$SM
SM Energy Co Stock $sm

$sm Overview Financials Valuation SEC Filings Company Website

2012 Q4 Form 10-K Financial Statement

#000089353813000011 Filed on February 21, 2013

Income Statement

Concept	2012 Q4	2011 Q4	2011
Revenue	$440.1M	$404.5M	$1.603B
YoY Change	8.8%	49.26%	46.71%
Cost Of Revenue	$111.2M	$93.20M	$290.1M
YoY Change	19.31%	63.51%	48.69%
Gross Profit	$328.9M	$311.3M	$1.093B
YoY Change	5.65%	45.4%	47.14%
Gross Profit Margin	74.73%	76.96%	68.14%
Selling, General & Admin	$28.40M	$35.60M	$118.5M
YoY Change	-20.22%	12.66%	11.06%
% of Gross Profit	8.63%	11.44%	10.85%
Research & Development	$24.20M	$20.00M	$53.50M
YoY Change	21.0%	-4.76%	-16.28%
% of Gross Profit	7.36%	6.42%	4.9%
Depreciation & Amortization	$204.3M	$167.3M	$511.1M
YoY Change	22.12%	76.48%	52.07%
% of Gross Profit	62.12%	53.74%	46.78%
Operating Expenses	$259.1M	$246.2M	$739.6M
YoY Change	5.24%	56.02%	36.46%
Operating Profit	$69.80M	$65.10M	$384.4M
YoY Change	7.22%	15.63%	13.46%
Interest Expense	-$2.800M	-$59.00M	$45.85M
YoY Change	-95.25%	233.33%	89.49%
% of Operating Profit	-4.01%	-90.63%	11.93%
Other Income/Expense, Net	$0.00	$100.0K	$500.0K
YoY Change	-100.0%	0.0%	66.67%
Pretax Income	-$104.1M	-$192.3M	$339.0M
YoY Change	-45.87%	-428.72%	7.65%
Income Tax	-$37.00M	-$71.60M	$123.6M
% Of Pretax Income			36.46%
Net Earnings	-$67.10M	-$120.7M	$215.4M
YoY Change	-44.41%	-425.34%	9.44%
Net Earnings / Revenue	-15.25%	-29.84%	13.44%
Basic Earnings Per Share			$3.38
Diluted Earnings Per Share	-$1.015M	-$1.886M	$3.19
COMMON SHARES
Basic Shares Outstanding	66.08M shares	63.44M shares	63.76M shares
Diluted Shares Outstanding			67.56M shares

Balance Sheet

Concept	2012 Q4	2011 Q4	2011
SHORT-TERM ASSETS
Cash & Short-Term Investments	$5.900M	$119.2M	$119.2M
YoY Change	-95.05%	2237.25%	2237.25%
Cash & Equivalents	$5.926M	$119.2M	$119.2M
Short-Term Investments
Other Short-Term Assets	$76.50M	$128.0M	$128.0M
YoY Change	-40.23%	30.75%	30.75%
Inventory
Prepaid Expenses
Receivables	$254.8M	$210.4M	$149.4M
Other Receivables	$17.70M	$20.80M	$66.50M
Total Short-Term Assets	$340.6M	$463.2M	$463.2M
YoY Change	-26.48%	68.66%	68.68%
LONG-TERM ASSETS
Property, Plant & Equipment	$3.677B	$3.097B	$3.097B
YoY Change	18.75%	27.22%	27.22%
Goodwill
YoY Change
Intangibles	$10.80M	$7.100M
YoY Change	52.11%	61.36%
Long-Term Investments
YoY Change
Other Assets	$78.53M	$83.38M	$239.1M
YoY Change	-5.81%	396.78%	571.63%
Total Long-Term Assets	$181.8M	$239.1M	$3.336B
YoY Change	-23.99%	571.29%	35.07%
TOTAL ASSETS
Total Short-Term Assets	$340.6M	$463.2M	$463.2M
Total Long-Term Assets	$181.8M	$239.1M	$3.336B
Total Assets	$4.200B	$3.799B	$3.799B
YoY Change	10.54%	38.43%	38.43%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$525.6M	$457.0M
YoY Change	15.01%	9.41%
Accrued Expenses			$420.4M
YoY Change			10.57%
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$541.5M	$505.8M	$505.8M
YoY Change	7.07%	0.75%	0.74%
LONG-TERM LIABILITIES
Long-Term Debt	$1.440B	$985.1M	$985.1M
YoY Change	46.18%	204.32%	204.32%
Other Long-Term Liabilities	$66.36M	$67.85M	$276.9M
YoY Change	-2.2%	290.95%	7.79%
Total Long-Term Liabilities	$2.244B	$1.830B	$1.262B
YoY Change	22.58%	78.78%	117.36%
TOTAL LIABILITIES
Total Short-Term Liabilities	$541.5M	$505.8M	$505.8M
Total Long-Term Liabilities	$2.244B	$1.830B	$1.262B
Total Liabilities	$2.785B	$2.336B	$2.336B
YoY Change	19.22%	53.1%	53.1%
SHAREHOLDERS EQUITY
Retained Earnings	$1.190B	$1.251B
YoY Change	-4.86%	20.06%
Common Stock	$234.3M	$217.6M
YoY Change	7.67%	13.16%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$1.221M	$1.544M
YoY Change	-20.92%	265.01%
Treasury Stock Shares	50.58K shares	81.07K shares
Shareholders Equity	$1.415B	$1.463B	$1.463B
YoY Change
Total Liabilities & Shareholders Equity	$4.200B	$3.799B	$3.799B
YoY Change	10.54%	38.43%	38.43%

