Derivatives (Details) (USD $) | 9 Months Ended | | | | | | | | | | | | | | | | | | | | | 0 Months Ended | | 0 Months Ended | | 0 Months Ended | | 0 Months Ended | | 0 Months Ended | | 0 Months Ended | | 0 Months Ended | | 0 Months Ended | | 0 Months Ended | | 0 Months Ended | | 0 Months Ended | | 0 Months Ended | | 0 Months Ended | | 0 Months Ended | | 0 Months Ended | | 0 Months Ended | | 0 Months Ended | |
In Thousands, unless otherwise specified | Sep. 30, 2014 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Sep. 30, 2014 | Sep. 30, 2014 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Sep. 30, 2014 | Sep. 30, 2014 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Sep. 30, 2014 | Sep. 30, 2014 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 | Sep. 30, 2014 | Dec. 31, 2013 | Sep. 30, 2014 |
| Commodity Basis Swap [Member] | Interest Rate Swap [Member] | Interest Rate Swap [Member] | Interest Rate Swap [Member] | Interest Rate Swap [Member] | Interest Rate Swap [Member] | Interest Rate Swap [Member] | Interest Rate Swap [Member] | Interest Rate Swap [Member] | Interest Rate Swap [Member] | Interest Rate Swap [Member] | Interest Rate Swap [Member] | Interest Rate Swap [Member] | Interest Rate Swap [Member] | Interest Rate Swap [Member] | Interest Rate Swap [Member] | Interest Rate Swap [Member] | Interest Rate Swap [Member] | Interest Rate Swap [Member] | Interest Rate Swap [Member] | Interest Rate Swap [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Natural Gas Reserves [Member] | Oil Reserves [Member] | Oil Reserves [Member] | Oil Reserves [Member] | Oil Reserves [Member] | Oil Reserves [Member] | Oil Reserves [Member] | Oil Reserves [Member] | Oil Reserves [Member] | Oil Reserves [Member] | Oil Reserves [Member] | Oil Reserves [Member] | Oil Reserves [Member] | Oil Reserves [Member] | Oil Reserves [Member] | Oil Reserves [Member] | Oil Reserves [Member] | Oil Reserves [Member] | Oil Reserves [Member] | Oil Reserves [Member] | Natural Gas Liquids Reserves [Member] | Natural Gas Liquids Reserves [Member] | Natural Gas Liquids Reserves [Member] | Natural Gas Liquids Reserves [Member] | Natural Gas Liquids Reserves [Member] | Natural Gas Liquids Reserves [Member] |
| item | February2012 To February2015 Term [Member] | February2012 To February2015 Term [Member] | February2012 To February2015 Term [Member] | February2012 To February2015 Term [Member] | February2015 To February2017 Term One [Member] | February2015 To February2017 Term One [Member] | February2015 To February2017 Term One [Member] | February2015 To February2017 Term One [Member] | February2015 To February2017 Term Two [Member] | February2015 To February2017 Term Two [Member] | February2015 To February2017 Term Two [Member] | February2015 To February2017 Term Two [Member] | June2012 To June2015 Term [Member] | June2012 To June2015 Term [Member] | June2012 To June2015 Term [Member] | June2012 To June2015 Term [Member] | June2015 To June2017 Term [Member] | June2015 To June2017 Term [Member] | June2015 To June2017 Term [Member] | June2015 To June2017 Term [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Basis Swap [Member] | Commodity Basis Swap [Member] | Commodity Basis Swap [Member] | Commodity Basis Swap [Member] | Commodity Basis Swap [Member] | Commodity Basis Swap [Member] | Commodity Basis Swap [Member] | Commodity Basis Swap [Member] | Commodity Basis Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Basis Swap [Member] | Commodity Basis Swap [Member] | Commodity Basis Swap [Member] | Commodity Basis Swap [Member] | Commodity Basis Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] | Commodity Price Swap [Member] |
