XML 66 R49.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Summary of Significant Accounting Policies Revenue Recognition Policy Additional Information (Details) - USD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Deferred Revenue Arrangement [Line Items] |  |
Unearned revenue | $ 77.0 | $ 114.3
Deferred costs | $ 14.4 | $ 34.4

X
- Definition The carrying amount of deferred costs. + References No definition available. + Details
Name: | us-gaap_DeferredCostsCurrentAndNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- 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 FASB -Name Accounting Standards Codification -Topic 605 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 13.A.3) -URI http://asc.fasb.org/extlink&oid=65893310&loc=d3e214044-122780 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) -URI http://asc.fasb.org/extlink&oid=65893310&loc=d3e214044-122780 + Details
Name: | us-gaap_DeferredRevenue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_DeferredRevenueArrangementLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration