v2.4.0.6

Convertible debentures (Details) | 12 Months Ended |  | 12 Months Ended | 38 Months Ended |  | 0 Months Ended | 12 Months Ended | 38 Months Ended | 0 Months Ended | 12 Months Ended | 0 Months Ended | 12 Months Ended | 0 Months Ended | 12 Months Ended
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Dec. 31, 2012 USD ($) | Dec. 31, 2011 USD ($) | Dec. 31, 2010 USD ($) | Dec. 31, 2006 6.25% 2006 Debentures due 2011 USD ($) | Dec. 31, 2006 6.25% 2006 Debentures due 2011 CAD | Dec. 31, 2012 6.25% 2006 Debentures due 2011 CAD | Dec. 31, 2012 6.5% Debentures due October 2014 USD ($) | Dec. 31, 2011 6.5% Debentures due October 2014 USD ($) | Feb. 27, 2013 6.5% Debentures due October 2014 CAD | Dec. 31, 2009 6.5% Debentures due October 2014 | Dec. 17, 2009 6.25% Debentures due March 2017 USD ($) | Dec. 17, 2009 6.25% Debentures due March 2017 CAD | Dec. 31, 2012 6.25% Debentures due March 2017 USD ($) | Dec. 31, 2012 6.25% Debentures due March 2017 CAD | Dec. 31, 2011 6.25% Debentures due March 2017 USD ($) | Feb. 27, 2013 6.25% Debentures due March 2017 CAD | Oct. 20, 2010 5.6% Debentures due June 2017 USD ($) | Oct. 20, 2010 5.6% Debentures due June 2017 CAD | Dec. 31, 2012 5.6% Debentures due June 2017 USD ($) | Dec. 31, 2012 5.6% Debentures due June 2017 CAD | Dec. 31, 2011 5.6% Debentures due June 2017 USD ($) | Dec. 31, 2012 5.75% convertible unsecured subordinated debentures USD ($) | Jul. 05, 2012 5.75% Debentures due June 2019 USD ($) | Dec. 31, 2012 5.75% Debentures due June 2019 USD ($) | Dec. 11, 2012 6.00% Debenture due December 2019 CAD | Dec. 31, 2012 6.00% Debenture due December 2019 USD ($)
Convertible debentures |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amount of convertible debentures issued | $ 230,640,000 |  |  |  | 60,000,000 |  |  |  |  |  |  | 86,300,000 |  |  |  |  |  | 80,500,000 |  |  |  | $ 130,000,000 | $ 130,000,000 | $ 130,000,000 | 100,000,000 | $ 100,640,000
Convertible debentures stated interest rate percentage |  |  |  | 6.25% | 6.25% |  |  |  |  | 6.50% | 6.25% | 6.25% |  |  |  |  | 5.60% | 5.60% |  |  |  |  | 5.75% |  | 6.00% |
Proceeds from issuance of convertible debenture, net of offering costs | 230,640,000 |  | 74,575,000 | 52,800,000 |  |  |  |  |  |  | 82,100,000 |  |  |  |  |  | 78,900,000 |  |  |  |  |  |  |  |  |
Conversion rate per Cdn$1,000 principal amount (in shares) |  |  |  | 80.6452 | 80.6452 |  |  |  |  |  |  |  | 76.9231 | 76.9231 |  |  |  |  | 55.2486 | 55.2486 |  |  | 57.9710 |  | 68.9655 |
Principal amount used for convertible debentures conversion ratio |  |  |  |  | 1,000 |  |  |  |  |  |  |  |  | 1,000 |  |  |  |  |  | 1,000 |  |  | 1,000 |  | 1,000 |
Conversion price of shares |  |  |  |  |  | 12.40 |  |  |  |  |  |  |  | 13.00 |  |  |  |  |  | 18.10 |  |  | $ 17.25 |  | 14.50 |
Net proceeds from issuance convertible debentures issued, after underwriting discounts and expenses |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 124,000,000 |  | 95,500,000 |
Movement in convertible debentures |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Balance at the beginning of the period | 189,563,000 | 220,616,000 |  |  |  |  | 44,103,000 | 56,104,000 |  |  |  |  | 66,306,000 |  | 83,575,000 |  |  |  | 79,154,000 |  | 80,937,000 |  |  |  |  |
Issuance of convertible debentures | 230,640,000 |  |  |  | 60,000,000 |  |  |  |  |  |  | 86,300,000 |  |  |  |  |  | 80,500,000 |  |  |  | 130,000,000 | 130,000,000 | 130,000,000 | 100,000,000 | 100,640,000
Principal amount converted to equity | 32,000 | 26,357,000 | 7,147,000 |  |  |  | (32,000) | (10,862,000) | 15,200,000 |  |  |  |  |  | (15,567,000) | 18,800,000 |  |  |  |  |  |  |  |  |  |
Foreign exchange loss | (547,000) | (13,838,000) | 1,014,000 |  |  |  | 978,000 | (1,139,000) |  |  |  |  | 1,470,000 |  | (1,702,000) |  |  |  | 1,757,000 |  | (1,783,000) |  |  |  |  | (130,000)
Balance at the end of the period | 424,246,000 | 189,563,000 | 220,616,000 |  |  |  | 45,049,000 | 44,103,000 |  |  |  |  | 67,776,000 |  | 66,306,000 |  |  |  | 80,911,000 |  | 79,154,000 | 130,000,000 |  | 130,000,000 |  | 100,510,000
Common shares issued on conversion |  |  |  |  |  |  |  |  | 1,200,000 |  |  |  |  |  |  | 1,400,000 |  |  |  |  |  |  |  |  |  |
Aggregate interest expenses | $ 15,800,000 | $ 12,100,000 | $ 9,900,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |

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- Definition Represents the denomination of the principal amount of debt used to state the number of shares that debt can be converted into and which is used in conversion calculations. + References No definition available. + Details
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- Definition The portion of the carrying value of convertible subordinated debt as of the balance sheet date that is scheduled to be repaid after one year or beyond the normal operating cycle if longer. This form of debt can be exchanged for a specified amount of another security, typically the entity's common stock, at the option of the issuer or the holder, and places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 + Details
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- Definition The price per share of the conversion feature embedded in the debt instrument. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 5 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6928298&loc=SL6031898-161870 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number APB14-1 -Paragraph 32 -Subparagraph b -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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- Definition The ratio applied to the debt for purposes of determining the number of shares of the equity security into which the debt will be converted. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21521-112644 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Conversion Rate -URI http://asc.fasb.org/extlink&oid=6509012 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 4 -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 6: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(5)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition Interest expense related to convertible debt instruments which has been recognized for the period, including the contractual interest coupon and amortization of the debt discount, if any. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 6 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6928298&loc=SL6036836-161870 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number APB14-1 -Paragraph 33 -Subparagraph b -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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- Definition Increase of additional borrowings on existing and new debt instruments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(f)) -URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph f -Article 4 + Details
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- Definition Interest rate stated in the contractual debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition The aggregate foreign currency transaction gain (loss) (both realized and unrealized) included in determining net income for the reporting period. Excludes foreign currency transactions designated as hedges of net investment in a foreign entity and intercompany foreign currency transactions that are of a long-term nature, when the entities to the transaction are consolidated, combined, or accounted for by the equity method in the reporting enterprise's financial statements. For certain enterprises, primarily banks, that are dealers in foreign exchange, foreign currency transaction gains (losses) may be disclosed as dealer gains (losses). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 52 -Paragraph 30 -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 830 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6450189&loc=d3e30690-110894 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6450222&loc=d3e30840-110895 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6450189&loc=d3e30700-110894 + Details
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- Definition The cash inflow from the issuance of a long-term debt instrument which can be exchanged for a specified amount of another security, typically the entity's common stock, at the option of the issuer or the holder. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 19 -Subparagraph b -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 -Glossary Financing Activities -URI http://asc.fasb.org/extlink&oid=6513228 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 18 -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 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3255-108585 + Details
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- Definition Number of shares issued during the period as a result of the conversion of convertible securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 10 -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 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29-30) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 4, 5 -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 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770 Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644 + Details
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