Value of liabilities assumed at the acquistion date related to acquiree's stock compensation plan

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- Definition

Percentage of share minority shareholders may put to the Company through redeemable noncontrolling interest

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Amount of direct costs of the business combination including legal, accounting, and other costs incurred to consummate the business acquisition.

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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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The amount of goodwill arising from a business combination that is expected to be deductible for tax purposes.

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- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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Amount of liability recognized arising from contingent consideration in a business combination.

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- Definition

This element represents the amount of earnings or loss of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

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This element represents the amount of revenue of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

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Percentage of voting equity interests acquired in a business combination achieved in stages, including equity interests in the acquiree held by the acquirer immediately before the acquisition date and acquired at the acquisition date.

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- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of loans from a bank with maturities initially due after one year or beyond the normal operating cycle if longer.

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The number of businesses acquired by the entity during the period.

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The cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase.

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- Definition

Fair value of noncontrolling interests which are redeemable by the parent entity and classified as other equity.

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Acquisitions and Dispositions of Businesses (Acquisitions) (Narrative) (Details) $ in Thousands		3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 14, 2021 USD ($)	Sep. 30, 2021 USD ($)	Mar. 31, 2020 business	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($) business	May 31, 2020 USD ($)
Business Acquisition [Line Items]
Number of businesses acquired \| business						3
Acquisition purchase price						$ 96,800
Purchase Price Net of Cash				$ 272,428	$ 20,080
Business Acquisition, Transaction Costs		$ 1,600		1,600	$ 1,100
Goodwill expected to be deductible for income tax purposes		43,400		43,400		$ 3,200
Revenues of acquired companies since acquisition date		57,500		66,700
Operating loss of acquired companies since acquisition date		(7,200)		(9,100)
Education [Member]
Business Acquisition [Line Items]
Number of businesses acquired \| business			2			2
Education [Member] \| Kaplan International [Member]
Business Acquisition [Line Items]
Number of businesses acquired \| business			1
Education [Member] \| Supplemental Education [Member]
Business Acquisition [Line Items]
Number of businesses acquired \| business			1
Other Businesses [Member]
Business Acquisition [Line Items]
Number of businesses acquired \| business						1
Other Businesses [Member] \| Framebridge [Member]
Business Acquisition [Line Items]
Business Combination, Contingent Consideration, Liability							$ 50,600
Percentage of Shares Eligible to be Redeemed							20.00%
Redeemable noncontrolling interest							$ 6,000
Business Combination, Step Acquisition, Equity Interest in Acquiree, Including Subsequent Acquisition, Percentage							93.40%
Other Businesses [Member] \| Leaf
Business Acquisition [Line Items]
Acquisition purchase price	$ 308,600
Stock Compensation Liabilities Assumed	$ 9,200
Pinnacle Bank Term Loan [Member]
Business Acquisition [Line Items]
Loans Payable to Bank		$ 9,840		$ 9,840		$ 10,692