Fair Value (Schedule Of Assets And Liabilities Measured At Fair Value By Class On A Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	$ 13,372,194	$ 7,643,116
Trading account, at fair value	114,803	48,168
Total assets	14,288,600	8,473,516
Securities sold, not yet purchased	25,321	30,158
Other liabilities		187,167
Financial and Nonfinancial Liabilities, Fair Value Disclosure	175,582
Mutual Funds And Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	184,416	100,636
Bank-owned life insurance [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other noninterest-bearing investments	497,466	485,978
Private Equity [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other noninterest-bearing investments	128,654	120,027
Interest-Only-Strip [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	20,248	13,514
Warranty, Rights and Obligations, Fair Value Option [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	91,040	84,570
Other liabilities	91,040	84,570
Available-for-sale Securities [Member] | U.S. Treasury, Agencies And Corporations [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	12,009,676	7,100,844
Available-for-sale Securities [Member] | Municipal Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	1,154,210	418,695
Asset-Backed Securities [Member] | Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	23,892	22,941
Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	64,195	78,143
Other liabilities	59,221
Derivatives [Member] | Interest Rate Related And Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	4,165	5,966
Other liabilities	1,499	835
Derivatives [Member] | Interest Rate Swaps For Customers [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	48,754	51,353
Other liabilities	49,050	53,843
Derivatives [Member] | Foreign Currency Exchange Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	11,276	20,824
Other liabilities	8,672	17,761
Derivatives [Member] | Total Return Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other liabilities		72,439
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	183,699	61,807
Total assets	286,015	167,201
Securities sold, not yet purchased	25,321	30,158
Other liabilities		132,489
Financial and Nonfinancial Liabilities, Fair Value Disclosure	125,033
Level 1 [Member] | Mutual Funds And Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	183,699	61,807
Level 1 [Member] | Warranty, Rights and Obligations, Fair Value Option [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	91,040	84,570
Other liabilities	91,040	84,570
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]
Investment securities	0	0
Level 1 [Member] | Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	11,276	20,824
Other liabilities	8,672
Level 1 [Member] | Derivatives [Member] | Foreign Currency Exchange Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	11,276	20,824
Other liabilities	8,672	17,761
Level 1 [Member] | Derivatives [Member] | Total Return Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other liabilities		17,761
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	13,188,495	7,581,309
Trading account, at fair value	114,803	48,168
Total assets	13,853,683	8,172,774
Securities sold, not yet purchased	0	0
Other liabilities		54,678
Financial and Nonfinancial Liabilities, Fair Value Disclosure	50,549
Level 2 [Member] | Mutual Funds And Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	717	38,829
Level 2 [Member] | Bank-owned life insurance [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other noninterest-bearing investments	497,466	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]
Investment securities	12,009,676	7,100,844
Level 2 [Member] | Available-for-sale Securities [Member] | Municipal Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	1,154,210	418,695
Level 2 [Member] | Asset-Backed Securities [Member] | Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	23,892	22,941
Level 2 [Member] | Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	52,919	57,319
Other liabilities	50,549
Level 2 [Member] | Derivatives [Member] | Interest Rate Related And Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	4,165	5,966
Other liabilities	1,499	835
Level 2 [Member] | Derivatives [Member] | Interest Rate Swaps For Customers [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	48,754	51,353
Other liabilities	49,050	53,843
Level 2 [Member] | Derivatives [Member] | Total Return Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other liabilities		54,678
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	0	0
Total assets	148,902	133,541
Securities sold, not yet purchased	0	0
Other liabilities		0
Financial and Nonfinancial Liabilities, Fair Value Disclosure	0
Fair Value, Inputs, Level 3 [Member] | Private Equity [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other noninterest-bearing investments	128,654	120,027
Fair Value, Inputs, Level 3 [Member] | Interest-Only-Strip [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	20,248	13,514
Fair Value, Inputs, 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]
Investment securities	0	0
Fair Value, Inputs, Level 3 [Member] | Available-for-sale Securities [Member] | Municipal Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities
Fair Value, Inputs, Level 3 [Member] | Asset-Backed Securities [Member] | Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities
Fair Value, Inputs, Level 3 [Member] | Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	0	0
Other liabilities	$ 0
Fair Value, Inputs, Level 3 [Member] | Derivatives [Member] | Total Return Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other liabilities		$ 0