Price-Risk Management Price-Risk Management (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($) MMBTU $ / MMBTU	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) MMBTU $ / MMBTU	Sep. 30, 2014 USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (Loss) on Price Risk Derivatives, Net	$ 0.1	$ 5.0	$ 0.3	$ (2.7)
Derivative, Fair Value, Net	$ 0.1		$ 0.1
Year 2015 [Member] | Natural Gas Basis Derivative Contract [Member] | Basis Swap [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Future Gas Production Hedged in MMBTU (Energy Item Type) | MMBTU	1,220,000		1,220,000
Derivative, Swap Type, Average Fixed Price | $ / MMBTU	(0.016)		(0.016)
Other Current Assets [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 0.1		$ 0.1