Investment Securities - Amortized cost and estimated fair value by contractual maturity of debt securities (Details 1) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Available-for-Sale Amortized Cost
Due in one year or less
Due after one year through five years	6,106
Due after five years through ten years
Due after ten years	1,000
Sub-total	7,106
Amortized cost	17,620	$ 19,974
Available-for-Sale Fair Value
Due in one year or less
Due after one year through five years	6,102
Due after five years through ten years
Due after ten years	1,005
Sub-total	7,107
Fair Value	17,652	19,968
Held-to-Maturity Amortized Cost
Due in one year or less	371
Due after one year through five years	3,193
Due after five years through ten years	2,003
Due after ten years
Sub-total	5,567
Amortized cost	6,369	12,979
Held-to-Maturity Fair Value
Due in one year or less	371
Due after one year through five years	3,247
Due after five years through ten years	2,051
Due after ten years
Sub-total	5,669
Fair Value	6,489	13,222
Mortgage-backed securities - residential
Available-for-Sale Amortized Cost
Amortized cost	10,514	13,974
Available-for-Sale Fair Value
Fair Value	10,545	14,000
Held-to-Maturity Amortized Cost
Amortized cost	802	1,535
Held-to-Maturity Fair Value
Fair Value	$ 820	$ 1,574