Acquisitions (Affiliated Acquisitions) (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended
	Dec. 28, 2012 December 2012 Transferred Properties [Member]	Dec. 31, 2013 December 2012 Transferred Properties [Member]	Oct. 03, 2011 October 2011 Purchase Agreement [Member]	Dec. 31, 2013 October 2011 Purchase Agreement [Member]
Business Acquisition [Line Items]
Date of acquisition		Dec. 28, 2012		Oct. 03, 2011
Effective date of acquisition				Oct. 01, 2011
Number of shares issued for acquisition of oil and gas properties			16,666,667
Cash paid for acquisition	$ 28.6
Assumed long-term debt	$ 115.0		$ 227.0