Nature of the business, Financing arrangements (Details) - Abengoa [Member] |
3 Months Ended | 12 Months Ended | |
|---|---|---|---|
Mar. 09, 2018 |
Mar. 31, 2018 |
Dec. 31, 2017 |
|
| Financing arrangements [Abstract] | |||
| Minimum ownership requirement percentage | 16.00% | 35.00% | |
| Ownership interest | 16.50% | 16.47% | |
| Percentage of outstanding shares pledged as collateral | 16.44% | ||
| Remaining ownership percentage | 16.47% | ||
| Solana and Mojave [Member] | |||
| Financing arrangements [Abstract] | |||
| Minimum ownership requirement percentage | 16.00% | 16.00% |