Property, plant and equipment (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 507,624		$ 488,004
Less: Accumulated depreciation and amortization	(127,384)		(111,556)
Total Property, plant and equipment, net	380,240		376,448
Depreciation and amortization	20,097	$ 17,770
Land and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	20,357		20,340
Buildings, Building Improvements and Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	150,416		147,130
Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	194,140		190,157
Software [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	52,616		52,564
Construction-in-progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 90,095		$ 77,813