Cashflow Statement

Concept	2012 Q4	2011 Q4	2011
OPERATING ACTIVITIES
Net Income	-$67.10M	-$120.7M	$215.4M
YoY Change	-44.41%	-425.34%	9.44%
Depreciation, Depletion And Amortization	$204.3M	$167.3M	$511.1M
YoY Change	22.12%	76.48%	52.07%
Cash From Operating Activities	$268.4M	$270.8M	$760.5M
YoY Change	-0.89%	244.09%	52.99%
INVESTING ACTIVITIES
Capital Expenditures	-$381.0M	-$551.5M	-$1.633B
YoY Change	-30.92%	207.07%	144.37%
Acquisitions
YoY Change
Other Investing Activities	$7.400M	$43.50M	-$3.661M
YoY Change	-82.99%	-20.04%	-188.75%
Cash From Investing Activities	-$373.6M	-$508.0M	-$1.265B
YoY Change	-26.46%	305.75%	249.84%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net			$7.327M
YoY Change			13.77%
Debt Paid & Issued, Net			$0.00
YoY Change
Cash From Financing Activities	111.0M	326.5M	$618.5M
YoY Change	-66.0%	633.71%	-538.35%
NET CHANGE
Cash From Operating Activities	268.4M	270.8M	$760.5M
Cash From Investing Activities	-373.6M	-508.0M	-$1.265B
Cash From Financing Activities	111.0M	326.5M	$618.5M
Net Change In Cash	5.800M	89.30M	$114.1M
YoY Change	-93.51%	-4565.0%	-2148.04%
FREE CASH FLOW
Cash From Operating Activities	$268.4M	$270.8M	$760.5M
Capital Expenditures	-$381.0M	-$551.5M	-$1.633B
Free Cash Flow	$649.4M	$822.3M	$2.394B
YoY Change	-21.03%	218.35%	105.39%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2012Q4	us-gaap	Asset Retirement Obligation Current AssetRetirementObligationCurrent	6200000	USD
CY2011Q4	us-gaap	Asset Retirement Obligation Current AssetRetirementObligationCurrent	7500000	USD
CY2012Q4	us-gaap	Accounts Payable And Accrued Liabilities Current AccountsPayableAndAccruedLiabilitiesCurrent	525627000	USD
CY2011Q4	us-gaap	Accounts Payable And Accrued Liabilities Current AccountsPayableAndAccruedLiabilitiesCurrent	456999000	USD
CY2011Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	210368000	USD
CY2012Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	254805000	USD
CY2012Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-9014000	USD
CY2011Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-4280000	USD
CY2011Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	216966000	USD
CY2012Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	233642000	USD
CY2010	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	26743000	USD
CY2011	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	26824000	USD
CY2012	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	30185000	USD
CY2010	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	13464000	USD
CY2012	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	6769000	USD
CY2011	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	18299000	USD
CY2011	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
CY2012	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	2102000	shares
CY2010	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
CY2012Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	120518000	USD
CY2011Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	95906000	USD
CY2010Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	82849000	USD
CY2011	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	5948000	USD
CY2012	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	4679000	USD
CY2011	us-gaap	Asset Retirement Obligation Cash Paid To Settle AssetRetirementObligationCashPaidToSettle	5849000	USD
CY2010	us-gaap	Asset Retirement Obligation Cash Paid To Settle AssetRetirementObligationCashPaidToSettle	8314000	USD
CY2012	us-gaap	Asset Retirement Obligation Cash Paid To Settle AssetRetirementObligationCashPaidToSettle	2856000	USD
CY2012	us-gaap	Asset Retirement Obligation Liabilities Incurred AssetRetirementObligationLiabilitiesIncurred	13050000	USD
CY2011	us-gaap	Asset Retirement Obligation Liabilities Incurred AssetRetirementObligationLiabilitiesIncurred	5465000	USD
CY2012	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	-8101000	USD
CY2011	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	-8365000	USD
CY2011	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	10009000	USD
CY2012	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	14984000	USD
CY2011Q4	us-gaap	Asset Retirement Obligations Noncurrent AssetRetirementObligationsNoncurrent	87167000	USD
CY2012Q4	us-gaap	Asset Retirement Obligations Noncurrent AssetRetirementObligationsNoncurrent	112912000	USD
CY2012Q4	us-gaap	Assets Assets	4199529000	USD
CY2011Q4	us-gaap	Assets Assets	3798980000	USD
CY2012Q4	us-gaap	Assets Current AssetsCurrent	340564000	USD
CY2011Q4	us-gaap	Assets Current AssetsCurrent	463204000	USD
CY2012Q4	us-gaap	Assets Held For Sale Long Lived AssetsHeldForSaleLongLived	33620000	USD
CY2011Q4	us-gaap	Assets Held For Sale Long Lived AssetsHeldForSaleLongLived	246000	USD
CY2012Q4	us-gaap	Assets Noncurrent AssetsNoncurrent	181768000	USD
CY2011Q4	us-gaap	Assets Noncurrent AssetsNoncurrent	239140000	USD
CY2011	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	214800000	USD
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CY2010	us-gaap	Capitalized Exploratory Well Cost Additions Pending Determination Of Proved Reserves CapitalizedExploratoryWellCostAdditionsPendingDeterminationOfProvedReserves	35862000	USD
CY2011	us-gaap	Capitalized Exploratory Well Cost Additions Pending Determination Of Proved Reserves CapitalizedExploratoryWellCostAdditionsPendingDeterminationOfProvedReserves	15618000	USD
CY2012	us-gaap	Capitalized Exploratory Well Cost Additions Pending Determination Of Proved Reserves CapitalizedExploratoryWellCostAdditionsPendingDeterminationOfProvedReserves	9100000	USD
CY2012Q3	us-gaap	Capitalized Exploratory Well Cost Charged To Expense CapitalizedExploratoryWellCostChargedToExpense	3600000	USD
CY2011	us-gaap	Capitalized Exploratory Well Cost Charged To Expense CapitalizedExploratoryWellCostChargedToExpense	0	USD
CY2010	us-gaap	Capitalized Exploratory Well Cost Charged To Expense CapitalizedExploratoryWellCostChargedToExpense	0	USD
CY2012	us-gaap	Capitalized Exploratory Well Cost Charged To Expense CapitalizedExploratoryWellCostChargedToExpense	-12735000	USD
CY2010Q4	us-gaap	Capitalized Exploratory Well Costs CapitalizedExploratoryWellCosts	35862000	USD
CY2012Q4	us-gaap	Capitalized Exploratory Well Costs CapitalizedExploratoryWellCosts	9100000	USD
CY2011Q4	us-gaap	Capitalized Exploratory Well Costs CapitalizedExploratoryWellCosts	18600000	USD
CY2009Q4	us-gaap	Capitalized Exploratory Well Costs CapitalizedExploratoryWellCosts	34384000	USD
CY2010Q4	us-gaap	Capitalized Exploratory Well Costs That Have Been Capitalized For Period Greater Than One Year CapitalizedExploratoryWellCostsThatHaveBeenCapitalizedForPeriodGreaterThanOneYear	0	USD
CY2011Q4	us-gaap	Capitalized Exploratory Well Costs That Have Been Capitalized For Period Greater Than One Year CapitalizedExploratoryWellCostsThatHaveBeenCapitalizedForPeriodGreaterThanOneYear	2982000	USD
CY2012Q4	us-gaap	Capitalized Exploratory Well Costs That Have Been Capitalized For Period Greater Than One Year CapitalizedExploratoryWellCostsThatHaveBeenCapitalizedForPeriodGreaterThanOneYear	0	USD
CY2012Q4	us-gaap	Capitalized Exploratory Well Costs That Have Been Capitalized For Period Of One Year Or Less CapitalizedExploratoryWellCostsThatHaveBeenCapitalizedForPeriodOfOneYearOrLess	9100000	USD
CY2012Q4	us-gaap	Contractual Obligation Due After Fifth Year ContractualObligationDueAfterFifthYear	469348000	USD
CY2012Q4	us-gaap	Contractual Obligation Due In Fifth Year ContractualObligationDueInFifthYear	101456000	USD
CY2012Q4	us-gaap	Contractual Obligation Due In Fourth Year ContractualObligationDueInFourthYear	102540000	USD
CY2012Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
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CY2011Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	200000000	shares
CY2012Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	200000000	shares
CY2012Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	66245816	shares
CY2011Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	64145482	shares
CY2011Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	64064415	shares
CY2012Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	66195235	shares
CY2011Q4	us-gaap	Common Stock Value CommonStockValue	641000	USD
CY2012Q4	us-gaap	Common Stock Value CommonStockValue	662000	USD
CY2010	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	219309000	USD
CY2010Q4	us-gaap	Capitalized Exploratory Well Costs That Have Been Capitalized For Period Of One Year Or Less CapitalizedExploratoryWellCostsThatHaveBeenCapitalizedForPeriodOfOneYearOrLess	35862000	USD
CY2011Q4	us-gaap	Capitalized Exploratory Well Costs That Have Been Capitalized For Period Of One Year Or Less CapitalizedExploratoryWellCostsThatHaveBeenCapitalizedForPeriodOfOneYearOrLess	15618000	USD
CY2011Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	119194000	USD
CY2012Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	5926000	USD
CY2010Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	5077000	USD
CY2009Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	10649000	USD
CY2011	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	114117000	USD
CY2010	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	-5572000	USD
CY2012	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	-113268000	USD
CY2012Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2011Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2011	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.10
CY2012	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.10
CY2010	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.10
CY2012	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-58983000	USD
CY2011	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	226618000	USD
CY2010	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	22472000	USD
CY2011	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	11202000	USD
CY2012	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-4734000	USD
CY2012Q4	us-gaap	Contractual Obligation ContractualObligation	1012625000	USD
CY2012Q4	us-gaap	Contractual Obligation Due In Next Twelve Months ContractualObligationDueInNextTwelveMonths	127753000	USD
CY2011Q4	us-gaap	Deferred Tax Assets Gross Current DeferredTaxAssetsGrossCurrent	7529000	USD
CY2011Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	92847000	USD
CY2012Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	172205000	USD
CY2011Q4	us-gaap	Deferred Tax Assets Net Current DeferredTaxAssetsNetCurrent	4222000	USD
CY2012Q4	us-gaap	Deferred Tax Assets Net Current DeferredTaxAssetsNetCurrent	8579000	USD
CY2012Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards Domestic DeferredTaxAssetsOperatingLossCarryforwardsDomestic	376600000	USD
CY2012Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards State And Local DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal	361200000	USD
CY2012Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Other DeferredTaxAssetsTaxCreditCarryforwardsOther	252000	USD
CY2012Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Research DeferredTaxAssetsTaxCreditCarryforwardsResearch	5000000	USD
CY2012Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Postretirement Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefits	6849000	USD
CY2012Q4	us-gaap	Contractual Obligation Due In Second Year ContractualObligationDueInSecondYear	111674000	USD
CY2012Q4	us-gaap	Contractual Obligation Due In Third Year ContractualObligationDueInThirdYear	99854000	USD
CY2012Q4	us-gaap	Convertible Debt Noncurrent ConvertibleDebtNoncurrent	0	USD
CY2011Q4	us-gaap	Convertible Debt Noncurrent ConvertibleDebtNoncurrent	285069000	USD
CY2010	us-gaap	Costs And Expenses CostsAndExpenses	754063000	USD
CY2012	us-gaap	Costs And Expenses CostsAndExpenses	1525119000	USD
CY2011	us-gaap	Costs And Expenses CostsAndExpenses	1218934000	USD
