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Fair Value Accounting - Financial Instruments Measured At Fair Value On A Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale	$ 10,918,329	$ 7,962,438
Mutual funds and mutual funds held in rabbi trusts	43,657	37,650
Derivative assets	191,708	401,295
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	779,633	1,218,017
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	939,623	1,250,377
Asset-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale	514,188
U.S. Treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale	117,838	20,257
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	8,012,301	5,000,046
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	481,744	370,921
Corporate debt securities and other debt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale	18,801	20,500
Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total trading securities	8,391	10,880
Total investment securities available for sale	10,918,329	7,962,438
Mortgage loans held for sale	108,198	216,647
Other investments	12,185	1,021
Mutual funds and mutual funds held in rabbi trusts	43,657	37,650
GGL/SBA loans servicing asset	3,233	3,258
Derivative assets	191,708	401,295
Trading liability for short positions	200	7,717
Mutual fund held in rabbi trusts	27,205	20,752
Earnout liability	0	5,677
Derivative liabilities	98,602	157,167
Fair Value, Measurements, Recurring | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total trading securities	0	0
Total investment securities available for sale	117,838	20,257
Mortgage loans held for sale	0	0
Other investments	0	0
Mutual funds and mutual funds held in rabbi trusts	43,657	37,650
GGL/SBA loans servicing asset	0	0
Derivative assets	0	0
Trading liability for short positions	0	0
Mutual fund held in rabbi trusts	27,205	20,752
Earnout liability	0	0
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total trading securities	8,391	10,880
Total investment securities available for sale	10,800,491	7,940,160
Mortgage loans held for sale	108,198	216,647
Other investments	0	0
Mutual funds and mutual funds held in rabbi trusts	0	0
GGL/SBA loans servicing asset	0	0
Derivative assets	191,708	401,295
Trading liability for short positions	200	7,717
Mutual fund held in rabbi trusts	0	0
Earnout liability	0	0
Derivative liabilities	95,067	155,119
Fair Value, Measurements, Recurring | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total trading securities	0	0
Total investment securities available for sale	0	2,021
Mortgage loans held for sale	0	0
Other investments	12,185	1,021
Mutual funds and mutual funds held in rabbi trusts	0	0
GGL/SBA loans servicing asset	3,233	3,258
Derivative assets	0	0
Trading liability for short positions	0	0
Mutual fund held in rabbi trusts	0	0
Earnout liability	0	5,677
Derivative liabilities	3,535	2,048
Fair Value, Measurements, Recurring | Mortgage-backed securities issued by U.S. Government agencies
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total trading securities	197	10,185
Total investment securities available for sale	779,633	1,218,017
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]
Total trading securities	0	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]
Total trading securities	197	10,185
Total investment securities available for sale	779,633	1,218,017
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]
Total trading securities	0	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
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total trading securities	671	158
Total investment securities available for sale	939,623	1,250,377
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]
Total trading securities	0	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]
Total trading securities	671	158
Total investment securities available for sale	939,623	1,250,377
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]
Total trading securities	0	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]
Total trading securities	0	178
Fair Value, Measurements, Recurring | Other mortgage-backed securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total trading securities	0	0
Fair Value, Measurements, Recurring | Other mortgage-backed securities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total trading securities	0	178
Fair Value, Measurements, Recurring | Other mortgage-backed securities | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total trading securities	0	0
Fair Value, Measurements, Recurring | State and municipal securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total trading securities	560	176
Fair Value, Measurements, Recurring | State and municipal securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total trading securities	0	0
Fair Value, Measurements, Recurring | State and municipal securities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total trading securities	560	176
Fair Value, Measurements, Recurring | State and municipal securities | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total trading securities	0	0
Fair Value, Measurements, Recurring | Asset-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total trading securities	6,963	183
Total investment securities available for sale	514,188	0
Fair Value, Measurements, Recurring | Asset-backed securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total trading securities	0	0
Total investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Asset-backed securities | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total trading securities	6,963	183
Total investment securities available for sale	514,188	0
Fair Value, Measurements, Recurring | Asset-backed securities | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total trading securities	0	0
Total investment securities available for sale	0	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	117,838	20,257
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	117,838	20,257
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	54,201	82,320
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	54,201	82,320
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 sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investment securities available for sale	8,012,301	5,000,046
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	8,012,301	5,000,046
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]
Total investment securities available for sale	481,744	370,921
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]
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]
Total investment securities available for sale	481,744	370,921
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]
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	18,801	20,500
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	18,801	18,479
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	$ 0	$ 2,021

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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