Accumulated Other Comprehensive Income (Loss) (Components of Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Before-Tax
Net change	$ (60,299)	$ 11,146	$ (145,143)	$ 71,435
Tax Effect
Net change	17,420	(966)	43,250	(19,713)
Net-of-Tax
Other comprehensive (loss) income	(42,879)	10,180	(101,893)	51,722
AFS Debt Securities
Before-Tax
Net unrealized (losses) gains arising during the period	(58,138)	7,304	(143,131)	82,767
Net realized losses (gains) reclassified into net income	(354)	(698)	(1,178)	(11,867)
Net change	(58,492)	6,606	(144,309)	70,900
Tax Effect
Net unrealized (losses) gains arising during the period	17,210	(2,178)	42,384	(24,505)
Net realized losses (gains) reclassified into net income	104	206	348	3,508
Net change	17,314	(1,972)	42,732	(20,997)
Net-of-Tax
Net unrealized gains (losses) arising during the period	(40,928)	5,126	(100,747)	58,262
Net realized losses (gains) reclassified into net income	(250)	(492)	(830)	(8,359)
Other comprehensive (loss) income	(41,178)	4,634	(101,577)	49,903
Cash Flow Hedges
Before-Tax
Net unrealized (losses) gains arising during the period	(170)	34	150	(1,449)
Net realized losses (gains) reclassified into net income	241	87	619	(290)
Net change	71	121	769	(1,739)
Tax Effect
Net unrealized (losses) gains arising during the period	49	(9)	(42)	411
Net realized losses (gains) reclassified into net income	(69)	(25)	(176)	82
Net change	(20)	(34)	(218)	493
Net-of-Tax
Net unrealized gains (losses) arising during the period	(121)	25	108	(1,038)
Net realized losses (gains) reclassified into net income	172	62	443	(208)
Other comprehensive (loss) income	51	87	551	(1,246)
Foreign Currency Translation Adjustments, Net of Hedges
Before-Tax
Net unrealized (losses) gains arising during the period	(1,878)	4,419	(1,603)	2,274
Net change	(1,878)	4,419	(1,603)	2,274
Tax Effect
Net unrealized (losses) gains arising during the period	126	1,040	736	791
Net change	126	1,040	736	791
Net-of-Tax
Net unrealized gains (losses) arising during the period	(1,752)	5,459	(867)	3,065
Net realized losses (gains) reclassified into net income	0	0	0	0
Other comprehensive (loss) income	$ (1,752)	$ 5,459	$ (867)	$ 3,065

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