Securities (Investments Classified by Contractual Maturity Date) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amortized cost, available for sale, total	$ 69,891	$ 54,528
Estimated fair value, available for sale, total	68,248	52,996
Amortized cost, held to maturity, total	99,246	109,247
Estimated fair value, held to maturity, total	98,007	108,034
Asset-backed securities issued by GSEs [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amortized cost, available for sale, within one year	9,853	7,879
Amortized cost, available for sale, over one year through five years	28,832	21,481
Amortized cost, available for sale, over five years through ten years	20,357	13,093
Amortized cost, available for sale, after ten years	6,369	7,689
Amortized cost, available for sale, total	65,411	50,142
Estimated fair value, available for sale, within one year	9,601	7,634
Estimated fair value, available for sale, over one year through five years	28,096	20,813
Estimated fair value, available for sale, over five years through ten years	19,838	12,686
Estimated fair value, available for sale, after ten years	6,206	7,450
Estimated fair value, available for sale, total	63,741	48,583
Amortized cost, held to maturity, within one year	18,722	18,844
Amortized cost, held to maturity, over one year through five years	41,433	47,168
Amortized cost, held to maturity, over five years through ten years	25,309	29,803
Amortized cost, held to maturity, after ten years	12,782	12,582
Amortized cost, held to maturity, total	98,246	108,397
Estimated fair value, held to maturity, within one year	22,512	21,104
Estimated fair value, held to maturity, over one year through five years	38,813	45,339
Estimated fair value, held to maturity, over five years through ten years	23,709	28,647
Estimated fair value, held to maturity, after ten years	11,973	12,094
Estimated fair value, held to maturity, total	97,007	107,184
Bond Mutual Funds [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amortized cost, available for sale, within one year	4,480	4,386
Estimated fair value, available for sale, within one year	4,507	4,413
Amortized cost, held to maturity, within one year
Estimated fair value, held to maturity, within one year
US Government Obligations [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amortized cost, available for sale, within one year
Estimated fair value, available for sale, within one year
Amortized cost, held to maturity, within one year	1,000	850
Estimated fair value, held to maturity, within one year	$ 1,000	$ 850