v2.4.0.6
Consolidating financial information (Details 3) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended 12 Months Ended
Dec. 31, 2012
Sep. 30, 2012
Jun. 30, 2012
Mar. 31, 2012
Dec. 31, 2011
Sep. 30, 2011
Jun. 30, 2011
Mar. 31, 2011
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Project revenue:                      
Energy sales                 $ 217,038 $ 43,590  
Energy capacity revenue                 154,851 34,009 786
Other                 68,488 16,296 265
Total project revenue 113,952 106,305 101,421 118,699 79,158 5,035 5,107 4,595 440,377 93,895 1,051
Project expenses:                      
Fuel                 169,093 37,471 193
Project operations and maintenance                 124,759 22,723 1,060
Depreciation and amortization                 118,031 23,682 88
Total project expenses                 411,883 83,876 1,341
Project other income (expense):                      
Change in fair value of derivative instruments                 (59,272) (14,594) 3,275
Equity in earnings of unconsolidated affiliates                 15,246 6,356 13,777
Interest expense, net                 (16,438) (7,244) (3,638)
Other income, net                 (516) 20 211
Total project other income (expense)                 (60,402) (15,462) 15,136
Project income (loss) (6,078) 18,646 (7,515) (36,961) 1,795 (6,991) (1,573) 1,326 (31,908) (5,443) 14,846
Administrative and other expenses (income):                      
Administration expense                 28,267 37,688 16,149
Interest, net                 89,868 25,953 11,701
Foreign exchange loss (gain) (Note 12)                 547 13,838 (1,014)
Other Income                 (5,728)   (26)
Total administrative and other expenses (income)                 112,954 77,479 26,810
Income (loss) from continuing operations before income taxes                 (144,862) (82,922) (11,964)
Income tax expense (benefit)                 (28,083) (11,104) 16,018
Net income (loss) from continuing operations                 (116,779) (71,818) (27,982)
Income from discontinued operations, net of tax (Note 19) (34,515) 20,106 19,319 11,549 (811) 10,442 13,682 12,864 16,459 36,177 24,127
Net loss                 (100,320) (35,641) (3,855)
Net loss attributable to noncontrolling interest                 (593) (480) (103)
Net income attributable to preferred shares dividends of a subsidiary company                 13,049 3,247  
Net loss attributable to Atlantic Power Corporation (57,952) (7,446) (5,086) (42,292) (29,830) (27,900) 13,186 6,136 (112,776) (38,408) (3,752)
Guarantor Subsidiaries
                      
Project revenue:                      
Energy sales                 182,854 34,581  
Energy capacity revenue                 154,851 34,009  
Other                 69,084 16,731  
Total project revenue                 406,789 85,321  
Project expenses:                      
Fuel                 169,093 37,471  
Project operations and maintenance                 119,220 21,225  
Depreciation and amortization                 102,744 21,043  
Total project expenses                 391,057 79,739  
Project other income (expense):                      
Change in fair value of derivative instruments                 (59,272) (14,594)  
Equity in earnings of unconsolidated affiliates                 15,824 5,989  
Interest expense, net                 (5,217) (3,885)  
Other income, net                 (556) 20  
Total project other income (expense)                 (49,221) (12,470)  
Project income (loss)                 (33,489) (6,888)  
Administrative and other expenses (income):                      
Administration expense                 17,590 12,216  
Interest, net                 79,740 67,621  
Foreign exchange loss (gain) (Note 12)                 1,185 4,057  
Other Income                 (6,045)    
Total administrative and other expenses (income)                 92,470 83,894  
Income (loss) from continuing operations before income taxes                 (125,959) (90,782)  
Income tax expense (benefit)                 (28,084) (11,346)  
Net income (loss) from continuing operations                 (97,875) (79,436)  
Income from discontinued operations, net of tax (Note 19)                 16,459 36,177  
Net loss                 (81,416) (43,259)  
Net loss attributable to noncontrolling interest                 (593) (480)  
Net income attributable to preferred shares dividends of a subsidiary company                 13,049 3,247  
Net loss attributable to Atlantic Power Corporation                 (93,872) (46,026)  
Curtis Palmer
                      
Project revenue:                      
Energy sales                 34,184 9,009  
Total project revenue                 34,184 9,009  
Project expenses:                      
Project operations and maintenance                 6,139 851  
Depreciation and amortization                 15,287 2,639  
Total project expenses                 21,426 3,490  
Project other income (expense):                      
Interest expense, net                 (11,215) (1,911)  
Other income, net                 40    
Total project other income (expense)                 (11,175) (1,911)  
Project income (loss)                 1,583 3,608  
Administrative and other expenses (income):                      
Income (loss) from continuing operations before income taxes                 1,583 3,608  
Net income (loss) from continuing operations                 1,583 3,608  
Net loss                 1,583 3,608  
Net loss attributable to Atlantic Power Corporation                 1,583 3,608  
APC
                      
Project expenses:                      
Project operations and maintenance                 (206) 922  
Total project expenses                 (206) 922  
Project other income (expense):                      
Interest expense, net                 (6) 128  
Total project other income (expense)                 (6) 128  
Project income (loss)                 200 (794)  
Administrative and other expenses (income):                      
Administration expense                 10,677 25,472  
Interest, net                 9,955 (41,668)  
Foreign exchange loss (gain) (Note 12)                 (638) 9,781  
Other Income                 317    
Total administrative and other expenses (income)                 20,311 (6,415)  
Income (loss) from continuing operations before income taxes                 (20,111) 5,621  
Income tax expense (benefit)                 1 242  
Net income (loss) from continuing operations                 (20,112) 5,379  
Net loss                 (20,112) 5,379  
Net loss attributable to Atlantic Power Corporation                 (20,112) 5,379  
Eliminations
                      
Project revenue:                      
Other                 (596) (435)  
Total project revenue                 (596) (435)  
Project expenses:                      
Project operations and maintenance                 (394) (275)  
Total project expenses                 (394) (275)  
Project other income (expense):                      
Equity in earnings of unconsolidated affiliates                   367  
Interest expense, net                   (1,576)  
Total project other income (expense)                   (1,209)  
Project income (loss)                 (202) (1,369)  
Administrative and other expenses (income):                      
Interest, net                 173    
Total administrative and other expenses (income)                 173    
Income (loss) from continuing operations before income taxes                 (375) (1,369)  
Net income (loss) from continuing operations                 (375) (1,369)  
Net loss                 (375) (1,369)  
Net loss attributable to Atlantic Power Corporation                 $ (375) $ (1,369)