Merger with Capella Education Company - Fair Value of Consideration Transferred (Details) $ / shares in Units, $ in Thousands	Aug. 01, 2018 USD ($) item $ / shares shares
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Number of independent universities \| item	2
Capella Merger
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Conversion ratio	0.875
Total fair value of consideration transferred	$ 1,236,961
Capella Merger \| Common Stock
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Fair value	$ 1,209,483
Number of common shares issued \| shares	10,263,775
Market price \| $ / shares	$ 117.84
Capella Merger \| Equity-based awards
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Fair value	$ 27,478

Represents the conversion ratio of number of shares exchanged in business combination.

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Represents the number of independent universities.

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Number of shares of equity interests issued or issuable to acquire entity.

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-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
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Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.

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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 equity interests of the acquirer, including instruments or interests issued or issuable in consideration for the business combination.

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