Other Comprehensive Income (Reclassifications out of Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ (27,868)	$ (30,577)
Income tax benefit	(28,608)	(16,979)
Investment securities gains, net	1,331	45
Salaries and other personnel expense	(184,161)	(182,286)
Net income available to common shareholders	45,857	14,798
Net Unrealized Gains (Losses) on Cash Flow Hedges [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(112)	(112)
Income tax benefit	43	43
Net income available to common shareholders	(69)	(69)
Net Unrealized Gains (Losses) on Investment Securities Available for Sale [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income tax benefit	(513)	(16)
Investment securities gains, net	1,331	45
Net income available to common shareholders	818	29
Post-Retirement Unfunded Health Benefit [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income tax benefit	(28)	(3)
Salaries and other personnel expense	72	26
Net income available to common shareholders	$ 44	$ 23