Summary of Significant Accounting Policies Property, Plant and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Capitalized Interest	$ 4.0	$ 2.2	$ 1.9
Land, land improvements and logging roads, net of road amortization	168.6	162.7
Buildings	329.9	347.5
Machinery and equipment	1,949.0	1,977.4
Construction in progress	148.1	98.5
Property, Plant and Equipment, Gross	2,595.6	2,586.1
Accumulated depreciation	1,585.2	1,660.0
Property, Plant and Equipment, Net	$ 1,010.4	$ 926.1