v3.8.0.1

Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Amortizable Intangible Assets
Useful life of capitalized content development costs	5 years
Non-Cash Long-Lived Asset Additions
Capital asset additions during the period	$ 31.0	$ 20.0
Cash capital expenditure		14.3
Accounts payable and accrued expenses
Marketing and Sales Costs
Accrued marketing costs	11.3		$ 11.7
Leasehold improvements
Non-Cash Long-Lived Asset Additions
Capital asset additions during the period		11.1
Capitalized technology and content development
Non-Cash Long-Lived Asset Additions
Capital asset additions during the period		4.8
Other property and equipment
Non-Cash Long-Lived Asset Additions
Capital asset additions during the period		4.1
Landlord funded leasehold improvements
Non-Cash Long-Lived Asset Additions
Non-cash capital expenditure	$ 7.4	$ 5.4
Graduate Program Segment | Minimum
Performance Obligations
Period of contract with university clients	10 years
Graduate Program Segment | Maximum
Performance Obligations
Period of contract with university clients	15 years
Short Course Segment | Minimum
Performance Obligations
Period of contract with university clients	42 days
Short Course Segment | Maximum
Performance Obligations
Period of contract with university clients	112 days

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- Definition

Represents the useful life of capitalized content development costs. Such life is expressed in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of acquisition of long-lived, physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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Period in which remaining performance obligation is expected to be recognized as revenue, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130556-203045

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 270
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=84173487&loc=SL51747714-108306

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