Commitments and Contingencies (Details) - Jun. 30, 2015 $ in Millions	USD ($) $ / MMBTU
Loss Contingencies [Line Items]
Purchase obligation calculated floor price | $ / MMBTU	57.14
Estimated total future purchase obligation	$ 58.5
Officer
Loss Contingencies [Line Items]
Employment agreements with officers, severance pay consideration period, minimum	24 months
Employment agreements with officers, severance pay consideration period, maximum	36 months