Investments - Investments Reported in Other Current and Non-Current Assets (Detail) (USD $)
In Millions, unless otherwise specified |
Dec. 31, 2013
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Dec. 31, 2012
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Schedule of Equity Method Investments [Line Items] | ||
Funding Commitments | $ 11.4 | |
Assets | 90.4 | 54.1 |
Chem-Mod LLC [Member]
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Schedule of Equity Method Investments [Line Items] | ||
Funding Commitments | ||
Assets | 4.0 | 4.0 |
Chem-Mod International LLC [Member]
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Schedule of Equity Method Investments [Line Items] | ||
Funding Commitments | ||
Assets | 2.0 | 2.0 |
C-Quest Technology LLC [Member]
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Schedule of Equity Method Investments [Line Items] | ||
Funding Commitments | ||
Assets | 2.0 | |
Clean-Coal Investments [Member] | Non-controlling Interest [Member] | Seven 2009 Era Clean Coal Plants [Member]
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Schedule of Equity Method Investments [Line Items] | ||
Funding Commitments | 0.6 | |
Assets | 4.5 | 2.8 |
Clean-Coal Investments [Member] | Non-controlling Interest [Member] | Five 2011 Era Clean Coal Plants [Member]
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Schedule of Equity Method Investments [Line Items] | ||
Funding Commitments | ||
Assets | 12.1 | 13.2 |
Clean-Coal Investments [Member] | Controlling Interest [Member] | Seven 2009 Era Clean Coal Plants [Member]
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Schedule of Equity Method Investments [Line Items] | ||
Funding Commitments | 2.7 | |
Assets | 13.8 | 6.3 |
Clean-Coal Investments [Member] | Controlling Interest [Member] | Eleven 2011 Era Clean Coal Plants [Member]
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Schedule of Equity Method Investments [Line Items] | ||
Funding Commitments | 2.7 | |
Assets | 46.0 | 9.2 |
Clean-Coal Investments [Member] | Controlling Interest [Member] | Four 2011 Era Clean Coal Plants [Member]
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Schedule of Equity Method Investments [Line Items] | ||
Funding Commitments | ||
Assets | 2.3 | 5.1 |
Clean-Coal Investments [Member] | Notes Receivable and Interest from Co-Investor [Member] | Three 2009 Era Plants [Member]
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Schedule of Equity Method Investments [Line Items] | ||
Funding Commitments | ||
Assets | 8.5 | |
Other Investments [Member]
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Schedule of Equity Method Investments [Line Items] | ||
Funding Commitments | 5.4 | |
Assets | $ 3.7 | $ 3.0 |