| | | | London Interbank Offered Rate L I B O R [Member] | London Interbank Offered Rate L I B O R [Member] | | | London Interbank Offered Rate L I B O R [Member] | London Interbank Offered Rate L I B O R [Member] | | | London Interbank Offered Rate L I B O R [Member] | London Interbank Offered Rate L I B O R [Member] | | | London Interbank Offered Rate L I B O R [Member] | London Interbank Offered Rate L I B O R [Member] | | | London Interbank Offered Rate L I B O R [Member] | London Interbank Offered Rate L I B O R [Member] | Derivative Contract Maturity In Year2014 [Member] | Derivative Contract Maturity In Year2014 [Member] | Derivative Contract Maturity In Year2014 [Member] | Derivative Contract Maturity In Year2015 [Member] | Derivative Contract Maturity In Year2015 [Member] | Derivative Contract Maturity In Year2015 [Member] | Derivative Contract Maturity In Year2016 [Member] | Derivative Contract Maturity In Year2016 [Member] | Derivative Contract Maturity In Year2016 [Member] | Derivative Contract Maturity In Year2017 [Member] | Derivative Contract Maturity In Year2017 [Member] | Derivative Contract Maturity In Year2017 [Member] | Derivative Contract Maturity In Year2018 [Member] | Derivative Contract Maturity In Year2018 [Member] | Derivative Contract Maturity In Year2014 [Member] | Derivative Contract Maturity In Year2014 [Member] | Derivative Contract Maturity In Year2014 [Member] | Derivative Contract Maturity In Year2015 [Member] | Derivative Contract Maturity In Year2015 [Member] | Derivative Contract Maturity In Year2015 [Member] | Derivative Contract Maturity In Year2016 [Member] | Derivative Contract Maturity In Year2016 [Member] | Derivative Contract Maturity In Year2016 [Member] | Derivative Contract Maturity In Year2014 [Member] | Derivative Contract Maturity In Year2014 [Member] | Derivative Contract Maturity In Year2014 [Member] | Derivative Contract Maturity In Year2015 [Member] | Derivative Contract Maturity In Year2015 [Member] | Derivative Contract Maturity In Year2015 [Member] | Derivative Contract Maturity In Year2016 [Member] | Derivative Contract Maturity In Year2016 [Member] | Derivative Contract Maturity In Year2016 [Member] | Derivative Contract Maturity In Year2017 [Member] | Derivative Contract Maturity In Year2017 [Member] | Derivative Contract Maturity In Year2017 [Member] | Derivative Contract Maturity In Year2018 [Member] | Derivative Contract Maturity In Year2018 [Member] | Derivative Contract Maturity In Year2014 [Member] | Derivative Contract Maturity In Year2014 [Member] | Derivative Contract Maturity In Year2014 [Member] | Derivative Contract Maturity In Year2015 [Member] | Derivative Contract Maturity In Year2015 [Member] | Derivative Contract Maturity In Year2014 [Member] | Derivative Contract Maturity In Year2014 [Member] | Derivative Contract Maturity In Year2014 [Member] | Derivative Contract Maturity In Year2015 [Member] | Derivative Contract Maturity In Year2015 [Member] | Derivative Contract Maturity In Year2015 [Member] |
| | | | | | | | | | | | | | | | | | | | | | MMBTU | MMBTU | | MMBTU | MMBTU | | MMBTU | MMBTU | | MMBTU | MMBTU | | MMBTU | | MMBTU | MMBTU | | MMBTU | MMBTU | | MMBTU | MMBTU | | bbl | bbl | | bbl | bbl | | bbl | bbl | | bbl | bbl | | bbl | | bbl | bbl | | bbl | | bbl | bbl | | bbl | bbl | |
Derivatives | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Number of indices for gas on which floating price is based | 2 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Volume of commodity hedge (in MMBTUs) | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 1,462,599 | 6,077,016 | ' | 5,500,236 | 5,500,236 | ' | 5,433,888 | 5,433,888 | ' | 5,045,760 | 5,045,760 | ' | 2,374,800 | ' | 1,412,369 | 5,876,098 | ' | 5,326,559 | 5,326,559 | ' | 2,877,047 | 2,877,047 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Volume of commodity hedge (in BBLs) | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 204,595 | 723,634 | ' | 757,321 | 561,833 | ' | 610,131 | 397,488 | ' | 266,574 | 198,744 | ' | 65,280 | ' | 95,570 | 410,400 | ' | 397,035 | ' | 66,569 | 183,857 | ' | 236,149 | 147,823 | ' |
Weighted average price of commodity hedge (in dollars per MMBTU/BBL) | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 5.53 | 5.61 | ' | 5.72 | 5.72 | ' | 4.29 | 4.29 | ' | 4.61 | 4.61 | ' | 428 | ' | -0.1521 | -0.1534 | ' | -0.1661 | -0.1661 | ' | -0.1115 | -0.1115 | ' | 95.76 | 96.14 | ' | 93.16 | 93.16 | ' | 86.02 | 87.27 | ' | 85.75 | 86.06 | ' | 86.45 | ' | -1 | -1 | ' | -3.4087 | ' | 34.11 | 34.71 | ' | 34.5 | 34.46 |
Notional Amount | ' | $150,000 | $150,000 | ' | ' | $75,000 | $75,000 | ' | ' | $75,000 | $75,000 | ' | ' | $70,000 | $70,000 | ' | ' | $70,000 | $70,000 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Average % | ' | ' | ' | 0.52% | 0.52% | ' | ' | 1.73% | 1.73% | ' | ' | 1.73% | 1.73% | ' | ' | 0.52% | 0.52% | ' | ' | 1.43% | 1.43% | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |