Fair Value Accounting (Carrying And Estimated Fair Values Of Financial Instruments Carried On Balance Sheet) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 367,092	$ 485,489
Interest bearing funds with Federal Reserve Bank	829,887	721,362
Interest earning deposits with banks	17,387	11,810
Federal funds sold and securities purchased under resale agreements	69,819	73,111
Trading account assets	5,097	13,863
Mortgage loans held for sale	59,275	63,328
Fair Value	3,587,818	3,041,406
Private equity investments	28,018	28,363
Loans, net of deferred fees and costs	22,177,069	20,836,382
Derivative asset positions	27,139	32,117
Non-interest bearing deposits	6,732,970	6,228,472
Interest bearing deposits	16,509,691	15,303,228
Federal funds purchased, other short-term borrowings and other short-term liabilities	177,025	126,916	$ 148,132
Long-term debt	2,186,893	2,139,325
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	367,092	485,489
Interest bearing funds with Federal Reserve Bank	829,887	721,362
Interest earning deposits with banks	17,387	11,810
Federal funds sold and securities purchased under resale agreements	69,819	73,111
Trading account assets	0	13,863
Mortgage loans held for sale	0	0
Other loans held for sale	0	0
Fair Value	56,102	51,609
Private equity investments	0	0
Mutual funds held in rabbi trusts	10,664	11,252
Loans, net of deferred fees and costs	0	0
Derivative asset positions	0	0
Trading account liabilities	0	0
Non-interest bearing deposits	0	0
Interest bearing deposits	0	0
Federal funds purchased, other short-term borrowings and other short-term liabilities	177,025	126,916
Salary stock units		1,206
Long-term debt	0	0
Derivative liabilities	0	0
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Interest bearing funds with Federal Reserve Bank	0	0
Interest earning deposits with banks	0	0
Federal funds sold and securities purchased under resale agreements	0	0
Trading account assets	5,097	0
Mortgage loans held for sale	59,275	63,328
Other loans held for sale	0	0
Fair Value	3,529,971	2,988,152
Private equity investments	870	995
Mutual funds held in rabbi trusts	0	0
Loans, net of deferred fees and costs	0	0
Derivative asset positions	27,139	32,117
Trading account liabilities	1,032	2,100
Non-interest bearing deposits	6,732,970	6,228,472
Interest bearing deposits	16,516,222	15,299,372
Federal funds purchased, other short-term borrowings and other short-term liabilities	0	0
Salary stock units		0
Long-term debt	2,244,376	2,191,279
Derivative liabilities	26,030	32,151
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Interest bearing funds with Federal Reserve Bank	0	0
Interest earning deposits with banks	0	0
Federal funds sold and securities purchased under resale agreements	0	0
Trading account assets	0	0
Mortgage loans held for sale	0	0
Other loans held for sale	425	3,606
Fair Value	1,745	1,645
Private equity investments	27,148	27,367
Mutual funds held in rabbi trusts	0	0
Loans, net of deferred fees and costs	22,192,903	20,872,939
Derivative asset positions	0	0
Trading account liabilities	0	0
Non-interest bearing deposits	0	0
Interest bearing deposits	0	0
Federal funds purchased, other short-term borrowings and other short-term liabilities	0	0
Salary stock units		0
Long-term debt	0	0
Derivative liabilities	1,415	1,401
Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	367,092	485,489
Interest bearing funds with Federal Reserve Bank	829,887	721,362
Interest earning deposits with banks	17,387	11,810
Federal funds sold and securities purchased under resale agreements	69,819	73,111
Trading account assets	5,097	13,863
Mortgage loans held for sale	59,275	63,328
Other loans held for sale	425	3,606
Fair Value	3,587,818	3,041,406
Private equity investments	28,018	28,362
Mutual funds held in rabbi trusts	10,664	11,252
Loans, net of deferred fees and costs	22,429,565	21,097,699
Derivative asset positions	27,139	32,117
Trading account liabilities	1,032	2,100
Non-interest bearing deposits	6,732,970	6,228,472
Interest bearing deposits	16,509,691	15,303,228
Federal funds purchased, other short-term borrowings and other short-term liabilities	177,025	126,916
Salary stock units		1,206
Long-term debt	2,186,893	2,140,319
Derivative liabilities	27,445	33,553
Estimated Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	367,092	485,489
Interest bearing funds with Federal Reserve Bank	829,887	721,362
Interest earning deposits with banks	17,387	11,810
Federal funds sold and securities purchased under resale agreements	69,819	73,111
Trading account assets	5,097	13,863
Mortgage loans held for sale	59,275	63,328
Other loans held for sale	425	3,606
Fair Value	3,587,818	3,041,406
Private equity investments	28,018	28,362
Mutual funds held in rabbi trusts	10,664	11,252
Loans, net of deferred fees and costs	22,192,903	20,872,939
Derivative asset positions	27,139	32,117
Trading account liabilities		2,100
Non-interest bearing deposits	6,732,970	6,228,472
Interest bearing deposits	16,516,222	15,299,372
Federal funds purchased, other short-term borrowings and other short-term liabilities	177,025	126,916
Salary stock units		1,206
Long-term debt	2,244,376	2,191,279
Derivative liabilities	27,445	33,553
Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	$ 9,672	$ 6,748