Fair Value Accounting (Financial Instruments Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale	$ 7,962,438	$ 6,778,670
Private equity investments	1,021	19,389
Mutual funds and mutual funds held in rabbi trusts	37,650	32,348
Derivative asset positions	401,295	140,016
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Total investment securities available for sale	20,257	19,855
Private equity investments	0	15,502
Mutual funds and mutual funds held in rabbi trusts	37,650	32,348
GGL/SBA loans servicing asset	0	0
Derivative asset positions	0	0
Trading liability for short positions	0	1,560
Earnout liability	0	0
Derivative liabilities	0	0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	10,880	7,212
Total investment securities available for sale	7,940,160	6,756,710
Private equity investments	0	0
Mutual funds and mutual funds held in rabbi trusts	0	0
GGL/SBA loans servicing asset	0	0
Derivative asset positions	401,295	140,016
Trading liability for short positions	7,717	0
Earnout liability	0	0
Derivative liabilities	155,119	34,732
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Total investment securities available for sale	2,021	2,105
Private equity investments	1,021	3,887
Mutual funds and mutual funds held in rabbi trusts	0	0
GGL/SBA loans servicing asset	3,258	3,040
Derivative asset positions	0	0
Trading liability for short positions	0	0
Earnout liability	5,677	11,016
Derivative liabilities	2,048	2,339
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale	1,250,377	636,851
State and municipal securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale		2,075
Asset-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale		327,400
U.S. Treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale	20,257	19,855
Mortgage-backed securities issued by U.S. Government agencies
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale	1,218,017	56,816
Mortgage-backed securities issued by U.S. Government sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale	5,000,046	5,180,815
Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale	370,921	371,592
Corporate debt securities and other debt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale	20,500	146,725
Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	10,880	7,212
Total investment securities available for sale	7,962,438	6,778,670
Mortgage loans held for sale	216,647	115,173
Private equity investments	1,021	19,389
GGL/SBA loans servicing asset	3,258	3,040
Derivative asset positions	401,295	140,016
Trading liability for short positions	7,717	1,560
Earnout liability	5,677	11,016
Derivative liabilities	157,167	37,071
Fair Value, Measurements, Recurring | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Total investment securities available for sale	20,257	19,855
Mortgage loans held for sale	0	0
Private equity investments	0	15,502
GGL/SBA loans servicing asset	0	0
Derivative asset positions	0	0
Trading liability for short positions	0	1,560
Earnout liability	0	0
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	10,880	7,212
Total investment securities available for sale	7,940,160	6,756,710
Mortgage loans held for sale	216,647	115,173
Private equity investments	0	0
GGL/SBA loans servicing asset	0	0
Derivative asset positions	401,295	140,016
Trading liability for short positions	7,717	0
Earnout liability	0	0
Derivative liabilities	155,119	34,732
Fair Value, Measurements, Recurring | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Total investment securities available for sale	2,021	2,105
Mortgage loans held for sale	0	0
Private equity investments	1,021	3,887
GGL/SBA loans servicing asset	3,258	3,040
Derivative asset positions	0	0
Trading liability for short positions	0	0
Earnout liability	5,677	11,016
Derivative liabilities	2,048	2,339
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	158
Total investment securities available for sale	1,250,377	636,851
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
Total 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	158
Total investment securities available for sale	1,250,377	636,851
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
Total investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Other mortgage-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	178	1,284
Fair Value, Measurements, Recurring | Other mortgage-backed securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Fair Value, Measurements, Recurring | Other mortgage-backed securities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	178	1,284
Fair Value, Measurements, Recurring | Other mortgage-backed securities | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Fair Value, Measurements, Recurring | State and municipal securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	176	65
Total investment securities available for sale		2,075
Fair Value, Measurements, Recurring | State and municipal securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Total investment securities available for sale		0
Fair Value, Measurements, Recurring | State and municipal securities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	176	65
Total investment securities available for sale		2,075
Fair Value, Measurements, Recurring | State and municipal securities | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Total investment securities available for sale		0
Fair Value, Measurements, Recurring | Asset-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	183	3,227
Total investment securities available for sale		327,400
Fair Value, Measurements, Recurring | Asset-backed securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Total investment securities available for sale		0
Fair Value, Measurements, Recurring | Asset-backed securities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	183	3,227
Total investment securities available for sale		327,400
Fair Value, Measurements, Recurring | Asset-backed securities | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Total investment securities available for sale		0
Fair Value, Measurements, Recurring | Other investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		150
Fair Value, Measurements, Recurring | Other investments | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		0
Fair Value, Measurements, Recurring | Other investments | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		150
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 | U.S. Treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale	20,257	19,855
Fair Value, Measurements, Recurring | U.S. Treasury securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale	20,257	19,855
Fair Value, Measurements, Recurring | U.S. Treasury securities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total 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]
Total investment securities available for sale	0	0
Fair Value, Measurements, Recurring | U.S. Government agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale	82,320	36,541
Fair Value, Measurements, Recurring | U.S. Government agency securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total 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]
Total investment securities available for sale	82,320	36,541
Fair Value, Measurements, Recurring | U.S. Government agency securities | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale	0	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	10,185
Total investment securities available for sale	1,218,017	56,816
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
Total 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	10,185
Total investment securities available for sale	1,218,017	56,816
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
Total 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]
Total investment securities available for sale	5,000,046	5,180,815
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]
Total 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]
Total investment securities available for sale	5,000,046	5,180,815
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]
Total investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		2,486
Total investment securities available for sale	370,921	371,592
Fair Value, Measurements, Recurring | Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		0
Total investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		2,486
Total investment securities available for sale	370,921	371,592
Fair Value, Measurements, Recurring | Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		0
Total investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Corporate debt securities and other debt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale	20,500	146,725
Fair Value, Measurements, Recurring | Corporate debt securities and other debt securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Corporate debt securities and other debt securities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale	18,479	144,620
Fair Value, Measurements, Recurring | Corporate debt securities and other debt securities | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale	2,021	2,105
Fair Value, Measurements, Recurring | Mutual funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mutual funds and mutual funds held in rabbi trusts	37,650	32,348
Fair Value, Measurements, Recurring | Mutual funds | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mutual funds and mutual funds held in rabbi trusts	37,650	32,348
Fair Value, Measurements, Recurring | Mutual funds | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mutual funds and mutual funds held in rabbi trusts	0	0
Fair Value, Measurements, Recurring | Mutual funds | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mutual funds and mutual funds held in rabbi trusts	$ 0	$ 0