Consolidated Statements Of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total		Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Retained Earnings [Member] Cumulative Effect, Period of Adoption, Adjustment Revision of Prior Period, Adjustment	AOCI Attributable to Parent	Treasury Stock at Cost [Member]	Parent [Member]	Non-controlling Interests
Balance, beginning of period at Dec. 31, 2019			$ 310,000	$ 16,749	$ 1,903,703	$ 1,715,704	$ (7,772)	$ (11,705)	$ (319,660)		$ 54,999
Common stock repurchased	$ (56,200)								(56,160)
Unit amortization, net of forfeitures					33,799
Distributions under employee plans					(105,570)	(46,717)			54,579
Net income	86,589					86,589
Dividends declared, Common						(14,916)
Dividends declared, Preferred						(4,844)
Dividends declared to equity-award holders					350
Unrealized losses on securities, net of tax	(73,227)	[1]						(73,227)
Unrealized gains/(losses) on cash flow hedging activities, net of tax								(1,706)
Foreign currency translation adjustment, net of tax	(9,822)							(9,822)
Other					85	867
Deconsolidation of non-controlling interest											$ (54,999)
Balance, end of period at Mar. 31, 2020	3,470,326		310,000	16,749	1,832,367	1,728,911		(96,460)	(321,241)	$ 3,470,326
Balance, beginning of period at Dec. 31, 2020	4,238,766		535,000	16,749	1,888,982	2,078,135		27,639	(307,739)
Common stock repurchased	(12,700)								(12,038)
Unit amortization, net of forfeitures					34,811
Distributions under employee plans					(109,224)	(21,587)			62,278
Net income	173,015					173,015
Dividends declared, Common						(18,470)
Dividends declared, Preferred						(8,289)
Unrealized losses on securities, net of tax	(22,670)	[1]						(22,670)
Foreign currency translation adjustment, net of tax	2,336							2,336
Other					47	(103)
Balance, end of period at Mar. 31, 2021	$ 4,318,872		$ 535,000	$ 16,749	$ 1,814,616	$ 2,202,701		$ 7,305	$ (257,499)	$ 4,318,872

[1] There were no reclassifications to earnings for the three months ended March 31, 2021. Net of reclassifications to earnings of realized losses of $0.5 million during the three months ended March 31, 2020.