2.2.0.7 true Share-Based Compensation (Details) (USD $) 009080 - Disclosure - Share-Based Compensation (Details) true false In Millions, except Share data, unless otherwise specified false false 1 USD false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u002 Standard http://www.xbrl.org/2003/instance shares xbrli 0 u003 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 u001 Standard http://www.xbrl.org/2003/instance pure xbrli 0 $ false 2 USD false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u001 Standard http://www.xbrl.org/2003/instance pure xbrli 0 u002 Standard http://www.xbrl.org/2003/instance shares xbrli 0 u003 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 $ false 3 USD false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u003 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 u002 Standard http://www.xbrl.org/2003/instance shares xbrli 0 u001 Standard http://www.xbrl.org/2003/instance pure xbrli 0 $ 2 Notes To Financial Statements [Abstract] 2 str_NotesToFinancialStatementsAbstract str false na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 3 Closing price of Questar stock (in dollars per share) 2 str_CommonStockPricePerShare str false na instant Price-per-share of common stock issued by the company. false false false false false false false false false false false terselabel true 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 true true false false 14.66 14.66 false false false us-types:perShareItemType decimal Price-per-share of common stock issued by the company. No authoritative reference available. false 4 Ratio used to modify the exercise price and the grant-day prices of stock options and restricted share awards, Questar (in hundredths) 2 str_RatioOfClosingPricesCompanyToTotal str false na instant The ratio used to modify the exercise price of options and the grant-day prices of restricted shares, to generally preserve... false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false true false false 0.3223 0.3223 false false false us-types:percentItemType pure The ratio used to modify the exercise price of options and the grant-day prices of restricted shares, to generally preserve the potential benefits under the LTSIP prior to the Spinoff. No authoritative reference available. false 5 Closing price of QEP stock (in dollars per share) 2 us-gaap_SubsidiaryOrEquityMethodInvesteePricePerShare us-gaap true na instant No definition available. false false false false false false false false false false false true 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 true true false false 30.83 30.83 false false false us-types:perShareItemType decimal Price-per-share of common or preferred stock issued or sold by the subsidiary or equity method investee. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 5 -Section H false 6 Ratio used to modify the exercise price and the grant-day prices of stock options and restricted share awards, QEP (in hundredths) 2 str_RatioOfClosingPricesEquityMethodInvesteeToTotal str false na instant The ratio used to modify the exercise price of options and the grant-day prices of restricted shares, to generally preserve... false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false true false false 0.6777 0.6777 false false false us-types:percentItemType pure The ratio used to modify the exercise price of options and the grant-day prices of restricted shares, to generally preserve the potential benefits under the LTSIP prior to the Spinoff. No authoritative reference available. false 7 Share-based compensation expense 2 us-gaap_ShareBasedCompensation us-gaap true debit duration No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 true true false false 13300000 13.3 false false false 3 false false false false 0 0 false false false xbrli:monetaryItemType monetary The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock options, amortization of restricted stock, and adjustment for officers compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 false 8 Deferred share-based compensation on restricted share awards 2 us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent us-gaap true credit instant No definition available. false false false false false false false false false false false false 1 false true false false 8800000 8.8 false false false 2 false true false false 8800000 8.8 false false false 3 false false false false 0 0 false false false xbrli:monetaryItemType monetary Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements. Represents currently earned compensation under compensation arrangements that is not actually paid until a later date. No authoritative reference available. false 9 Income tax benefits from share-based compensation 2 us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities us-gaap true debit duration No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 true true false false 2600000 2.6 false false false 3 false false false false 0 0 false false false xbrli:monetaryItemType monetary Reductions in the entity's income taxes that arise when compensation cost (from non-qualified share-based compensation) recognized on the entity's tax return exceeds compensation cost from share-based compensation recognized in financial statements. This element represents the cash inflow reported in the enterprise's financing activities. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph i Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 00-15 -Paragraph 3 false 10 Shares available for future grant (in shares) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant us-gaap true na instant No definition available. false false false false false false false false false false false false 1 false true false false 8347021 8347021 false false false 2 false true false false 8347021 8347021 false false false 3 false false false false 0 0 false false false xbrli:sharesItemType shares The difference between the maximum number of shares authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares already issued upon exercise of options or other share-based awards under the plan, and 2) shares reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. No authoritative reference available. false 11 Major assumptions used in the calculation of fair value of options granted [Abstract] 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 12 Fair value of options at grant date (recast) (in dollars per share) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue us-gaap true na duration No definition available. false false false false false false false false false false false true 1 false false false false 0 0 false false false 2 true true false false 13.10 13.10 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph c(1) false 13 Risk-free interest rate (in hundredths) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate us-gaap true na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false true false false 0.0230 0.0230 false false false 3 false false false false 0 0 false false false us-types:percentItemType pure The risk-free interest rate assumption that is used in valuing an option on its own shares. