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Commitments (Narrative) (Details) (USD $) In Millions, unless otherwise specified | 12 Months Ended
--- | ---
Dec. 31, 2011 | Dec. 31, 2010 | Dec. 31, 2009
Commitments [Abstract] |  |  |
Rental expense | $ 10.3 | $ 11.0 | $ 10.6
Lease expiration year | 2023 |  |

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- Details
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- Definition The date upon which a lease or a group of leases is set to expire. + References No definition available. + Details
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Namespace Prefix: | us-gaap_
Data Type: | us-types:dateStringItemType
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- Definition Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41499-112717 + Details
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