EQUITY (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended							9 Months Ended
	May 31, 2026	Sep. 30, 2026	Jun. 30, 2026	Mar. 31, 2026	Dec. 31, 2025	Sep. 30, 2025	Jun. 30, 2025	Mar. 31, 2025	Sep. 30, 2026
Class of Stock [Line Items]
Quarterly dividend on all classes of common stock (in dollars per share)		$ 1.60	$ 1.60	$ 1.60	$ 1.50	$ 1.50	$ 1.50	$ 1.50
Repurchase of Class C Common Stock (in shares)									47,319
Repurchase of Class C Common Stock				$ 7,178
Remaining authorized amount for repurchase		$ 30,000							$ 30,000
Capital required for capital adequacy		1,200,000			$ 1,000,000				1,200,000
Capital		1,900,000			1,700,000				1,900,000
Excess capital		$ 734,600			$ 677,700				734,600
Class C non-voting common stock
Class of Stock [Line Items]
Repurchase of Class C Common Stock									$ 7,100
Series I
Class of Stock [Line Items]
Preferred stock, shares issued (in shares)	4,000,000.0	4,000,000			4,000,000				4,000,000
Preferred stock, dividend rate	6.875%
Preferred stock, par value (in dollars per share)	$ 25.00	$ 25			$ 25				$ 25
Payments of stock issuance costs	$ 3,200