Name:	str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAwardedToEquityMethodInvestee
Namespace Prefix:	str_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

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 definition available.

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

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 definition available.

Name:	str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedWeightedAverageExercisePriceRelatedToSpinoffAndBifurcationOfAwards
Namespace Prefix:	str_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

The number of unvested restricted shares 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.

No definition available.

Name:	str_ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedRestrictedSharesAwardedToEquityMethodInvestee
Namespace Prefix:	str_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

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 definition available.

Name:	str_ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedRestrictedSharesRelatedToSpinoffAndBifurcationOfAwards
Namespace Prefix:	str_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

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, awarded to officers, employees and nonemployee directors of the equity method investee.

No definition available.

Name:	str_ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedRestrictedSharesWeightedAverageGrantDateFairValue
Namespace Prefix:	str_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

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 definition available.

Name:	str_ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedRestrictedSharesWeightedAverageGrantDateFairValueRelatedToSpinoffAndBifurcationOfAwards
Namespace Prefix:	str_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

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 definition available.

Name:	str_ShareBasedCompensationArrangementByShareBasedPaymentAwardWeightedAverageExercisePriceOptionsAwardedToEquityMethodInvestee
Namespace Prefix:	str_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

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).

No definition available.

Name:	str_ShareBasedCompensationArrangementByShareBasedPaymentAwardWeightedAverageRemainingLifeOptionsAwardedToEquityMethodInvestee
Namespace Prefix:	str_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

Period 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, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(i)-(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(2)(a)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit 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 or units.

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.