Condensed Parent Company Financial Statements (Statements Of Cash Flows) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Activities:
Net income	$ 466,151	$ 292,990	$ 355,697
Adjustments to reconcile net income to net cash provided by operating activities
Provision for credit losses	(59,263)	214,220	53,864
Gains on investment securities, net	1,059	2,373	(3,525)
Depreciation and amortization	101,797	96,369	88,362
Deferred income tax (benefit) expense	(2,861)	(4,058)	44,557
Stock-based compensation expense	16,177	(4,938)	11,304
Decrease in other assets	187,743	(131,870)	(133,022)
Increase (decrease) in other liabilities	78,475	46,924	(11,898)
Net Cash Provided by (Used for) Operating Activities	1,130,872	(518,465)	265,993
Investing Activities:
Payments to Acquire Businesses, Net of Cash Acquired	(585,402)	0	(108,365)
Net Cash Used for Investing Activities	(5,928,859)	(7,182,424)	(4,018,949)
Financing Activities:
(Decrease) increase in subordinated notes, other borrowings and junior subordinated debentures, net	(27,784)	88,596	15,480
Proceeds from the issuance of preferred stock, net	0	277,613	0
Issuance of common shares resulting from exercise of stock options and employee stock purchase plan	19,824	15,059	10,667
Dividends paid	(98,629)	(85,890)	(65,110)
Common stock repurchases under authorized program	(9,540)	(92,055)	0
Common stock repurchases for tax withholdings related to stock-based compensation	0	(1,377)	(1,297)
Net Cash Provided by Financing Activities	4,886,718	7,736,887	3,647,232
Net Increase (Decrease) in Cash and Cash Equivalents	88,731	35,998	(105,724)
Cash and Cash Equivalents at Beginning of Period	322,474	286,476	392,200
Cash and Cash Equivalents at End of Period	411,205	322,474	286,476
Reportable Legal Entities | Parent Company
Operating Activities:
Net income	466,151	292,990	355,697
Adjustments to reconcile net income to net cash provided by operating activities
Provision for credit losses	0	0	(18)
Gains on investment securities, net	(1,794)	(192)	(1,900)
Depreciation and amortization	28,783	22,224	15,675
Deferred income tax (benefit) expense	(5,350)	11,336	8,342
Stock-based compensation expense	6,769	(2,813)	5,611
Decrease in other assets	6,598	4,838	4,940
Increase (decrease) in other liabilities	1,225	2,388	(13,181)
Equity in undistributed net income of subsidiaries	(482,336)	(162,942)	(336,665)
Net Cash Provided by (Used for) Operating Activities	20,046	167,829	38,501
Investing Activities:
Capital contributions to subsidiaries, net	(27,000)	(12,000)	(22,500)
Payments to Acquire Businesses, Net of Cash Acquired	0	0	(124,338)
Other investing activity, net	(22,877)	(40,127)	(51,495)
Net Cash Used for Investing Activities	(49,877)	(52,127)	(198,333)
Financing Activities:
(Decrease) increase in subordinated notes, other borrowings and junior subordinated debentures, net	(23,274)	(2,690)	273,886
Proceeds from the issuance of preferred stock, net	0	277,613	0
Issuance of common shares resulting from exercise of stock options and employee stock purchase plan	19,824	15,059	10,667
Dividends paid	(98,629)	(85,890)	(65,110)
Common stock repurchases under authorized program	(9,540)	(92,055)	0
Common stock repurchases for tax withholdings related to stock-based compensation	0	(1,377)	(1,297)
Net Cash Provided by Financing Activities	(111,619)	110,660	218,146
Net Increase (Decrease) in Cash and Cash Equivalents	(141,450)	226,362	58,314
Cash and Cash Equivalents at Beginning of Period	322,607	96,245	37,931
Cash and Cash Equivalents at End of Period	$ 181,157	$ 322,607	$ 96,245