Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 156,749	$ 151,398	$ 137,210
Unrealized (losses) gains on securities
Before tax	(13,176)	72,488	(102,790)
Tax effect	5,153	(28,660)	40,608
Net of tax	(8,023)	43,828	(62,182)
Reclassification of net gains (losses) included in net income
Before tax	323	(504)	(3,000)
Tax effect	(127)	200	1,193
Net of tax	196	(304)	(1,807)
Reclassification of amortization of unrealized losses on investment securities transferred to held-to-maturity from available-for-sale
Before tax	(128)	0	0
Tax effect	50	0	0
Net of tax	(78)	0	0
Net unrealized (losses) gains on securities	(8,141)	44,132	(60,375)
Unrealized gains (losses) on derivative instruments
Before tax	533	(91)	4,702
Tax effect	(209)	36	(1,872)
Net unrealized gains (losses) on derivative instruments	324	(55)	2,830
Foreign currency translation adjustment
Before tax	(24,001)	(24,346)	(17,564)
Tax effect	6,442	5,973	4,362
Net foreign currency translation adjustment	(17,559)	(18,373)	(13,202)
Total other comprehensive (loss) income	(25,376)	25,704	(70,747)
Comprehensive income	$ 131,373	$ 177,102	$ 66,463