Fair Value Accounting (Financial Instruments Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	$ 3,045	$ 9,314
Investment securities available for sale	3,827,058	3,718,195
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	722,420	890,442
State and municipal securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	290	2,794
U.S. Treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	83,133	107,802
Mortgage-backed securities issued by U.S. Government agencies
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	132,225	174,202
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	2,856,405	2,506,340
Corporate debt and other securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	20,274	19,840
Equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale		3,782
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	1,890
Investment securities available for sale	86,275	114,676
Private equity investments	0	0
GGL/SBA loans servicing asset	0
Derivative assets	0	0
Earnout liability	0	0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	3,045	7,424
Investment securities available for sale	3,738,856	3,601,723
Private equity investments	0	0
GGL/SBA loans servicing asset	0
Derivative assets	16,725	20,623
Earnout liability	0	0
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Investment securities available for sale	1,927	1,796
Private equity investments	15,698	25,493
GGL/SBA loans servicing asset	4,297
Derivative assets	0	0
Earnout liability	13,941	14,000
Fair Value, Measurements, Recurring Basis
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		9,314
Mortgage loans held for sale	61,893	51,545
Investment securities available for sale	3,827,058	3,718,195
Private equity investments	15,698	25,493
Mutual funds held in Rabbi Trusts	12,867	11,479
GGL/SBA loans servicing asset	4,297
Derivative assets	16,725	20,623
Earnout liability	13,941	14,000
Derivative liabilities	18,442	23,299
Fair Value, Measurements, Recurring Basis | Corporate debt and other securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		1,990
Fair Value, Measurements, Recurring Basis | U.S. Government agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	1,587
Investment securities available for sale	12,311	12,993
Fair Value, Measurements, Recurring Basis | Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	386	3,438
Investment securities available for sale	722,420	890,442
Fair Value, Measurements, Recurring Basis | State and municipal securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	1,072	426
Investment securities available for sale	290	2,794
Fair Value, Measurements, Recurring Basis | U.S. Treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	83,133	107,802
Fair Value, Measurements, Recurring Basis | 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	132,225	174,202
Fair Value, Measurements, Recurring Basis | 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	2,856,405	2,506,340
Fair Value, Measurements, Recurring Basis | Corporate debt and other securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	20,274	19,840
Fair Value, Measurements, Recurring Basis | Equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale		3,782
Fair Value, Measurements, Recurring Basis | Interest rate contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	15,332	17,157
Derivative liabilities	13,389	17,531
Fair Value, Measurements, Recurring Basis | Mortgage derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	1,393	3,466
Fair Value, Measurements, Recurring Basis | Visa derivative
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	5,053	5,768
Fair Value, Measurements, Recurring Basis | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	1,890
Mortgage loans held for sale	0	0
Investment securities available for sale	86,275	114,676
Private equity investments		0
Mutual funds held in Rabbi Trusts	12,867	11,479
GGL/SBA loans servicing asset	0
Derivative assets	0	0
Earnout liability	0	0
Derivative liabilities	0	0
Fair Value, Measurements, Recurring Basis | Level 1 | Corporate debt and other securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		1,890
Fair Value, Measurements, Recurring Basis | Level 1 | U.S. Government agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring Basis | Level 1 | Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring Basis | Level 1 | State and municipal securities
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 Basis | Level 1 | U.S. Treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	83,133	107,802
Fair Value, Measurements, Recurring Basis | Level 1 | Mortgage-backed securities issued by U.S. Government agencies
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring Basis | Level 1 | Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		0
Fair Value, Measurements, Recurring Basis | Level 1 | 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	0	0
Fair Value, Measurements, Recurring Basis | Level 1 | Corporate debt and other securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	3,142	3,092
Fair Value, Measurements, Recurring Basis | Level 1 | Equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale		3,782
Fair Value, Measurements, Recurring Basis | Level 1 | Interest rate contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Fair Value, Measurements, Recurring Basis | Level 1 | Mortgage derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0	0
Fair Value, Measurements, Recurring Basis | Level 1 | Visa derivative
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	0	0
Fair Value, Measurements, Recurring Basis | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	3,045	7,424
Mortgage loans held for sale	61,893	51,545
Investment securities available for sale	3,738,856	3,601,723
Private equity investments	0	0
Mutual funds held in Rabbi Trusts	0	0
GGL/SBA loans servicing asset	0
Derivative assets	16,725	20,623
Earnout liability	0	0
Derivative liabilities	13,389	17,531
Fair Value, Measurements, Recurring Basis | Level 2 | Corporate debt and other securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		100
Fair Value, Measurements, Recurring Basis | Level 2 | U.S. Government agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	1,587
Investment securities available for sale	12,311	12,993
Fair Value, Measurements, Recurring Basis | Level 2 | Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	386	3,438
Investment securities available for sale	722,420	890,442
Fair Value, Measurements, Recurring Basis | Level 2 | State and municipal securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	1,072	426
Investment securities available for sale	290	2,794
Fair Value, Measurements, Recurring Basis | Level 2 | U.S. Treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring Basis | Level 2 | 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	132,225	174,202
Fair Value, Measurements, Recurring Basis | Level 2 | 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	2,856,405	2,506,340
Fair Value, Measurements, Recurring Basis | Level 2 | Corporate debt and other securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	15,205	14,952
Fair Value, Measurements, Recurring Basis | Level 2 | Equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale		0
Fair Value, Measurements, Recurring Basis | Level 2 | Interest rate contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	15,332	17,157
Derivative liabilities	13,389	17,531
Fair Value, Measurements, Recurring Basis | Level 2 | Mortgage derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	1,393	3,466
Fair Value, Measurements, Recurring Basis | Level 2 | Visa derivative
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	0	0
Fair Value, Measurements, Recurring Basis | 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	1,927	1,796
Private equity investments	15,698	25,493
Mutual funds held in Rabbi Trusts	0	0
GGL/SBA loans servicing asset	4,297
Derivative assets	0	0
Earnout liability	13,941	14,000
Derivative liabilities	5,053	5,768
Fair Value, Measurements, Recurring Basis | Level 3 | Corporate debt and other securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		0
Fair Value, Measurements, Recurring Basis | Level 3 | U.S. Government agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring Basis | Level 3 | Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises
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 Basis | Level 3 | State and municipal securities
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 Basis | Level 3 | U.S. Treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring Basis | Level 3 | Mortgage-backed securities issued by U.S. Government agencies
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		0
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring Basis | Level 3 | 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	0	0
Fair Value, Measurements, Recurring Basis | Level 3 | Corporate debt and other securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	1,927	1,796
Fair Value, Measurements, Recurring Basis | Level 3 | Equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale		0
Fair Value, Measurements, Recurring Basis | Level 3 | Interest rate contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Fair Value, Measurements, Recurring Basis | Level 3 | Mortgage derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0	0
Fair Value, Measurements, Recurring Basis | Level 3 | Visa derivative
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	$ 5,053	$ 5,768