Segment and Geographical Information - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) segment core_business_area
Segment Reporting Information [Line Items]
Number of reportable segments | segment	5
Sale of timberlands reclassification threshold | $	$ 20
Trading
Segment Reporting Information [Line Items]
Number of core business areas | core_business_area	2