Property, plant and equipment (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 469,163		$ 431,381
Less: Accumulated depreciation and amortization	(110,129)		(99,525)
Total Property, plant and equipment, net	359,034		331,856
Depreciation and amortization	17,770	$ 17,298
Land and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	17,208		16,520
Buildings, Building Improvements and Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	142,687		111,060
Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	201,455		136,528
Software [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	56,716		39,784
Construction-in-progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 51,097		$ 127,489