Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Preference shares	Common shares	Additional paid-in capital	Accumulated other comprehensive income (loss)	Retained earnings
Beginning balance at Dec. 31, 2020		$ 525,000	$ 50,811	$ 1,623,206	$ (12,642)	$ 5,373,873
Statement of Changes in Stockholders' Equity
Issuance of shares (Note 12)		500,000	0	0
Repurchase of shares (Note 12)		(275,000)	(6,579)	(1,024,751)
Offering expenses (Note 12)				(11,347)
Change in redeemable noncontrolling interest				(6,994)
Exercise of options and issuance of restricted stock awards (Notes 12 and 17)			213	28,007
Change in net unrealized gains (loss) on investments, net of tax	$ (2,492)				(2,492)
Foreign currency translation adjustments, net of tax	4,225
Net income (loss)	(103,440)
Net (income) loss attributable to redeemable noncontrolling interests (Note 10)	63,285					63,285
Dividends on common shares (Note 12)	(67,800)					(67,828)
Dividends on preference shares (Note 12)	(33,266)					(33,266)
Ending balance at Dec. 31, 2021	6,624,281	750,000	44,445	608,121	(10,909)	5,232,624
Statement of Changes in Stockholders' Equity
Issuance of shares (Note 12)		0	0	0
Repurchase of shares (Note 12)		0	(1,051)	(161,788)
Offering expenses (Note 12)				0
Change in redeemable noncontrolling interest				(5,549)
Exercise of options and issuance of restricted stock awards (Notes 12 and 17)			324	34,863
Change in net unrealized gains (loss) on investments, net of tax	(4,923)				(4,923)
Foreign currency translation adjustments, net of tax	370				370
Net income (loss)	(1,159,816)
Net (income) loss attributable to redeemable noncontrolling interests (Note 10)	98,613					98,613
Dividends on common shares (Note 12)	(64,700)					(64,675)
Dividends on preference shares (Note 12)	(35,375)					(35,375)
Ending balance at Dec. 31, 2022	5,325,274	750,000	43,718	475,647	(15,462)	4,071,371
Statement of Changes in Stockholders' Equity
Issuance of shares (Note 12)		0	8,568	1,628,209
Repurchase of shares (Note 12)		0	0	0
Offering expenses (Note 12)				0
Change in redeemable noncontrolling interest				(1,404)
Exercise of options and issuance of restricted stock awards (Notes 12 and 17)			408	42,007
Change in net unrealized gains (loss) on investments, net of tax	1,082				1,082
Foreign currency translation adjustments, net of tax	169				169
Net income (loss)	3,620,127
Net (income) loss attributable to redeemable noncontrolling interests (Note 10)	(1,058,995)					(1,058,995)
Dividends on common shares (Note 12)	(75,100)					(75,112)
Dividends on preference shares (Note 12)	(35,375)					(35,375)
Ending balance at Dec. 31, 2023	$ 9,454,958	$ 750,000	$ 52,694	$ 2,144,459	$ (14,211)	$ 6,522,016