Debt (Additional Information) (Details) - USD ($) $ in Thousands							1 Months Ended	3 Months Ended
	Nov. 22, 2022	Sep. 22, 2022	Apr. 11, 2022	Mar. 11, 2022	Aug. 12, 2021	Mar. 01, 2021	Jun. 30, 2022	Mar. 31, 2024	Sep. 30, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Nov. 09, 2023	Jun. 30, 2023
Line of Credit Facility [Line Items]
Repayment of long-term debt									$ 0	$ 100,861
Gain on extinguishment of debt									0	71
Long-term debt, gross									708,283							$ 708,283
Surety Bond [Member]
Line of Credit Facility [Line Items]
Guarantor Obligations, Current Carrying Value									31,400
Revolver
Line of Credit Facility [Line Items]
Maximum borrowing capacity					$ 400,000
Letters of credit outstanding									76,200
Long-term Line of Credit									$ 0	0
Term														5 years
Revolver | Subsequent Event [Member]
Line of Credit Facility [Line Items]
Undrawn amount on letters of credit															$ 165,900
Revolver | Forecast
Line of Credit Facility [Line Items]
Letters of credit outstanding															$ 157,900
Revolver | LIBOR Floor
Line of Credit Facility [Line Items]
Basic spread rate									0.75%
Revolver | LIBOR Floor | Minimum
Line of Credit Facility [Line Items]
Basic spread rate									3.75%
Revolver | LIBOR Floor | Maximum
Line of Credit Facility [Line Items]
Basic spread rate									4.25%
Revolver | Alternate Base Rate | Minimum
Line of Credit Facility [Line Items]
Basic spread rate									2.75%
Revolver | Alternate Base Rate | Maximum
Line of Credit Facility [Line Items]
Basic spread rate									3.25%
Walden Title IV Letter Of Credit
Line of Credit Facility [Line Items]
Letters of credit outstanding									$ 84,000
Commitment fee percentage									0.25%
Undrawn amount on letters of credit									$ 323,800
Senior Secured Notes Due 2028 And Term B Loan
Line of Credit Facility [Line Items]
Term														7 years
Cap percentage									20.00%
Senior Secured Notes Due 2028 And Term B Loan | Scenario, Plan
Line of Credit Facility [Line Items]
Total net leverage ratio								3.25%					4.00%
Senior Secured Notes Due 2028
Line of Credit Facility [Line Items]
Debt instrument, face amount						$ 800,000
Fixed interest rate						5.50%
Repayment of long-term debt			$ 373,300				$ 20,800			900	$ 394,100
Gain on extinguishment of debt										$ 100
Long-term debt, gross									$ 404,950							404,950
Percentage of notes issued on par value						100.00%
Redemption price, percentage of principal amount redeemed			100.00%			100.00%	90.00%			92.00%
Debt covenant, percentage of principal amount of notes outstanding						25.00%
Debt Issuance Costs Write-off									0	$ 15
Senior Secured Notes Due 2028 | Accrued Liabilities
Line of Credit Facility [Line Items]
Debt Instrument, Accrued Interest									$ 1,900							7,400
Senior Secured Notes Due 2028 | 2024
Line of Credit Facility [Line Items]
Redemption price, percentage of principal amount redeemed						102.75%
Senior Secured Notes Due 2028 | 2025
Line of Credit Facility [Line Items]
Redemption price, percentage of principal amount redeemed						101.375%
Senior Secured Notes Due 2028 | 2026
Line of Credit Facility [Line Items]
Redemption price, percentage of principal amount redeemed						100.00%
Senior Secured Notes Due 2028 | Prior to March 1,2024
Line of Credit Facility [Line Items]
Redemption price percentage						105.50%
Senior Secured Notes Due 2028 | Maximum | Prior to March 1,2024
Line of Credit Facility [Line Items]
Redemption price, percentage of principal amount redeemed						40.00%
Term B Loan
Line of Credit Facility [Line Items]
Debt instrument, face amount					850,000
Fixed interest rate									9.43%
Repayment of long-term debt	$ 50,000	$ 100,000		$ 396,700	$ 396,700					100,000
Long-term debt, gross									$ 303,333							$ 303,333
Principal payment												$ 2,125
Debt Instrument, Issuance Price, Percent Of Principal Amount					99.00%
Debt Instrument, Issuance Discount, Percent					1.00%
Debt Issuance Costs Write-off									$ 0	$ 2,880
Asset sale or disposition period									1 year
Asset sale or disposition investments									$ 20,000
Mandatory prepayment terms									$ 0
Term B Loan | LIBOR Floor
Line of Credit Facility [Line Items]
Basic spread rate					0.75%
Term B Loan | Alternate Base Rate | Minimum
Line of Credit Facility [Line Items]
Basic spread rate					3.00%
Term B Loan | Alternate Base Rate | Maximum
Line of Credit Facility [Line Items]
Basic spread rate					3.50%
Term B Loan | Eurocurrency Rate | Minimum
Line of Credit Facility [Line Items]
Basic spread rate					4.00%
Term B Loan | Eurocurrency Rate | Maximum
Line of Credit Facility [Line Items]
Basic spread rate					4.50%