XML 33 R48.htm IDEA: XBRL DOCUMENT v3.19.3

Credit Facility and Derivative Counterparties (Details)	Sep. 30, 2019
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Percentage of proved property secured for credit facility borrowing	85.00%

X

- Definition

Percentage of Proved Property Secured for Credit Facility Borrowing

+ References

No definition available.

+ Details

Name:	sm_PercentageofProvedPropertySecuredforCreditFacilityBorrowing
Namespace Prefix:	sm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- References

No definition available.

+ Details

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