Amount received from the government as relief under the CARES Act

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Percentage of Revenue Recognized During Period from Contract with Customer, Excluding Assessed Tax

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Revenue Remaining Performance Obligation Percentage of Revenue Expected to be Recognized Over Next 12 Months

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- Definition

Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time, classified as noncurrent.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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- 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.

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Revenue from Contracts with Customers (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Apr. 30, 2020	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Deferred revenue recognized in period related to beginning balance		$ 145.1
CARES Act relief from COVID-19 [Member] \| Medicare Accelerated Advanced Payment Program Relief Fund [Member] \| Graham Healthcare Group [Member]
Disaggregation of Revenue [Line Items]
Government Relief, CARES Act	$ 31.5
Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Percentage of Revenue		70.00%	73.00%
Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Percentage of Revenue		30.00%	27.00%
U.S. [Member]
Disaggregation of Revenue [Line Items]
Percentage of Revenue		77.00%	74.00%
Non-US [Member]
Disaggregation of Revenue [Line Items]
Percentage of Revenue		23.00%	26.00%
Kaplan International [Member]
Disaggregation of Revenue [Line Items]
Contract with Customer, Asset, Net, Noncurrent		$ 10.0		$ 8.7
Supplemental Education [Member] \| Long-term Contract with Customer [Member]
Disaggregation of Revenue [Line Items]
Minimum Term of Contract		12 months
Revenue Remaining Performance Obligation Percentage of Revenue Expected to be Recognized Over Next 12 Months		64.00%