Long Term Debt (Details) - USD ($)		12 Months Ended
	Nov. 03, 2020	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Money market funds		$ 168,481,000	$ 213,667,000
Repayments of lines of credit		40,000,000	40,000,000	$ 0
Revolving Credit Facility
Debt Instrument [Line Items]
Interest paid		6,800,000	4,200,000	$ 2,700,000
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
Money market funds	$ 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
Revolving credit facility, outstanding		61,400,000	101,400,000
Repayments of lines of credit		40,000,000	40,000,000
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
Amendment to the Credit Facility, Subfacility for Borrowings in Foreign Currencies | Revolving Credit Facility | Australia, Dollars
Debt Instrument [Line Items]
Revolving credit facility, outstanding		$ 3,400,000	$ 3,400,000