Intangible assets (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	$ 400	$ 100
Finite-Lived Intangible Assets, Gross	12,578		$ 13,093
Finite-Lived Intangible Assets, Accumulated Amortization	(1,615)		(1,280)
Finite-Lived Intangible Assets, Net	10,963		11,813
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	7,874		8,182
Finite-Lived Intangible Assets, Accumulated Amortization	(1,159)		(957)
Finite-Lived Intangible Assets, Net	6,715		7,225
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	4,704		4,911
Finite-Lived Intangible Assets, Accumulated Amortization	(456)		(323)
Finite-Lived Intangible Assets, Net	$ 4,248		$ 4,588