Leases (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($) lease item	Mar. 31, 2022 USD ($)
Leases
Lessee, Operating Lease, Existence of Option to Extend [true false]	false
Operating lease costs	$ 3,018	$ 2,396
Non-cancelable operating lease commitments not yet commenced	$ 34,106
Number of off-campus classroom and laboratory sites | item	6
Optical fiber communication lines not yet commenced	$ 192
Weighted-average remaining lease term	7 years 10 months 6 days
Weighted-average discount rate of operating leases	3.35%
Number of financing leases | lease	0
Minimum
Leases
Term of operating leases	6 months
Maximum
Leases
Term of operating leases	10 years 5 months