Acquisitions (Details Textual) - USD ($) $ in Thousands, shares in Millions				3 Months Ended								12 Months Ended
	Apr. 17, 2018	Jul. 17, 2017	Sep. 30, 2016	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Revenues				$ 611,863	$ 633,996	$ 595,794	$ 661,609	$ 606,806	$ 545,922	$ 473,089	$ 456,100	$ 2,503,262	$ 2,081,917	$ 1,332,164
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest				$ 2,972	$ 8,461	$ (2,726)	$ (33,035)	2,619	$ (19,103)	$ 9,611	$ (10,277)	(24,328)	(17,150)	13,262
Gain on pension curtailment												$ 0	3,008	$ 0
HFOTCO LLC [Member]
Business Acquisition [Line Items]
Payments to acquire businesses		$ 297,800
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned		330,000
Revenues													76,900
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest													(2,400)
Business Acquisition, Transaction Costs		$ 19,200
Gain on pension curtailment													3,000
HFOTCO LLC [Member] | Common Class A [Member]
Business Acquisition [Line Items]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares		12.4
Rose Rock Midstream L P [Member]
Business Acquisition [Line Items]
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs			$ 5,300
Income Tax Effects Allocated Directly to Equity, Equity Transactions			$ 143,300
Rose Rock Midstream L P [Member] | Common Class A [Member]
Business Acquisition [Line Items]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares			13.1
Secured Debt [Member] | HFOTCO LLC [Member]
Business Acquisition [Line Items]
Business Combination, Consideration Transferred, Liabilities Incurred		$ 766,000
Other Pension, Postretirement and Supplemental Plans [Member] | HFOTCO LLC [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other		$ 10,000						$ 7,000					$ 7,000
Second Payment [Member]
Business Acquisition [Line Items]
Extinguishment of Debt, Amount	$ 579,600
Second Payment [Member] | HFOTCO LLC [Member]
Business Acquisition [Line Items]
Extinguishment of Debt, Amount	$ 579,600