Stock incentive plan (Details Textual) - USD ($)
|
3 Months Ended |
12 Months Ended |
Sep. 30, 2016 |
Jun. 30, 2016 |
Sep. 30, 2015 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
|
|
| Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options |
|
|
|
$ 374,000
|
|
|
| Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition |
|
|
|
1 year 9 months 14 days
|
|
|
| Allocated Share-based Compensation Expense |
|
|
|
$ 213,000
|
$ 262,000
|
$ 131,000
|
| Restricted Stock [Member] |
|
|
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
|
|
| Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options |
|
|
|
$ 697,000
|
$ 514,000
|
|
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |
6,250
|
|
40,675
|
10,850
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value |
$ 22.50
|
|
$ 19.72
|
$ 21.88
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Beginning Balance |
|
|
|
39,080
|
47,893
|
|
| Performance Shares [Member] |
|
|
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |
|
4,000
|
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value |
|
$ 20.00
|
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