Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 343,166	$ 257,682	$ 206,875
Unrealized (losses) gains on available-for-sale securities
Before tax	(27,408)	22,123	(28,932)
Tax effect	7,354	(7,706)	11,378
Net of tax	(20,054)	14,417	(17,554)
Reclassification of net gains on available-for-sale securities included in net income
Before tax	33	45	7,645
Tax effect	(9)	(18)	(3,004)
Net of tax	24	27	4,641
Reclassification of amortization of unrealized losses on investment securities transferred to held-to-maturity from available-for-sale
Before tax	89	1,479	(17,386)
Tax effect	(24)	(585)	6,826
Net of tax	65	894	(10,560)
Net unrealized (losses) gains on available-for-sale securities	(20,143)	13,496	(11,635)
Unrealized (losses) gains on derivative instruments
Before tax	(1,160)	4,958	10,473
Tax effect	310	(1,959)	(4,115)
Net unrealized (losses) gains on derivative instruments	(850)	2,999	6,358
Foreign currency translation adjustment
Before tax	(12,216)	9,446	3,737
Tax effect	3,026	(2,448)	(1,080)
Net foreign currency translation adjustment	(9,190)	6,998	2,657
Total other comprehensive (loss) income	(30,183)	23,493	(2,620)
Comprehensive income	$ 312,983	$ 281,175	$ 204,255