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph e(2)(d) false 14 Expected price volatility (in hundredths) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate us-gaap true na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false true false false 0.303 0.303 false false false 3 false false false false 0 0 false false false us-types:percentItemType pure The estimated measure of the percentage amount by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph e(2)(b) false 15 Expected dividend yield (in hundredths) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate us-gaap true na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false true false false 0.0118 0.0118 false false false 3 false false false false 0 0 false false false us-types:percentItemType pure The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph e(2)(c) false 16 Expected life in years (in years) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedTerm us-gaap true na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false true false false 5.2 5.2 false false false 3 false false false false 0 0 false false false xbrli:decimalItemType decimal The period of time a share-based award is expected to be outstanding. A share-based award's expected term shall be determined based on, among other factors, the instrument's contractual term and the effects of employees' expected exercise and post-vesting employment termination behavior. An entity is required to aggregate individual awards into relatively homogeneous groups. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph e(2)(a) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 14 -Section D -Subsection 2 false 17 Unvested stock options decrease in period (in shares) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedInPeriod str false na duration The decrease in the number of unvested stock options, or conversely, the number of stock options vested during the period. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false 520137 520137 false false false 3 false false false false 0 0 false false false xbrli:sharesItemType shares The decrease in the number of unvested stock options, or conversely, the number of stock options vested during the period. No authoritative reference available. false 18 Stock-option transactions under the terms of the LTSIP recast for the effect of the Spinoff [Roll Forward] 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:stringItemType string A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. false 19 Options outstanding, beginning balance (recast) (in shares) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber us-gaap true na instant No definition available. false false false false false false false false true false false periodstartlabel false 1 false false false false 0 0 false false false 2 false true false false 3001999 3001999 false false false 3 false false false false 0 0 false false false xbrli:sharesItemType shares The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance-sheet date, including vested options. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(a) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(b) false 20 Granted (in shares) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod us-gaap true na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false true false false 266000 266000 false false false 3 false false false false 0 0 false false false xbrli:sharesItemType shares The quantity of shares issuable on stock options awarded under the plan during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(d) false 21 Questar employees transferred to QEP (in shares) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsTransferredToEquityMethodInvestee str false na duration The reduction in the number of reserved shares that could potentially be issued under the option plan attributable to... false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false -143800 -143800 false false false 3 false false false false 0 0 false false false xbrli:sharesItemType shares The reduction in the number of reserved shares that could potentially be issued under the option plan attributable to employees transferred to the the equity method investee, due to Spinoff. No authoritative reference available. false 22 Exercised (in shares) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriod us-gaap true na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false true false false -194330 -194330 false false false 3 false false false false 0 0 false false false xbrli:sharesItemType shares The decrease in the number of reserved shares that could potentially be issued attributable to the exercise or conversion during the reporting period of previously issued stock options under the option plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(e) false 23 Options outstanding, ending balance (in shares) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber us-gaap true na instant No definition available. false false false false false false false false false true false periodendlabel false 1 false true false false 2929869 2929869 false false false 2 false true false false 2929869 2929869 false false false 3 false false false false 0 0 false false false xbrli:sharesItemType shares The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance-sheet date, including vested options. