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, 2019		$ 650,000	$ 44,148	$ 568,277	$ (1,939)	$ 4,710,881
Statement of Changes in Stockholders' Equity
Issuance of shares (Note 11)		0	6,777	1,088,730
Repurchase of shares (Note 11)		(125,000)	(406)	(62,215)
Offering expenses (Note 11)				0
Change in redeemable noncontrolling interest				(334)
Exercise of options and issuance of restricted stock awards (Notes 11 and 16)			292	28,748
Change in net unrealized gains (loss) on investments, net of tax	$ 606				606
Foreign currency translation adjustments, net of tax	(11,309)
Net income (loss)	993,058
Net (income) loss attributable to redeemable noncontrolling interests (Note 9)	(230,653)					(230,653)
Dividends on common shares (Note 11)	(68,500)					(68,490)
Dividends on preference shares (Note 11)	(30,923)					(30,923)
Ending balance at Dec. 31, 2020	7,560,248	525,000	50,811	1,623,206	(12,642)	5,373,873
Statement of Changes in Stockholders' Equity
Issuance of shares (Note 11)		500,000	0	0
Repurchase of shares (Note 11)		(275,000)	(6,579)	(1,024,751)
Offering expenses (Note 11)				(11,347)
Change in redeemable noncontrolling interest				(6,994)
Exercise of options and issuance of restricted stock awards (Notes 11 and 16)			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				4,225
Net income (loss)	(103,440)
Net (income) loss attributable to redeemable noncontrolling interests (Note 9)	63,285					63,285
Dividends on common shares (Note 11)	(67,800)					(67,828)
Dividends on preference shares (Note 11)	(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 11)		0	0	0
Repurchase of shares (Note 11)		0	(1,051)	(161,788)
Offering expenses (Note 11)				0
Change in redeemable noncontrolling interest				(5,549)
Exercise of options and issuance of restricted stock awards (Notes 11 and 16)			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 9)	98,613					98,613
Dividends on common shares (Note 11)	(64,700)					(64,675)
Dividends on preference shares (Note 11)	(35,375)					(35,375)
Ending balance at Dec. 31, 2022	$ 5,325,274	$ 750,000	$ 43,718	$ 475,647	$ (15,462)	$ 4,071,371