Summary of Significant Accounting Policies- Project Assets (Details) - USD ($) |
3 Months Ended | 6 Months Ended | |||
|---|---|---|---|---|---|
Jun. 30, 2016 |
Jun. 30, 2015 |
Jun. 30, 2016 |
Jun. 30, 2015 |
Dec. 31, 2015 |
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| Accounting Policies [Abstract] | |||||
| Interest costs capitalized | $ 163,000 | $ 134,000 | $ 327,000 | $ 248,000 | |
| Minimum qualifying operating period for prorated repayments of grants | 5 years | ||||
| Deferred grant income | $ 8,015,000 | $ 8,015,000 | $ 8,291,000 | ||
| Asset retirement obligation | $ 0 | ||||
| X | ||||||||||
- Definition Government Grant, Qualification Requirement, Prorated Repayment Effective Period from Date Placed in Service No definition available.
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of interest capitalized during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of unearned revenue or income classified as other, expected to be taken into income after one year or the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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