Fair Value Measurements (Fair Value Assets And Liabilities Measured On Recurring and Nonrecurring Basis) (Detail) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Financial Assets:
Total available-for-sale securities	$ 7,759,341	$ 7,892,697
Asset derivatives	11,914	22,682
Value under fair value options	1,800	1,991
Financial Liabilities:
Liability derivatives	381,423	398,370
U.S. Treasury notes
Financial Assets:
Total available-for-sale securities	384,067	717,040
Government agency debentures
Financial Assets:
Total available-for-sale securities	261,101	258,374
Municipal bonds and notes
Financial Assets:
Total available-for-sale securities	1,604,150	1,633,202
Agency CMO
Financial Assets:
Total available-for-sale securities	53,360	59,965
Agency MBS
Financial Assets:
Total available-for-sale securities	2,184,907	2,158,024
Agency CMBS
Financial Assets:
Total available-for-sale securities	1,734,922	1,406,486
Non-agency CMBS
Financial Assets:
Total available-for-sale securities	876,119	896,640
CLO
Financial Assets:
Total available-for-sale securities		2,107
Corporate debt securities
Financial Assets:
Total available-for-sale securities	608,759	704,412
Private label MBS
Financial Assets:
Total available-for-sale securities	43,050	44,249
Other
Financial Assets:
Total available-for-sale securities	8,906	12,198
Fair Value, Recurring
Financial Assets:
Total available-for-sale securities	7,759,341	7,892,697
Alternative investments	29,023	89,678
Total financial assets	8,178,472	8,219,375
Financial Liabilities:
Liability derivatives	433,696	414,499
Contingent consideration	16,039
Liabilities, Fair Value Disclosure	449,735
Fair Value, Recurring | Level 1
Financial Assets:
Total available-for-sale securities	384,067	717,040
Alternative investments	567	430
Total financial assets	397,048	729,652
Financial Liabilities:
Liability derivatives	262	843
Contingent consideration	0
Liabilities, Fair Value Disclosure	262
Fair Value, Recurring | Level 2
Financial Assets:
Total available-for-sale securities	7,375,274	7,175,657
Alternative investments	0	0
Total financial assets	7,752,968	7,400,475
Financial Liabilities:
Liability derivatives	433,434	413,656
Contingent consideration	0
Liabilities, Fair Value Disclosure	433,434
Fair Value, Recurring | Level 3
Financial Assets:
Total available-for-sale securities	0	0
Alternative investments	0	0
Total financial assets	0	0
Financial Liabilities:
Liability derivatives	0	0
Contingent consideration	16,039
Liabilities, Fair Value Disclosure	16,039
Fair Value, Recurring | Derivative instruments
Financial Assets:
Asset derivatives	375,961	222,906
Fair Value, Recurring | Derivative instruments | Level 1
Financial Assets:
Asset derivatives	67	79
Fair Value, Recurring | Derivative instruments | Level 2
Financial Assets:
Asset derivatives	375,894	222,827
Fair Value, Recurring | Derivative instruments | Level 3
Financial Assets:
Asset derivatives	0	0
Fair Value, Recurring | Loan Origination Commitments
Financial Assets:
Value under fair value options	1,800	1,991
Fair Value, Recurring | Loan Origination Commitments | Level 1
Financial Assets:
Value under fair value options	0	0
Fair Value, Recurring | Loan Origination Commitments | Level 2
Financial Assets:
Value under fair value options	1,800	1,991
Fair Value, Recurring | Loan Origination Commitments | Level 3
Financial Assets:
Value under fair value options	0	0
Fair Value, Recurring | Investments Held In Rabbi Trust
Financial Assets:
Other assets	12,347	12,103
Fair Value, Recurring | Investments Held In Rabbi Trust | Level 1
Financial Assets:
Other assets	12,347	12,103
Fair Value, Recurring | Investments Held In Rabbi Trust | Level 2
Financial Assets:
Other assets	0	0
Fair Value, Recurring | Investments Held In Rabbi Trust | Level 3
Financial Assets:
Other assets	0	0
Fair Value, Recurring | U.S. Treasury notes
Financial Assets:
Total available-for-sale securities	384,067	717,040
Fair Value, Recurring | U.S. Treasury notes | Level 1
Financial Assets:
Total available-for-sale securities	384,067	717,040
Fair Value, Recurring | U.S. Treasury notes | Level 2
