Timber and Timberlands (Narrative) (Details) $ in Millions		3 Months Ended	12 Months Ended
	Apr. 21, 2016 USD ($) a	Jun. 30, 2016 USD ($) a	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Timber And Timberlands [Line Items]
Depletion from Company Owned Lands			$ 20.8	$ 25.3	$ 14.5
Amortization of Logging Roads			$ 3.1	$ 3.1	$ 2.8
Acres sold through timberland sale | a	172,000	172,000
Land Sales	$ 114.0	$ 114.0
Real Estate [Member]
Timber And Timberlands [Line Items]
Net loss		$ 48.5