Amount of consideration transferred in asset acquisition. Includes, but is not limited to, cash, liability incurred by acquirer, and equity interest issued by acquirer.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Acquisition Activity - Narrative (Details) - USD ($) $ in Thousands			3 Months Ended	9 Months Ended
	Sep. 01, 2021	Aug. 11, 2021	Sep. 30, 2021	Sep. 30, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Ending balance			$ 243,766	$ 243,766	$ 26,563
Acquisition-related expenses			$ 1,500	$ 5,000
RU
Business Acquisition [Line Items]
Payments to acquire businesses, net of cash acquired	$ 325,500
Ending balance	$ 217,203
Graduate School USA
Business Acquisition [Line Items]
Asset acquisition, consideration transferred		$ 1,000