Significant Accounting Policies (Property, Plant and Equipment) (Details)	12 Months Ended
	Dec. 31, 2017
Software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	5 years
Equipment and Furnishings | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	3 years
Equipment and Furnishings | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	14 years
Buildings and Improvements | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	10 years
Buildings and Improvements | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	40 years