Accumulated Other Comprehensive Income (Loss) (Components of Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Before - Tax
Other comprehensive income (loss)	$ 61,909	$ (18,015)	$ 9,084
Tax Effect
Other comprehensive income (loss)	(22,143)	3,631	1,543
Net-of- Tax
Net unrealized gains (losses) arising during the period	42,534	(12,598)	15,284
Net realized gains reclassified into net income	(2,768)	(1,786)	(4,657)
Other comprehensive income (loss)	39,766	(14,384)	10,627
Available- for-Sale Debt Investment Securities
Before - Tax
Net unrealized gains (losses) arising during the period	65,549	(9,748)	4,368
Net realized gains reclassified into net income	(3,930)	(2,535)	(8,037)
Other comprehensive income (loss)	61,619	(12,283)	(3,669)
Tax Effect
Net unrealized gains (losses) arising during the period	(19,379)	2,882	(1,837)
Net realized gains reclassified into net income	1,162	749	3,380
Other comprehensive income (loss)	(18,217)	3,631	1,543
Net-of- Tax
Net unrealized gains (losses) arising during the period	46,170	(6,866)	2,531
Net realized gains reclassified into net income	(2,768)	(1,786)	(4,657)
Other comprehensive income (loss)	43,402	(8,652)	(2,126)
Foreign Currency Translation Adjustments
Before - Tax
Net unrealized gains (losses) arising during the period	290	(5,732)	12,753
Other comprehensive income (loss)	290	(5,732)	12,753
Tax Effect
Net unrealized gains (losses) arising during the period	(3,926)	0	0
Other comprehensive income (loss)	(3,926)	0	0
Net-of- Tax
Net unrealized gains (losses) arising during the period	(3,636)	(5,732)	12,753
Net realized gains reclassified into net income	0	0	0
Other comprehensive income (loss)	$ (3,636)	$ (5,732)	$ 12,753