Shareholders' Equity And Earnings Per Share (Components Of Other Comprehensive Income (Loss)) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Activity Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	$ 4,339,011	$ 3,990,218	$ 4,115,995	$ 3,691,250
Other comprehensive (loss) income during the period, net of tax, before reclassifications	(13,393)	(4,325)	(27,933)	25,160
Amount reclassified from accumulated other comprehensive income (loss) into net income, net of tax	4,717	4,121	14,084	8,808
Amount reclassified from accumulated other comprehensive income (loss) related to amortization of unrealized gains on investment securities transferred to held-to-maturity from available-for-sale, net of tax	(40)	(40)	(116)	(131)
Total other comprehensive (loss) income	(8,716)	(244)	(13,965)	33,837
Ending balance	4,410,317	4,074,089	4,410,317	4,074,089
Accumulated Unrealized Gains (Losses) on Securities
Activity Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	30,189	85,506	70,737	14,982
Other comprehensive (loss) income during the period, net of tax, before reclassifications	(10,374)	(10,682)	(50,265)	60,043
Amount reclassified from accumulated other comprehensive income (loss) into net income, net of tax	(256)	(36)	(837)	(146)
Amount reclassified from accumulated other comprehensive income (loss) related to amortization of unrealized gains on investment securities transferred to held-to-maturity from available-for-sale, net of tax	(40)	(40)	(116)	(131)
Total other comprehensive (loss) income	(10,670)	(10,758)	(51,218)	59,766
Ending balance	19,519	74,748	19,519	74,748
Accumulated Unrealized Gains (Losses) on Derivative Instruments
Activity Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	7,720	(43,606)	(23,090)	(13,141)
Other comprehensive (loss) income during the period, net of tax, before reclassifications	1,631	3,466	22,493	(31,796)
Amount reclassified from accumulated other comprehensive income (loss) into net income, net of tax	4,973	4,157	14,921	8,954
Amount reclassified from accumulated other comprehensive income (loss) related to amortization of unrealized gains on investment securities transferred to held-to-maturity from available-for-sale, net of tax	0	0	0	0
Total other comprehensive (loss) income	6,604	7,623	37,414	(22,842)
Ending balance	14,324	(35,983)	14,324	(35,983)
Accumulated Foreign Currency Translation Adjustments
Activity Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(27,776)	(42,497)	(32,265)	(36,519)
Other comprehensive (loss) income during the period, net of tax, before reclassifications	(4,650)	2,891	(161)	(3,087)
Amount reclassified from accumulated other comprehensive income (loss) into net income, net of tax	0	0	0	0
Amount reclassified from accumulated other comprehensive income (loss) related to amortization of unrealized gains on investment securities transferred to held-to-maturity from available-for-sale, net of tax	0	0	0	0
Total other comprehensive (loss) income	(4,650)	2,891	(161)	(3,087)
Ending balance	(32,426)	(39,606)	(32,426)	(39,606)
Accumulated other comprehensive (loss) income
Activity Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	10,133	(597)	15,382	(34,678)
Total other comprehensive (loss) income	(8,716)	(244)	(13,965)	33,837
Ending balance	$ 1,417	$ (841)	$ 1,417	$ (841)