Shareholders' Equity And Earnings Per Share (Components Of Other Comprehensive Income (Loss)) (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Jan. 01, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Activity Accumulated Other Comprehensive Income [Roll Forward]
Balance	$ 2,976,939	$ 3,371,972	$ 3,031,250	$ 3,267,570	$ 2,976,939
Cumulative effect adjustment from the adoption of ASU 2018-02	(2,974)
Other comprehensive income (loss) during the period, net of tax, before reclassifications		8,448	(7,139)	37,642	(33,764)
Amount reclassified from accumulated other comprehensive loss into net income, net of tax		(3,376)	(967)	(5,939)	(751)
Amount reclassified from accumulated other comprehensive loss related to amortization of unrealized losses on investment securities transferred to held-to-maturity from available-for-sale, net of tax		(157)	(15)	(260)	(12)
Total other comprehensive income (loss)		4,915	(8,121)	31,443	(34,527)
Balance		3,446,950	3,106,871	3,446,950	3,106,871
Accumulated Unrealized Losses on Securities
Activity Accumulated Other Comprehensive Income [Roll Forward]
Balance	(15,813)	(14,451)	(47,968)	(42,353)	(15,813)
Cumulative effect adjustment from the adoption of ASU 2018-02	(4,517)
Other comprehensive income (loss) during the period, net of tax, before reclassifications		19,200	(6,914)	47,156	(33,388)
Amount reclassified from accumulated other comprehensive loss into net income, net of tax		(383)	12	(334)	725
Amount reclassified from accumulated other comprehensive loss related to amortization of unrealized losses on investment securities transferred to held-to-maturity from available-for-sale, net of tax		(157)	(15)	(260)	(12)
Total other comprehensive income (loss)		18,660	(6,917)	46,562	(32,675)
Balance		4,209	(54,885)	4,209	(54,885)
Accumulated Unrealized Gains on Derivative Instruments
Activity Accumulated Other Comprehensive Income [Roll Forward]
Balance	7,164	4,206	10,956	7,857	7,164
Cumulative effect adjustment from the adoption of ASU 2018-02	1,543
Other comprehensive income (loss) during the period, net of tax, before reclassifications		(13,257)	1,771	(14,296)	4,517
Amount reclassified from accumulated other comprehensive loss into net income, net of tax		(2,993)	(979)	(5,605)	(1,476)
Amount reclassified from accumulated other comprehensive loss related to amortization of unrealized losses on investment securities transferred to held-to-maturity from available-for-sale, net of tax		0	0	0	0
Total other comprehensive income (loss)		(16,250)	792	(19,901)	3,041
Balance		(12,044)	11,748	(12,044)	11,748
Accumulated Foreign Currency Translation Adjustments
Activity Accumulated Other Comprehensive Income [Roll Forward]
Balance	(33,186)	(40,099)	(36,083)	(42,376)	(33,186)
Cumulative effect adjustment from the adoption of ASU 2018-02	0
Other comprehensive income (loss) during the period, net of tax, before reclassifications		2,505	(1,996)	4,782	(4,893)
Amount reclassified from accumulated other comprehensive loss into net income, net of tax		0	0	0	0
Amount reclassified from accumulated other comprehensive loss related to amortization of unrealized losses on investment securities transferred to held-to-maturity from available-for-sale, net of tax		0	0	0	0
Total other comprehensive income (loss)		2,505	(1,996)	4,782	(4,893)
Balance		(37,594)	(38,079)	(37,594)	(38,079)
Accumulated other comprehensive loss
Activity Accumulated Other Comprehensive Income [Roll Forward]
Balance	(41,835)	(50,344)	(73,095)	(76,872)	(41,835)
Cumulative effect adjustment from the adoption of ASU 2018-02	(2,974)
Total other comprehensive income (loss)		4,915	(8,121)	31,443	(34,527)
Balance		$ (45,429)	$ (81,216)	$ (45,429)	$ (81,216)
ASU 2016-01
Activity Accumulated Other Comprehensive Income [Roll Forward]
Cumulative effect adjustment from the adoption of new accounting pronouncement	(1,880)
ASU 2016-01 | Accumulated Unrealized Losses on Securities
Activity Accumulated Other Comprehensive Income [Roll Forward]
Cumulative effect adjustment from the adoption of new accounting pronouncement	(1,880)
ASU 2016-01 | Accumulated Unrealized Gains on Derivative Instruments
Activity Accumulated Other Comprehensive Income [Roll Forward]
Cumulative effect adjustment from the adoption of new accounting pronouncement	0
ASU 2016-01 | Accumulated Foreign Currency Translation Adjustments
Activity Accumulated Other Comprehensive Income [Roll Forward]
Cumulative effect adjustment from the adoption of new accounting pronouncement	0
ASU 2016-01 | Accumulated other comprehensive loss
Activity Accumulated Other Comprehensive Income [Roll Forward]
Cumulative effect adjustment from the adoption of new accounting pronouncement	$ (1,880)