Accumulated Other Comprehensive Income (Loss) (Components of Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Before-Tax
Net change	$ 11,146	$ 15,224	$ 71,435	$ 87,876
Tax Effect
Net change	(966)	(6,219)	(19,713)	(30,669)
Net-of-Tax
Other comprehensive income	10,180	9,005	51,722	57,207
AFS Debt Securities
Before-Tax
Net unrealized gains (losses) arising during the period	7,304	16,900	82,767	92,369
Net realized (gains) losses reclassified into net income	(698)	(58)	(11,867)	(3,066)
Net change	6,606	16,842	70,900	89,303
Tax Effect
Net unrealized gains (losses) arising during the period	(2,178)	(4,996)	(24,505)	(27,308)
Net realized (gains) losses reclassified into net income	206	17	3,508	906
Net change	(1,972)	(4,979)	(20,997)	(26,402)
Net-of-Tax
Net unrealized gains (losses) arising during the period	5,126	11,904	58,262	65,061
Net realized (gains) losses reclassified into net income	(492)	(41)	(8,359)	(2,160)
Other comprehensive income	4,634	11,863	49,903	62,901
Cash Flow Hedges
Before-Tax
Net unrealized gains (losses) arising during the period	34	0	(1,449)	0
Net realized (gains) losses reclassified into net income	87	0	(290)	0
Net change	121	0	(1,739)	0
Tax Effect
Net unrealized gains (losses) arising during the period	(9)	0	411	0
Net realized (gains) losses reclassified into net income	(25)	0	82	0
Net change	(34)	0	493	0
Net-of-Tax
Net unrealized gains (losses) arising during the period	25	0	(1,038)	0
Net realized (gains) losses reclassified into net income	62	0	(208)	0
Other comprehensive income	87	0	(1,246)	0
Foreign Currency Translation Adjustments, Net of Hedges
Before-Tax
Net unrealized gains (losses) arising during the period	4,419	(1,618)	2,274	(1,427)
Net change	4,419	(1,618)	2,274	(1,427)
Tax Effect
Net unrealized gains (losses) arising during the period	1,040	(1,240)	791	(4,267)
Net change	1,040	(1,240)	791	(4,267)
Net-of-Tax
Net unrealized gains (losses) arising during the period	5,459	(2,858)	3,065	(5,694)
Net realized (gains) losses reclassified into net income	0	0	0	0
Other comprehensive income	$ 5,459	$ (2,858)	$ 3,065	$ (5,694)