Consolidated Statements Of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 64,897	$ 50,041	$ 123,275	$ 99,152
Unrealized gains on securities
Before tax	17,593	5,968	24,972	31,144
Tax effect	(6,910)	(2,244)	(9,810)	(12,232)
Net of tax	10,683	3,724	15,162	18,912
Reclassification of net gains (losses) included in net income
Before tax	47	1,440	(8)	2,765
Tax effect	(18)	(565)	3	(1,086)
Net of tax	29	875	(5)	1,679
Reclassification of amortization of unrealized gains and losses on investment securities transferred to held-to-maturity from available-for-sale
Before tax	22	(3,832)	1,450	(7,257)
Tax effect	(9)	1,506	(570)	2,845
Net of tax	13	(2,326)	880	(4,412)
Net unrealized gains on securities	10,641	5,175	14,287	21,645
Unrealized (losses) gains on derivative instruments
Before tax	(310)	(523)	1,305	(45)
Tax effect	123	206	(511)	18
Net unrealized (losses) gains on derivative instruments	(187)	(317)	794	(27)
Foreign currency adjustment
Before tax	3,820	856	5,035	9,203
Tax effect	(987)	(244)	(1,325)	(2,553)
Net foreign currency adjustment	2,833	612	3,710	6,650
Total other comprehensive income	13,287	5,470	18,791	28,268
Comprehensive income	$ 78,184	$ 55,511	$ 142,066	$ 127,420