Unaudited Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Non-cumulative preferred shares	Common shares	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income (loss), net of deferred income tax	Unrealized appreciation (decline) in value of available-for-sale securities, net of deferred income tax	Foreign currency translation adjustments, net of deferred income tax	Common shares held in treasury, at cost
Balance at beginning of period at Dec. 31, 2020		$ 780,000	$ 643	$ 1,977,794	$ 12,362,463	$ 488,895	$ 501,295	$ (12,400)	$ (2,503,909)
Common shares issued, net			2
Amortization of share-based compensation				40,573
Other changes				(3,626)
Net income (loss)	$ 475,708				475,708
Net (income) loss attributable to noncontrolling interests	(37,552)				(37,552)
Preferred share dividends	(10,403)				(10,403)
Unrealized holding gains (losses) during period, net of reclassification adjustment							(259,053)
Unrealized holding gains (losses) during period attributable to noncontrolling interests							4,469
Foreign currency translation adjustments	(28,584)							(28,584)
Foreign currency translation adjustments attributable to noncontrolling interests								100
Shares repurchased for treasury									(191,048)
Balance at end of period at Mar. 31, 2021	13,096,472	780,000	645	2,014,741	12,790,216	205,827	246,711	(40,884)	(2,694,957)
Non-redeemable noncontrolling interests, end of period at Mar. 31, 2021	876,864
Total shareholders’ equity at Mar. 31, 2021	13,973,336
Balance at beginning of period at Dec. 31, 2021	13,545,896	830,000	648	2,085,075	14,455,868	(64,600)	13,486	(78,086)	(3,761,095)
Common shares issued, net			3
Amortization of share-based compensation				45,368
Other changes				3,798
Net income (loss)	197,432				197,432
Net (income) loss attributable to noncontrolling interests	(1,632)				(1,632)
Preferred share dividends	(10,184)				(10,184)
Unrealized holding gains (losses) during period, net of reclassification adjustment							(582,077)
Unrealized holding gains (losses) during period attributable to noncontrolling interests							0
Foreign currency translation adjustments	(2,768)							(2,768)
Foreign currency translation adjustments attributable to noncontrolling interests								0
Shares repurchased for treasury									(276,247)
Balance at end of period at Mar. 31, 2022	12,919,589	$ 830,000	$ 651	$ 2,134,241	$ 14,641,484	$ (649,445)	$ (568,591)	$ (80,854)	$ (4,037,342)
Non-redeemable noncontrolling interests, end of period at Mar. 31, 2022	0
Total shareholders’ equity at Mar. 31, 2022	$ 12,919,589