Consolidated Statements Of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 38,355	$ 40,224	$ 121,238	$ 113,265
Unrealized gains on securities
Before tax	31,268	1,345	4,144	49,920
Tax effect	(12,273)	(533)	(1,645)	(19,669)
Net of tax	18,995	812	2,499	30,251
Less: Reclassification of net (losses) gains included in net income
Before tax	(98)	(153)	402	(522)
Tax effect	38	62	(158)	208
Net of tax	(60)	(91)	244	(314)
Net unrealized gains on securities	19,055	903	2,255	30,565
Unrealized gains (losses) on derivative instruments
Before tax	99	971	(247)	247
Tax effect	(39)	(386)	97	(98)
Net unrealized gains (losses) on derivative instruments	60	585	(150)	149
Foreign currency translation adjustment
Before tax	(8,682)	(13,062)	(18,900)	(13,976)
Tax effect	2,345	3,377	5,034	3,598
Net foreign currency translation adjustment	(6,337)	(9,685)	(13,866)	(10,378)
Total other comprehensive income (loss)	12,778	(8,197)	(11,761)	20,336
Comprehensive income	$ 51,133	$ 32,027	$ 109,477	$ 133,601