Contingencies and Other Information - Narrative (Details) $ in Thousands	3 Months Ended		6 Months Ended	24 Months Ended
	Dec. 31, 2018	Jun. 30, 2013 USD ($)	Sep. 30, 2019 USD ($) facility	Dec. 31, 2005 USD ($)	Mar. 18, 2014 USD ($)	Mar. 31, 2013 USD ($)	Oct. 26, 2007 USD ($)
Loss Contingencies [Line Items]
Amount of federal taxes offset				$ 24,142
Decrease in sales and other operating revenues (as a percent)	12.00%
Number of facilities with an associated asset retirement obligation | facility			1
Other Income (Expense)
Loss Contingencies [Line Items]
Benefit of excise tax		$ 24,142
IPI Credit Bonus
Loss Contingencies [Line Items]
Gain contingency, unrecorded amount						$ 94,316
Tax Assessment | Brazilian State of Parana
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss			$ 11,159				$ 3,163
Tax Assessment | Brazilian State of Santa Catarina
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss			7,275		$ 2,736
Tax Assessment | Brazil State of Rio Grande do Sul and the State of Santa Catarina
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss			$ 10,649