Fair Value Accounting (Financial Instruments Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	$ 5,097	$ 13,863
Fair Value	3,587,818	3,041,406
Private equity investments	28,018	28,363
Derivative asset positions	27,139	32,117
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	13,863
Fair Value	56,102	51,609
Private equity investments	0	0
Derivative asset positions	0	0
Salary stock units		1,206
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	5,097	0
Fair Value	3,529,971	2,988,152
Private equity investments	870	995
Derivative asset positions	27,139	32,117
Salary stock units		0
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Fair Value	1,745	1,645
Private equity investments	27,148	27,367
Derivative asset positions	0	0
Salary stock units		0
Fair Value, Measurements, Recurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	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	28,362
Mutual funds held in rabbi trusts	10,664	11,252
Derivative asset positions	27,139	32,117
Salary stock units		1,206
Derivative liabilities	27,445	33,552
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Mortgage 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
Derivative asset positions	0	0
Salary stock units		1,206
Derivative liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	5,097	13,863
Mortgage loans held for sale	59,275	63,328
Fair Value	3,529,971	2,988,152
Private equity investments	870	995
Mutual funds held in rabbi trusts	0	0
Derivative asset positions	27,139	32,117
Salary stock units		0
Derivative liabilities	26,030	32,151
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Mortgage loans held for sale	0	0
Fair Value	1,745	1,645
Private equity investments	27,148	27,367
Mutual funds held in rabbi trusts	0	0
Derivative asset positions	0	0
Salary stock units		0
Derivative liabilities	1,415	1,401
Fair Value, Measurements, Recurring [Member] | Trading Account Liabilities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading account liabilities	1,032	2,100
Fair Value, Measurements, Recurring [Member] | Trading Account Liabilities [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading account liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Trading Account Liabilities [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading account liabilities	1,032	2,100
Fair Value, Measurements, Recurring [Member] | Trading Account Liabilities [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading account liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Interest Rate Contract [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	26,030	31,398
Fair Value, Measurements, Recurring [Member] | Interest Rate Contract [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Interest Rate Contract [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	26,030	31,398
Fair Value, Measurements, Recurring [Member] | Interest Rate Contract [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Mortgage Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities		753
Fair Value, Measurements, Recurring [Member] | Mortgage Derivatives [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities		753
Fair Value, Measurements, Recurring [Member] | Other Derivative Liability Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	1,415	1,401
Fair Value, Measurements, Recurring [Member] | Other Derivative Liability Contracts [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Other Derivative Liability Contracts [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Other Derivative Liability Contracts [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	1,415	1,401
Fair Value, Measurements, Recurring [Member] | U.S. Treasury Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	2,922	145
Fair Value	43,357	42,826
Fair Value, Measurements, Recurring [Member] | U.S. Treasury Securities [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Fair Value	43,357	42,826
Fair Value, Measurements, Recurring [Member] | U.S. Treasury Securities [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	2,922	145
Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | U.S. Treasury Securities [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	1,078	2,449
Fair Value	529,597	417,076
Fair Value, Measurements, Recurring [Member] | Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	1,078	2,449
Fair Value	529,597	417,076
Fair Value, Measurements, Recurring [Member] | Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | State And Municipal Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	1,097	1,976
Fair Value	4,434	5,206
Fair Value, Measurements, Recurring [Member] | State And Municipal Securities [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | State And Municipal Securities [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	1,097	1,976
Fair Value	4,434	5,206
Fair Value, Measurements, Recurring [Member] | State And Municipal Securities [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Residential Mortgage Backed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		2,483
Fair Value, Measurements, Recurring [Member] | Residential Mortgage Backed Securities [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		0
Fair Value, Measurements, Recurring [Member] | Residential Mortgage Backed Securities [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		2,483
Fair Value, Measurements, Recurring [Member] | Residential Mortgage Backed Securities [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		0
Fair Value, Measurements, Recurring [Member] | US Government Agencies Debt Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	13,623	27,324
Fair Value, Measurements, Recurring [Member] | US Government Agencies Debt Securities [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | US Government Agencies Debt Securities [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	13,623	27,324
Fair Value, Measurements, Recurring [Member] | US Government Agencies Debt Securities [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Securities Issued By U S Government Sponsored Enterprises [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	126,909	82,042
Fair Value, Measurements, Recurring [Member] | Securities Issued By U S Government Sponsored Enterprises [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Securities Issued By U S Government Sponsored Enterprises [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	126,909	82,042
Fair Value, Measurements, Recurring [Member] | Securities Issued By U S Government Sponsored Enterprises [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Mortgage-Backed Securities Issued By U.S. Government Agencies [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	210,004	179,816
Fair Value, Measurements, Recurring [Member] | Mortgage-Backed Securities Issued By U.S. Government Agencies [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Mortgage-Backed Securities Issued By U.S. Government Agencies [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	210,004	179,816
Fair Value, Measurements, Recurring [Member] | Mortgage-Backed Securities Issued By U.S. Government Agencies [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Trading Account Liabilities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	2,630,419	2,261,681
Fair Value, Measurements, Recurring [Member] | Trading Account Liabilities [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Trading Account Liabilities [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	2,630,419	2,261,681
Fair Value, Measurements, Recurring [Member] | Trading Account Liabilities [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	9,672	6,748
Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	9,672	6,748
Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Other Investments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		6,810
Fair Value	19,803	18,687
Fair Value, Measurements, Recurring [Member] | Other Investments [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		0
Fair Value	3,073	2,035
Fair Value, Measurements, Recurring [Member] | Other Investments [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		6,810
Fair Value	14,985	15,007
Fair Value, Measurements, Recurring [Member] | Other Investments [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		0
Fair Value	1,745	1,645
Fair Value, Measurements, Recurring [Member] | Interest Rate Contract [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative asset positions	25,580	30,904
Fair Value, Measurements, Recurring [Member] | Interest Rate Contract [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative asset positions	0	0
Fair Value, Measurements, Recurring [Member] | Interest Rate Contract [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative asset positions	25,580	30,904
Fair Value, Measurements, Recurring [Member] | Interest Rate Contract [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative asset positions	0	0
Fair Value, Measurements, Recurring [Member] | Mortgage Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative asset positions	1,559	1,213
Fair Value, Measurements, Recurring [Member] | Mortgage Derivatives [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative asset positions	0	0
Fair Value, Measurements, Recurring [Member] | Mortgage Derivatives [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative asset positions	1,559	1,213
Fair Value, Measurements, Recurring [Member] | Mortgage Derivatives [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative asset positions	$ 0	$ 0