Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Millions |
9 Months Ended | |
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Sep. 30, 2016 |
Dec. 31, 2015 |
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| Wind Projects [Member] | ||
| Fair Value, Option, Qualitative Disclosures Related to Election [Line Items] | ||
| Senior secured debt investment | $ 13.0 | |
| Recognized gain on sale of debt investment | $ 0.8 | |
| Wind Projects [Member] | Large Financial Institution [Member] | ||
| Fair Value, Option, Qualitative Disclosures Related to Election [Line Items] | ||
| Senior secured debt investment | $ 45.0 | |
| Level 3 [Member] | ||
| Fair Value, Option, Qualitative Disclosures Related to Election [Line Items] | ||
| Fair value interest rate spreads, minimum | 1.00% | |
| Fair value interest rate spreads, maximum | 5.00% |
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- Definition Fair Value Interest Rate Spreads Maximum No definition available.
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- Definition Fair Value Interest Rate Spreads Minimum No definition available.
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- Definition Amount of debt securities categorized neither as held-to-maturity nor trading. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition The difference between the carrying value and the sale price of debt securities, not separately or otherwise categorized as trading, available-for-sale, or held-to-maturity. This element refers to the gain (loss) included in earnings and not to the cash proceeds of the sale. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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