Borrowings (Short-Term Borrowings) (Details) (Federal Funds Purchased And Repurchase Agreements [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Federal Funds Purchased And Repurchase Agreements [Member]
Short-term Debt [Line Items]
Year End Weighted Rate	0.10%	0.10%	0.10%
Average Weighted Rate	0.10%	0.10%	0.10%
Average Balance Outstanding	$ 1,119,578	$ 914,554	$ 785,978
Maximum Outstanding at any Month End	1,862,518	1,479,849	1,149,156
Balance at December 31	$ 1,862,518	$ 996,558	$ 683,550