Shareholders' Equity And Earnings Per Share (Components Of Other Comprehensive Income (Loss)) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Activity Accumulated Other Comprehensive Income [Roll Forward]
Balance	$ 3,990,218	$ 3,446,950	$ 3,691,250	$ 3,267,570
Other comprehensive (loss) income during the period, net of tax, before reclassifications	(4,325)	8,667	25,160	46,309
Amount reclassified from accumulated other comprehensive income (loss) into net income, net of tax	4,121	(2,073)	8,808	(8,012)
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)	(42)	(131)	(302)
Total other comprehensive (loss) income	(244)	6,552	33,837	37,995
Balance	4,074,089	3,540,325	4,074,089	3,540,325
Accumulated Unrealized Gains (Losses) on Securities
Activity Accumulated Other Comprehensive Income [Roll Forward]
Balance	85,506	4,209	14,982	(42,353)
Other comprehensive (loss) income during the period, net of tax, before reclassifications	(10,682)	13,371	60,043	60,527
Amount reclassified from accumulated other comprehensive income (loss) into net income, net of tax	(36)	(292)	(146)	(626)
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)	(42)	(131)	(302)
Total other comprehensive (loss) income	(10,758)	13,037	59,766	59,599
Balance	74,748	17,246	74,748	17,246
Accumulated Unrealized (Losses) Gains on Derivative Instruments
Activity Accumulated Other Comprehensive Income [Roll Forward]
Balance	(43,606)	(12,044)	(13,141)	7,857
Other comprehensive (loss) income during the period, net of tax, before reclassifications	3,466	(3,233)	(31,796)	(17,529)
Amount reclassified from accumulated other comprehensive income (loss) into net income, net of tax	4,157	(1,781)	8,954	(7,386)
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	7,623	(5,014)	(22,842)	(24,915)
Balance	(35,983)	(17,058)	(35,983)	(17,058)
Accumulated Foreign Currency Translation Adjustments
Activity Accumulated Other Comprehensive Income [Roll Forward]
Balance	(42,497)	(37,594)	(36,519)	(42,376)
Other comprehensive (loss) income during the period, net of tax, before reclassifications	2,891	(1,471)	(3,087)	3,311
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	2,891	(1,471)	(3,087)	3,311
Balance	(39,606)	(39,065)	(39,606)	(39,065)
Accumulated other comprehensive loss
Activity Accumulated Other Comprehensive Income [Roll Forward]
Balance	(597)	(45,429)	(34,678)	(76,872)
Total other comprehensive (loss) income	(244)	6,552	33,837	37,995
Balance	$ (841)	$ (38,877)	$ (841)	$ (38,877)