Annual report pursuant to Section 13 and 15(d)

Consolidated Balance Sheets (Parenthetical)

v2.4.1.9
Consolidated Balance Sheets (Parenthetical) (USD $)
In Thousands, except Share data, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Statement of Financial Position [Abstract]    
Capitalized costs of oil and natural gas properties excluded from amortization $ 1,465,538us-gaap_CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationCumulative $ 1,020,835us-gaap_CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationCumulative
Equity investments attributable to fair value option $ 0us-gaap_InvestmentsFairValueDisclosure $ 178,708us-gaap_InvestmentsFairValueDisclosure
Preferred stock, par value (usd per share) $ 0.01us-gaap_PreferredStockParOrStatedValuePerShare $ 0.01us-gaap_PreferredStockParOrStatedValuePerShare
Preferred stock, shares authorized (shares) 5,000,000us-gaap_PreferredStockSharesAuthorized 5,000,000us-gaap_PreferredStockSharesAuthorized
Temporary Equity, Shares Authorized (shares) 30,000us-gaap_TemporaryEquitySharesAuthorized 30,000us-gaap_TemporaryEquitySharesAuthorized
Preferred stock dividend rate 12.00%us-gaap_PreferredStockDividendRatePercentage 12.00%us-gaap_PreferredStockDividendRatePercentage
Preferred stock Series A, issued (shares) 0us-gaap_PreferredStockSharesIssued 0us-gaap_PreferredStockSharesIssued
Preferred stock Series A, outstanding (shares) 0us-gaap_PreferredStockSharesOutstanding 0us-gaap_PreferredStockSharesOutstanding
Common stock, par value (usd per share) $ 0.01us-gaap_CommonStockParOrStatedValuePerShare $ 0.01us-gaap_CommonStockParOrStatedValuePerShare
Common Stock, Shares Authorized (shares) 200,000,000us-gaap_CommonStockSharesAuthorized 200,000,000us-gaap_CommonStockSharesAuthorized
Common Stock, Shares, Issued (shares) 85,655,438us-gaap_CommonStockSharesIssued 85,177,532us-gaap_CommonStockSharesIssued
Common Stock, Shares, Outstanding (shares) 85,655,438us-gaap_CommonStockSharesOutstanding 85,177,532us-gaap_CommonStockSharesOutstanding