Fair Value Measurements Fair Value Measurements, Schedule of Quantitative Information for Level 3 Derivative Contracts (Details)	3 Months Ended
	Mar. 31, 2016 USD ($)
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Midwest Premium Swap Asset Beginning Curve Value	$ 0.083
Midwest Premium Swap Asset Ending Curve Value	0.084
Midwest Premium Swap Liability Ending Curve Value	0.084
Midwest Premium Swap Liability Beginning Curve Value	$ 0.083