CY2011	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	-1757000	USD
CY2010	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	2903000	USD
CY2012	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	0	USD
CY2010	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	639000	USD
CY2011	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	1553000	USD
CY2012	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	370000	USD
CY2011Q4	us-gaap	Deferred Compensation Cashbased Arrangements Liability Classified Noncurrent DeferredCompensationCashbasedArrangementsLiabilityClassifiedNoncurrent	107731000	USD
CY2012Q4	us-gaap	Deferred Compensation Cashbased Arrangements Liability Classified Noncurrent DeferredCompensationCashbasedArrangementsLiabilityClassifiedNoncurrent	78827000	USD
CY2012	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-29638000	USD
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CY2011	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	123789000	USD
CY2011Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	656888000	USD
CY2012Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	701009000	USD
CY2012Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	177520000	USD
CY2011Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	96638000	USD
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CY2011Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	17728000	USD
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CY2011Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	3791000	USD
CY2012Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	5315000	USD
CY2012Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	528804000	USD
CY2011Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	564041000	USD
CY2012Q4	us-gaap	Deferred Tax Liabilities Derivatives DeferredTaxLiabilitiesDerivatives	15942000	USD
CY2011Q4	us-gaap	Deferred Tax Liabilities Derivatives DeferredTaxLiabilitiesDerivatives	13274000	USD
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CY2012Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	6443000	USD
CY2011Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	4129000	USD
CY2011Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	639485000	USD
CY2011Q4	us-gaap	Deferred Tax Liabilities Gross Current DeferredTaxLiabilitiesGrossCurrent	-3307000	USD
CY2011Q4	us-gaap	Deferred Tax Liabilities Noncurrent DeferredTaxLiabilitiesNoncurrent	568263000	USD
CY2012Q4	us-gaap	Deferred Tax Liabilities Noncurrent DeferredTaxLiabilitiesNoncurrent	537383000	USD
CY2012Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	678624000	USD
CY2011Q4	us-gaap	Defined Benefit Plan Accumulated Benefit Obligation DefinedBenefitPlanAccumulatedBenefitObligation	21697000	USD
CY2012Q4	us-gaap	Defined Benefit Plan Accumulated Benefit Obligation DefinedBenefitPlanAccumulatedBenefitObligation	29437000	USD
CY2011Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax	8671000	USD
CY2012Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax	12580000	USD
CY2011Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Net Gains Losses Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax	8501000	USD
CY2012Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Net Gains Losses Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax	12427000	USD
CY2012Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Net Transition Assets Obligations Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetTransitionAssetsObligationsBeforeTax	0	USD
CY2011Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Net Transition Assets Obligations Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetTransitionAssetsObligationsBeforeTax	0	USD
CY2011	us-gaap	Defined Benefit Plan Actual Return On Plan Assets DefinedBenefitPlanActualReturnOnPlanAssets	-176000	USD
CY2012	us-gaap	Defined Benefit Plan Actual Return On Plan Assets DefinedBenefitPlanActualReturnOnPlanAssets	1952000	USD
CY2011	us-gaap	Defined Benefit Plan Actuarial Gain Loss DefinedBenefitPlanActuarialGainLoss	1957000	USD
CY2012	us-gaap	Defined Benefit Plan Actuarial Gain Loss DefinedBenefitPlanActuarialGainLoss	5467000	USD
CY2010	us-gaap	Defined Benefit Plan Amortization Of Gains Losses DefinedBenefitPlanAmortizationOfGainsLosses	-367000	USD
CY2012	us-gaap	Defined Benefit Plan Amortization Of Gains Losses DefinedBenefitPlanAmortizationOfGainsLosses	-754000	USD
CY2011	us-gaap	Defined Benefit Plan Amortization Of Gains Losses DefinedBenefitPlanAmortizationOfGainsLosses	-405000	USD
CY2011	us-gaap	Defined Benefit Plan Amortization Of Prior Service Cost Credit DefinedBenefitPlanAmortizationOfPriorServiceCostCredit	0	USD
CY2012	us-gaap	Defined Benefit Plan Amortization Of Prior Service Cost Credit DefinedBenefitPlanAmortizationOfPriorServiceCostCredit	17000	USD
CY2010	us-gaap	Defined Benefit Plan Amortization Of Prior Service Cost Credit DefinedBenefitPlanAmortizationOfPriorServiceCostCredit	0	USD
CY2011	us-gaap	Defined Benefit Plan Amounts Recognized In Other Comprehensive Income Net Prior Service Cost Credit Before Tax DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax	170000	USD
CY2012	us-gaap	Defined Benefit Plan Amounts Recognized In Other Comprehensive Income Net Prior Service Cost Credit Before Tax DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax	153000	USD
CY2012	us-gaap	Defined Benefit Plan Amounts That Will Be Amortized From Accumulated Other Comprehensive Income Loss In Next Fiscal Year DefinedBenefitPlanAmountsThatWillBeAmortizedFromAccumulatedOtherComprehensiveIncomeLossInNextFiscalYear	876000	USD
CY2010Q4	us-gaap	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate	0.053
CY2011Q4	us-gaap	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate	0.047
CY2012Q4	us-gaap	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate	0.039
CY2011Q4	us-gaap	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Rate Of Compensation Increase DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease	0.062
CY2010Q4	us-gaap	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Rate Of Compensation Increase DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease	0.062
CY2012Q4	us-gaap	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Rate Of Compensation Increase DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease	0.062
CY2011	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate	0.053
CY2010	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate	0.061
CY2012	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate	0.047
CY2012	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Expected Long Term Return On Assets DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets	0.075
CY2011	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Expected Long Term Return On Assets DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets	0.075
CY2010	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Expected Long Term Return On Assets DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets	0.075
CY2011	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Rate Of Compensation Increase DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease	0.062
CY2012	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Rate Of Compensation Increase DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease	0.062
CY2010	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Rate Of Compensation Increase DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease	0.062
CY2012Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	40237000	USD
CY2011Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	29480000	USD
CY2010Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	23867000	USD
CY2012	us-gaap	Defined Benefit Plan Benefits Paid DefinedBenefitPlanBenefitsPaid	-1018000	USD
CY2011	us-gaap	Defined Benefit Plan Benefits Paid DefinedBenefitPlanBenefitsPaid	-1498000	USD
CY2010	us-gaap	Defined Benefit Plan Contributions By Employer DefinedBenefitPlanContributionsByEmployer	1700000	USD
CY2012	us-gaap	Defined Benefit Plan Contributions By Employer DefinedBenefitPlanContributionsByEmployer	5380000	USD
CY2011	us-gaap	Defined Benefit Plan Contributions By Employer DefinedBenefitPlanContributionsByEmployer	5260000	USD
CY2012Q4	us-gaap	Defined Benefit Plan Estimated Future Employer Contributions In Next Fiscal Year DefinedBenefitPlanEstimatedFutureEmployerContributionsInNextFiscalYear	373000	USD
CY2012Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Five Fiscal Years Thereafter DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter	29884000	USD
CY2012Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Next Twelve Months DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths	2631000	USD
CY2011	us-gaap	Defined Benefit Plan Plan Amendments DefinedBenefitPlanPlanAmendments	170000	USD
CY2012	us-gaap	Defined Benefit Plan Plan Amendments DefinedBenefitPlanPlanAmendments	0	USD
CY2012	us-gaap	Defined Benefit Plan Service Cost DefinedBenefitPlanServiceCost	4934000	USD
CY2011	us-gaap	Defined Benefit Plan Service Cost DefinedBenefitPlanServiceCost	3800000	USD
CY2010	us-gaap	Defined Benefit Plan Service Cost DefinedBenefitPlanServiceCost	3392000	USD
CY2012	us-gaap	Defined Benefit Plan Target Plan Asset Allocations DefinedBenefitPlanTargetPlanAssetAllocations	1.000
CY2012Q4	us-gaap	Defined Benefit Plan Weighted Average Asset Allocations DefinedBenefitPlanWeightedAverageAssetAllocations	1.000
CY2011Q4	us-gaap	Defined Benefit Plan Weighted Average Asset Allocations DefinedBenefitPlanWeightedAverageAssetAllocations	1.000
CY2012Q4	us-gaap	Derivative Assets Current DerivativeAssetsCurrent	37873000	USD
CY2011Q4	us-gaap	Derivative Assets Current DerivativeAssetsCurrent	55813000	USD
CY2012Q4	us-gaap	Derivative Assets Noncurrent DerivativeAssetsNoncurrent	16466000	USD
CY2011Q4	us-gaap	Derivative Assets Noncurrent DerivativeAssetsNoncurrent	31062000	USD
CY2011Q4	us-gaap	Derivative Liabilities Current DerivativeLiabilitiesCurrent	42806000	USD
CY2012Q4	us-gaap	Derivative Liabilities Current DerivativeLiabilitiesCurrent	8999000	USD
CY2012Q4	us-gaap	Derivative Liabilities Noncurrent DerivativeLiabilitiesNoncurrent	6645000	USD
CY2011Q4	us-gaap	Derivative Liabilities Noncurrent DerivativeLiabilitiesNoncurrent	12875000	USD
CY2012Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Five DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive	3885000	USD
CY2012Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Four DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour	3298000	USD
CY2012Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Three DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree	2715000	USD
CY2012Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Two DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo	2385000	USD
CY2010	us-gaap	Defined Benefit Plan Expected Return On Plan Assets DefinedBenefitPlanExpectedReturnOnPlanAssets	638000	USD
CY2012	us-gaap	Defined Benefit Plan Expected Return On Plan Assets DefinedBenefitPlanExpectedReturnOnPlanAssets	1165000	USD
CY2011	us-gaap	Defined Benefit Plan Expected Return On Plan Assets DefinedBenefitPlanExpectedReturnOnPlanAssets	880000	USD
CY2012Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	20254000	USD
CY2011Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	13940000	USD
CY2010Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	10332000	USD
CY2011Q4	us-gaap	Defined Benefit Plan Funded Status Of Plan DefinedBenefitPlanFundedStatusOfPlan	-15540000	USD
CY2012Q4	us-gaap	Defined Benefit Plan Funded Status Of Plan DefinedBenefitPlanFundedStatusOfPlan	-19983000	USD
CY2010	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	1120000	USD
CY2012	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	1374000	USD
CY2011	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	1184000	USD
CY2010	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	4241000	USD
CY2011	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	4509000	USD
CY2012	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	5914000	USD
CY2012	us-gaap	Derivatives Hedge Discontinuances Termination Of Hedging Instrument Or Hedged Item DerivativesHedgeDiscontinuancesTerminationOfHedgingInstrumentOrHedgedItem	<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;text-align:left;text-indent:48px;font-size:11pt;"><font style="font-family:inherit;font-size:11pt;">Prior to January 1, 2011, the Company designated its commodity derivative contracts as cash flow hedges, for which unrealized changes in fair value were recorded to AOCIL, to the extent the hedges were effective.  As of January 1, 2011, the Company elected to de-designate all of its commodity derivative contracts that had been previously designated as cash flow hedges at December 31, 2010. As a result, subsequent to December 31, 2010, the Company recognizes all gains and losses from changes in commodity derivative fair values immediately in earnings rather than deferring any such amounts in AOCIL. The Company had no derivatives designated as cash flow hedges for the years ended </font><font style="font-family:inherit;font-size:11pt;color:#000000;text-decoration:none;">December 31, 2012</font><font style="font-family:inherit;font-size:11pt;">, and </font><font style="font-family:inherit;font-size:11pt;color:#000000;text-decoration:none;">2011</font><font style="font-family:inherit;font-size:11pt;">, and as such, no ineffectiveness was recognized in earnings for the respective periods.</font></div><div style="line-height:120%;text-align:left;text-indent:48px;font-size:11pt;"><font style="font-family:inherit;font-size:11pt;"><br clear="none"/></font></div></div>
CY2012	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	-6511000	USD
CY2010	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	-6297000	USD
CY2011	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	-6382000	USD
CY2011	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.38
CY2012	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.83
CY2010	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.13
CY2010	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.04
CY2011	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.19
CY2012	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.83
CY2010	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.375
CY2012	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.350
CY2011	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.365
CY2011	us-gaap	Entity Wide Revenue Major Customer Percentage EntityWideRevenueMajorCustomerPercentage	0.18
CY2010	us-gaap	Entity Wide Revenue Major Customer Percentage EntityWideRevenueMajorCustomerPercentage	0.11
CY2011	us-gaap	Excess Tax Benefit From Share Based Compensation Financing Activities ExcessTaxBenefitFromShareBasedCompensationFinancingActivities	0	USD
CY2010	us-gaap	Excess Tax Benefit From Share Based Compensation Financing Activities ExcessTaxBenefitFromShareBasedCompensationFinancingActivities	854000	USD
CY2012	us-gaap	Excess Tax Benefit From Share Based Compensation Financing Activities ExcessTaxBenefitFromShareBasedCompensationFinancingActivities	0	USD
CY2012	us-gaap	Excess Tax Benefit From Share Based Compensation Operating Activities ExcessTaxBenefitFromShareBasedCompensationOperatingActivities	0	USD
CY2010	us-gaap	Excess Tax Benefit From Share Based Compensation Operating Activities ExcessTaxBenefitFromShareBasedCompensationOperatingActivities	854000	USD
CY2011	us-gaap	Excess Tax Benefit From Share Based Compensation Operating Activities ExcessTaxBenefitFromShareBasedCompensationOperatingActivities	0	USD
CY2012	us-gaap	Exploration Abandonment And Impairment Expense ExplorationAbandonmentAndImpairmentExpense	20861000	USD
CY2010	us-gaap	Exploration Abandonment And Impairment Expense ExplorationAbandonmentAndImpairmentExpense	289000	USD
CY2011	us-gaap	Exploration Abandonment And Impairment Expense ExplorationAbandonmentAndImpairmentExpense	277000	USD
CY2011	us-gaap	Exploration Expense ExplorationExpense	53537000	USD
CY2012	us-gaap	Exploration Expense ExplorationExpense	90248000	USD
CY2010	us-gaap	Exploration Expense ExplorationExpense	63860000	USD
CY2011Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	0	USD
CY2012Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	2384000	USD
CY2011	us-gaap	Gain Loss On Oil And Gas Hedging Activity GainLossOnOilAndGasHedgingActivity	-20707000	USD
CY2010	us-gaap	Gain Loss On Oil And Gas Hedging Activity GainLossOnOilAndGasHedgingActivity	23465000	USD
CY2012	us-gaap	Gain Loss On Oil And Gas Hedging Activity GainLossOnOilAndGasHedgingActivity	3866000	USD
CY2011	us-gaap	Gain Loss On Sale Of Proved Property GainLossOnSaleOfProvedProperty	220676000	USD
CY2010	us-gaap	Gain Loss On Sale Of Proved Property GainLossOnSaleOfProvedProperty	155277000	USD
CY2012	us-gaap	Gain Loss On Sale Of Proved Property GainLossOnSaleOfProvedProperty	-27018000	USD
CY2012	us-gaap	Gas Gathering Transportation Marketing And Processing Costs GasGatheringTransportationMarketingAndProcessingCosts	47583000	USD
CY2011	us-gaap	Gas Gathering Transportation Marketing And Processing Costs GasGatheringTransportationMarketingAndProcessingCosts	64249000	USD
CY2010	us-gaap	Gas Gathering Transportation Marketing And Processing Costs GasGatheringTransportationMarketingAndProcessingCosts	66726000	USD
CY2011	us-gaap	Gas Gathering Transportation Marketing And Processing Revenue GasGatheringTransportationMarketingAndProcessingRevenue	69898000	USD
CY2012	us-gaap	Gas Gathering Transportation Marketing And Processing Revenue GasGatheringTransportationMarketingAndProcessingRevenue	52808000	USD
CY2010	us-gaap	Gas Gathering Transportation Marketing And Processing Revenue GasGatheringTransportationMarketingAndProcessingRevenue	70110000	USD
CY2011Q4	us-gaap	Gas Imbalance Payable Current And Noncurrent GasImbalancePayableCurrentAndNoncurrent	1100000	USD
CY2012Q4	us-gaap	Gas Imbalance Payable Current And Noncurrent GasImbalancePayableCurrentAndNoncurrent	1300000	USD
CY2010	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	106663000	USD
CY2012	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	119815000	USD
CY2011	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	118526000	USD
CY2010	us-gaap	Impairment Of Leasehold ImpairmentOfLeasehold	1986000	USD
CY2012	us-gaap	Impairment Of Leasehold ImpairmentOfLeasehold	16342000	USD
CY2011	us-gaap	Impairment Of Leasehold ImpairmentOfLeasehold	7367000	USD
CY2010	us-gaap	Impairment Of Oil And Gas Properties ImpairmentOfOilAndGasProperties	6127000	USD
CY2011	us-gaap	Impairment Of Oil And Gas Properties ImpairmentOfOilAndGasProperties	219037000	USD
CY2012	us-gaap	Impairment Of Oil And Gas Properties ImpairmentOfOilAndGasProperties	208923000	USD
CY2010	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	314896000	USD
CY2012	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	-83517000	USD
CY2011	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	339001000	USD
CY2011Q4	us-gaap	Income Tax Examination Liability Refund Adjustment From Settlement With Taxing Authority IncomeTaxExaminationLiabilityRefundAdjustmentFromSettlementWithTaxingAuthority	25000000	USD
CY2011	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	123585000	USD
CY2010	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	118059000	USD
CY2012	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-29268000	USD
CY2012	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	-1524000	USD
CY2010	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	1039000	USD
CY2011	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	-1627000	USD
CY2011	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	-118652000	USD
CY2012	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	29231000	USD
CY2010	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	-110214000	USD
CY2010	us-gaap	Income Tax Reconciliation Nondeductible Expense Depletion IncomeTaxReconciliationNondeductibleExpenseDepletion	266000	USD
CY2012	us-gaap	Income Tax Reconciliation Nondeductible Expense Depletion IncomeTaxReconciliationNondeductibleExpenseDepletion	210000	USD
CY2011	us-gaap	Income Tax Reconciliation Nondeductible Expense Depletion IncomeTaxReconciliationNondeductibleExpenseDepletion	341000	USD
CY2011	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-1705000	USD
CY2010	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-1400000	USD
CY2012	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-611000	USD
CY2010	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	-7750000	USD
CY2011	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	-6458000	USD
CY2012	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	992000	USD
CY2012	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	-970000	USD
CY2010	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	0	USD
CY2011	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	-4516000	USD
CY2010	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	25578000	USD
CY2011	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	4046000	USD
CY2012	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	1389000	USD
CY2012Q4	us-gaap	Income Taxes Receivable IncomeTaxesReceivable	3364000	USD
CY2011Q4	us-gaap	Income Taxes Receivable IncomeTaxesReceivable	5581000	USD
CY2011	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	-18073000	USD
CY2010	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	53198000	USD
CY2012	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	31136000	USD
CY2010	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	47153000	USD
CY2011	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	41998000	USD
CY2012	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	21389000	USD
CY2011	us-gaap	Increase Decrease In Income Taxes Receivable IncreaseDecreaseInIncomeTaxesReceivable	-2901000	USD
CY2012	us-gaap	Increase Decrease In Income Taxes Receivable IncreaseDecreaseInIncomeTaxesReceivable	-2217000	USD
CY2010	us-gaap	Increase Decrease In Income Taxes Receivable IncreaseDecreaseInIncomeTaxesReceivable	-24291000	USD
CY2011	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	-16376000	USD
CY2010	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	35363000	USD
CY2012	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	1484000	USD
CY2010	us-gaap	Incremental Common Shares Attributable To Conversion Of Debt Securities IncrementalCommonSharesAttributableToConversionOfDebtSecurities	0	shares
CY2012	us-gaap	Incremental Common Shares Attributable To Conversion Of Debt Securities IncrementalCommonSharesAttributableToConversionOfDebtSecurities	0	shares
CY2011	us-gaap	Incremental Common Shares Attributable To Conversion Of Debt Securities IncrementalCommonSharesAttributableToConversionOfDebtSecurities	1217000	shares
CY2011	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	2592000	shares
CY2010	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	1720000	shares
CY2012	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	0	shares
CY2011Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	7100000	USD
CY2012Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	10800000	USD
CY2012	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	12100000	USD
CY2010	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	4300000	USD
CY2011	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	10800000	USD
CY2011	us-gaap	Interest Expense InterestExpense	45849000	USD
CY2012	us-gaap	Interest Expense InterestExpense	63720000	USD
CY2010	us-gaap	Interest Expense InterestExpense	24196000	USD
CY2012	us-gaap	Interest Income Operating InterestIncomeOperating	220000	USD
CY2011	us-gaap	Interest Income Operating InterestIncomeOperating	466000	USD
CY2010	us-gaap	Interest Income Operating InterestIncomeOperating	321000	USD
