XML 21 R37.htm IDEA: XBRL DOCUMENT
v3.2.0.727

Compensation Plans Non Stock-based Compensation (Details) - Net Profits Plan [Member] - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2015 | Jun. 30, 2014 | Jun. 30, 2015 | Jun. 30, 2014
Total Cash Payments, Made or Accrued under Profit Sharing Plan | $ 1.9 | $ 2.2 | $ 3.2 | $ 5.4
Cash Payments Made or Accrued under Profit Sharing Plan Related to Divestiture Proceeds | $ 3.8 | $ 8.5 | $ 3.8 | $ 8.5

X
- Definition Cash Payments Made or Accrued under Profit Sharing Plan Related to Divestiture Proceeds + References No definition available. + Details
Name: | sm_CashPaymentsMadeorAccruedunderProfitSharingPlanRelatedtoDivestitureProceeds
Namespace Prefix: | sm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Total amount expensed related to cash payments made or accrued under the profit sharing plan. + References No definition available. + Details
Name: | sm_TotalCashPaymentsMadeOrAccruedUnderProfitSharingPlan
Namespace Prefix: | sm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_DeferredCompensationArrangementWithIndividualExcludingShareBasedPaymentsAndPostretirementBenefitsByTypeOfDeferredCompensationAxis=sm_NetProfitsPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |