Property, plant and equipment (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 519,723		$ 488,004
Less: Accumulated depreciation and amortization	(133,266)		(111,556)
Total Property, plant and equipment, net	386,457		376,448
Depreciation and amortization	29,899	$ 28,155
Land and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	20,333		20,340
Buildings, Building Improvements and Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	152,064		147,130
Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	194,385		190,157
Software [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	52,613		52,564
Construction-in-progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 100,328		$ 77,813