Condensed Financial Information - Parent Company Only Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash Flows From Operating Activities:
Net Income	$ 275,497	$ 178,040	$ 226,339
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities [Abstract]
Amortization of issuance costs and discounts on long-term borrowings	1,846	1,128	842
Stock-based compensation	8,402	7,529	7,413
(Decrease) increase in other liabilities and payable to non-bank subsidiaries	(62,559)	(110,781)	(195,903)
Total adjustments	66,775	(20,675)	(98,626)
Net cash provided by operating activities	342,272	157,365	127,713
Cash Flows From Investing Activities
Net cash used in investing activities	(213,967)	(2,499,480)	(893,346)
Cash Flows From Financing Activities:
Repayments of long-term borrowings	(710,633)	(85,410)	(596,056)
Proceeds from long-term borrowings	620	495,898	485,000
Net proceeds from issuance of preferred stock	0	192,878	0
Net proceeds from issuance of common stock	7,437	7,375	6,362
Dividends paid	(112,028)	(90,956)	(92,330)
Acquisition of treasury stock	(43,909)	(39,748)	(111,457)
Net cash (used in) provided by financing activities	(337,523)	3,672,156	837,737
Parent
Cash Flows From Operating Activities:
Net Income	275,497	178,040	226,339
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities [Abstract]
Amortization of issuance costs and discounts on long-term borrowings	1,846	1,128	842
Stock-based compensation	8,402	7,529	7,413
(Increase) decrease in other assets	119,822	(307,976)	(20,449)
Equity in undistributed net income of subsidiaries	148,091	(55,895)	(38,400)
Amortization of Other Deferred Charges	12,390	0	0
(Decrease) increase in other liabilities and payable to non-bank subsidiaries	78,716	(244,598)	1,580
Total adjustments	369,267	(599,812)	(49,014)
Net cash provided by operating activities	644,764	(421,772)	177,325
Cash Flows From Investing Activities
Net cash used in investing activities	0	0	0
Cash Flows From Financing Activities:
Repayments of long-term borrowings	(153,612)	(19,453)	0
Proceeds from long-term borrowings	0	370,898	0
Net proceeds from issuance of preferred stock	0	192,878	0
Net proceeds from issuance of common stock	7,437	7,375	6,362
Dividends paid	(112,028)	(90,956)	(92,330)
Acquisition of treasury stock	(43,909)	(39,748)	(111,457)
Net cash (used in) provided by financing activities	(302,112)	420,994	(197,425)
Net (Decrease) Increase in Cash and Cash Equivalents	342,652	(778)	(20,100)
Cash and Cash Equivalents at Beginning of Year	10,063	10,841	30,941
Cash and Cash Equivalents at End of Year	$ 352,715	$ 10,063	$ 10,841