Nature of Operations (Details) $ in Thousands		3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 27, 2016 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) agreement	Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Liquidity
Net loss attributable to common shareholders		$ 13,154	$ 9,253	$ 24,934	$ 20,330	$ 55,800	$ 88,600	$ 62,800
Accumulated deficit		1,018,810		1,018,810		993,876
Net cash used in operating activities				15,761	24,255
Net loss attributable to the Company		(13,128)	(9,226)	(24,882)	(20,277)
Noncash gains				2,700
Net inflows of noncash operating assets and liabilities				6,400
Cash and cash equivalents		66,040	$ 109,139	66,040	$ 109,139	63,961	$ 146,205
Net working capital		77,800		77,800		88,500
Cash added to the restricted accounts		0		$ 0		$ 14,200
Number of power purchase agreements | agreement				7
Remaining lease payment		91,196		$ 91,196
Purchases of property, plant, and equipement and cash outflows associated with construction of leased assets				28,800
Power purchase agreements
Liquidity
Remaining lease payment		$ 23,600		23,600
Master Lease
Liquidity
Minimum level of unrestricted cash				$ 50,000
Number of years that the underlying assets not be deployed				5 years
Residual exposure				$ 12,000
Master Lease | Subsequent event
Liquidity
Minimum level of unrestricted cash	$ 40,000
Secured term loan facility
Liquidity
Prior to net income milestones met, required minimum cash and cash equivalents percent of outstanding principal amount		75.00%
Accounts payable days outstanding threshold		150 days