Fair Value (Schedule Of Assets And Liabilities Measured At Fair Value By Class On A Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Level Transfers Among Levels 1, 2, and 3	0	0
Trading account	$ 71,392		$ 70,601
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	124,443		105,348
Total assets	236,184		210,851
Securities sold, not yet purchased	6,749		24,230
Total liabilities	116,788		128,380
Level 1 [Member] | Other Postretirement Benefits, Individual Contracts, Type of Deferred Compensation [Domain]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	91,368		88,878
Other liabilities	91,368		88,878
Level 1 [Member] | Mutual Funds And Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	124,443		105,348
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
Level 1 [Member] | Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	20,373		16,625
Other liabilities	18,671		15,272
Level 1 [Member] | Derivatives [Member] | Foreign Currency Exchange Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	20,373		16,625
Other liabilities	18,671		15,272
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	3,880,430		3,336,943
Trading account	71,392		70,601
Total assets	4,495,138		3,933,629
Securities sold, not yet purchased	0
Total liabilities	62,628		50,966
Level 2 [Member] | Mutual Funds And Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	28,247		30,275
Level 2 [Member] | Bank-owned life insurance [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other noninterest-bearing investments	478,926		476,290
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	3,655,221		3,098,208
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	173,145		185,093
Level 2 [Member] | Asset-Backed Securities [Member] | Banks, Trust and Insurance, Equities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	23,179		22,701
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			666
Level 2 [Member] | Asset-Backed Securities [Member] | Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	638
Level 2 [Member] | Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	64,390		49,795
Other liabilities	62,628		50,966
Level 2 [Member] | Derivatives [Member] | Interest Rate Related And Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	5,408		1,508
Other liabilities	176		297
Level 2 [Member] | Derivatives [Member] | Interest Rate Swaps [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	58,982		48,287
Other liabilities	62,452		50,669
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	445,629		401,957
Total assets	565,078		514,049
Other liabilities			13
Total liabilities	0		13
Level 3 [Member] | Private Equity [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other noninterest-bearing investments	107,448		99,865
Level 3 [Member] | Interest-Only-Strip [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	12,001		12,227
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	2,465		4,164
Level 3 [Member] | Asset-Backed Securities [Member] | Banks, Trust and Insurance, Equities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	438,338		393,007
Level 3 [Member] | Asset-Backed Securities [Member] | Auction Rate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure			4,761
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			25
Level 3 [Member] | Asset-Backed Securities [Member] | Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	4,826
Level 3 [Member] | Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other liabilities	0		0
Estimated Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	4,450,502		3,844,248
Trading account	71,392		70,601
Total assets	5,296,400		4,658,529
Securities sold, not yet purchased	6,749		24,230
Other liabilities	0		13
Total liabilities	179,416		179,359
Estimated Fair Value [Member] | Other Postretirement Benefits, Individual Contracts, Type of Deferred Compensation [Domain]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	91,368		88,878
Other liabilities	91,368		88,878
Estimated Fair Value [Member] | Mutual Funds And Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	152,690		135,623
Estimated Fair Value [Member] | Bank-owned life insurance [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other noninterest-bearing investments	478,926		476,290
Estimated Fair Value [Member] | Private Equity [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other noninterest-bearing investments	107,448		99,865
Estimated Fair Value [Member] | Interest-Only-Strip [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	12,001		12,227
Estimated Fair Value [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	3,655,221		3,098,208
Estimated Fair Value [Member] | Available-for-sale Securities [Member] | Municipal Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	175,610		189,257
Estimated Fair Value [Member] | Asset-Backed Securities [Member] | Banks, Trust and Insurance, Equities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	461,517		415,708
Estimated Fair Value [Member] | Asset-Backed Securities [Member] | Auction Rate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure			4,761
Estimated Fair Value [Member] | Asset-Backed Securities [Member] | Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, Fair Value Disclosure	5,464		691
Estimated Fair Value [Member] | Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	84,763		66,420
Other liabilities	81,299		66,238
Estimated Fair Value [Member] | Derivatives [Member] | Interest Rate Related And Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	5,408		1,508
Other liabilities	176		297
Estimated Fair Value [Member] | Derivatives [Member] | Interest Rate Swaps [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	58,982		48,287
Other liabilities	62,452		50,669
Estimated Fair Value [Member] | Derivatives [Member] | Foreign Currency Exchange Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	20,373		16,625
Other liabilities	$ 18,671		$ 15,272