v2.4.0.8

Basis of presentation and summary of significant accounting policies (Details) | 1 Months Ended | 6 Months Ended |  |
--- | --- | --- | --- | ---
Apr. 30, 2013 item | Jun. 30, 2013 MW state province project | Jun. 30, 2013 Gregory | Dec. 31, 2012 Delta-Person
Basis of presentation and summary of significant accounting policies |  |  |  |
Percentage of ownership interest |  |  | 17.10% | 40.00%
Gross generating capacity of project (in MW) |  | 3,018 |  |
Ownership interest in operational power generation projects (in MW) |  | 2,098 |  |
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 |  |
Power of project that achieved commercial operations | 53 |  |  |
Number of projects Which are wholly owned subsidiaries |  | 23 |  |

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

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

X
- 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
Period Type: | instant

X
- Definition The number of provinces in which the power generation projects operate. + References No definition available. + Details
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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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- Definition Represents the ownership interest in operational power generation projects. + References No definition available. + Details
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- Definition Represents the power of project that achieved commercial operations during the period. + References No definition available. + Details
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- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 159 -Paragraph 18 -Subparagraph f -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 18 -Paragraph 20 -Subparagraph a (1) -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
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- Details
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