Preferred Stock (Details Textual) $ / shares in Units, $ in Thousands, $ in Millions							3 Months Ended
	Mar. 01, 2019 USD ($)	Feb. 25, 2019 USD ($) $ / shares shares	Feb. 25, 2019 CAD ($)	Oct. 31, 2018 USD ($)	Aug. 29, 2018 USD ($)	May 25, 2018 USD ($)	Mar. 31, 2019 USD ($) shares	Mar. 31, 2019 CAD ($) shares	Feb. 25, 2019 CAD ($) shares	Dec. 31, 2018 shares
Preferred Stock, Shares Issued | shares							350,000	350,000		350,000
Redeemable Preferred Stock [Member]
Convertible Preferred Stock, Shares Issued upon Conversion | shares							11,326,954	11,326,954
Dividends, Preferred Stock, Paid-in-kind | $	$ 6,430			$ 6,317	$ 6,211	$ 4,832
SemCAMS Midstream [Member] | Subsidiary redeemable preferred stock [Member]
Preferred Stock, Shares Issued | shares		300,000							300,000
Preferred stock per share annualized dividend		$ 87.50
Proceeds from Issuance of Redeemable Preferred Stock		$ 223,800	$ 293.7
Payments of Stock Issuance Costs		4,800	$ 6.3
Preferred Stock, Redemption Amount		$ 250,200							$ 330.0
Dividends, Preferred Stock, Paid-in-kind							$ 1,900	$ 2.5
Canada, Dollars | SemCAMS Midstream [Member] | Subsidiary redeemable preferred stock [Member]
Shares Issued, Price Per Share		$ 1,000
Preferred Stock, Redemption Price Per Share		1,100
United States of America, Dollars | SemCAMS Midstream [Member] | Subsidiary redeemable preferred stock [Member]
Shares Issued, Price Per Share		749
Preferred Stock, Redemption Price Per Share		$ 824