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

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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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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in YYYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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+ Details

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Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

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Balance Type:	na
Period Type:	duration

- Definition

Fair value amount of debt instrument that was repurchased.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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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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Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow from additional borrowings, net of cash paid to third parties in connection with debt origination.

+ References

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

- 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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Balance Type:	debit
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of uncollateralized debt obligation (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion.

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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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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- Details

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Senior Unsecured Notes (Details) - USD ($) $ in Thousands			3 Months Ended			6 Months Ended
Senior Unsecured Notes (Details) - USD ($) $ in Thousands	Feb. 14, 2022	Jun. 23, 2021	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Senior Secured Notes [Line Items]
Unsecured Long-term Debt, Noncurrent			$ 1,570,648			$ 1,570,648		$ 1,673,452
Loss on extinguishment of debt			$ (67,226)		$ (2,144)	$ (67,605)	$ (2,144)
5.0% Senior Unsecured Notes due 2024
Senior Secured Notes [Line Items]
Senior Notes, interest rate, stated percentage			5.00%			5.00%		5.00%
Senior Notes, Principal amount			$ 0			$ 0		$ 104,769
Senior Notes, unamortized deferred financing costs			0			0		403
Unsecured Long-term Debt, Noncurrent			$ 0			$ 0		$ 104,366
Senior Notes, exchanged or repurchased face amount	$ 104,800	$ 172,300
Senior Notes, Redemption Price, Percentage	100.00%
Loss on extinguishment of debt				$ (400)
5.0% Senior Unsecured Notes due 2024 \| Accelerated unamortized deferred financing costs
Senior Secured Notes [Line Items]
Write off of Deferred Debt Issuance Cost				$ 400
5.625% Senior Unsecured Notes due 2025
Senior Secured Notes [Line Items]
Senior Notes, interest rate, stated percentage			5.625%			5.625%		5.625%
Senior Notes, Principal amount			$ 349,118			$ 349,118		$ 349,118
Senior Notes, unamortized deferred financing costs			1,844			1,844		2,160
Unsecured Long-term Debt, Noncurrent			$ 347,274			$ 347,274		$ 346,958
6.75% Senior Unsecured Notes due 2026
Senior Secured Notes [Line Items]
Senior Notes, interest rate, stated percentage			6.75%			6.75%		6.75%
Senior Notes, Principal amount			$ 419,235			$ 419,235		$ 419,235
Senior Notes, unamortized deferred financing costs			2,919			2,919		3,270
Unsecured Long-term Debt, Noncurrent			$ 416,316			$ 416,316		$ 415,965
6.625% Senior Unsecured Notes due 2027
Senior Secured Notes [Line Items]
Senior Notes, interest rate, stated percentage			6.625%			6.625%		6.625%
Senior Notes, Principal amount			$ 416,791			$ 416,791		$ 416,791
Senior Notes, unamortized deferred financing costs			3,560			3,560		3,949
Unsecured Long-term Debt, Noncurrent			$ 413,231			$ 413,231		$ 412,842
6.5% Senior Unsecured Notes Due 2028
Senior Secured Notes [Line Items]
Senior Notes, interest rate, stated percentage			6.50%			6.50%		6.50%
Senior Notes, Principal amount		$ 400,000	$ 400,000			$ 400,000		$ 400,000
Senior Notes, unamortized deferred financing costs			6,173			6,173		6,679
Unsecured Long-term Debt, Noncurrent			393,827			393,827		393,321
Debt Instrument, Maturity Date		Jul. 15, 2028
Proceeds from Debt, Net of Issuance Costs		$ 392,800
Senior Secured Notes, Debt Issuance Costs, Gross		$ 7,200
Senior Unsecured Notes
Senior Secured Notes [Line Items]
Senior Notes, Principal amount			1,585,144			1,585,144		1,689,913
Senior Notes, unamortized deferred financing costs			$ 14,496			$ 14,496		$ 16,461
6.125% Senior Unsecured Notes due 2022
Senior Secured Notes [Line Items]
Senior Notes, interest rate, stated percentage		6.125%
Senior Notes, exchanged or repurchased face amount		$ 193,100			19,300		19,300
6.125% Senior Unsecured Notes Due 2022 and 5.0% Senior Unsecured Notes Due 2024 [Member]
Senior Secured Notes [Line Items]
Senior Unsecured Notes, repurchased settlement amount					385,300		$ 385,300
Loss on extinguishment of debt					(2,100)
Debt Instrument, Repurchase Premium					600
6.125% Senior Unsecured Notes Due 2022 and 5.0% Senior Unsecured Notes Due 2024 [Member] \| Accelerated unamortized deferred financing costs
Senior Secured Notes [Line Items]
Write off of Deferred Debt Issuance Cost					$ 1,500