Derivative Instruments and Hedging Activities (Schedule of Derivative Instruments Outstanding) (Details) (Fixed Price Swaps [Member])	Dec. 31, 2013
January 2014 [Member] | Oil Contract [Member]
Derivative [Line Items]
Daily Average Volume	16,350
Volume	506,850
Average Swap Price	93.11
February 2014 [Member] | Oil Contract [Member]
Derivative [Line Items]
Daily Average Volume	16,350
Volume	457,800
Average Swap Price	93.11
March 2014 [Member] | Oil Contract [Member]
Derivative [Line Items]
Daily Average Volume	16,350
Volume	506,850
Average Swap Price	93.11
April 2014 [Member] | Oil Contract [Member]
Derivative [Line Items]
Daily Average Volume	15,350
Volume	460,500
Average Swap Price	94.27
May 2014 [Member] | Oil Contract [Member]
Derivative [Line Items]
Daily Average Volume	15,350
Volume	475,850
Average Swap Price	94.27
June 2014 [Member] | Oil Contract [Member]
Derivative [Line Items]
Daily Average Volume	15,350
Volume	460,500
Average Swap Price	94.27
July 2014 [Member] | Oil Contract [Member]
Derivative [Line Items]
Daily Average Volume	14,350
Volume	444,850
Average Swap Price	93.56
August 2014 [Member] | Oil Contract [Member]
Derivative [Line Items]
Daily Average Volume	8,750
Volume	271,250
Average Swap Price	94.28
September 2014 [Member] | Oil Contract [Member]
Derivative [Line Items]
Daily Average Volume	8,750
Volume	262,500
Average Swap Price	94.28
October 2014 [Member] | Oil Contract [Member]
Derivative [Line Items]
Daily Average Volume	8,750
Volume	271,250
Average Swap Price	94.28
November 2014 [Member] | Oil Contract [Member]
Derivative [Line Items]
Daily Average Volume	8,750
Volume	262,500
Average Swap Price	94.28
December 2014 [Member] | Oil Contract [Member]
Derivative [Line Items]
Daily Average Volume	11,700
Volume	362,700
Average Swap Price	91.90
2014 Totals [Member] | Oil Contract [Member]
Derivative [Line Items]
Daily Average Volume	12,996
Volume	4,743,400
Average Swap Price	93.67
January 2014 To December 2014 [Member] | Gas Contract [Member]
Derivative [Line Items]
Daily Average Volume	5,000
Volume	1,825,000
Average Swap Price	4.01
January 2015 To December 2015 [Member] | Oil Contract [Member]
Derivative [Line Items]
Daily Average Volume	1,500
Volume	547,500
Average Swap Price	97.70
January 2015 To December 2015 [Member] | Gas Contract [Member]
Derivative [Line Items]
Daily Average Volume	4,300
Volume	1,569,500
Average Swap Price	4.31