Intangible assets Schedule of intangibles (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 13,093	$ 1,716
Finite-Lived Intangible Assets, Accumulated Amortization	(1,280)	(872)
Finite-Lived Intangible Assets, Net	11,813	844
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	8,182	1,000
Finite-Lived Intangible Assets, Accumulated Amortization	(957)	(787)
Finite-Lived Intangible Assets, Net	7,225	213
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	4,911	716
Finite-Lived Intangible Assets, Accumulated Amortization	(323)	(85)
Finite-Lived Intangible Assets, Net	$ 4,588	$ 631