Shareholders' Equity (Components of Other Comprehensive Income (Loss), Including the Related Income Tax Effects) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2018
Activity Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	$ 3,267,570	$ 2,976,939	$ 2,695,617
Other comprehensive income during the period, net of tax, before reclassification	50,717	(24,746)	24,425
Amount reclassified from accumulated other comprehensive income into net income, net of tax	(8,175)	(5,372)	(38)
Amount reclassified from accumulated other comprehensive income related to amortization of unrealized gains on investment securities transferred to held-to-maturity from available-for-sale	(348)	(65)	(894)
Total other comprehensive income (loss)	42,194	(30,183)	23,493
Balance at end of period	3,691,250	3,267,570	2,976,939
Accumulated Unrealized Gains (Losses) on Securities
Activity Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	(42,353)	(15,813)	(29,309)
Other comprehensive income during the period, net of tax, before reclassification	58,341	(20,054)	14,417
Amount reclassified from accumulated other comprehensive income into net income, net of tax	(658)	(24)	(27)
Amount reclassified from accumulated other comprehensive income related to amortization of unrealized gains on investment securities transferred to held-to-maturity from available-for-sale	(348)	(65)	(894)
Total other comprehensive income (loss)	57,335	(20,143)	13,496
Balance at end of period	14,982	(42,353)	(15,813)
Accumulated Unrealized Gains (Losses) on Derivative Instruments
Activity Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	7,857	7,164	4,165
Other comprehensive income during the period, net of tax, before reclassification	(13,481)	4,498	3,010
Amount reclassified from accumulated other comprehensive income into net income, net of tax	(7,517)	(5,348)	(11)
Amount reclassified from accumulated other comprehensive income related to amortization of unrealized gains on investment securities transferred to held-to-maturity from available-for-sale	0	0	0
Total other comprehensive income (loss)	(20,998)	(850)	2,999
Balance at end of period	(13,141)	7,857	7,164
Accumulated Foreign Currency Translation Adjustments
Activity Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	(42,376)	(33,186)	(40,184)
Other comprehensive income during the period, net of tax, before reclassification	5,857	(9,190)	6,998
Amount reclassified from accumulated other comprehensive income into net income, net of tax	0	0	0
Amount reclassified from accumulated other comprehensive income related to amortization of unrealized gains on investment securities transferred to held-to-maturity from available-for-sale	0	0	0
Total other comprehensive income (loss)	5,857	(9,190)	6,998
Balance at end of period	(36,519)	(42,376)	(33,186)
Total Accumulated Other Comprehensive Loss
Activity Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	(76,872)	(41,835)	(65,328)
Balance at end of period	$ (34,678)	(76,872)	$ (41,835)
ASU 2016-01
Activity Accumulated Other Comprehensive Income [Roll Forward]
Cumulative effect adjustment from adoption				$ 0
ASU 2016-01 | Accumulated Unrealized Gains (Losses) on Securities
Activity Accumulated Other Comprehensive Income [Roll Forward]
Cumulative effect adjustment from adoption				(1,880)
ASU 2016-01 | Accumulated Unrealized Gains (Losses) on Derivative Instruments
Activity Accumulated Other Comprehensive Income [Roll Forward]
Cumulative effect adjustment from adoption				0
ASU 2016-01 | Accumulated Foreign Currency Translation Adjustments
Activity Accumulated Other Comprehensive Income [Roll Forward]
Cumulative effect adjustment from adoption				0
ASU 2016-01 | Total Accumulated Other Comprehensive Loss
Activity Accumulated Other Comprehensive Income [Roll Forward]
Cumulative effect adjustment from adoption				$ (1,880)
ASU 2018-02
Activity Accumulated Other Comprehensive Income [Roll Forward]
Cumulative effect adjustment from adoption		0
ASU 2018-02 | Accumulated Unrealized Gains (Losses) on Securities
Activity Accumulated Other Comprehensive Income [Roll Forward]
Cumulative effect adjustment from adoption		(4,517)
ASU 2018-02 | Accumulated Unrealized Gains (Losses) on Derivative Instruments
Activity Accumulated Other Comprehensive Income [Roll Forward]
Cumulative effect adjustment from adoption		1,543
ASU 2018-02 | Accumulated Foreign Currency Translation Adjustments
Activity Accumulated Other Comprehensive Income [Roll Forward]
Cumulative effect adjustment from adoption		0
ASU 2018-02 | Total Accumulated Other Comprehensive Loss
Activity Accumulated Other Comprehensive Income [Roll Forward]
Cumulative effect adjustment from adoption		$ (2,974)