Accumulated Other Comprehensive Income (Loss) (Details 2) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Before-Tax
Net change	$ 582	$ (9,022)	$ 21,672	$ 17,194
Tax Effect
Net change	1,382	3,560	(5,743)	(9,427)
Net-of-Tax
Net unrealized gains (losses) arising during the period	2,856	(4,424)	19,831	12,675
Net realized gains reclassified into net income	(892)	(1,038)	(3,902)	(4,908)
Other comprehensive income (loss)	1,964	(5,462)	15,929	7,767
Available-for-Sale Investment Securities
Before-Tax
Net unrealized gains (losses) arising during the period	(1,749)	(6,677)	20,392	30,888
Net realized gains reclassified into net income	(1,539)	(1,790)	(6,733)	(8,468)
Net change	(3,288)	(8,467)	13,659	22,420
Tax Effect
Net unrealized gains (losses) arising during the period	735	2,808	(8,574)	(12,987)
Net realized gains reclassified into net income	647	752	2,831	3,560
Net change	1,382	3,560	(5,743)	(9,427)
Net-of-Tax
Net unrealized gains (losses) arising during the period	(1,014)	(3,869)	11,818	17,901
Net realized gains reclassified into net income	(892)	(1,038)	(3,902)	(4,908)
Other comprehensive income (loss)	(1,906)	(4,907)	7,916	12,993
Foreign Currency Translation Adjustments
Before-Tax
Net unrealized gains (losses) arising during the period	3,870	(555)	8,013	(5,226)
Net change	3,870	(555)	8,013	(5,226)
Tax Effect
Net unrealized gains (losses) arising during the period	0	0	0	0
Net change	0	0	0	0
Net-of-Tax
Net unrealized gains (losses) arising during the period	3,870	(555)	8,013	(5,226)
Net realized gains reclassified into net income	0	0	0	0
Other comprehensive income (loss)	$ 3,870	$ (555)	$ 8,013	$ (5,226)