INVESTMENTS IN DEBT SECURITIES - Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Short-term debt securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Less than 12 Months, Fair Value	$ 257,602	$ 190,928
Less than 12 Months, Gross Unrealized Losses	(984)	(1,299)
Greater than 12 months, Fair Value	633,612	813,607
Greater than 12 months, Gross Unrealized Losses	(14,396)	(17,679)
Total, Fair Value	891,213	1,004,535
Total, Gross Unrealized Losses	(15,380)	(18,978)
Short-term debt securities | U.S. agency securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Less than 12 Months, Fair Value	31,429	8,572
Less than 12 Months, Gross Unrealized Losses	(77)	(24)
Greater than 12 months, Fair Value	81,787	84,628
Greater than 12 months, Gross Unrealized Losses	(2,226)	(2,096)
Total, Fair Value	113,216	93,200
Total, Gross Unrealized Losses	(2,303)	(2,120)
Short-term debt securities | Corporate bonds
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Less than 12 Months, Fair Value	31,531	34,795
Less than 12 Months, Gross Unrealized Losses	(136)	(423)
Greater than 12 months, Fair Value	269,500	320,748
Greater than 12 months, Gross Unrealized Losses	(5,570)	(7,052)
Total, Fair Value	301,031	355,543
Total, Gross Unrealized Losses	(5,706)	(7,475)
Short-term debt securities | Municipal securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Less than 12 Months, Fair Value	0	587
Less than 12 Months, Gross Unrealized Losses	0	(13)
Greater than 12 months, Fair Value	4,941	5,811
Greater than 12 months, Gross Unrealized Losses	(44)	(178)
Total, Fair Value	4,941	6,398
Total, Gross Unrealized Losses	(44)	(191)
Short-term debt securities | U.S. government securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Less than 12 Months, Fair Value	194,642	146,974
Less than 12 Months, Gross Unrealized Losses	(771)	(839)
Greater than 12 months, Fair Value	269,263	394,880
Greater than 12 months, Gross Unrealized Losses	(6,415)	(8,098)
Total, Fair Value	463,904	541,854
Total, Gross Unrealized Losses	(7,186)	(8,937)
Short-term debt securities | Foreign government securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Gross Unrealized Losses	0	0
Greater than 12 months, Fair Value	8,121	7,540
Greater than 12 months, Gross Unrealized Losses	(141)	(255)
Total, Fair Value	8,121	7,540
Total, Gross Unrealized Losses	(141)	(255)
Long-term debt securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Less than 12 Months, Fair Value	122,264	100,235
Less than 12 Months, Gross Unrealized Losses	(939)	(905)
Greater than 12 months, Fair Value	170,835	471,619
Greater than 12 months, Gross Unrealized Losses	(8,670)	(25,980)
Total, Fair Value	293,098	571,854
Total, Gross Unrealized Losses	(9,609)	(26,885)
Long-term debt securities | U.S. agency securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Less than 12 Months, Fair Value	10,613	11,501
Less than 12 Months, Gross Unrealized Losses	(72)	(20)
Greater than 12 months, Fair Value	17,928	58,814
Greater than 12 months, Gross Unrealized Losses	(1,069)	(3,762)
Total, Fair Value	28,541	70,315
Total, Gross Unrealized Losses	(1,141)	(3,782)
Long-term debt securities | Corporate bonds
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Less than 12 Months, Fair Value	22,584	33,862
Less than 12 Months, Gross Unrealized Losses	(169)	(262)
Greater than 12 months, Fair Value	43,968	201,791
Greater than 12 months, Gross Unrealized Losses	(1,283)	(8,909)
Total, Fair Value	66,552	235,653
Total, Gross Unrealized Losses	(1,452)	(9,171)
Long-term debt securities | Municipal securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Less than 12 Months, Fair Value	1,436	467
Less than 12 Months, Gross Unrealized Losses	(64)	(33)
Greater than 12 months, Fair Value	8,946	8,784
Greater than 12 months, Gross Unrealized Losses	(459)	(631)
Total, Fair Value	10,382	9,251
Total, Gross Unrealized Losses	(523)	(664)
Long-term debt securities | U.S. government securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Less than 12 Months, Fair Value	87,631	54,405
Less than 12 Months, Gross Unrealized Losses	(634)	(590)
Greater than 12 months, Fair Value	99,993	201,288
Greater than 12 months, Gross Unrealized Losses	(5,859)	(12,620)
Total, Fair Value	187,623	255,693
Total, Gross Unrealized Losses	(6,493)	(13,210)
Long-term debt securities | Foreign government securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Gross Unrealized Losses	0	0
Greater than 12 months, Fair Value	0	942
Greater than 12 months, Gross Unrealized Losses	0	(58)
Total, Fair Value	0	942
Total, Gross Unrealized Losses	$ 0	$ (58)