Divestitures and Discontinued Operations - (Long-Lived Assets Held-for-Sale) (Details) - Disposal Group, Held-for-sale, Not Discontinued Operations - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale	$ 6,152	$ 9,579
Terminalling and storage
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale	3,552	4,152
Marine transportation
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale	$ 2,600	$ 5,427