INVESTMENTS - Maturity Period (Details) $ in Thousands	Dec. 31, 2023 USD ($)
INVESTMENTS
Amortized Cost	$ 1,032,810
Fair Value	1,032,036
Commercial paper | Less than 1 year
INVESTMENTS
Amortized Cost	163,775
Fair Value	163,774
Municipal securities | Less than 1 year
INVESTMENTS
Amortized Cost	361
Fair Value	361
U.S. government agency securities | Less than 1 year
INVESTMENTS
Amortized Cost	116,524
Fair Value	116,548
U.S. government agency securities | Due 1 - 10 years
INVESTMENTS
Amortized Cost	23,485
Fair Value	23,531
Certificates of deposit | Less than 1 year
INVESTMENTS
Amortized Cost	15,590
Fair Value	15,590
U.S. treasuries | Less than 1 year
INVESTMENTS
Amortized Cost	412,936
Fair Value	412,057
U.S. treasuries | Due 1 - 10 years
INVESTMENTS
Amortized Cost	35,896
Fair Value	35,967
Corporate bonds | Less than 1 year
INVESTMENTS
Amortized Cost	247,340
Fair Value	247,275
Corporate bonds | Due 1 - 10 years
INVESTMENTS
Amortized Cost	16,903
Fair Value	$ 16,933