Investment securities available for sale (Details) - USD ($)
$ in Thousands |
Sep. 30, 2017 |
Dec. 31, 2016 |
| Schedule of Available-for-sale Securities [Line Items] |
|
|
| Par value |
$ 44,810
|
$ 43,972
|
| Amortized Cost |
45,020
|
44,169
|
| Gross Unrealized Gains |
3
|
1
|
| Gross Unrealized Losses |
(189)
|
(276)
|
| Estimated Fair Value |
$ 44,834
|
$ 43,894
|
| AverageYield |
1.75%
|
1.45%
|
| U.S. Government Agencies [Member] |
|
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
| Par value |
$ 31,948
|
$ 32,262
|
| Amortized Cost |
32,160
|
32,475
|
| Gross Unrealized Gains |
0
|
0
|
| Gross Unrealized Losses |
(169)
|
(229)
|
| Estimated Fair Value |
$ 31,991
|
$ 32,246
|
| AverageYield |
1.37%
|
1.24%
|
| U.S. Government Agencies [Member] | One To five Years [Member] |
|
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
| Par value |
$ 27,400
|
$ 29,400
|
| Amortized Cost |
27,558
|
29,607
|
| Gross Unrealized Gains |
0
|
0
|
| Gross Unrealized Losses |
(150)
|
(213)
|
| Estimated Fair Value |
$ 27,408
|
$ 29,394
|
| AverageYield |
1.29%
|
1.25%
|
| U.S. Government Agencies [Member] | Five To Ten Years [Member] |
|
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
| Par value |
$ 2,000
|
|
| Amortized Cost |
2,049
|
|
| Gross Unrealized Gains |
0
|
|
| Gross Unrealized Losses |
(4)
|
|
| Estimated Fair Value |
$ 2,045
|
|
| AverageYield |
2.00%
|
|
| U.S. Government Agencies [Member] | More Than Ten Years [Member] |
|
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
| Par value |
$ 2,548
|
$ 2,862
|
| Amortized Cost |
2,553
|
2,868
|
| Gross Unrealized Gains |
0
|
0
|
| Gross Unrealized Losses |
(15)
|
(16)
|
| Estimated Fair Value |
$ 2,538
|
$ 2,852
|
| AverageYield |
1.78%
|
1.08%
|
| Mortgage Backed Securities [Member] |
|
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
| Par value |
$ 10,562
|
$ 11,710
|
| Amortized Cost |
10,537
|
11,694
|
| Gross Unrealized Gains |
1
|
1
|
| Gross Unrealized Losses |
(20)
|
(47)
|
| Estimated Fair Value |
$ 10,518
|
$ 11,648
|
| AverageYield |
2.08%
|
2.05%
|
| Mortgage Backed Securities [Member] | One To five Years [Member] |
|
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
| Par value |
$ 3,595
|
$ 3,457
|
| Amortized Cost |
3,673
|
3,524
|
| Gross Unrealized Gains |
0
|
0
|
| Gross Unrealized Losses |
(12)
|
(33)
|
| Estimated Fair Value |
$ 3,661
|
$ 3,491
|
| AverageYield |
1.44%
|
1.78%
|
| Mortgage Backed Securities [Member] | More Than Ten Years [Member] |
|
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
| Par value |
$ 6,967
|
$ 8,253
|
| Amortized Cost |
6,864
|
8,170
|
| Gross Unrealized Gains |
1
|
1
|
| Gross Unrealized Losses |
(8)
|
(14)
|
| Estimated Fair Value |
$ 6,857
|
$ 8,157
|
| AverageYield |
2.41%
|
2.16%
|
| Corporate Debt Securities [Member] | Five To Ten Years [Member] |
|
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
| Par value |
$ 2,300
|
|
| Amortized Cost |
2,323
|
|
| Gross Unrealized Gains |
2
|
|
| Gross Unrealized Losses |
0
|
|
| Estimated Fair Value |
$ 2,325
|
|
| AverageYield |
5.42%
|
|