Commitments and contingencies (Details) - USD ($)
$ in Thousands |
Mar. 31, 2016 |
Dec. 31, 2015 |
| Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |
|
|
| Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability |
$ 67,425
|
$ 57,272
|
| Standby Letters of Credit [Member] |
|
|
| Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |
|
|
| Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability |
1,474
|
1,484
|
| Undisbursed credit lines [Member] |
|
|
| Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |
|
|
| Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability |
43,799
|
46,656
|
| Commitments to extend or originate credit [Member] |
|
|
| Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] |
|
|
| Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability |
$ 22,152
|
$ 9,132
|