CONSOLIDATED STATEMENT OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
OPERATING REVENUES
Natural gas	$ 1,590,625us-gaap_NaturalGasProductionRevenue	$ 1,405,262us-gaap_NaturalGasProductionRevenue	$ 934,134us-gaap_NaturalGasProductionRevenue
Crude oil and condensate	313,889us-gaap_OilAndCondensateRevenue	291,418us-gaap_OilAndCondensateRevenue	227,933us-gaap_OilAndCondensateRevenue
Gain (loss) on derivative instruments	219,319us-gaap_GainLossOnSaleOfDerivatives	0us-gaap_GainLossOnSaleOfDerivatives	(494)us-gaap_GainLossOnSaleOfDerivatives
Brokered natural gas	34,416cog_BrokeredNaturalGasRevenue	36,450cog_BrokeredNaturalGasRevenue	34,005cog_BrokeredNaturalGasRevenue
Other	14,762us-gaap_OtherSalesRevenueNet	13,148us-gaap_OtherSalesRevenueNet	8,968us-gaap_OtherSalesRevenueNet
TOTAL OPERATING REVENUES	2,173,011us-gaap_Revenues	1,746,278us-gaap_Revenues	1,204,546us-gaap_Revenues
OPERATING EXPENSES
Direct operations	145,529us-gaap_DirectOperatingCosts	140,856us-gaap_DirectOperatingCosts	118,243us-gaap_DirectOperatingCosts
Transportation and gathering	349,321	229,489	143,309
Brokered natural gas cost	30,030cog_BrokeredNaturalGasCosts	29,936cog_BrokeredNaturalGasCosts	28,502cog_BrokeredNaturalGasCosts
Taxes other than income	47,012	43,045	48,874
Exploration	28,746us-gaap_ExplorationExpense	18,165us-gaap_ExplorationExpense	37,476us-gaap_ExplorationExpense
Depreciation, depletion and amortization	632,760	651,052	451,405
Impairment of oil and gas properties	771,037us-gaap_ImpairmentOfOilAndGasProperties	0us-gaap_ImpairmentOfOilAndGasProperties	0us-gaap_ImpairmentOfOilAndGasProperties
General and administrative	82,590us-gaap_GeneralAndAdministrativeExpense	104,606us-gaap_GeneralAndAdministrativeExpense	121,239us-gaap_GeneralAndAdministrativeExpense
TOTAL OPERATING EXPENSES	2,087,025us-gaap_OperatingExpenses	1,217,149us-gaap_OperatingExpenses	949,048us-gaap_OperatingExpenses
Earnings (loss) on equity method investments	3,080	1,102	53
Gain (loss) on sale of assets	17,120	21,351	50,635
INCOME FROM OPERATIONS	106,186us-gaap_OperatingIncomeLoss	551,582us-gaap_OperatingIncomeLoss	306,186us-gaap_OperatingIncomeLoss
Interest expense	73,785us-gaap_InterestIncomeExpenseNet	66,044us-gaap_InterestIncomeExpenseNet	68,346us-gaap_InterestIncomeExpenseNet
Income before income taxes	32,401	485,538	237,840
Income tax (benefit) expense	(72,067)us-gaap_IncomeTaxExpenseBenefit	205,765us-gaap_IncomeTaxExpenseBenefit	106,110us-gaap_IncomeTaxExpenseBenefit
NET INCOME	$ 104,468	$ 279,773	$ 131,730
Earnings per share
Basic (in dollars per share)	$ 0.25us-gaap_EarningsPerShareBasic	$ 0.67us-gaap_EarningsPerShareBasic	$ 0.31us-gaap_EarningsPerShareBasic
Diluted (in dollars per share)	$ 0.25us-gaap_EarningsPerShareDiluted	$ 0.66us-gaap_EarningsPerShareDiluted	$ 0.31us-gaap_EarningsPerShareDiluted
Weighted-average common shares outstanding
Basic (in shares)	415,840	420,188	419,075
Diluted (in shares)	417,601	422,375	421,987
Dividends per common share (in dollars per share)	$ 0.08	$ 0.06	$ 0.04

Costs incurred in brokering natural gas during the reporting period. The entity buys and sells natural gas utilizing separate purchase and sale transactions, typically with separate counterparties, whereby the entity and/or counterparty takes title to the natural gas purchases or sold. The entity recognizes the related revenues and expenses gross and realizes brokered margin as a result of buying and selling natural gas.

No definition available.