Share Repurchase Program - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Sep. 24, 2007
Text Block [Abstract]
Stock repurchase program authorized aggregate amount		$ 100,000
Stock repurchase program total cost	$ 7,071
Stock repurchase program average price	$ 23.57sgy_StockRepurchaseProgramAveragePrice
Share repurchased under share repurchase program	300,000

Total cost of shares repurchased divided by the total number of shares repurchased under a stock repurchase program.

No definition available.

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Namespace Prefix:	sgy_
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Balance Type:	na
Period Type:	duration

- Definition

Number of shares that have been repurchased and retired during the period.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5

+ Details

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

- Definition

Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital).

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of stock repurchase plan authorized.

+ References

No definition available.

+ Details

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

- Details

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