v2.4.1.9

Summary of Significant Accounting Policies Revenue Recognition Policy Additional Information (Details) (USD $) In Millions, unless otherwise specified | Dec. 31, 2014 | Dec. 31, 2013
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Deferred Revenue Arrangement [Line Items] |  |
Unearned revenue | $ 76.6 us-gaap_DeferredRevenue | $ 69.8 us-gaap_DeferredRevenue
Deferred costs | $ 24.9 us-gaap_DeferredCostsCurrentAndNoncurrent | $ 23.5 us-gaap_DeferredCostsCurrentAndNoncurrent

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- Definition The carrying amount of deferred costs. + References No definition available. + Details
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Balance Type: | debit
Period Type: | instant

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- Definition Amount of deferred revenue as of balance sheet date. Deferred revenue represents collections of cash or other assets related to a revenue producing activity for which revenue has not yet been recognized. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 13 -Section A Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 605 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 13.A.4(a).Q1 Response) -URI http://asc.fasb.org/extlink&oid=27012821&loc=d3e214044-122780 + Details
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Namespace Prefix: | us-gaap_
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Balance Type: | credit
Period Type: | instant

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- Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration