LEASES (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023 USD ($) Squarefeet	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($) Lease Option Squarefeet	Jun. 30, 2022 USD ($)	Aug. 31, 2022 USD ($)
Operating Leases [Abstract]
Approximate area of leased school space | Squarefeet	55,000		55,000
Undiscounted lease payments	$ 46,081		$ 46,081		$ 12,200
Operating lease term	12 years		12 years
Number of renewal options | Option			2
Renewal lease term	5 years		5 years
Capital expenditures	$ 5,300
Rent paid	400
Operating lease cost	4,900	$ 4,700	$ 9,800	$ 9,300
Variable lease cost			100
Operating cash flow information [Abstract]
Cash paid for amounts included in the measurement of operating lease liabilities	4,278	4,665	8,196	9,320
Non-cash activity [Abstract]
Lease liabilities arising from obtaining right-of-use assets	$ 0	$ 73	$ 2,142	$ 6,717
Number of new leases | Lease			1
Number of lease modifications | Lease			1
Weighted Average Remaining Lease Term and Discount Rate [Abstract]
Weighted-average remaining lease term	11 years 1 month 17 days	11 years 4 months 6 days	11 years 1 month 17 days	11 years 4 months 6 days
Weighted-average discount rate	6.92%	7.36%	6.92%	7.36%
Maturities of Lease Liabilities [Abstract]
2023 (excluding the six months ended June 30, 2023)	$ 7,897		$ 7,897
2024	17,373		17,373
2025	15,702		15,702
2026	13,334		13,334
2027	10,053		10,053
2028	9,959		9,959
Thereafter	69,824		69,824
Total lease payments	144,142		144,142
Less: imputed interest	(46,081)		(46,081)		$ (12,200)
Present value of lease liabilities	$ 98,061		$ 98,061
Minimum [Member]
Operating Leases [Abstract]
Remaining lease term	1 year		1 year
Maximum [Member]
Operating Leases [Abstract]
Remaining lease term	19 years		19 years
Variable lease cost	$ 100	$ 100		$ 100