Significant Accounting Policies - Property and Equipment (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) uSHigherEducationCampus	Dec. 31, 2022 USD ($) uSHigherEducationCampus	Dec. 31, 2021 USD ($) uSHigherEducationCampus
Property, Plant and Equipment [Line Items]
Impairment loss	$ 0.4	$ 2.5	$ 2.7
Impairment, long-lived asset, held-for-use, statement of income or comprehensive income [Extensible Enumeration]	Restructuring costs
Depreciation and amortization	$ 48.4	$ 52.0	$ 59.1
Number of long-lived assets sold | uSHigherEducationCampus	1	1	2
Gain on sale of asset	$ 2.1	$ 2.9	$ 2.7
Capella Education Company And Torrens University and Related Assets in Australia and New Zealand (ANZ) | Computer Software And Content
Property, Plant and Equipment [Line Items]
Depreciation	$ 2.6	$ 3.2	$ 7.2
Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life of property and equipment	3 years
Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life of property and equipment	40 years