Leases (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) item lease	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Leases
Lessee, Operating Lease, Existence of Option to Extend [true false]	false
Operating lease costs	$ 10,666	$ 9,723	$ 7,594
Non-cancelable operating lease commitments not yet commenced	$ 23,310
Number of off-campus classroom and laboratory sites | item	4
Optical fiber communication lines not yet commenced	$ 192
Weighted-average remaining lease term	8 years 14 days
Weighted-average discount rate of operating leases	3.35%
Number of financing leases | lease	0
Minimum
Leases
Term of operating leases	2 months
Maximum
Leases
Term of operating leases	10 years 8 months