Operating Property And Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Land	$ 217,885	$ 212,660
Buildings and improvements	822,931	808,909
Machinery and equipment	797,084	737,899
Other	131,181	114,442
Gross	1,969,081	1,873,910
Accumulated depreciation	(1,192,377)	(1,128,040)
Total	776,704	745,870
Operating equipment depreciation expense	$ 94,000	$ 88,000	$ 84,000
Minimum | Buildings and improvements
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	10 years
Minimum | Machinery and equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	3 years
Minimum | Other
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	3 years
Maximum | Buildings and improvements
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	40 years
Maximum | Machinery and equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	10 years
Maximum | Other
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	10 years