Goodwill and intangible assets (Details 1) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Balance at January 1, 2015			$ 1,608
Disposals			(179)
Amortization expense	$ 55	$ 62	170	$ 241
Balance at September 30, 2015	$ 1,259		$ 1,259