CY2011	us-gaap	Interest Paid InterestPaid	-22133000	USD
CY2012	us-gaap	Interest Paid InterestPaid	-51328000	USD
CY2010	us-gaap	Interest Paid InterestPaid	-13340000	USD
CY2011Q4	us-gaap	Inventory Raw Materials InventoryRawMaterials	16537000	USD
CY2012Q4	us-gaap	Inventory Raw Materials InventoryRawMaterials	13444000	USD
CY2012Q4	us-gaap	Inventory Raw Materials And Supplies Net Of Reserves InventoryRawMaterialsAndSuppliesNetOfReserves	13400000	USD
CY2011Q4	us-gaap	Inventory Raw Materials And Supplies Net Of Reserves InventoryRawMaterialsAndSuppliesNetOfReserves	16500000	USD
CY2011Q4	us-gaap	Land Land	1548000	USD
CY2012Q4	us-gaap	Land Land	1845000	USD
CY2010	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	2700000	USD
CY2012	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	5400000	USD
CY2011	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	3700000	USD
CY2011Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	3798980000	USD
CY2012Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	4199529000	USD
CY2012Q4	us-gaap	Liabilities Current LiabilitiesCurrent	541546000	USD
CY2011Q4	us-gaap	Liabilities Current LiabilitiesCurrent	505805000	USD
CY2012Q4	us-gaap	Liabilities Noncurrent LiabilitiesNoncurrent	2243517000	USD
CY2011Q4	us-gaap	Liabilities Noncurrent LiabilitiesNoncurrent	1830235000	USD
CY2012Q4	us-gaap	Line Of Credit Facility Amount Outstanding LineOfCreditFacilityAmountOutstanding	340000000	USD
CY2011Q4	us-gaap	Line Of Credit Facility Amount Outstanding LineOfCreditFacilityAmountOutstanding	0	USD
CY2011	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	618495000	USD
CY2010	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-141096000	USD
CY2012	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	422096000	USD
CY2010	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-361573000	USD
CY2011	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-1264910000	USD
CY2012	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-1457333000	USD
CY2012	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	921969000	USD
CY2011	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	760532000	USD
CY2010	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	497097000	USD
CY2010	us-gaap	Oil And Gas Production Expense OilAndGasProductionExpense	195075000	USD
CY2011	us-gaap	Oil And Gas Production Expense OilAndGasProductionExpense	290111000	USD
CY2012	us-gaap	Oil And Gas Production Expense OilAndGasProductionExpense	391872000	USD
CY2012Q4	us-gaap	Oil And Gas Property Successful Effort Method Accumulated Depreciation Depletion And Amortization OilAndGasPropertySuccessfulEffortMethodAccumulatedDepreciationDepletionAndAmortization	2376170000	USD
CY2011Q4	us-gaap	Oil And Gas Property Successful Effort Method Accumulated Depreciation Depletion And Amortization OilAndGasPropertySuccessfulEffortMethodAccumulatedDepreciationDepletionAndAmortization	1766445000	USD
CY2012	us-gaap	Oil And Gas Sales Revenue OilAndGasSalesRevenue	1473868000	USD
CY2010	us-gaap	Oil And Gas Sales Revenue OilAndGasSalesRevenue	836288000	USD
CY2011	us-gaap	Oil And Gas Sales Revenue OilAndGasSalesRevenue	1332392000	USD
CY2011	us-gaap	Operating Income Loss OperatingIncomeLoss	384384000	USD
CY2012	us-gaap	Operating Income Loss OperatingIncomeLoss	-20017000	USD
CY2010	us-gaap	Operating Income Loss OperatingIncomeLoss	338771000	USD
CY2011Q4	us-gaap	Operating Loss Carryforwards OperatingLossCarryforwards	23651000	USD
CY2012Q4	us-gaap	Operating Loss Carryforwards OperatingLossCarryforwards	113522000	USD
CY2012Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	78529000	USD
CY2011Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	83375000	USD
CY2010	us-gaap	Other Comprehensive Income Defined Benefit Plan Net Prior Service Cost Credit Arising During Period Before Tax OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax	0	USD
CY2011	us-gaap	Other Comprehensive Income Defined Benefit Plan Net Prior Service Cost Credit Arising During Period Before Tax OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax	-170000	USD
CY2012	us-gaap	Other Comprehensive Income Defined Benefit Plan Net Prior Service Cost Credit Arising During Period Before Tax OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax	0	USD
CY2011	us-gaap	Other Comprehensive Income Defined Benefit Plans Adjustment Before Tax Portion Attributable To Parent OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPortionAttributableToParent	2779000	USD
CY2010	us-gaap	Other Comprehensive Income Defined Benefit Plans Adjustment Before Tax Portion Attributable To Parent OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPortionAttributableToParent	1570000	USD
CY2012	us-gaap	Other Comprehensive Income Defined Benefit Plans Adjustment Before Tax Portion Attributable To Parent OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPortionAttributableToParent	3909000	USD
CY2011	us-gaap	Other Comprehensive Income Defined Benefit Plans Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent	1795000	USD
CY2012	us-gaap	Other Comprehensive Income Defined Benefit Plans Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent	2470000	USD
CY2010	us-gaap	Other Comprehensive Income Defined Benefit Plans Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent	980000	USD
CY2010	us-gaap	Other Comprehensive Income Defined Benefit Plans Tax Portion Attributable To Parent OtherComprehensiveIncomeDefinedBenefitPlansTaxPortionAttributableToParent	590000	USD
CY2012	us-gaap	Other Comprehensive Income Defined Benefit Plans Tax Portion Attributable To Parent OtherComprehensiveIncomeDefinedBenefitPlansTaxPortionAttributableToParent	1439000	USD
CY2011	us-gaap	Other Comprehensive Income Defined Benefit Plans Tax Portion Attributable To Parent OtherComprehensiveIncomeDefinedBenefitPlansTaxPortionAttributableToParent	984000	USD
CY2012	us-gaap	Other Comprehensive Income Derivatives Qualifying As Hedges Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPortionAttributableToParent	0	USD
CY2011	us-gaap	Other Comprehensive Income Derivatives Qualifying As Hedges Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPortionAttributableToParent	0	USD
CY2010	us-gaap	Other Comprehensive Income Derivatives Qualifying As Hedges Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPortionAttributableToParent	16811000	USD
CY2010	us-gaap	Other Comprehensive Income Derivatives Qualifying As Hedges Tax Portion Attributable To Parent OtherComprehensiveIncomeDerivativesQualifyingAsHedgesTaxPortionAttributableToParent	10093000	USD
CY2012Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	6920000	USD
CY2012Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	66357000	USD
CY2011Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	67853000	USD
CY2011	us-gaap	Other Comprehensive Income Derivatives Qualifying As Hedges Tax Portion Attributable To Parent OtherComprehensiveIncomeDerivativesQualifyingAsHedgesTaxPortionAttributableToParent	0	USD
CY2012	us-gaap	Other Comprehensive Income Derivatives Qualifying As Hedges Tax Portion Attributable To Parent OtherComprehensiveIncomeDerivativesQualifyingAsHedgesTaxPortionAttributableToParent	0	USD
CY2011	us-gaap	Other Comprehensive Income Loss Amortization Pension And Other Postretirement Benefit Plans Net Prior Service Cost Recognized In Net Periodic Benefit Cost Before Tax OtherComprehensiveIncomeLossAmortizationPensionAndOtherPostretirementBenefitPlansNetPriorServiceCostRecognizedInNetPeriodicBenefitCostBeforeTax	0	USD
CY2012	us-gaap	Other Comprehensive Income Loss Amortization Pension And Other Postretirement Benefit Plans Net Prior Service Cost Recognized In Net Periodic Benefit Cost Before Tax OtherComprehensiveIncomeLossAmortizationPensionAndOtherPostretirementBenefitPlansNetPriorServiceCostRecognizedInNetPeriodicBenefitCostBeforeTax	-17000	USD
CY2010	us-gaap	Other Comprehensive Income Loss Amortization Pension And Other Postretirement Benefit Plans Net Prior Service Cost Recognized In Net Periodic Benefit Cost Before Tax OtherComprehensiveIncomeLossAmortizationPensionAndOtherPostretirementBenefitPlansNetPriorServiceCostRecognizedInNetPeriodicBenefitCostBeforeTax	0	USD
CY2012	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Before Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax	0	USD
CY2010	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Before Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax	26904000	USD
CY2011	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Before Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax	0	USD
CY2010	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	22472000	USD
CY2012	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-4734000	USD
CY2011	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	11202000	USD
CY2010	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax	-1570000	USD
CY2011	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax	-2779000	USD
CY2012	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax	-3909000	USD
CY2011	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	-3014000	USD
CY2010	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	-1937000	USD
CY2012	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	-4680000	USD
CY2011	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment On Derivatives Included In Net Income Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeBeforeTax	20707000	USD
CY2012	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment On Derivatives Included In Net Income Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeBeforeTax	-3865000	USD
CY2010	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment On Derivatives Included In Net Income Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeBeforeTax	10608000	USD
CY2011	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment On Derivatives Included In Net Income Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeNetOfTax	12997000	USD
CY2010	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment On Derivatives Included In Net Income Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeNetOfTax	6641000	USD
CY2012	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment On Derivatives Included In Net Income Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeNetOfTax	-2264000	USD
CY2012	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment On Derivatives Included In Net Income Tax OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeTax	-1601000	USD
CY2011	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment On Derivatives Included In Net Income Tax OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeTax	7710000	USD
CY2010	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment On Derivatives Included In Net Income Tax OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeTax	3967000	USD
CY2011	us-gaap	Other Comprehensive Income Reclassification Of Defined Benefit Plans Net Gain Loss Recognized In Net Periodic Benefit Cost Net Of Tax OtherComprehensiveIncomeReclassificationOfDefinedBenefitPlansNetGainLossRecognizedInNetPeriodicBenefitCostNetOfTax	-405000	USD
CY2012	us-gaap	Other Comprehensive Income Reclassification Of Defined Benefit Plans Net Gain Loss Recognized In Net Periodic Benefit Cost Net Of Tax OtherComprehensiveIncomeReclassificationOfDefinedBenefitPlansNetGainLossRecognizedInNetPeriodicBenefitCostNetOfTax	-754000	USD
CY2010	us-gaap	Other Comprehensive Income Reclassification Of Defined Benefit Plans Net Gain Loss Recognized In Net Periodic Benefit Cost Net Of Tax OtherComprehensiveIncomeReclassificationOfDefinedBenefitPlansNetGainLossRecognizedInNetPeriodicBenefitCostNetOfTax	-367000	USD
CY2010	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	16811000	USD
CY2012	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	0	USD
CY2011	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	0	USD
