Property and Equipment (Narratives) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Net book value	$ 79,123	$ 57,996
Depreciation	36,500	25,200	$ 22,600
Cost of Sales [Member]
Property, Plant and Equipment [Line Items]
Depreciation	7,700
Software Development
Property, Plant and Equipment [Line Items]
Net book value	41,300	33,300
Software Development Work-in-Progress
Property, Plant and Equipment [Line Items]
Net book value	$ 3,100	$ 3,200