Pension benefits (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Pension Expense	$ 223	$ 617	$ 717
Defined Benefit Plan, Accumulated Benefit Obligation	1,500	$ 1,700
Defined Contribution Plan, Entities Matching Contribution, Amount	$ 100