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(a) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(b) false 24 Stock-option transactions under the terms of the LTSIP recast for the effect of the Spinoff, additional disclosures [Abstract] 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 25 Minimum exercise price of options outstanding, beginning of period (in dollars per share) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingMinimumExercisePrice str false na instant The minimum exercise price within a price range of options outstanding. false false false false false false false false true false false periodstartlabel true 1 false false false false 0 0 false false false 2 true true false false 2.42 2.42 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The minimum exercise price within a price range of options outstanding. No authoritative reference available. false 26 Maximum exercise price of options outstanding, beginning of the period (in dollars per share) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingMaximumExercisePrice str false na instant The maximum exercise price within a price range of options outstanding. false false false false false false false false true false false periodstartlabel true 1 false false false false 0 0 false false false 2 true true false false 17.35 17.35 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The maximum exercise price within a price range of options outstanding. No authoritative reference available. false 27 Exercise price of options granted during the period (in dollars per share) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodExercisePrice str false na duration The exercise price of options granted during the reporting period false false false false false false false false false false false terselabel true 1 false false false false 0 0 false false false 2 true true false false 13.10 13.10 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The exercise price of options granted during the reporting period No authoritative reference available. false 28 Minimum exercise price of options transferred to QEP (in dollars per share) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsTransferredToEquityMethodInvesteeMinimumExercisePrice str false na duration The minimum exercise price within a price range of options transferred to the equity method investee, due to Spinoff. false false false false false false false false false false false terselabel true 1 false false false false 0 0 false false false 2 true true false false 10.91 10.91 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The minimum exercise price within a price range of options transferred to the equity method investee, due to Spinoff. No authoritative reference available. false 29 Maximum exercise price of options transferred to QEP (in dollars per share) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsTransferredToEquityMethodInvesteeMaximumExercisePrice str false na duration The maximum exercise price within a price range of options transferred to the equity method investee, due to Spinoff. false false false false false false false false false false false terselabel true 1 false false false false 0 0 false false false 2 true true false false 13.10 13.10 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The maximum exercise price within a price range of options transferred to the equity method investee, due to Spinoff. No authoritative reference available. false 30 Minimum exercise price of options exercised during the period (in dollars per share) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodMinimumExercisePrice str false na duration The minimum exercise price of options exercised during the reporting period false false false false false false false false false false false terselabel true 1 false false false false 0 0 false false false 2 true true false false 2.42 2.42 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The minimum exercise price of options exercised during the reporting period No authoritative reference available. false 31 Maximum exercise price of options exercised during the period (in dollars per share) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodMaximumExercisePrice str false na duration The maximum exercise price of options exercised during the reporting period false false false false false false false false false false false terselabel true 1 false false false false 0 0 false false false 2 true true false false 11.40 11.40 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The maximum exercise price of options exercised during the reporting period No authoritative reference available. false 32 Minimum exercise price of options outstanding, end of period (in dollars per share) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingMinimumExercisePrice str false na instant The minimum exercise price within a price range of options outstanding. false false false false false false false false false true false periodendlabel true 1 true true false false 3.70 3.70 false false false 2 true true false false 3.70 3.70 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The minimum exercise price within a price range of options outstanding. No authoritative reference available. false 33 Maximum exercise price of options outstanding, end of period (in dollars per share) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingMaximumExercisePrice str false na instant The maximum exercise price within a price range of options outstanding. false false false false false false false false false true false periodendlabel true 1 true true false false 17.35 17.35 false false false 2 true true false false 17.35 17.35 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The maximum exercise price within a price range of options outstanding. No authoritative reference available. false 34 Options outstanding, Weighted-average exercise price, beginning of period (in dollars per share) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice us-gaap true na instant No definition available. false false false false false false false false true false false periodstartlabel true 1 false false false false 0 0 false false false 2 true true false false 6.42 6.42 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The weighted average price as of the beginning of the year at which grantees can acquire the shares reserved for issuance under the stock option plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(a) false 35 Weighted-average exercise price, options granted (in dollars per share) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice us-gaap true na instant No definition available. false false false false false false false false false false false true 1 true true false false 13.10 13.10 false false false 2 true true false false 13.10 13.10 