Derivative Instruments and Hedging Activities (Schedule of Derivative Instruments Outstanding) (Details)	Sep. 30, 2013
October 2013 [Member] | Oil Contract [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	5,719
Volume	177,300
Average Swap Price	103.94
October 2013 [Member] | Gas Contract [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	8,000
Volume	248,000
Average Swap Price	3.58
November 2013 [Member] | Oil Contract [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	6,233
Volume	187,000
Average Swap Price	103.93
November 2013 [Member] | Gas Contract [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	7,500
Volume	225,000
Average Swap Price	3.67
December 2013 [Member] | Oil Contract [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	9,156
Volume	283,850
Average Swap Price	103.24
December 2013 [Member] | Gas Contract [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	6,500
Volume	201,500
Average Swap Price	3.83
2013 Totals [Member] | Oil Contract [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	7,045
Volume	648,150
Average Swap Price	103.63
2013 Totals [Member] | Gas Contract [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	7,332
Volume	674,500
Average Swap Price	3.68
January 2014 [Member] | Oil Contract [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	14,350
Volume	444,850
Average Swap Price	100.00
February 2014 [Member] | Oil Contract [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	14,350
Volume	401,800
Average Swap Price	100.00
March 2014 [Member] | Oil Contract [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	14,350
Volume	444,850
Average Swap Price	100.00
April 2014 [Member] | Oil Contract [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	13,350
Volume	400,500
Average Swap Price	99.83
May 2014 [Member] | Oil Contract [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	13,350
Volume	413,850
Average Swap Price	99.83
June 2014 [Member] | Oil Contract [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	13,350
Volume	400,500
Average Swap Price	99.83
July 2014 [Member] | Oil Contract [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	12,350
Volume	382,850
Average Swap Price	99.46
August 2014 [Member] | Oil Contract [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	6,750
Volume	209,250
Average Swap Price	98.83
September 2014 [Member] | Oil Contract [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	6,750
Volume	202,500
Average Swap Price	98.83
October 2014 [Member] | Oil Contract [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	6,750
Volume	209,250
Average Swap Price	98.83
November 2014 [Member] | Oil Contract [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	6,750
Volume	202,500
Average Swap Price	98.83
December 2014 [Member] | Oil Contract [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	9,700
Volume	300,700
Average Swap Price	98.52
2014 Totals [Member] | Oil Contract [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	10,996
Volume	4,013,400
Average Swap Price	99.54
October 2013 To December 2013 [Member] | Oil Contract [Member] | Collars [Member]
Derivative [Line Items]
Daily Average Volume	1,000
Volume	92,000
October 2013 To December 2013 [Member] | Oil Contract [Member] | Collars [Member] | Minimum [Member]
Derivative [Line Items]
Average Swap Price	80.00
October 2013 To December 2013 [Member] | Oil Contract [Member] | Collars [Member] | Maximum [Member]
Derivative [Line Items]
Average Swap Price	104.10
January 2014 To December 2014 [Member] | Gas Contract [Member] | Fixed Price Swaps [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] | Fixed Price Swaps [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] | Fixed Price Swaps [Member]
Derivative [Line Items]
Daily Average Volume	4,300
Volume	1,569,500
Average Swap Price	4.31