Organization and Summary of Significant Accounting Policies Organization and Summary of Significant Accounting Policies - Revenues (Details) (Oil and Gas Revenue [Member], Customer Concentration Risk [Member])	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Shell Trading Co.
Concentration Risk [Line Items]
Net oil and gas revenues (percent)	30.00%	35.00%	30.00%
Laclede Energy
Concentration Risk [Line Items]
Net oil and gas revenues (percent)	24.00%	14.00%	17.00%
Unimark, LLC
Concentration Risk [Line Items]
Net oil and gas revenues (percent)	14.00%	14.00%
JP Morgan Ventures Energy
Concentration Risk [Line Items]
Net oil and gas revenues (percent)			12.00%