value	7,910	3,023
Collateralized Mortgage Obligations - Private Label [Member]
Available-for-sale securities, debt maturities, amortized cost [Abstract]
Amortized cost	8,472	6,682
Available-for-sale securities, debt maturities, Estimated Fair Value [Abstract]
Available-for-sale securities, debt maturities, fair value, totals	8,417
Held-to-maturity Securities, debt maturities, amortized cost [Abstract]
Held-to-maturity securities, at amortized cost (fair value of $68,041 and $54,429, respectively)	3,802	1,467
Held-to-maturity Securities, debt maturities, Estimated Fair Value [Abstract]
Held-to-maturity securities at fair value	$ 3,784	$ 1,396