Summary of Significant Accounting Policies - Disaggregation of revenue (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2021 USD ($) item	Dec. 31, 2020 USD ($)	Dec. 31, 2021 USD ($) item	Dec. 31, 2020 USD ($)
Summary of Significant Accounting Policies
Number of lines of revenue | item	2		2
Total Revenues	$ 409,507	$ 376,145	$ 809,733	$ 747,105
General Education
Summary of Significant Accounting Policies
Percentage of revenues from funding-based contracts	88.00%	88.00%	89.00%	88.00%
Total Revenues	$ 313,241	$ 313,989	$ 619,582	$ 627,838
Career Learning
Summary of Significant Accounting Policies
Total Revenues	$ 96,266	$ 62,156	$ 190,151	$ 119,267
Middle - High School
Summary of Significant Accounting Policies
Percentage of revenues from funding-based contracts	99.00%	98.00%	99.00%	98.00%
Total Revenues	$ 75,287	$ 51,376	$ 146,699	$ 100,147
Adult
Summary of Significant Accounting Policies
Total Revenues	$ 20,979	$ 10,780	$ 43,452	$ 19,120