CY2012	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	6993000	USD
CY2011	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	17567000	USD
CY2010	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	3027000	USD
CY2012	us-gaap	Other Labor Related Expenses OtherLaborRelatedExpenses	-28904000	USD
CY2010	us-gaap	Other Labor Related Expenses OtherLaborRelatedExpenses	-34441000	USD
CY2011	us-gaap	Other Labor Related Expenses OtherLaborRelatedExpenses	-25477000	USD
CY2011Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	6000000	USD
CY2012	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-527000	USD
CY2011	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	6027000	USD
CY2010	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	3993000	USD
CY2010	us-gaap	Other Sales Revenue Net OtherSalesRevenueNet	7694000	USD
CY2011	us-gaap	Other Sales Revenue Net OtherSalesRevenueNet	1059000	USD
CY2011	us-gaap	Proceeds From Sale Of Oil And Gas Property And Equipment ProceedsFromSaleOfOilAndGasPropertyAndEquipment	364522000	USD
CY2010	us-gaap	Profit Loss ProfitLoss	196837000	USD
CY2012	us-gaap	Other Sales Revenue Net OtherSalesRevenueNet	1578000	USD
CY2011	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-3661000	USD
CY2012	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-893000	USD
CY2010	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	4125000	USD
CY2010	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	6297000	USD
CY2011	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	6382000	USD
CY2012	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	6511000	USD
CY2011	us-gaap	Payments Of Financing Costs PaymentsOfFinancingCosts	8719000	USD
CY2010	us-gaap	Payments Of Financing Costs PaymentsOfFinancingCosts	0	USD
CY2012	us-gaap	Payments Of Financing Costs PaymentsOfFinancingCosts	0	USD
CY2010	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	2093000	USD
CY2011	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	9973000	USD
CY2012	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	21622000	USD
CY2011	us-gaap	Payments To Acquire Oil And Gas Property And Equipment PaymentsToAcquireOilAndGasPropertyAndEquipment	0	USD
CY2010	us-gaap	Payments To Acquire Oil And Gas Property And Equipment PaymentsToAcquireOilAndGasPropertyAndEquipment	664000	USD
CY2012	us-gaap	Payments To Acquire Oil And Gas Property And Equipment PaymentsToAcquireOilAndGasPropertyAndEquipment	5773000	USD
CY2010	us-gaap	Payments To Explore And Develop Oil And Gas Properties PaymentsToExploreAndDevelopOilAndGasProperties	668288000	USD
CY2011	us-gaap	Payments To Explore And Develop Oil And Gas Properties PaymentsToExploreAndDevelopOilAndGasProperties	1633093000	USD
CY2012	us-gaap	Payments To Explore And Develop Oil And Gas Properties PaymentsToExploreAndDevelopOilAndGasProperties	1507828000	USD
CY2011Q4	us-gaap	Prepaid Expense And Other Assets Current PrepaidExpenseAndOtherAssetsCurrent	68026000	USD
CY2012Q4	us-gaap	Prepaid Expense And Other Assets Current PrepaidExpenseAndOtherAssetsCurrent	30017000	USD
CY2010	us-gaap	Price Risk Cash Flow Hedge Gain Or Loss Reclassified To Earnings Net PriceRiskCashFlowHedgeGainOrLossReclassifiedToEarningsNet	6641000	USD
CY2012	us-gaap	Price Risk Cash Flow Hedge Gain Or Loss Reclassified To Earnings Net PriceRiskCashFlowHedgeGainOrLossReclassifiedToEarningsNet	-2264000	USD
CY2011	us-gaap	Price Risk Cash Flow Hedge Gain Or Loss Reclassified To Earnings Net PriceRiskCashFlowHedgeGainOrLossReclassifiedToEarningsNet	12997000	USD
CY2011Q4	us-gaap	Price Risk Derivatives At Fair Value Net PriceRiskDerivativesAtFairValueNet	31200000	USD
CY2012Q4	us-gaap	Price Risk Derivatives At Fair Value Net PriceRiskDerivativesAtFairValueNet	38700000	USD
CY2012	us-gaap	Proceeds From Income Tax Refunds ProceedsFromIncomeTaxRefunds	22900000	USD
CY2011	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	7327000	USD
CY2012	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	5816000	USD
CY2010	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	6440000	USD
CY2010	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	571559000	USD
CY2012	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	1609000000	USD
CY2011	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	322000000	USD
CY2011	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	0	USD
CY2010	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	0	USD
CY2012	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-225000	USD
CY2012	us-gaap	Proceeds From Sale Of Oil And Gas Property And Equipment ProceedsFromSaleOfOilAndGasPropertyAndEquipment	55375000	USD
CY2010	us-gaap	Proceeds From Sale Of Oil And Gas Property And Equipment ProceedsFromSaleOfOilAndGasPropertyAndEquipment	311504000	USD
CY2012	us-gaap	Profit Loss ProfitLoss	-54249000	USD
CY2011	us-gaap	Profit Loss ProfitLoss	215416000	USD
CY2010Q4	us-gaap	Projects That Have Exploratory Well Costs That Have Been Capitalized For Period Greater Than One Year ProjectsThatHaveExploratoryWellCostsThatHaveBeenCapitalizedForPeriodGreaterThanOneYear	0
CY2012Q4	us-gaap	Projects That Have Exploratory Well Costs That Have Been Capitalized For Period Greater Than One Year ProjectsThatHaveExploratoryWellCostsThatHaveBeenCapitalizedForPeriodGreaterThanOneYear	0
CY2011Q4	us-gaap	Projects That Have Exploratory Well Costs That Have Been Capitalized For Period Greater Than One Year ProjectsThatHaveExploratoryWellCostsThatHaveBeenCapitalizedForPeriodGreaterThanOneYear	2
CY2012	us-gaap	Property Plant And Equipment Estimated Useful Lives PropertyPlantAndEquipmentEstimatedUsefulLives	three to thirty years
CY2012	us-gaap	Property Plant And Equipment Impairment PropertyPlantAndEquipmentImpairment	<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;padding-bottom:16px;text-align:left;font-size:11pt;"><font style="font-family:inherit;font-size:11pt;font-style:italic;">Impairment of Proved and Unproved Properties</font></div><div style="line-height:120%;padding-bottom:16px;text-align:left;text-indent:48px;font-size:11pt;"><font style="font-family:inherit;font-size:11pt;">Proved oil and gas property costs are evaluated for impairment and reduced to fair value, which is based on expected future discounted cash flows, when there is an indication that the carrying costs may not be recoverable. Expected future cash flows are calculated on all developed proved reserves and risk adjusted proved undeveloped, probable, and possible reserves using a discount rate and price forecasts selected by the Company’s management. The discount rate is a rate that management believes is representative of current market conditions. The prices for oil and gas are forecasted based on NYMEX strip pricing, adjusted for basis differentials, for the first </font><font style="font-family:inherit;font-size:11pt;color:#000000;text-decoration:none;">five</font><font style="font-family:inherit;font-size:11pt;"> years, after which a flat terminal price is used for each commodity stream. The prices for NGLs are forecasted using OPIS pricing, adjusted for basis differentials, for as long as the market is actively trading, after which a flat terminal price is used. Future operating costs are also adjusted as deemed appropriate for these estimates.</font><font style="font-family:inherit;font-size:10pt;"> </font><font style="font-family:inherit;font-size:11pt;">An impairment is recorded on unproved property when the Company determines that either the property will not be developed or the carrying value is not realizable.</font></div></div>
CY2011Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	3096636000	USD
CY2012Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	3677197000	USD
CY2012Q4	us-gaap	Property Plant And Equipment Other Net PropertyPlantAndEquipmentOtherNet	153559000	USD
CY2011Q4	us-gaap	Property Plant And Equipment Other Net PropertyPlantAndEquipmentOtherNet	71369000	USD
CY2012Q4	us-gaap	Property Plant And Equipment Salvage Value PropertyPlantAndEquipmentSalvageValue	64400000	USD
CY2011Q4	us-gaap	Property Plant And Equipment Salvage Value PropertyPlantAndEquipmentSalvageValue	64100000	USD
CY2012Q4	us-gaap	Proved Oil And Gas Property Successful Effort Method ProvedOilAndGasPropertySuccessfulEffortMethod	5401684000	USD
CY2011Q4	us-gaap	Proved Oil And Gas Property Successful Effort Method ProvedOilAndGasPropertySuccessfulEffortMethod	4378987000	USD
CY2011	us-gaap	Reclassification To Well Facilities And Equipment Based On Determination Of Proved Reserves ReclassificationToWellFacilitiesAndEquipmentBasedOnDeterminationOfProvedReserves	-32880000	USD
CY2012	us-gaap	Reclassification To Well Facilities And Equipment Based On Determination Of Proved Reserves ReclassificationToWellFacilitiesAndEquipmentBasedOnDeterminationOfProvedReserves	-5865000	USD
CY2010	us-gaap	Reclassification To Well Facilities And Equipment Based On Determination Of Proved Reserves ReclassificationToWellFacilitiesAndEquipmentBasedOnDeterminationOfProvedReserves	-34384000	USD
CY2012	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	1269000000	USD
CY2011	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	370000000	USD
CY2010	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	711559000	USD
CY2010	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	0	USD
CY2012	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	287500000	USD
CY2011	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	0	USD
CY2011Q4	us-gaap	Restricted Cash And Cash Equivalents Noncurrent RestrictedCashAndCashEquivalentsNoncurrent	124703000	USD
CY2012Q4	us-gaap	Restricted Cash And Cash Equivalents Noncurrent RestrictedCashAndCashEquivalentsNoncurrent	86773000	USD
CY2011Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	1251157000	USD
CY2012Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	1190397000	USD
CY2012	us-gaap	Revenues Revenues	1505102000	USD
CY2010	us-gaap	Revenues Revenues	1092834000	USD
CY2011	us-gaap	Revenues Revenues	1603318000	USD
CY2012Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant	1400000	shares
CY2012	us-gaap	Stock Issued During Period Value Conversion Of Convertible Securities StockIssuedDuringPeriodValueConversionOfConvertibleSecurities	2641000	USD
CY2012	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	2776000	USD
CY2010	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	1670000	USD
CY2011	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	2300000	USD
CY2011	us-gaap	Stock Issued During Period Value Other StockIssuedDuringPeriodValueOther	26824000	USD
CY2010	us-gaap	Stock Issued During Period Value Other StockIssuedDuringPeriodValueOther	26743000	USD
CY2012	us-gaap	Stock Issued During Period Value Other StockIssuedDuringPeriodValueOther	30185000	USD
CY2010	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	-2093000	USD
CY2012	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	-21622000	USD
CY2011	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	-9973000	USD
CY2010	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	5624000	USD
CY2012	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	3040000	USD
CY2011	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	5027000	USD
CY2011Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1462940000	USD
CY2012Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1414466000	USD
CY2009Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	973570000	USD
CY2010Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1218526000	USD
CY2012Q4	us-gaap	Tax Credit Carryforward Amount TaxCreditCarryforwardAmount	5271000	USD
CY2011Q4	us-gaap	Tax Credit Carryforward Amount TaxCreditCarryforwardAmount	4301000	USD
CY2011Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	81067	shares
CY2012Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	50581	shares
CY2011Q4	us-gaap	Treasury Stock Value TreasuryStockValue	1544000	USD
CY2012Q4	us-gaap	Treasury Stock Value TreasuryStockValue	1221000	USD
CY2011Q4	us-gaap	Unproved Oil And Gas Property Successful Effort Method UnprovedOilAndGasPropertySuccessfulEffortMethod	120966000	USD
CY2012Q4	us-gaap	Unproved Oil And Gas Property Successful Effort Method UnprovedOilAndGasPropertySuccessfulEffortMethod	175287000	USD
CY2012	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	11366000	USD
CY2011	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	62757000	USD
CY2010	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	-8899000	USD
CY2012	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	0	USD
CY2011	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	1172000	USD
CY2010	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	0	USD
CY2012	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	317000	USD
CY2010	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	244000	USD
CY2011	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	183000	USD
CY2012	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	0	USD
CY2011	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	-201000	USD
CY2010	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	-321000	USD
CY2012Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	2278000	USD
CY2010Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	807000	USD
CY2011Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	1961000	USD
CY2009Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	884000	USD
CY2012	us-gaap	Use Of Estimates UseOfEstimates	<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;padding-bottom:16px;text-align:left;font-size:11pt;"><font style="font-family:inherit;font-size:11pt;font-style:italic;">Use of Estimates in the Preparation of Financial Statements</font></div><div style="line-height:120%;padding-bottom:16px;text-align:left;text-indent:48px;font-size:11pt;"><font style="font-family:inherit;font-size:11pt;">The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of proved oil and gas reserves, assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Estimates of proved oil and gas reserve quantities provide the basis for the calculation of depletion, depreciation, and amortization (“DD&A”), impairment of proved properties, asset retirement obligations, and the Net Profits Interest Bonus Plan (“Net Profits Plan”) liability, each of which represents a significant component of the accompanying consolidated financial statements.</font></div></div>
CY2012	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	0	shares
CY2010	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	1720000	shares
CY2011	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	3809000	shares
CY2011	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	67564000	shares
CY2010	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	64689000	shares
CY2012	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	65138000	shares
CY2011	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	63755000	shares
CY2010	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	62969000	shares
CY2012	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	65138000	shares
CY2012Q4	us-gaap	Wells In Process Of Drilling WellsInProcessOfDrilling	273928000	USD
CY2011Q4	us-gaap	Wells In Process Of Drilling WellsInProcessOfDrilling	273428000	USD
CY2011Q4	sm	A650 Senior Notes Due2021 A650SeniorNotesDue2021	350000000	USD
CY2012Q4	sm	A650 Senior Notes Due2021 A650SeniorNotesDue2021	350000000	USD
CY2012Q4	sm	A650 Senior Notes Due2023 A650SeniorNotesDue2023	400000000	USD
CY2011Q4	sm	A650 Senior Notes Due2023 A650SeniorNotesDue2023	0	USD
CY2011Q4	sm	A6625 Senior Notes Due2019 A6625SeniorNotesDue2019	350000000	USD
CY2012Q4	sm	A6625 Senior Notes Due2019 A6625SeniorNotesDue2019	350000000	USD
CY2012Q4	sm	Asset Retirement Obligations Assets Held For Sale Noncurrent AssetRetirementObligationsAssetsHeldForSaleNoncurrent	1393000	USD
CY2011Q4	sm	Asset Retirement Obligations Assets Held For Sale Noncurrent AssetRetirementObligationsAssetsHeldForSaleNoncurrent	1277000	USD
CY2012	sm	Assets Held For Sale Reasonably Certain Period For Sale AssetsHeldForSaleReasonablyCertainPeriodForSale	1
CY2012	sm	Cash Settlement Gain Loss On Derivative Instruments CashSettlementGainLossOnDerivativeInstruments	-44264000	USD
CY2011	sm	Cash Settlement Gain Loss On Derivative Instruments CashSettlementGainLossOnDerivativeInstruments	25671000	USD
CY2012Q4	sm	Deferred Tax Assets Net Profits Plan Liability DeferredTaxAssetsNetProfitsPlanLiability	29233000	USD
CY2011Q4	sm	Deferred Tax Assets Net Profits Plan Liability DeferredTaxAssetsNetProfitsPlanLiability	40148000	USD
CY2011Q4	sm	Deferred Tax Assets Other Long Term Liabilities DeferredTaxAssetsOtherLongTermLiabilities	4908000	USD
CY2012Q4	sm	Deferred Tax Assets Other Long Term Liabilities DeferredTaxAssetsOtherLongTermLiabilities	4619000	USD
CY2011Q4	sm	Defined Benefit Plan Accumulated Unfunded Benefit Obligation DefinedBenefitPlanAccumulatedUnfundedBenefitObligation	7757000	USD
CY2012Q4	sm	Defined Benefit Plan Accumulated Unfunded Benefit Obligation DefinedBenefitPlanAccumulatedUnfundedBenefitObligation	9183000	USD
CY2012Q4	sm	Defined Benefit Plan Annual Vesting Increment DefinedBenefitPlanAnnualVestingIncrement	0.20
CY2012	sm	Defined Benefit Plan Benefits Paid Qualified Pension Plan DefinedBenefitPlanBenefitsPaidQualifiedPensionPlan	-1018000	USD
CY2010	sm	Defined Benefit Plan Benefits Paid Qualified Pension Plan DefinedBenefitPlanBenefitsPaidQualifiedPensionPlan	-1700000	USD
CY2011	sm	Defined Benefit Plan Benefits Paid Qualified Pension Plan DefinedBenefitPlanBenefitsPaidQualifiedPensionPlan	-1476000	USD
CY2011	sm	Defined Benefit Plan Investment Threshold Bonds DefinedBenefitPlanInvestmentThresholdBonds	0.80
CY2012Q4	sm	Defined Benefit Plan Percent Vested After Two Years Of Service DefinedBenefitPlanPercentVestedAfterTwoYearsOfService	0.40
CY2012Q4	sm	Defined Benefit Plan Years Of Service Required For Initial Vesting DefinedBenefitPlanYearsOfServiceRequiredForInitialVesting	2
CY2010	sm	Depletion Depreciation Amortization And Asset Retirement Obligation Liability Accretion DepletionDepreciationAmortizationAndAssetRetirementObligationLiabilityAccretion	336141000	USD
CY2011	sm	Depletion Depreciation Amortization And Asset Retirement Obligation Liability Accretion DepletionDepreciationAmortizationAndAssetRetirementObligationLiabilityAccretion	511103000	USD
CY2012	sm	Depletion Depreciation Amortization And Asset Retirement Obligation Liability Accretion DepletionDepreciationAmortizationAndAssetRetirementObligationLiabilityAccretion	727877000	USD
CY2012	sm	Depletion Depreciation Amortization And Asset Retirement Obligation Liability Accretion Cash Flow Impact DepletionDepreciationAmortizationAndAssetRetirementObligationLiabilityAccretionCashFlowImpact	727877000	USD
CY2010	sm	Depletion Depreciation Amortization And Asset Retirement Obligation Liability Accretion Cash Flow Impact DepletionDepreciationAmortizationAndAssetRetirementObligationLiabilityAccretionCashFlowImpact	336141000	USD
CY2011	sm	Depletion Depreciation Amortization And Asset Retirement Obligation Liability Accretion Cash Flow Impact DepletionDepreciationAmortizationAndAssetRetirementObligationLiabilityAccretionCashFlowImpact	511103000	USD
CY2012Q4	sm	Discount Rate Used For Fair Value Of Oil And Gas Properties DiscountRateUsedForFairValueOfOilAndGasProperties	0.12
CY2010	sm	Employee Service Share Bassed Compensation Cash Received From Exercise All Grant Types EmployeeServiceShareBassedCompensationCashReceivedFromExerciseAllGrantTypes	4800000	USD
CY2011	sm	Employee Service Share Bassed Compensation Cash Received From Exercise All Grant Types EmployeeServiceShareBassedCompensationCashReceivedFromExerciseAllGrantTypes	5000000	USD
CY2012	sm	Employee Service Share Bassed Compensation Cash Received From Exercise All Grant Types EmployeeServiceShareBassedCompensationCashReceivedFromExerciseAllGrantTypes	3000000	USD
CY2011Q4	sm	Gas Balancing Receivable GasBalancingReceivable	1900000	USD
CY2012Q4	sm	Gas Balancing Receivable GasBalancingReceivable	1700000	USD
CY2012	sm	Impact Of Issuance Of One Performance Share Award On Available Shares Under Equity Incentive Plan ImpactOfIssuanceOfOnePerformanceShareAwardOnAvailableSharesUnderEquityIncentivePlan	2.86	shares
CY2012	sm	Impact Outright Issuance Of One Share Has On Number Of Available Shares ImpactOutrightIssuanceOfOneShareHasOnNumberOfAvailableShares	1.43	shares
CY2012	sm	Number Of Counterparties Downgraded NumberOfCounterpartiesDowngraded	2
CY2012Q4	sm	Number Of Derivative Counterparties NumberOfDerivativeCounterparties	10
CY2012	sm	Number Of Major Customers NumberOfMajorCustomers	2
CY2012Q4	sm	Pension And Other Post Retirement Benefit Plans Gain Loss Amortization Threshold PensionAndOtherPostRetirementBenefitPlansGainLossAmortizationThreshold	0.10
CY2012	sm	Period Of New York Mercantile Exchange Strip Pricing Used For Price Forecast PeriodOfNewYorkMercantileExchangeStripPricingUsedForPriceForecast	5
CY2010	sm	Proceeds From Debt Issuance Net Of Issuance Costs650 Senior Notes Due2021 ProceedsFromDebtIssuanceNetOfIssuanceCosts650SeniorNotesDue2021	0	USD
CY2012	sm	Proceeds From Debt Issuance Net Of Issuance Costs650 Senior Notes Due2021 ProceedsFromDebtIssuanceNetOfIssuanceCosts650SeniorNotesDue2021	0	USD
CY2011	sm	Proceeds From Debt Issuance Net Of Issuance Costs650 Senior Notes Due2021 ProceedsFromDebtIssuanceNetOfIssuanceCosts650SeniorNotesDue2021	343120000	USD
CY2011	sm	Proceeds From Debt Issuance Net Of Issuance Costs650 Senior Notes Due2023 ProceedsFromDebtIssuanceNetOfIssuanceCosts650SeniorNotesDue2023	0	USD
CY2010	sm	Proceeds From Debt Issuance Net Of Issuance Costs650 Senior Notes Due2023 ProceedsFromDebtIssuanceNetOfIssuanceCosts650SeniorNotesDue2023	0	USD
CY2012	sm	Proceeds From Debt Issuance Net Of Issuance Costs650 Senior Notes Due2023 ProceedsFromDebtIssuanceNetOfIssuanceCosts650SeniorNotesDue2023	392138000	USD
CY2012	sm	Proceeds From Debt Issuance Net Of Issuance Costs6625 Senior Notes ProceedsFromDebtIssuanceNetOfIssuanceCosts6625SeniorNotes	0	USD
CY2011	sm	Proceeds From Debt Issuance Net Of Issuance Costs6625 Senior Notes ProceedsFromDebtIssuanceNetOfIssuanceCosts6625SeniorNotes	341122000	USD
CY2010	sm	Proceeds From Debt Issuance Net Of Issuance Costs6625 Senior Notes ProceedsFromDebtIssuanceNetOfIssuanceCosts6625SeniorNotes	0	USD
CY2012Q4	sm	Revenue Receipt Days After Sale High End Of Range RevenueReceiptDaysAfterSaleHighEndOfRange	90
CY2012Q4	sm	Revenue Receipt Days After Sale Low End Of Range RevenueReceiptDaysAfterSaleLowEndOfRange	30
CY2012	sm	Unrealized And Realized Derivative Gain Loss UnrealizedAndRealizedDerivativeGainLoss	55630000	USD
CY2010	sm	Unrealized And Realized Derivative Gain Loss UnrealizedAndRealizedDerivativeGainLoss	-8899000	USD
CY2011	sm	Unrealized And Realized Derivative Gain Loss UnrealizedAndRealizedDerivativeGainLoss	37086000	USD
CY2012Q4	sm	Unrecognized Tax Benefits Exercise Of Stock Awards UnrecognizedTaxBenefitsExerciseOfStockAwards	93400000	USD
CY2012	dei	Amendment Flag AmendmentFlag	false
CY2012	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2012	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2012	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2012
CY2012	dei	Document Period End Date DocumentPeriodEndDate	2012-12-31
CY2012	dei	Document Type DocumentType	10-K
CY2012	dei	Entity Central Index Key EntityCentralIndexKey	0000893538
CY2013Q1	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	66205901	shares
CY2012	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2012	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2012Q2	dei	Entity Public Float EntityPublicFloat	3171827251	USD
CY2012	dei	Entity Registrant Name EntityRegistrantName	SM Energy Co
CY2012	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2012	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes

