Long Term Debt (Details) - USD ($)		3 Months Ended
	Nov. 03, 2020	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Debt Instrument [Line Items]
Cash and cash equivalents		$ 222,116,000	$ 202,824,000	$ 168,481,000
Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit facility, outstanding		61,300,000		61,400,000
Interest paid		1,200,000	$ 2,400,000
Revolving Credit Facility | Australia, Dollars
Debt Instrument [Line Items]
Revolving credit facility, outstanding		$ 3,300,000		$ 3,400,000
Revolving Credit Facility | Minimum
Debt Instrument [Line Items]
Unused commitment fee	0.20%
Revolving Credit Facility | Minimum | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Margin rate	1.50%
Revolving Credit Facility | Maximum
Debt Instrument [Line Items]
Unused commitment fee	0.30%
Revolving Credit Facility | Maximum | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Margin rate	2.00%
Amended Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit facility, value	$ 350,000,000
Maximum aggregate incremental term loans	$ 300,000,000
Percentage of consolidated EBITDA to be funded	100.00%
Maximum leverage ratio allowed in order to increase obligation	1.75
Debt financing costs	$ 1,900,000
Debt instrument term	5 years
Maximum total leverage ratio	2.00
Cash and cash equivalents	$ 150,000,000
Minimum coverage ratio	1.75
Minimum department of education financial composite score	1.0
Minimum department of education financial composite score for two consecutive fiscal years	1.5
Amendment to the Credit Facility, Subfacility for Borrowings in Foreign Currencies | Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit facility, value	$ 150,000,000