Equity method investments in unconsolidated affiliates (Details) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2016 |
Mar. 31, 2015 |
|
| Operating results | ||
| Revenue | $ 33.0 | $ 37.8 |
| Project expenses | 21.8 | 26.6 |
| Project other income (expense) | (0.5) | (0.4) |
| Project income (loss) | 10.7 | 10.8 |
| Chambers | ||
| Operating results | ||
| Revenue | 12.7 | 15.4 |
| Project expenses | 8.8 | 11.4 |
| Project other income (expense) | (0.5) | (0.5) |
| Project income (loss) | 3.4 | 3.5 |
| Frederickson | ||
| Operating results | ||
| Revenue | 5.1 | 4.7 |
| Project expenses | 4.5 | 4.1 |
| Project income (loss) | 0.6 | 0.6 |
| Orlando | ||
| Operating results | ||
| Revenue | 13.4 | 12.8 |
| Project expenses | 6.6 | 6.6 |
| Project income (loss) | 6.8 | 6.2 |
| Other | ||
| Operating results | ||
| Revenue | 1.8 | 4.9 |
| Project expenses | 1.9 | 4.5 |
| Project other income (expense) | 0.1 | |
| Project income (loss) | $ (0.1) | $ 0.5 |
| Other | Maximum | ||
| Operating results | ||
| Percentage of ownership interest | 10.00% | |