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The weighted average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on stock options awarded under the plan during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(d) false 36 Weighted-average exercise price, options transferred to QEP (in dollars per share) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsTransferredToEquityMethodInvesteeWeightedAverageExercisePrice str false na instant The weighted average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on... false false false false false false false false false false false terselabel true 1 true true false false 11.47 11.47 false false false 2 true true false false 11.47 11.47 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The weighted average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on stock options transferred to the equity method investee, due to Spinoff. No authoritative reference available. false 37 Weighted average exercise price of options exercised during the period (in dollars per share) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice us-gaap true na instant No definition available. false false false false false false false false false false false true 1 true true false false 4.00 4.00 false false false 2 true true false false 4.00 4.00 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The weighted average price at which option holders acquired shares when converting their stock options into shares under the plan during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(e) false 38 Options outstanding, Weighted-average exercise price, end of period (in dollars per share) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice us-gaap true na instant No definition available. false false false false false false false false false true false periodendlabel true 1 true true false false 6.94 6.94 false false false 2 true true false false 6.94 6.94 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The weighted average price as of the beginning of the year at which grantees can acquire the shares reserved for issuance under the stock option plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(a) false 39 Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Line Items] 2 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:stringItemType string 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. false 40 Minimum exercise price of options outstanding, end of period (in dollars per share) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingMinimumExercisePrice str false na instant The minimum exercise price within a price range of options outstanding. false false false false false false false false false false false terselabel true 1 true true false false 3.70 3.70 false false false 2 true true false false 3.70 3.70 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The minimum exercise price within a price range of options outstanding. No authoritative reference available. false 41 Maximum exercise price of options outstanding, end of period (in dollars per share) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingMaximumExercisePrice str false na instant The maximum exercise price within a price range of options outstanding. false false false false false false false false false false false terselabel true 1 true true false false 17.35 17.35 false false false 2 true true false false 17.35 17.35 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The maximum exercise price within a price range of options outstanding. No authoritative reference available. false 42 Options outstanding, Ending balance (in shares) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber us-gaap true na instant No definition available. false false false false false false false false false false false terselabel false 1 false true false false 2929869 2929869 false false false 2 false true false false 2929869 2929869 false false false 3 false false false false 0 0 false false false xbrli:sharesItemType shares The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance-sheet date, including vested options. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(a) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(b) false 43 Options outstanding, Weighted-average remaining term (in years) 2 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm us-gaap true na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false true false false 2.7 2.7 false false false 3 false false false false 0 0 false false false xbrli:decimalItemType decimal The weighted-average period remaining as of the balance-sheet date until option expiration pertaining to the outstanding stock options for all option plans in the customized range of exercise prices, which may be expressed in a variety of ways (for example, years, months). Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph d(1) false 44 Options outstanding, Weighted-average exercise price, end of period (in dollars per share) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice us-gaap true na instant No definition available. false false false false false false false false false false false terselabel true 1 true true false false 6.94 6.94 false false false 2 true true false false 6.94 6.94 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The weighted average price as of the beginning of the year at which grantees can acquire the shares reserved for issuance under the stock option plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(a) false 45 Options exercisable, Ending Balance (in shares) 2 us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions us-gaap true na instant No definition available. false false false false false false false false false false false false 1 false true false false 2655674 2655674 false false false 2 false true false false 2655674 2655674 false false false 3 false false false false 0 0 false false false xbrli:sharesItemType shares The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance-sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(c) false 46 Options exercisable, Weighted-average exercise price (in dollars per share) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice us-gaap true na instant No definition available. false false false false false false false false false false false true 1 true true false false 6.43 6.43 false false false 2 true true false false 6.43 6.43 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(1)(c) false 47 Unvested Options, Ending Balance (in shares) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedNumber str false na instant The number of outstanding awards on stock option plans for which the employer is contingently obligated to issue equity... false false false false false false false false false false false terselabel false 1 false true false false 274195 274195 false false false 2 false true false false 274195 274195 false false false 3 false false false false 0 0 false false false xbrli:sharesItemType shares The number of outstanding awards on stock option plans for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares. No authoritative reference available. false 48 Unvested Options, Weighted-average exercise price (in dollars per share) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedWeightedAverageExercisePrice str false na instant As of the balance sheet date, the weighted-average exercise price for outstanding stock options that are nonvested. false false false false false false false false false false false terselabel true 1 true true false false 11.89 11.89 false false false 2 true true false false 11.89 11.89 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal As of the balance sheet date, the weighted-average exercise price for outstanding stock options that are nonvested. No authoritative reference available. false 49 Restricted Shares [Abstract] 2 str_RestrictedSharesAbstract str false na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 50 Restricted share grants, vesting rights 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingRights us-gaap true na duration No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 Restricted-share grants typically vest in equal installments over a three or four-year period from the grant date false false false 3 false false false false 0 0 false false false xbrli:stringItemType string Description of award terms as to how many shares or portion of an award are no longer contingent on satisfaction of either a service condition, market condition or a performance condition, thereby giving the employee the legal right to convert the award to shares, to sell the shares, and be entitled to the cash proceeds of such sale. For example, vesting may be expressed as being 25 percent of the shares under option on each anniversary of the grant date. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph a false 51 Restricted shares, weighted-average vesting period 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod us-gaap true na duration No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 25M false false false 3 false false false false 0 0 false false false us-types:durationStringItemType normalizedstring Description of the period of time over which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, which may be expressed in a variety of ways (for example, in years, month and year). Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph a false 52 Restricted share transactions under the terms of the LTSIP recast for the effect of the Spinoff [Roll Forward] 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:stringItemType string A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. false 53 Unvested restricted shares, beginning balance (recast) (in shares) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber us-gaap true na instant No definition available. false false false false false false false false true false false periodstartlabel false 1 false false false false 0 0 false false false 2 false true false false 331475 331475 false false false 3 false false false false 0 0 false false false xbrli:sharesItemType shares The number of outstanding awards on nonstock option plans (for example, phantom stock plan, stock appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(2)(a) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(2)(b) false 54 Unvested restricted shares, Granted (in shares) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod us-gaap true na duration No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false 540277 540277 false false false 3 false false false false 0 0 false false false xbrli:sharesItemType shares The number of shares issuable under a share-based award plan pertaining to grants made during the period on other than stock option plans (for example, phantom stock plan, stock appreciation rights plan, performance target plan). Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(2)(c) false 55 Unvested restricted shares, Questar employees transferred to QEP (in shares) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsTransferredToEquityMethodInvestee str false na duration The reduction in the number of unvested restricted shares that could potentially be issued under the LTSIP attributable to... false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false -26252 -26252 false false false 3 false false false false 0 0 false false false xbrli:sharesItemType shares The reduction in the number of unvested restricted shares that could potentially be issued under the LTSIP attributable to employees transferred to the the equity method investee, due to Spinoff. No authoritative reference available. false 56 Unvested restricted shares, Distributed (in shares) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod us-gaap true na duration No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false -262229 -262229 false false false 3 false false false false 0 0 false false false xbrli:sharesItemType shares The decrease in the number of shares potentially issuable under a share-based award plan pertaining to awards for which the grantee has gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares, other instruments, or cash in accordance with the terms of the arrangement. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(2)(d) false 57 Unvested restricted shares, ending balance (in shares) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber us-gaap true na instant No definition available. false false false false false false false false false true false periodendlabel false 1 false true false false 583271 583271 false false false 2 false true false false 583271 583271 false false false 3 false false false false 0 0 false false false xbrli:sharesItemType shares The number of outstanding awards on nonstock option plans (for example, phantom stock plan, stock appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(2)(a) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(2)(b) false 58 Restricted share transactions under the terms of the LTSIP recast for the effect of the Spinoff, additional disclosures [Abstract] 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract us-gaap true na duration No definition available. false false false false false true false false false false false label false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 59 Minimum price of unvested restricted shares, beginning of period (in dollars per share) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedRestrictedSharesMinimumPrice str false na instant The minimum price within a price range of unvested restricted shares. false false false false false false false false true false false periodstartlabel true 1 false false false false 0 0 false false false 2 true true false false 10.01 10.01 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The minimum price within a price range of unvested restricted shares. No authoritative reference available. false 60 Maximum price of unvested restricted shares, beginning of the period (in dollars per share) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedRestrictedSharesMaximumPrice str false na instant The maximum price within a price range of unvested restricted shares. false false false false false false false false true false false periodstartlabel true 1 false false false false 0 0 false false false 2 true true false false 17.57 17.57 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The maximum price within a price range of unvested restricted shares. No authoritative reference available. false 61 Minimum price of unvested restricted shares, granted (in dollars per share) 2 str_ShareBasedCompensationUnvestedRestrictedSharesGrantsInPeriodMinimumPrice str false na duration The minimum price at which granted unvested restricted shares are converted into shares under the plan false false false false false false false false false false false terselabel true 1 false false false false 0 0 false false false 2 true true false false 13.10 13.10 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The minimum price at which granted unvested restricted shares are converted into shares under the plan No authoritative reference available. false 62 Maximum price of unvested restricted shares, granted (in dollars per share) 2 str_ShareBasedCompensationUnvestedRestrictedSharesGrantsInPeriodMaximumPrice str false na duration The maximum price at which granted unvested restricted shares are converted into shares under the plan false false false false false false false false false false false terselabel true 1 false false false false 0 0 false false false 2 true true false false 15.98 15.98 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The maximum price at which granted unvested restricted shares are converted into shares under the plan No authoritative reference available. false 63 Minimum price of unvested restricted shares, transferred to QEP (in dollars per share) 2 str_ShareBasedCompensationUnvestedRestrictedSharesTransferredToEquityMethodInvesteeMinimumPrice str false na duration The minimum price within a price range of unvested restricted shares transferred to the equity method investee, due to... false false false false false false false false false false false terselabel true 1 false false false false 0 0 false false false 2 true true false false 10.91 10.91 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The minimum price within a price range of unvested restricted shares transferred to the equity method investee, due to Spinoff. No authoritative reference available. false 64 Maximum price of unvested restricted shares, transferred to QEP (in dollars per share) 2 str_ShareBasedCompensationUnvestedRestrictedSharesTransferredToEquityMethodInvesteeMaximumPrice str false na duration The maximum price within a price range of unvested restricted shares transferred to the equity method investee, due to... false false false false false false false false false false false terselabel true 1 false false false false 0 0 false false false 2 true true false false 20.31 20.31 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The maximum price within a price range of unvested restricted shares transferred to the equity method investee, due to Spinoff. No authoritative reference available. false 65 Minimum price of unvested restricted shares, distributed (in dollars per share) 2 str_ShareBasedCompensationUnvestedRestrictedSharesVestedInPeriodMinimumPrice str false na duration The minimum price at which unvested restricted shares are converted into shares and distributed under the plan false false false false false false false false false false false terselabel true 1 false false false false 0 0 false false false 2 true true false false 10.01 10.01 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The minimum price at which unvested restricted shares are converted into shares and distributed under the plan No authoritative reference available. false 66 Maximum price of unvested restricted shares, distributed (in dollars per share) 2 str_ShareBasedCompensationUnvestedRestrictedSharesVestedInPeriodMaximumPrice str false na duration The maximum price at which unvested restricted shares are converted into shares and distributed under the plan false false false false false false false false false false false terselabel true 1 false false false false 0 0 false false false 2 true true false false 17.57 17.57 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The maximum price at which unvested restricted shares are converted into shares and distributed under the plan No authoritative reference available. false 67 Minimum price of unvested restricted shares, end of period (in dollars per share) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedRestrictedSharesMinimumPrice str false na instant The minimum price within a price range of unvested restricted shares. false false false false false false false false false true false periodendlabel true 1 true true false false 11.40 11.40 false false false 2 true true false false 11.40 11.40 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The minimum price within a price range of unvested restricted shares. No authoritative reference available. false 68 Maximum price of unvested restricted shares, end of period (in dollars per share) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedRestrictedSharesMaximumPrice str false na instant The maximum price within a price range of unvested restricted shares. false false false false false false false false false true false periodendlabel true 1 true true false false 20.31 20.31 false false false 2 true true false false 20.31 20.31 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The maximum price within a price range of unvested restricted shares. No authoritative reference available. false 69 Weighted-average price, restricted shares beginning of period (in dollars per share) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue us-gaap true na instant No definition available. false false false false false false false false true false false periodstartlabel true 1 false false false false 0 0 false false false 2 true true false false 13.43 13.43 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The weighted average fair value of nonvested awards on share-based plans excluding option plans (for example, phantom stock plan, stock appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(2)(a) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(2)(b) false 70 Weighted-average price, restricted shares granted (in dollars per share) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue us-gaap true na duration No definition available. false false false false false false false false false false false true 1 false false false false 0 0 false false false 2 true true false false 14.57 14.57 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The weighted average fair value at grant for nonvested share-based awards issued during the period on other than stock option plans (for example, phantom stock plan, stock appreciation rights plan, performance target plan). Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(2)(c) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph c(1) false 71 Weighted-average price, restricted shares transferred to QEP (in dollars per share) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsTransferredToEquityMethodInvesteeWeightedAverageGrantDateFairValue str false na duration The weighted average fair value at grant for nonvested share-based awards issued during the period on other than stock option... false false false false false false false false false false false terselabel true 1 false false false false 0 0 false false false 2 true true false false 7.44 7.44 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The weighted average fair value at grant for nonvested share-based awards issued during the period on other than stock option plans (for example, phantom stock plan, stock appreciation rights plan, performance target plan), transferred to the equity method investee due to Spinoff. No authoritative reference available. false 72 Weighted-average price, restricted shares distributed (in dollars per share) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue us-gaap true na duration No definition available. false false false false false false false false false false false true 1 false false false false 0 0 false false false 2 true true false false 13.73 13.73 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The weighted average fair value as of grant dates pertaining to a share-based award plan other than a stock option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares, other instruments, or cash in accordance with the terms of the arrangement. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(2)(d) false 73 Weighted-average price, restricted shares end of period (in dollars per share) 2 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue us-gaap true na instant No definition available. false false false false false false false false false true false periodendlabel true 1 true true false false 14.62 14.62 false false false 2 true true false false 14.62 14.62 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The weighted average fair value of nonvested awards on share-based plans excluding option plans (for example, phantom stock plan, stock appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(2)(a) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(2)(b) false 74 Restricted stock units [Abstract] 2 str_RestrictedStockUnitsAbstract str false na duration No definition available. false false false false false true false false false false false terselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 75 Number of restricted stock units issued (in shares) 2 str_NumberOfRestrictedStockUnitsIssued str false na duration The number of restricted stock units issued during the period. false false false false false false false false false false false terselabel false 1 false true false false 66235 66235 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:sharesItemType shares The number of restricted stock units issued during the period. No authoritative reference available. false 76 Weighted-average price of restricted stock units issued (in dollars per share) 2 str_WeightedAveragePriceOfRestrictedStockUnitsIssued str false na duration The weighted average fair value at grant for nonvested restricted stock units issued during the period. false false false false false false false false false false false terselabel true 1 true true false false 15.24 15.24 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The weighted average fair value at grant for nonvested restricted stock units issued during the period. No authoritative reference available. false 77 Weighted-average vesting period of restricted stock units issued 2 str_WeightedAverageVestingPeriodOfRestrictedStockUnitsIssued str false na duration Description of the period of time over which an employee's right to exercise a restricted stock unit award is no longer... false false false false false false false false false false false terselabel false 1 false false false false 0 0 21M false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false us-types:durationStringItemType normalizedstring Description of the period of time over which an employee's right to exercise a restricted stock unit award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, which may be expressed in a variety of ways (for example, in years, month and year). No authoritative reference available. false 78 Number of unvested restricted shares awarded as result of Spinoff and bifurcation of share-based awards (in