Schedule II Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Sep. 01, 2021
Allowance for receivables
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 5,983	$ 6,174	$ 6,648
Additions/ (Reductions)	11,888	3,802	4,178
Write-Offs	(6,475)	(3,993)	(4,652)
Balance at End of Period	11,396	5,983	6,174
Additions, beginning balance	11,396	5,983	6,174
APUS Segment
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	2,196	2,240	2,669
Additions/ (Reductions)	1,693	1,276	2,004
Write-Offs	(2,139)	(1,320)	(2,433)
Balance at End of Period	1,750	2,196	2,240
Additions, beginning balance	1,750	2,196	2,240
RU Segment
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	0
Additions/ (Reductions)	5,902
Write-Offs	(2,458)
Balance at End of Period	3,444	0
Additions, beginning balance	3,444	0		$ 3,500
HCN Segment
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	3,787	3,934	3,979
Additions/ (Reductions)	4,293	2,526	2,174
Write-Offs	(1,878)	(2,673)	(2,219)
Balance at End of Period	6,202	3,787	3,934
Additions, beginning balance	$ 6,202	$ 3,787	$ 3,934