OTHER COMPREHENSIVE INCOME (LOSS) - Summary of Tax Effects Allocated to Each Component of Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Before tax amount
Unrealized gains (losses) arising during the year, net of reclassification adjustment	$ (909,150)	$ (405,378)	$ 269,937
Foreign currency translation adjustment	(10,986)	621	3,571
Total other comprehensive income (loss), net of tax	(920,136)	(404,757)	273,508
Income tax (expense) benefit
Unrealized gains (losses) arising during the year, net of reclassification adjustment	103,300	46,898	(30,823)
Foreign currency translation adjustment	0	0	0
Total other comprehensive income (loss), net of tax	103,300	46,898	(30,823)
Net of tax amount
Unrealized gains (losses) arising during the year, net of reclassification adjustment	(805,850)	(358,480)	239,114
Foreign currency translation adjustment	(10,986)	621	3,571
Total other comprehensive income (loss), net of tax	(816,836)	(357,859)	242,685
Available for sale investments
Before tax amount
Adjustment for reclassification of net realized (gains) losses and impairment losses recognized in net income (loss)	335,294	(94,749)	(90,380)
Income tax (expense) benefit
Adjustment for reclassification of net realized (gains) losses and impairment losses recognized in net income (loss)	(30,369)	7,635	12,368
Net of tax amount
Adjustment for reclassification of net realized (gains) losses and impairment losses recognized in net income (loss)	304,925	(87,114)	(78,012)
Unrealized gains (losses) arising during the year, net of reclassification adjustment	(805,850)	(358,480)	239,114
Available for sale investments | Unrealized gains (losses) arising during the year for which an allowance for expected credit losses has not been recognized
Before tax amount
Unrealized gains (losses) arising during the period	(1,171,381)	(310,710)	360,357
Income tax (expense) benefit
Unrealized gains (losses) arising during the period	127,756	39,263	(43,191)
Net of tax amount
Unrealized gains (losses) arising during the period	(1,043,625)	(271,447)	317,166
Available for sale investments | Unrealized gains (losses) arising during the year for which an allowance for expected credit losses has been recognized
Before tax amount
Unrealized gains (losses) arising during the period	(73,063)	81	(40)
Income tax (expense) benefit
Unrealized gains (losses) arising during the period	5,913	0	0
Net of tax amount
Unrealized gains (losses) arising during the period	$ (67,150)	$ 81	$ (40)