Supplemental Information on Oil and Natural Gas Operations - Unaudited - Net Costs Incurred on Unevaluated Properties (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Extractive Industries [Abstract]
Acquisition costs evaluated during the year	$ (42,384)sgy_AcquisitionCostsEvaluatedDuringYear	$ 30,271sgy_AcquisitionCostsEvaluatedDuringYear	$ 9,739sgy_AcquisitionCostsEvaluatedDuringYear
Exploration costs evaluated during the year	(186,308)sgy_ExplorationCostsEvaluatedDuringYear	188,830sgy_ExplorationCostsEvaluatedDuringYear	(1,209)sgy_ExplorationCostsEvaluatedDuringYear
Capitalized interest costs evaluated during the year	45,722	46,860	37,656
Total costs incurred during the year, net of divestitures	$ (182,970)sgy_NetCostsEvaluated	$ 265,961sgy_NetCostsEvaluated	$ 46,186sgy_NetCostsEvaluated

The portion of capitalized costs of identifying areas that may warrant examination and in examining specific areas that are considered to have prospects of containing oil and gas reserves (including costs of drilling exploratory wells and exploratory-type stratigraphic test wells), that was previously unevaluated, but is evaluated during the current reporting period.

No definition available.

Name:	sgy_ExplorationCostsEvaluatedDuringYear
Namespace Prefix:	sgy_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration