v2.4.0.6
Income taxes (Details) (USD $)
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Components of income tax expenses (benefit)      
Current income tax expense (benefit) $ 7,773,000 $ 1,584,000 $ 960,000
Deferred tax expense (benefit) (34,055,000) (9,908,000) 17,964,000
Total income tax expense (benefit) (28,083,000) (11,104,000) 16,018,000
Canadian enacted statutory rate (as a percent) 25.00% 26.50% 28.50%
Reconciliation of income taxes      
Computed income taxes at Canadian statutory rate (36,216,000) (21,975,000) (3,410,000)
Increases (decreases) resulting from:      
Dividend withholding tax 5,912,000 371,000 765,000
Various Income Tax rates for Operating Countries (8,532,000) (10,553,000) (1,220,000)
Foreign exchange 1,505,000 (113,000)  
Permanent differences (6,459,000) (1,479,000)  
Changes in tax rates 1,805,000    
Non-deductible acquisition costs 637,000 4,287,000  
Non-deductible interest expense   2,134,000  
Federal grant   (6,573,000)  
Prior year true-up (5,142,000) 2,246,000  
Other (1,779,000) (1,118,000) 38,000
Income tax expense (benefit) after adjustments for operating countries with different income tax rates (44,748,000) (32,528,000) (4,630,000)
Valuation allowance 20,186,000 21,669,000 19,845,000
Income tax expense (benefit) after adjustments for operating countries with different income tax rates and valuation allowance (24,562,000) (10,859,000) 15,215,000
Total other reconciliation items (3,521,000) (245,000) 803,000
Total income tax expense (benefit) (28,083,000) (11,104,000) 16,018,000
Deferred tax assets:      
Loss carryforwards 130,149,000 122,472,000  
Other accrued liabilities 10,906,000 28,059,000  
Finance and share issuance costs 8,349,000 6,532,000  
Disallowed interest carryforward 2,214,000 9,189,000  
Derivative contracts 3,481,000    
Unrealized foreign exchange loss   441,000  
Other 6,094,000    
Total deferred tax assets 161,193,000 166,693,000  
Valuations allowance (116,002,000) (89,020,000)  
Net deferred tax assets 45,191,000 77,673,000  
Deferred tax liabilities:      
Intangible assets (113,277,000) (121,055,000)  
Property, plant and equipment (94,660,000) (133,689,000)  
Derivative contracts   (4,752,000)  
Other long-term investments 1,272,000 (921,000)  
Other   (181,000)  
Total deferred tax liabilities (209,209,000) (260,598,000)  
Net deferred tax liability (164,018,000) (182,925,000)  
Net deferred tax position      
Long-term deferred tax liabilities, net (164,018,000) (182,925,000)  
Net deferred tax liability $ (164,018,000) $ (182,925,000)