Consolidated Statements Of Changes In Shareholders' Equity - 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	AOCI Attributable to Parent Cumulative Effect, Period of Adoption, Adjustment Revision of Prior Period, Adjustment	Treasury Stock at Cost [Member]	Noncontrolling Interest	Parent [Member]
Balance, beginning of year at Dec. 31, 2017				$ 150,000	$ 16,329	$ 1,727,765	$ 1,033,526		$ (26,736)		$ (39,308)
Distributions under employee plans					123	(60,256)	(10,985)				28,655
Common stock repurchased											(170,204)
Issuance of common stock for acquisitions					297	110,374
Unit amortization, net of forfeitures						102,971
Net income		$ 393,968					393,968
Dividends declared, Common							(41,450)
Dividends declared, Preferred							(9,375)
Dividends declared to equity-award holders						6,812
Other						55	1,943
Unrealized gains/(losses) on securities, net of tax		(36,254)	[1],[2],[3],[4]						(36,254)
Unrealized losses on cash flow hedging activities, net of tax									(792)
Foreign currency translation adjustment, net of tax		(5,691)	[2],[4]						(5,691)
Capital contributions from non-controlling interest holders												$ 30,000
Balance, end of year at Dec. 31, 2018		3,197,593		150,000	16,749	1,887,721	1,366,503		(72,523)		(180,857)	30,000	$ 3,167,593
Cumulative adjustments for accounting changes	[5]							$ (1,124)		$ (3,050)
Distributions under employee plans						(91,898)	(19,819)				76,627
Common stock repurchased		(215,400)									(215,430)
Unit amortization, net of forfeitures						112,864
Net income		448,396					449,986					1,590
Dividends declared, Common							(50,743)
Dividends declared, Preferred							(17,319)
Issuance of preferred stock				160,000		(5,012)
Other						28	(1,787)
Unrealized gains/(losses) on securities, net of tax		60,288	[1],[2],[3],[4]						60,288
Unrealized losses on cash flow hedging activities, net of tax									(4,402)
Foreign currency translation adjustment, net of tax		4,932	[2],[4]						4,932
Capital contributions from non-controlling interest holders												26,800
Distributions to non-controlling interest holders												(3,391)
Balance, end of year at Dec. 31, 2019		3,669,790		310,000	16,749	1,903,703	1,715,704		(11,705)		(319,660)	54,999	3,614,791
Cumulative adjustments for accounting changes	[5]							(11,117)
Distributions under employee plans						(126,514)	(49,427)				70,182
Common stock repurchased		(58,300)									(58,261)
Unit amortization, net of forfeitures						118,229
Net income		503,472					503,472
Dividends declared, Common							(56,967)
Dividends declared, Preferred							(27,261)
Issuance of preferred stock				225,000		(7,005)
Dividends declared to equity-award holders						350
Other						219	386
Unrealized gains/(losses) on securities, net of tax		33,133	[1],[2],[3],[4]						33,133
Unrealized losses on cash flow hedging activities, net of tax									(651)
Foreign currency translation adjustment, net of tax		6,862	[2],[4]						6,862
Deconsolidation of non-controlling interest												$ (54,999)
Balance, end of year at Dec. 31, 2020		$ 4,238,766		$ 535,000	$ 16,749	$ 1,888,982	$ 2,078,135		$ 27,639		$ (307,739)		$ 4,238,766
Cumulative adjustments for accounting changes	[5]							$ (7,772)

[1] As part of the adoption of ASU 2019-04, in the third quarter of 2019, the Company made a one-time election to transfer a portion of its held-to-maturity securities to available-for-sale. The transfer resulted in a net of tax increase to comprehensive income of $17.9 million. See Notes 2 and 7 for additional information on the transfer.

[2] Net of a tax expense of $11.5 million, tax expense of $20.2 million, and tax benefit of $11.2 million for the years ended December 31, 2020, 2019, and 2018, respectively.

[3] Reclassifications to earnings were immaterial for the years ended December 31, 2020 and 2019. Amounts are net of reclassifications to earnings of realized losses of $2.9 million for the year ended December 31, 2018.

[4] The adoption of ASU 2018-02 on January 1, 2018, resulted in a reclassification of $3.1 million to retained earnings related to cash flow hedges and investment portfolio risk. The reclassification is reflected in the activity for the year ended December 31, 2018. See Note 2 for further details.

[5] Cumulative adjustments for accounting changes relate to the adoption of certain accounting updates. See Note 2 of the Notes to Consolidated Financial Statements for additional information.