Fair Value (Schedule Of Assets And Liabilities Measured At Fair Value By Class On A Recurring Basis) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading account	$ 65,838	$ 48,168
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	8,641,960	7,581,309
Trading account	65,838	48,168
Total assets	9,304,737	8,172,774
Securities sold, not yet purchased	0	0
Total liabilities	90,021	54,678
Level 2 [Member] | Mutual Funds And Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	36,311	38,829
Level 2 [Member] | Bank-owned life insurance [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other noninterest-bearing investments	$ 489,297	$ 485,978
Level 2 [Member] | Private Equity [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other noninterest-bearing investments
Level 2 [Member] | Available-for-sale Securities [Member] | U.S. Treasury, Agencies And Corporations [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	$ 8,027,667	$ 7,100,844
Level 2 [Member] | Available-for-sale Securities [Member] | Municipal Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	556,073	418,695
Level 2 [Member] | Available-for-sale Securities [Member] | Debt Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	21,909
Level 2 [Member] | Asset-Backed Securities [Member] | Other (Including ABS CDOs) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure		22,941
Level 2 [Member] | Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	107,642	57,319
Other Liabilities, Fair Value Disclosure	90,021	54,678
Level 2 [Member] | Derivatives [Member] | Interest Rate Related And Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	22,958	5,966
Other Liabilities, Fair Value Disclosure	250	835
Level 2 [Member] | Derivatives [Member] | Interest Rate Swaps [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	84,684	51,353
Other Liabilities, Fair Value Disclosure	89,771	53,843
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	0	0
Total assets	136,289	133,541
Securities sold, not yet purchased	0	0
Total liabilities	0	0
Level 3 [Member] | Private Equity [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other noninterest-bearing investments	119,222	120,027
Level 3 [Member] | Interest-Only-Strip [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	17,067	13,514
Level 3 [Member] | Available-for-sale Securities [Member] | U.S. Treasury, Agencies And Corporations [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	$ 0	$ 0
Level 3 [Member] | Available-for-sale Securities [Member] | Municipal Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure
Level 3 [Member] | Asset-Backed Securities [Member] | Other (Including ABS CDOs) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure
Level 3 [Member] | Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	$ 0	$ 0
Other Liabilities, Fair Value Disclosure	0	0
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	8,701,885	7,643,116
Trading account	65,838	48,168
Total assets	9,600,851	8,473,516
Securities sold, not yet purchased	6,515	30,158
Total liabilities	193,163	187,167
Estimate of Fair Value Measurement [Member] | Mutual Funds And Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	96,236	100,636
Estimate of Fair Value Measurement [Member] | Bank-owned life insurance [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other noninterest-bearing investments	489,297	485,978
Estimate of Fair Value Measurement [Member] | Private Equity [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other noninterest-bearing investments	119,222	120,027
Estimate of Fair Value Measurement [Member] | Interest-Only-Strip [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	17,067	13,514
Estimate of Fair Value Measurement [Member] | Available-for-sale Securities [Member] | U.S. Treasury, Agencies And Corporations [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	8,027,667	7,100,844
Estimate of Fair Value Measurement [Member] | Available-for-sale Securities [Member] | Municipal Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	556,073	418,695
Estimate of Fair Value Measurement [Member] | Available-for-sale Securities [Member] | Debt Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	21,909
Estimate of Fair Value Measurement [Member] | Asset-Backed Securities [Member] | Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure		22,941
Estimate of Fair Value Measurement [Member] | Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	125,363	78,143
Other Liabilities, Fair Value Disclosure	104,469	72,439
Estimate of Fair Value Measurement [Member] | Derivatives [Member] | Interest Rate Related And Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	22,958	5,966
Other Liabilities, Fair Value Disclosure	250	835
Estimate of Fair Value Measurement [Member] | Derivatives [Member] | Interest Rate Swaps [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	84,684	51,353
Other Liabilities, Fair Value Disclosure	89,771	53,843
Estimate of Fair Value Measurement [Member] | Derivatives [Member] | Foreign Currency Exchange Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	17,721	20,824
Other Liabilities, Fair Value Disclosure	14,448	17,761
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	59,925	61,807
Total assets	159,825	167,201
Securities sold, not yet purchased	6,515	30,158
Total liabilities	103,142	132,489
Fair Value, Inputs, Level 1 [Member] | Mutual Funds And Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	59,925	61,807
Fair Value, Inputs, Level 1 [Member] | Available-for-sale Securities [Member] | U.S. Treasury, Agencies And Corporations [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 [Member] | Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	17,721	20,824
Other Liabilities, Fair Value Disclosure	14,448	17,761
Fair Value, Inputs, Level 1 [Member] | Derivatives [Member] | Foreign Currency Exchange Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Assets, Fair Value Disclosure	17,721	20,824
Other Liabilities, Fair Value Disclosure	$ 14,448	$ 17,761