Commitments and Contingencies (Details)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Number of officers subject to change in control agreements			4
Additional potential lump sum payments			$ 4,600,000
Minimum gas purchase obligation through the end of the fiscal year		$ 592,000
Minimum gas purchase obligations in the following fiscal year	$ 612,000