Debt Instrument, Repurchase Premium

No definition available.

Name:	sm_DebtInstrumentRepurchasePremium
Namespace Prefix:	sm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- 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.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of the original debt instrument that was repurchased.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentRepurchasedFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount, after accumulated amortization, of debt discount.

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Balance Type:	debit
Period Type:	instant

- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of the cost of borrowed funds accounted for as interest expense for debt.

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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash outflow from the repayment of a long-term debt instrument which can be exchanged for a specified amount of another security, typically the entity's common stock, at the option of the issuer or the holder.

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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Carrying amount of collateralized debt obligations with maturities initially due after one year or beyond the operating cycle, if longer, excluding the current portion. Obligations include, but not limited to, mortgage loans, chattel loans, and other borrowings secured by assets.

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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Write-off of amounts previously capitalized as debt issuance cost in an extinguishment of debt.

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- Details

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Namespace Prefix:
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Balance Type:
Period Type:

- Details

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Namespace Prefix:
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Balance Type:
Period Type:

- Details

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Namespace Prefix:
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Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=sm_A150SeniorSecuredConvertibleNotesDue2021Member
Namespace Prefix:
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Balance Type:
Period Type:

Senior Secured Notes (Details) - USD ($) $ in Thousands			3 Months Ended		9 Months Ended
Senior Secured Notes (Details) - USD ($) $ in Thousands	Jun. 17, 2022	Jul. 01, 2021	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Senior Secured Notes [Line Items]
Secured Long-term Debt, Noncurrent							$ 407,712
Loss on extinguishment of debt			$ 0	$ 5	$ (67,605)	$ (2,139)
10.0% Senior Secured Notes due 2025
Senior Secured Notes [Line Items]
Senior Notes, interest rate, stated percentage							10.00%
Senior Notes, Principal amount			$ 0		$ 0		$ 446,675
Senior Secured Notes, Unamortized Debt Discount							30,236
Senior Notes, unamortized deferred financing costs							$ 8,727
Senior Notes, exchanged or repurchased face amount	$ 446,700
Senior Notes, Redemption Price, Percentage	107.50%
Loss on extinguishment of debt	$ 67,200
Debt Instrument, Repurchase Premium	33,500
10.0% Senior Secured Notes due 2025 \| Accelerated Unamortized Debt Discount
Senior Secured Notes [Line Items]
Write off of Deferred Debt Issuance Cost	26,300
10.0% Senior Secured Notes due 2025 \| Accelerated unamortized deferred financing costs
Senior Secured Notes [Line Items]
Write off of Deferred Debt Issuance Cost	$ 7,400
1.50% Senior Secured Convertible Notes Due 2021
Senior Secured Notes [Line Items]
Senior Notes, interest rate, stated percentage							1.50%
Repayment of 1.50% Senior Convertible Notes due 2021		$ 65,500
Interest Expense, Debt				$ 0		$ 2,300