Parent Company Only Condensed Financial Statements (Details 3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Statements Of Comprehensive Income
Net income	$ 232,516	$ 209,133	$ 176,055
Securities available-for-sale:
Net unrealized (losses) gains arising during the period	(98,205)	13,973	42,173
Reclassification adjustment for net gains included in net income	(3,962)	(107)	(2,882)
Total other comprehensive (loss) income	(102,223)	14,210	35,519
Comprehensive income	130,293	223,343	211,574
Parent Company
Condensed Statements Of Comprehensive Income
Net income	230,009	208,049	172,421
Securities available-for-sale:
Net unrealized (losses) gains arising during the period	(1,116)	111	466
Reclassification adjustment for net gains included in net income	584		(2,074)
Total other comprehensive (loss) income	(532)	111	(1,608)
Comprehensive income	$ 229,477	$ 208,160	$ 170,813