Commitments and Contingencies - Minimum Net Annual Commitments Under all Leases, Subleases and Contracts with Non-Cancelable Terms in Excess of 12 Months (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2015	$ 1,416
2016	1,571
2017	1,524
2018	1,339
2019	1,194
2020	1,206
2021	879
2022	779
2023	792
2024	805
2025	$ 474

Commitments and Contingencies - Minimum Net Annual Commitments Under all Leases, Subleases and Contracts with Non-Cancelable Terms in Excess of 12 Months (Detail) (USD $)
In Thousands, unless otherwise specified

Dec. 31, 2014

Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]

$ 1,416us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent

2016

1,571us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears

2017

1,524us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears

2018

1,339us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears

2019

1,194us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears

2020

1,206sgy_OperatingLeasesFutureMinimumPaymentsDueInSixYears

2021

879sgy_OperatingLeasesFutureMinimumPaymentsDueInSevenYears

2022

779sgy_OperatingLeasesFutureMinimumPaymentsDueInEightYears

2023

792sgy_OperatingLeasesFutureMinimumPaymentsDueInNineYears

2024

805sgy_OperatingLeasesFutureMinimumPaymentsDueInTenYears

2025

$ 474sgy_OperatingLeasesFutureMinimumPaymentsDueInElevenYears

- Definition

Operating Leases, Future Minimum Payments, Due in Eight Years

+ References

No definition available.

+ Details

Name:	sgy_OperatingLeasesFutureMinimumPaymentsDueInEightYears
Namespace Prefix:	sgy_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Operating and capital leases future minimum payments due in eleven years.

+ References

No definition available.

+ Details

Name:	sgy_OperatingLeasesFutureMinimumPaymentsDueInElevenYears
Namespace Prefix:	sgy_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Operating Leases, Future Minimum Payments, Due in Nine Years

+ References

No definition available.

+ Details

Name:	sgy_OperatingLeasesFutureMinimumPaymentsDueInNineYears
Namespace Prefix:	sgy_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Operating Leases, Future Minimum Payments, Due in Seven Years

+ References

No definition available.

+ Details

Name:	sgy_OperatingLeasesFutureMinimumPaymentsDueInSevenYears
Namespace Prefix:	sgy_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Operating Leases, Future Minimum Payments, Due in Six Years

+ References

No definition available.

+ Details

Name:	sgy_OperatingLeasesFutureMinimumPaymentsDueInSixYears
Namespace Prefix:	sgy_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Operating Leases, Future Minimum Payments, Due in Ten Years

+ References

No definition available.

+ Details

Name:	sgy_OperatingLeasesFutureMinimumPaymentsDueInTenYears
Namespace Prefix:	sgy_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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

- Definition

Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41502-112717

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 10

-Section 55

-Paragraph 40

-Subparagraph (Note 3)

-URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697

+ Details

Name:	us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

Name:	us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

Name:	us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

Name:	us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

Name:	us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant