Finite Lived Intangible Asset and Liability (Tables)

6 Months Ended

Jun. 30, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Finite-lived Intangible Assets Amortization Expense [Table Text Block]

The following table presents estimated future amortization for the next five years related to the PPA asset and PPA liability and other intangible assets (in thousands):

Year ended December 31,	Power purchase agreements, net		Industrial revenue bond tax savings		Other intangible assets
2017 (remainder)	$	1,543	$	193	$	305
2018	3,031		513		605
2019	3,031		513		605
2020	3,049		513		605
2021	3,031		513		605
Thereafter	16,930		10,379		11,724

Schedule Of Finite Lived Intangible Assets and Liability [Table Text Block]

The following presents the major components of the finite-lived intangible assets and liability (in thousands):

	June 30, 2017
	Weighted Average Remaining Life	Gross		Accumulated Amortization			Net
Intangible assets
Power purchase agreement	13	$	97,400	$	(13,856	)	$	83,544
Industrial revenue bond tax savings	25	12,778		(154		)	12,624
Other intangible assets	34	15,234		(785		)	14,449
Total intangible assets		$	125,412	$	(14,795	)	$	110,617
Intangible liability
Power purchase agreement	15	$	60,300	$	(7,371	)	$	52,929

	December 31, 2016
	Weighted Average Remaining Life	Gross		Accumulated Amortization			Net
Intangible assets
Power purchase agreement	13	$	97,400	$	(10,632	)	$	86,768
Other intangible assets	15	5,666		(539		)	5,127
Total intangible assets		$	103,066	$	(11,171	)	$	91,895
Intangible liability
Power purchase agreement	16	$	60,300	$	(5,637	)	$	54,663