LEASES (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022 USD ($) Squarefeet	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) Squarefeet Lease Option	Sep. 30, 2021 USD ($)	Aug. 31, 2022 USD ($)
Operating Leases [Abstract]
Approximate area of leased school space | Squarefeet	55,000		55,000
Undiscounted lease payments	$ 41,664		$ 41,664		$ 12,200
Operating lease term	12 years		12 years
Number of renewal options | Option			2
Renewal lease term	5 years		5 years
Capital expenditures	$ 100
Rent paid	100
Operating lease cost	4,800	$ 3,800	$ 14,100	$ 11,400
Operating cash flow information [Abstract]
Cash paid for amounts included in the measurement of operating lease liabilities	4,382	3,972	13,702	11,009
Non-cash activity [Abstract]
Lease liabilities arising from obtaining right-of-use assets	$ 5,844	$ 1,220	$ 12,561	$ 4,421
Number of new leases | Lease			2
Number of lease modifications | Lease			1
Weighted Average Remaining Lease Term and Discount Rate [Abstract]
Weighted-average remaining lease term	11 years 4 months 9 days	5 years 5 months 26 days	11 years 4 months 9 days	5 years 5 months 26 days
Weighted-average discount rate	7.21%	10.77%	7.21%	10.77%
Maturities of Lease Liabilities [Abstract]
2022 (excluding the nine months ended September 30, 2022)	$ 4,741		$ 4,741
2023	16,167		16,167
2024	16,780		16,780
2025	14,841		14,841
2026	12,416		12,416
2027	9,532		9,532
Thereafter	69,499		69,499
Total lease payments	143,976		143,976
Less: imputed interest	(41,664)		(41,664)		$ (12,200)
Present value of lease liabilities	$ 102,312		$ 102,312
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