Fair Value Accounting (Financial Instruments Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	$ 3,820	$ 9,314
Investment securities available for sale	3,987,069	3,718,195
Private equity investments	15,771	25,493
Derivative asset positions	11,722	20,623
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	522	1,890
Investment securities available for sale	85,836	114,676
Private equity investments	0	0
GGL/SBA loans servicing asset	0
Derivative asset positions	0	0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	3,298	7,424
Investment securities available for sale	3,899,298	3,601,723
Private equity investments	0	0
GGL/SBA loans servicing asset	0
Derivative asset positions	11,722	20,623
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Investment securities available for sale	1,935	1,796
Private equity investments	15,771	25,493
GGL/SBA loans servicing asset	4,101
Derivative asset positions	0	0
Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	3,820	9,314
Mortgage loans held for sale	48,024	51,545
Investment securities available for sale	3,987,069	3,718,195
Private equity investments	15,771	25,493
GGL/SBA loans servicing asset	4,101
Mutual funds held in rabbi trusts	14,140	11,479
Derivative asset positions	11,722	20,623
Derivative liabilities	17,097	23,299
Fair Value, Measurements, Recurring | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	522	1,890
Mortgage loans held for sale	0	0
Investment securities available for sale	85,836	114,676
Private equity investments	0	0
GGL/SBA loans servicing asset	0
Mutual funds held in rabbi trusts	14,140	11,479
Derivative asset positions	0	0
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	3,298	7,424
Mortgage loans held for sale	48,024	51,545
Investment securities available for sale	3,899,298	3,601,723
Private equity investments	0	0
GGL/SBA loans servicing asset	0
Mutual funds held in rabbi trusts	0	0
Derivative asset positions	11,722	20,623
Derivative liabilities	12,767	17,531
Fair Value, Measurements, Recurring | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Mortgage loans held for sale	0	0
Investment securities available for sale	1,935	1,796
Private equity investments	15,771	25,493
GGL/SBA loans servicing asset	4,101
Mutual funds held in rabbi trusts	0	0
Derivative asset positions	0	0
Derivative liabilities	4,330	5,768
Fair Value, Measurements, Recurring | Visa Derivative
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities		5,768
Fair Value, Measurements, Recurring | Visa Derivative | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities		0
Fair Value, Measurements, Recurring | Visa Derivative | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities		0
Fair Value, Measurements, Recurring | Visa Derivative | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities		5,768
Fair Value, Measurements, Recurring | Trading account liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading account liabilities	1,000
Fair Value, Measurements, Recurring | Trading account liabilities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading account liabilities	0
Fair Value, Measurements, Recurring | Trading account liabilities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading account liabilities	1,000
Fair Value, Measurements, Recurring | Trading account liabilities | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading account liabilities	0
Fair Value, Measurements, Recurring | Interest rate contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	12,638	17,531
Fair Value, Measurements, Recurring | Interest rate contracts | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Interest rate contracts | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	12,638	17,531
Fair Value, Measurements, Recurring | Interest rate contracts | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Mortgage derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	129
Fair Value, Measurements, Recurring | Mortgage derivatives | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	0
Fair Value, Measurements, Recurring | Mortgage derivatives | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	129
Fair Value, Measurements, Recurring | Mortgage derivatives | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	0
Fair Value, Measurements, Recurring | Visa derivative
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	4,330
Fair Value, Measurements, Recurring | Visa derivative | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	0
Fair Value, Measurements, Recurring | Visa derivative | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	0
Fair Value, Measurements, Recurring | Visa derivative | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	4,330
Fair Value, Measurements, Recurring | Earnout Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Earnout liability	11,348	14,000
Fair Value, Measurements, Recurring | Earnout Liabilities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Earnout liability	0	0
Fair Value, Measurements, Recurring | Earnout Liabilities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Earnout liability	0	0
Fair Value, Measurements, Recurring | Earnout Liabilities | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Earnout liability	11,348	14,000
Fair Value, Measurements, Recurring | U.S. Government agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	3,002
Investment securities available for sale	10,862	12,993
Fair Value, Measurements, Recurring | U.S. Government agency securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | U.S. Government agency securities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	3,002
Investment securities available for sale	10,862	12,993
Fair Value, Measurements, Recurring | U.S. Government agency securities | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	296	3,438
Investment securities available for sale	1,111,999	890,442
Fair Value, Measurements, Recurring | Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	296	3,438
Investment securities available for sale	1,111,999	890,442
Fair Value, Measurements, Recurring | Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Other investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		1,990
Fair Value, Measurements, Recurring | Other investments | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		1,890
Fair Value, Measurements, Recurring | Other investments | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		100
Fair Value, Measurements, Recurring | Other investments | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		0
Fair Value, Measurements, Recurring | Mortgage-backed securities issued by U.S. Government agencies
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		3,460
Investment securities available for sale	120,440	174,202
Fair Value, Measurements, Recurring | Mortgage-backed securities issued by U.S. Government agencies | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		0
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Mortgage-backed securities issued by U.S. Government agencies | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		3,460
Investment securities available for sale	120,440	174,202
Fair Value, Measurements, Recurring | Mortgage-backed securities issued by U.S. Government agencies | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		0
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | State and municipal securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		426
Investment securities available for sale	180	2,794
Fair Value, Measurements, Recurring | State and municipal securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		0
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | State and municipal securities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		426
Investment securities available for sale	180	2,794
Fair Value, Measurements, Recurring | State and municipal securities | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		0
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Corporate debt and other securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	522
Investment securities available for sale	20,391	19,840
Fair Value, Measurements, Recurring | Corporate debt and other securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	522
Investment securities available for sale	3,162	3,092
Fair Value, Measurements, Recurring | Corporate debt and other securities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0
Investment securities available for sale	15,294	14,952
Fair Value, Measurements, Recurring | Corporate debt and other securities | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0
Investment securities available for sale	1,935	1,796
Fair Value, Measurements, Recurring | U.S. Treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	82,674	107,802
Fair Value, Measurements, Recurring | U.S. Treasury securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	82,674	107,802
Fair Value, Measurements, Recurring | U.S. Treasury securities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | U.S. Treasury securities | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Mortgage-backed securities issued by U.S. Government sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	2,640,523	2,506,340
Fair Value, Measurements, Recurring | Mortgage-backed securities issued by U.S. Government sponsored enterprises | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Mortgage-backed securities issued by U.S. Government sponsored enterprises | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	2,640,523	2,506,340
Fair Value, Measurements, Recurring | Mortgage-backed securities issued by U.S. Government sponsored enterprises | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale		3,782
Fair Value, Measurements, Recurring | Equity securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale		3,782
Fair Value, Measurements, Recurring | Equity securities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale		0
Fair Value, Measurements, Recurring | Equity securities | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale		0
Fair Value, Measurements, Recurring | Interest rate contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative asset positions	10,786	17,157
Fair Value, Measurements, Recurring | Interest rate contracts | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative asset positions	0	0
Fair Value, Measurements, Recurring | Interest rate contracts | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative asset positions	10,786	17,157
Fair Value, Measurements, Recurring | Interest rate contracts | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative asset positions	0	0
Fair Value, Measurements, Recurring | Mortgage derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative asset positions	936	3,466
Fair Value, Measurements, Recurring | Mortgage derivatives | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative asset positions	0	0
Fair Value, Measurements, Recurring | Mortgage derivatives | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative asset positions	936	3,466
Fair Value, Measurements, Recurring | Mortgage derivatives | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative asset positions	$ 0	$ 0