v2.4.0.6

Nature of business (Details) | 12 Months Ended
--- | ---
Dec. 31, 2012 MW province state project
Nature of business |
Gross generating capacity of project (in MW) | 3,366
Ownership interest in operational power generation projects (in MW) | 2,117
Number of operational power generation projects | 29
Number of states in which power generation projects operate | 11
Number of provinces in which power generation projects operate | 2
Number of biomass projects under construction in Georgia | 1
Generating capacity of biomass project under construction in Georgia (in MW) | 53
Number of projects Which are wholly owned subsidiaries | 23

X
- Definition Represents the generating capacity of biomass project under construction. + References No definition available. + Details
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Data Type: | num:powerItemType
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Period Type: | duration

X
- Definition Represents the gross power generating capacity of project. + References No definition available. + Details
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Data Type: | num:powerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the number of biomass projects under construction in Georgia. + References No definition available. + Details
Name: | at_NumberOfBiomassProjectUnderConstruction
Namespace Prefix: | at_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the number of operational power generation projects. + References No definition available. + Details
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Namespace Prefix: | at_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

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- Definition Represents the number of power generation projects which are wholly-owned subsidiaries of the reporting entity. + References No definition available. + Details
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Namespace Prefix: | at_
Data Type: | xbrli:integerItemType
Balance Type: | na
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- Definition The number of provinces in which the power generation projects operate. + References No definition available. + Details
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Data Type: | xbrli:integerItemType
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- Definition The number of states in which the power generation projects operate. + References No definition available. + Details
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Namespace Prefix: | at_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

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- Definition Represents the ownership interest in operational power generation projects. + References No definition available. + Details
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Namespace Prefix: | at_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | duration

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- Details
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