Other Comprehensive Income (Loss) (Reclassifications out of Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ 29,436	$ 40,453	$ 60,012	$ 82,148
Income tax benefit	27,371	(2,105)	44,350	(2,182)
Investment securities gains, net	1,403	4,170	1,448	24,253
Salaries and other personnel expense	181,186	208,264	363,472	411,399
Reclassifications, net of income taxes	30,717	24,803	45,515	46,172
Net Unrealized Gains (Losses) on Cash Flow Hedges [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(112)		(224)
Income tax benefit	45		88
Reclassifications, net of income taxes	(67)		(136)
Net Unrealized Gains (Losses) on Investment Securities Available for Sale [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income tax benefit	(541)		(557)
Investment securities gains, net	1,403		1,448
Reclassifications, net of income taxes	862		891
Amortization of Post-Retirement Unfunded Health Benefit [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income tax benefit	(7)		(10)
Salaries and other personnel expense	0		26
Reclassifications, net of income taxes	$ (7)		$ 16