Organization, Description of Business and Basis of Presentation (Narrative) (Details) $ in Thousands, bbl in Millions		3 Months Ended			9 Months Ended
	Jan. 01, 2019 USD ($)	Sep. 30, 2018 USD ($) Terminal bbl mi	Mar. 31, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) Terminal bbl mi	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Organization and Description of Business [Line Items]
Operating		$ 172,115		$ 165,368	$ 475,256	$ 442,254
General and administrative		47,389		37,202	147,235	120,876
Other expense		1,694		$ 549	10,299	$ 3,762
Long-term pension and benefits		125,088			125,088		$ 111,305
Accumulated other comprehensive loss		$ 118,200			$ 118,200		$ 137,578
Refined Products Segment [Member]
Organization and Description of Business [Line Items]
Number of Pipeline Terminals | Terminal		53			53
Number of Independent Terminals | Terminal		26			26
Refined Products Segment [Member] | Refined Products Transportation Services [Member]
Organization and Description of Business [Line Items]
Pipeline Length | mi		9,700			9,700
Refined Products Segment [Member] | Ammonia Transportation Services [Member]
Organization and Description of Business [Line Items]
Pipeline Length | mi		1,100			1,100
Crude Oil Pipeline and Terminals Segment [Member]
Organization and Description of Business [Line Items]
Pipeline Length | mi		2,200			2,200
Storage Capacity | bbl		33			33
Contracted Storage | bbl		21			21
Marine Storage Segment [Member]
Organization and Description of Business [Line Items]
Number of Independent Terminals | Terminal		5			5
Storage Capacity | bbl		26			26
Error in Actuarial Assumptions [Member]
Organization and Description of Business [Line Items]
Net periodic benefit cost (credit)			$ 16,000
Operating			5,700
General and administrative			3,400
Other expense			6,900
Long-term pension and benefits			18,800
Accumulated other comprehensive loss			$ 2,800
Scenario, Forecast | Assets, Total [Member] | Accounting Standards Update 2016-02 [Member]
Organization and Description of Business [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 80,000
Scenario, Forecast | Liabilities, Total [Member] | Accounting Standards Update 2016-02 [Member]
Organization and Description of Business [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 80,000