CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands		Total	Preferred shares	Common shares (par value)	Additional paid-in capital	Accumulated other comprehensive income (loss)	Unrealized gains (losses) on available for sale investments, net of tax:	Cumulative foreign currency translation adjustments, net of tax:	Retained earnings	Treasury shares, at cost
Balance at beginning of period at Dec. 31, 2023			$ 550,000	$ 2,206	$ 2,383,030	$ (365,836)	$ (347,659)	$ (18,177)	$ 6,440,528	$ (3,746,732)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares reissued					(27,816)					30,060
Share-based compensation expense					21,030
Other comprehensive income (loss)		$ (29,132)					(18,378)	(10,754)
Net income		607,425							607,425
Preferred share dividends	[1]								(15,125)
Common share dividends	[1]								(75,643)
Shares repurchased										(114,524)
Balance at end of period at Jun. 30, 2024		5,659,471	550,000	2,206	2,376,244	(394,968)	(366,037)	(28,931)	6,957,185	(3,831,196)
Balance at beginning of period at Mar. 31, 2024			550,000	2,206	2,368,144	(411,849)	(384,721)	(27,128)	6,790,558	(3,793,904)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares reissued					(1,504)					1,504
Share-based compensation expense					9,604
Other comprehensive income (loss)		16,881					18,684	(1,803)
Net income		211,964							211,964
Preferred share dividends	[1]								(7,563)
Common share dividends	[1]								(37,774)
Shares repurchased										(38,796)
Balance at end of period at Jun. 30, 2024		5,659,471	550,000	2,206	2,376,244	(394,968)	(366,037)	(28,931)	6,957,185	(3,831,196)
Balance at beginning of period at Dec. 31, 2024		6,089,379	550,000	2,206	2,394,063	(267,557)	(225,617)	(41,940)	7,341,569	(3,930,902)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares reissued					(30,464)					32,495
Share-based compensation expense					21,060
Other comprehensive income (loss)		245,847					229,980	15,867
Net income		417,427							417,427
Preferred share dividends	[1]								(15,125)
Common share dividends	[1]								(70,625)
Shares repurchased										(515,596)
Balance at end of period at Jun. 30, 2025		6,174,398	550,000	2,206	2,384,659	(21,710)	4,363	(26,073)	7,673,246	(4,414,003)
Balance at beginning of period at Mar. 31, 2025			550,000	2,206	2,374,804	(152,376)	(110,280)	(42,096)	7,492,484	(4,364,319)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares reissued					(1,406)					1,406
Share-based compensation expense					11,261
Other comprehensive income (loss)		130,666					114,643	16,023
Net income		223,358							223,358
Preferred share dividends	[1]								(7,563)
Common share dividends	[1]								(35,033)
Shares repurchased										(51,090)
Balance at end of period at Jun. 30, 2025		$ 6,174,398	$ 550,000	$ 2,206	$ 2,384,659	$ (21,710)	$ 4,363	$ (26,073)	$ 7,673,246	$ (4,414,003)

[1] Refer to Note 9 'Shareholders' Equity' for details on dividends declared and paid related to the Company's common and preferred shares.