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Summary of Significant Accounting Policies (Details 5) | Dec. 31, 2011 USD ($) | Dec. 31, 2010 USD ($) | Dec. 31, 2011 Swedish kronor SEK | Dec. 31, 2011 Swedish kronor Beginning of period SEK | Dec. 31, 2010 Swedish kronor Beginning of period SEK | Dec. 31, 2011 Swedish kronor End of period SEK | Dec. 31, 2010 Swedish kronor End of period SEK | Dec. 31, 2011 British pound Beginning of period GBP (£) | Dec. 31, 2010 British pound Beginning of period GBP (£) | Dec. 31, 2011 British pound End of period GBP (£) | Dec. 31, 2010 British pound End of period GBP (£) | Dec. 31, 2011 Canadian dollar Beginning of period CAD | Dec. 31, 2010 Canadian dollar Beginning of period CAD | Dec. 31, 2011 Canadian dollar End of period CAD | Dec. 31, 2010 Canadian dollar End of period CAD
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Summary of Significant Accounting Policies |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unrealized foreign currency translation gains | $ 46,100,000 | $ 61,400,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Rates of exchange for the U.S. dollar |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Exchange rate |  |  | 6.86 | 6.7030 | 7.1280 | 6.8645 | 6.7030 | £ 0.6420 | £ 0.6191 | £ 0.6434 | £ 0.6420 | 0.9981 | 1.0485 | 1.0193 | 0.9981

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- Definition Accumulated adjustment, net of tax, that results from the process of translating subsidiary financial statements and foreign equity investments into the reporting currency from the functional currency of the reporting entity, net of reclassification of realized foreign currency translation gains or losses. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 30 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=6915805&loc=d3e32022-110900 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 17, 18, 19, 22, 23, 24, 25, 26 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e653-108580 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 45 -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 220 -SubTopic 10 -Section 45 -Paragraph 14 -URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e681-108580 Reference 6: 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 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 30 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6450520&loc=d3e32583-110901 Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 52 -Paragraph 31 -Subparagraph a -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 9: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 52 -Paragraph 12, 13 -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 10: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e637-108580 + Details
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