shares) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedRestrictedSharesRelatedToSpinoffAndBifurcationOfAwards str false na instant The number of outstanding unvested restricted shares for which the employer is contingently obligated to issue equity... false false false false false false false false false false false terselabel false 1 false true false false 256591 256591 false false false 2 false true false false 256591 256591 false false false 3 false false false false 0 0 false false false xbrli:sharesItemType shares The number of outstanding unvested restricted shares for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares. Granted to certain officers, employees and non-employee directors of the Company as a result of the Spinoff and bifurcation of share-based awards. No authoritative reference available. false 79 Weighted average price per share of unvested restricted shares awarded as result of Spinoff and bifurcation of share-based awards (in dollars per share) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedRestrictedSharesWeightedAverageGrantDateFairValueRelatedToSpinoffAndBifurcationOfAwards str false na instant The weighted average fair value of unvested restricted shares for which the employer is contingently obligated to issue... false false false false false false false false false false false terselabel true 1 true true false false 29.20 29.20 false false false 2 true true false false 29.20 29.20 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The weighted average fair value of unvested restricted shares for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares. Granted to certain officers, employees and non-employee directors of the Company as a result of the Spinoff and bifurcation of share-based awards. No authoritative reference available. false 80 Number of unvested stock options awarded as result of Spinoff and bifurcation of share-based awards (in shares) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedNumberRelatedToSpinoffAndBifurcationOfAwards str false na instant The number of outstanding awards on stock option plans for which the employer is contingently obligated to issue equity... false false false false false false false false false false false terselabel false 1 false true false false 274195 274195 false false false 2 false true false false 274195 274195 false false false 3 false false false false 0 0 false false false xbrli:sharesItemType shares The number of outstanding awards on stock option plans for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares. Granted to certain officers, employees and non-employee directors of the Company as a result of the Spinoff and bifurcation of share-based awards. No authoritative reference available. false 81 Weighted average price per share of unvested stock options awarded as result of Spinoff and bifurcation of share-based awards (in dollars per share) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedWeightedAverageExercisePriceRelatedToSpinoffAndBifurcationOfAwards str false na instant As of the balance sheet date, the weighted-average exercise price for outstanding stock options that are nonvested. Granted... false false false false false false false false false false false terselabel true 1 true true false false 25.01 25.01 false false false 2 true true false false 25.01 25.01 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal As of the balance sheet date, the weighted-average exercise price for outstanding stock options that are nonvested. Granted to certain officers, employees and non-employee directors of the Company as a result of the Spinoff and bifurcation of share-based awards. No authoritative reference available. false 82 Number of stock options awarded to certain officers, employees and nonemployee directors of QEP (in shares) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAwardedToEquityMethodInvestee str false na instant The number of shares reserved for issuance under stock option agreements awarded under the plan, to officers, employees and... false false false false false false false false false false false terselabel false 1 false true false false 1725913 1725913 false false false 2 false true false false 1725913 1725913 false false false 3 false false false false 0 0 false false false xbrli:sharesItemType shares The number of shares reserved for issuance under stock option agreements awarded under the plan, to officers, employees and nonemployee directors of the equity method investee, that validly exist and are outstanding as of the balance-sheet date, including vested options. No authoritative reference available. false 83 Weighted-average exercise price of stock options awarded to certain officers, employees and nonemployee directors of QEP (in dollars per share) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardWeightedAverageExercisePriceOptionsAwardedToEquityMethodInvestee str false na instant The weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan. These... false false false false false false false false false false false terselabel true 1 true true false false 9.55 9.55 false false false 2 true true false false 9.55 9.55 false false false 3 false false false false 0 0 false false false us-types:perShareItemType decimal The weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan. These grantees are certain officers, employees and nonemployee directors of the equity method investee. No authoritative reference available. false 84 Weighted-average remaining life of stock options awarded to certain officers, employees and nonemployee directors of QEP (in years) 2 str_ShareBasedCompensationArrangementByShareBasedPaymentAwardWeightedAverageRemainingLifeOptionsAwardedToEquityMethodInvestee str false na instant The weighted-average period remaining as of the balance-sheet date until option expiration pertaining to the outstanding... false false false false false false false false false false false terselabel false 1 false true false false 4.1 4.1 false false false 2 false true false false 4.1 4.1 false false false 3 false false false false 0 0 false false false xbrli:decimalItemType decimal The weighted-average period remaining as of the balance-sheet date until option expiration pertaining to the outstanding stock options awarded to certain officers, employees and nonemployee directors of the equity method investee, which may be expressed in a variety of ways (for example, years, months). 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