Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands		3 Months Ended			9 Months Ended		12 Months Ended
	Jul. 01, 2018 USD ($)	Sep. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) segment	Sep. 30, 2021 USD ($)	Dec. 31, 2019 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Mar. 31, 2020 USD ($)
Summary Of Significant Accounting Policies
Investments		$ 68,403	$ 0		$ 68,403
Other assets		1,683	1,943		$ 1,683
Number of operating segments | segment					1
Number of reporting units | segment					1
Unbilled revenue		11,973	3,841		$ 11,973
Amounts written off					0
Allowance for doubtful accounts		0			0
Allowance for credit losses				$ 5,000		$ 5,000
Stockholders equity		591,556	1,045,047	1,400,776	591,556	1,400,776		$ 606,638	$ 706,437	$ 1,542,683	$ 1,588,678	$ 1,574,329
Income tax expense		6,249		$ 12,166	34,463	$ 47,186
Reversal of credit loss reserve			5,000
Cash in excess of FDIC insured limits		38,851	600,130		$ 38,851
Revenue Benchmark | Customer Concentration Risk | Grand Canyon University
Summary Of Significant Accounting Policies
Concentration risk percentage					84.80%	85.00%
Computer Software
Summary Of Significant Accounting Policies
Estimated average useful life					3 years
Capitalized Content Development
Summary Of Significant Accounting Policies
Estimated average useful life					4 years
Other assets		$ 1,038	$ 1,168		$ 1,038
Minimum
Summary Of Significant Accounting Policies
Initial contract terms of service agreements					7 years
Maximum
Summary Of Significant Accounting Policies
Initial contract terms of service agreements					15 years
Grand Canyon University
Summary Of Significant Accounting Policies
Purchase price of assets	$ 870,097
Master Services Agreement | Grand Canyon University
Summary Of Significant Accounting Policies
Percentage of tuition and fee revenue used for closing of purchase agreement	60.00%
Cumulative Effect of Adoption Adjustment | ASU 2016-13
Summary Of Significant Accounting Policies
Allowance for credit losses												$ 5,000	$ 5,000
Stockholders equity							$ (3,832)
Income tax expense							$ 1,168