INVESTMENTS - Gross Unrealized Losses (Narrative) (Details) $ in Thousands	Jun. 30, 2025 USD ($) security	Dec. 31, 2024 USD ($) security
Debt Securities, Available-for-sale [Line Items]
Number of securities in unrealized loss position | security	2,389	3,994
Unrealized loss position	$ 140,424	$ 311,335
Number of securities in a continuous unrealized loss position | security	1,590	2,108
Debt securities fair value	$ 1,548,088	$ 2,253,146
Below Investment Grade or Not Rated
Debt Securities, Available-for-sale [Line Items]
Unrealized loss position	$ 9,000	$ 14,000