Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount of unamortized debt discount (premium) and debt issuance costs.

+ References

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Balance Type:	debit
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- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Balance Type:	credit
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- Definition

The effective interest rate at the end of the reporting period.

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Topic 470
-SubTopic 20
-Section 50
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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Long-Term Debt (Details) $ in Thousands, $ in Millions	Mar. 31, 2019 USD ($)	Feb. 25, 2019 CAD ($)	Dec. 31, 2018 USD ($)
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	$ (34,949)		$ (31,666)
Long-term Debt and Capital Lease Obligations, Including Current Maturities	2,467,583		2,284,834
less: current portion of long-term debt	6,000		6,000
Long-term debt	$ 2,461,583		2,278,834
Revolving Credit Facility [Member] \| Corporate Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Interest Rate at Period End	2.50%
Senior Notes [Member] \| Senior Unsecured Notes due 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.625%
Long-term Debt, Gross	$ 400,000		400,000
Senior Notes [Member] \| Senior unsecured notes due 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.625%
Long-term Debt, Gross	$ 350,000		350,000
Senior Notes [Member] \| Senior Unsecured Notes due 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.375%
Long-term Debt, Gross	$ 325,000		325,000
Senior Notes [Member] \| Senior Unsecured Notes due 2026 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.25%
Long-term Debt, Gross	$ 300,000		300,000
Line of Credit [Member] \| Revolving Credit Facility [Member] \| HFOTCO Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Interest Rate at Period End	0.00%
Long-term Line of Credit	$ 0		0
Alternate Base Rate [Member] \| Line of Credit [Member] \| Revolving Credit Facility [Member] \| Corporate Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Interest Rate at Period End	0.00%
Long-term Line of Credit	$ 0		24,500
Alternate Base Rate [Member] \| Line of Credit [Member] \| Revolving Credit Facility [Member] \| SemCAMS Midstream Credit Facility [Member] [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Interest Rate at Period End	4.5198%
Long-term Line of Credit	$ 18,722		0
Eurodollar [Member] \| Line of Credit [Member] \| Revolving Credit Facility [Member] \| Corporate Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Interest Rate at Period End	0.00%
Long-term Line of Credit	$ 0		95,000
Prime Rate [Member] \| Line of Credit [Member] \| Revolving Credit Facility [Member] \| SemCAMS Midstream Credit Facility [Member] [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Interest Rate at Period End	5.45%
Long-term Line of Credit	$ 26,210		0
SemCAMS Midstream [Member] \| Term Loan A [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 350
SemCAMS Midstream [Member] \| Alternate Base Rate [Member] \| Term Loan A [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.5501%
Long-term Debt, Gross	$ 262,096		0
SemCAMS Midstream [Member] \| Prime Rate [Member] \| Term Loan A [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.45%
Long-term Debt, Gross	$ 4		0
HFOTCO LLC [Member] \| Term Loan B [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.25%
Long-term Debt, Gross	$ 595,500		597,000
HFOTCO LLC [Member] \| Tax Exempt Notes Payable due 2050 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.5178%
Long-term Debt, Gross	$ 225,000		$ 225,000