Finite Lived Intangible Asset and Liability Schedule of Major Components of the Finite Lived Intangible Assets and Liabilities (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 125,412	$ 103,066
Finite-Lived Intangible Assets, Accumulated Amortization	(14,795)	(11,171)
Finite-Lived Intangible Assets, Net	110,617	91,895
Finite Lived Intangible Liability Net	$ 52,929	$ 54,663
Power Purchase Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period	13 years	13 years
Finite-Lived Intangible Assets, Gross	$ 97,400	$ 97,400
Finite-Lived Intangible Assets, Accumulated Amortization	(13,856)	(10,632)
Finite-Lived Intangible Assets, Net	$ 83,544	$ 86,768
Finite Lived Intangible Liabilities Remaining Amortization Period	15 years	16 years
Finite Lived Intangible Liabilities Gross	$ 60,300	$ 60,300
Finite Lived Intangible Liability Accumulated Amortization	(7,371)	(5,637)
Finite Lived Intangible Liability Net	$ 52,929	$ 54,663
Industrial revenue bond tax savings [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period	25 years
Finite-Lived Intangible Assets, Gross	$ 12,778
Finite-Lived Intangible Assets, Accumulated Amortization	(154)
Finite-Lived Intangible Assets, Net	$ 12,624
Other Intangible Assets [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period	34 years	15 years
Finite-Lived Intangible Assets, Gross	$ 15,234	$ 5,666
Finite-Lived Intangible Assets, Accumulated Amortization	(785)	(539)
Finite-Lived Intangible Assets, Net	$ 14,449	$ 5,127