Divestitures Divestitures - Other Assets and Liabilities Held for Sale (Details) - USD ($) $ in Thousands		12 Months Ended
	Dec. 14, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash proceeds from divestitures, net		$ 6,857	$ 3,325,571	$ 8,883
Current assets		39,152	0
Net property, plant and equipment		215,900
Current liabilities		1,938	$ 0
Noncurrent liabilities		600
Assets held for sale, excluding discontinued operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash proceeds from divestitures, net	$ 416,000
Current assets		39,152
Net property, plant and equipment		121,759
Goodwill		14,422
Other intangibles, net of amortization		3,632
Assets held for sale		178,965
Current liabilities		1,938
Noncurrent liabilities		614
Liabilities held for sale		$ 2,552