Files In Submission

Name	View Source	Status
0000893538-13-000011-index-headers.html	Edgar Link	pending
0000893538-13-000011-index.html	Edgar Link	pending
0000893538-13-000011.txt	Edgar Link	pending
0000893538-13-000011-xbrl.zip	Edgar Link	pending
exhibit1027-summaryofcompe.htm	Edgar Link	pending
exhibit121-ratioofearnings.htm	Edgar Link	pending
exhibit211-subsidiaries1.htm	Edgar Link	pending
exhibit231-consentofpublic.htm	Edgar Link	pending
exhibit232-consentofindepe.htm	Edgar Link	pending
exhibit311-certificationtb.htm	Edgar Link	pending
exhibit312-certificationwp.htm	Edgar Link	pending
exhibit321-906ceritificati.htm	Edgar Link	pending
exhibit991-ryderscottaudit.htm	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
Financial_Report.xls	Edgar Link	pending
performancegraph.jpg	Edgar Link	pending
R1.htm	Edgar Link	pending
R10.htm	Edgar Link	pending
R11.htm	Edgar Link	pending
R12.htm	Edgar Link	pending
R13.htm	Edgar Link	pending
R14.htm	Edgar Link	pending
R15.htm	Edgar Link	pending
R16.htm	Edgar Link	pending
R17.htm	Edgar Link	pending
R18.htm	Edgar Link	pending
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R2.htm	Edgar Link	pending
R20.htm	Edgar Link	pending
R21.htm	Edgar Link	pending
R22.htm	Edgar Link	pending
R23.htm	Edgar Link	pending
R24.htm	Edgar Link	pending
R25.htm	Edgar Link	pending
R26.htm	Edgar Link	pending
R27.htm	Edgar Link	pending
R28.htm	Edgar Link	pending
R29.htm	Edgar Link	pending
R3.htm	Edgar Link	pending
R30.htm	Edgar Link	pending
R31.htm	Edgar Link	pending
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R34.htm	Edgar Link	pending
R35.htm	Edgar Link	pending
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R4.htm	Edgar Link	pending
R40.htm	Edgar Link	pending
R41.htm	Edgar Link	pending
R42.htm	Edgar Link	pending
R43.htm	Edgar Link	pending
R44.htm	Edgar Link	pending
R45.htm	Edgar Link	pending
R46.htm	Edgar Link	pending
R47.htm	Edgar Link	pending
R48.htm	Edgar Link	pending
R49.htm	Edgar Link	pending
R5.htm	Edgar Link	pending
R50.htm	Edgar Link	pending
R51.htm	Edgar Link	pending
R52.htm	Edgar Link	pending
R53.htm	Edgar Link	pending
R54.htm	Edgar Link	pending
R55.htm	Edgar Link	pending
R56.htm	Edgar Link	pending
R57.htm	Edgar Link	pending
R6.htm	Edgar Link	pending
R7.htm	Edgar Link	pending
R8.htm	Edgar Link	pending
R9.htm	Edgar Link	pending
report.css	Edgar Link	pending
ryder_scotta.jpg	Edgar Link	pending
seala01.jpg	Edgar Link	pending
Show.js	Edgar Link	pending
sm-20121231.xml	Edgar Link	completed
sm-20121231.xsd	Edgar Link	pending
sm-20121231x10k.htm	Edgar Link	pending
sm-20121231_cal.xml	Edgar Link	unprocessable
sm-20121231_def.xml	Edgar Link	unprocessable
sm-20121231_lab.xml	Edgar Link	unprocessable
sm-20121231_pre.xml	Edgar Link	unprocessable

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$SM
SM Energy Co Stock $sm

2012 Q4 Form 10-K Financial Statement

#000089353813000011 Filed on February 21, 2013

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$SM SM Energy Co Stock $sm

2012 Q4 Form 10-K Financial Statement

#000089353813000011 Filed on February 21, 2013

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$SM
SM Energy Co Stock $sm