Assets Held-for-Sale and Discontinued Operations (Details 2) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Income (loss) from discontinued operations
Income (loss) from discontinued operations, net of tax	$ (926)	$ (817)
Gas transport and processing
Contracts for gas transport and processing
Contractual Obligation	23,000		$ 23,300
Gas transport and processing | Disposal Group, Held-for-sale, Not Discontinued Operations
Contracts for gas transport and processing
Recorded contractual commitments	16,100		16,100
Gas transport and processing | Disposal Group, Held-for-sale, Not Discontinued Operations | Accrued liabilities
Contracts for gas transport and processing
Recorded contractual commitments	5,500		$ 5,200
Oil and Gas | Discontinued Operations, Held-for-sale or Disposed of by Sale
Income (loss) from discontinued operations
Operating revenues	377	1,450
Income (loss) from discontinued operations	(1,326)	(1,386)
Less: Income tax expense (benefit)	(400)	(569)
Income (loss) from discontinued operations, net of tax	$ (926)	$ (817)