Consolidated Statements of Changes in Owners' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest [Member]
Beginning Balance at Dec. 31, 2015	$ 1,196,356	$ 439	$ 1,217,255	$ (5,593)	$ (38,012)	$ (58,562)	$ 80,829
Net income (loss)	13,262				2,095		11,167
Other comprehensive income (loss), net of income taxes	(15,352)					(15,352)
Issuance of common stock	228,546	86	228,460
Acquisition of Rose Rock's noncontrolling interest	137,392	133	198,381				(61,122)
Distributions to noncontrolling interests	(32,133)						(32,133)
Dividends	(92,910)		(92,910)
Unvested dividend equivalent rights	587		521				66
Non-cash equity compensation	9,945		8,752				1,193
Issuance of common stock under compensation plans	1,237	1	1,236
Treasury Stock, Value, Acquired, Cost Method	(965)			(965)
Ending Balance at Dec. 31, 2016	1,445,965	659	1,561,695	(6,558)	(35,917)	(73,914)	0
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	288		(2,073)		2,361
Net income (loss)	(17,150)				(17,150)
Other comprehensive income (loss), net of income taxes	20,113	0				20,113
Dividends	(129,925)		(129,925)
Unvested dividend equivalent rights	(1,033)		(1,033)
Non-cash equity compensation	10,066		10,066		0
Stock Issued During Period, Value, Acquisitions	330,341	124	330,217		0
Issuance of common stock under compensation plans	1,173	3	1,170
Treasury Stock, Value, Acquired, Cost Method	(1,473)			(1,473)
Ending Balance at Dec. 31, 2017	1,658,365	786	1,770,117	(8,031)	(50,706)	(53,801)	0
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	11,513				11,513
Net income (loss)	(24,328)				(26,749)		2,421
Other comprehensive income (loss), net of income taxes	2,554	0	0	0	0	2,554	0
Distributions to noncontrolling interests	(2,932)						(2,932)
Dividends	(165,842)		(165,842)
Unvested dividend equivalent rights	(728)		(728)
Non-cash equity compensation	11,398		11,398
Noncontrolling Interest, Increase from Subsidiary Equity Issuance	350,000						350,000
Issuance of common stock under compensation plans	1,026	2	1,024
Treasury Stock, Retired, Cost Method, Amount		(2)		8,031	(8,029)
Treasury Stock, Value, Acquired, Cost Method	(705)			(705)
Ending Balance at Dec. 31, 2018	$ 1,840,321	$ 786	$ 1,615,969	$ (705)	$ (73,971)	$ (51,247)	$ 349,489