Financial Assets:
Total available-for-sale securities	0	0
Fair Value, Recurring | U.S. Treasury notes | Level 3
Financial Assets:
Total available-for-sale securities	0	0
Fair Value, Recurring | Government agency debentures
Financial Assets:
Total available-for-sale securities	261,101	258,374
Fair Value, Recurring | Government agency debentures | Level 1
Financial Assets:
Total available-for-sale securities	0	0
Fair Value, Recurring | Government agency debentures | Level 2
Financial Assets:
Total available-for-sale securities	261,101	258,374
Fair Value, Recurring | Government agency debentures | Level 3
Financial Assets:
Total available-for-sale securities	0	0
Fair Value, Recurring | Municipal bonds and notes
Financial Assets:
Total available-for-sale securities	1,604,150	1,633,202
Fair Value, Recurring | Municipal bonds and notes | Level 1
Financial Assets:
Total available-for-sale securities	0	0
Fair Value, Recurring | Municipal bonds and notes | Level 2
Financial Assets:
Total available-for-sale securities	1,604,150	1,633,202
Fair Value, Recurring | Municipal bonds and notes | Level 3
Financial Assets:
Total available-for-sale securities	0	0
Fair Value, Recurring | Agency CMO
Financial Assets:
Total available-for-sale securities	53,360	59,965
Fair Value, Recurring | Agency CMO | Level 1
Financial Assets:
Total available-for-sale securities	0	0
Fair Value, Recurring | Agency CMO | Level 2
Financial Assets:
Total available-for-sale securities	53,360	59,965
Fair Value, Recurring | Agency CMO | Level 3
Financial Assets:
Total available-for-sale securities	0	0
Fair Value, Recurring | Agency MBS
Financial Assets:
Total available-for-sale securities	2,184,907	2,158,024
Fair Value, Recurring | Agency MBS | Level 1
Financial Assets:
Total available-for-sale securities	0	0
Fair Value, Recurring | Agency MBS | Level 2
Financial Assets:
Total available-for-sale securities	2,184,907	2,158,024
Fair Value, Recurring | Agency MBS | Level 3
Financial Assets:
Total available-for-sale securities	0	0
Fair Value, Recurring | Agency CMBS
Financial Assets:
Total available-for-sale securities	1,734,922	1,406,486
Fair Value, Recurring | Agency CMBS | Level 1
Financial Assets:
Total available-for-sale securities	0	0
Fair Value, Recurring | Agency CMBS | Level 2
Financial Assets:
Total available-for-sale securities	1,734,922	1,406,486
Fair Value, Recurring | Agency CMBS | Level 3
Financial Assets:
Total available-for-sale securities	0	0
Fair Value, Recurring | Non-agency CMBS
Financial Assets:
Total available-for-sale securities	876,119	896,640
Fair Value, Recurring | Non-agency CMBS | Level 1
Financial Assets:
Total available-for-sale securities	0	0
Fair Value, Recurring | Non-agency CMBS | Level 2
Financial Assets:
Total available-for-sale securities	876,119	896,640
Fair Value, Recurring | Non-agency CMBS | Level 3
Financial Assets:
Total available-for-sale securities	0	0
Fair Value, Recurring | CLO
Financial Assets:
Total available-for-sale securities		2,107
Fair Value, Recurring | CLO | Level 1
Financial Assets:
Total available-for-sale securities		0
Fair Value, Recurring | CLO | Level 2
Financial Assets:
Total available-for-sale securities		2,107
Fair Value, Recurring | CLO | Level 3
Financial Assets:
Total available-for-sale securities		0
Fair Value, Recurring | Corporate debt securities
Financial Assets:
Total available-for-sale securities	608,759	704,412
Fair Value, Recurring | Corporate debt securities | Level 1
Financial Assets:
Total available-for-sale securities	0	0
Fair Value, Recurring | Corporate debt securities | Level 2
Financial Assets:
Total available-for-sale securities	608,759	704,412
Fair Value, Recurring | Corporate debt securities | Level 3
Financial Assets:
Total available-for-sale securities	0	0
Fair Value, Recurring | Private label MBS
Financial Assets:
Total available-for-sale securities	43,050	44,249
Fair Value, Recurring | Private label MBS | Level 1
Financial Assets:
Total available-for-sale securities	0	0
Fair Value, Recurring | Private label MBS | Level 2
Financial Assets:
Total available-for-sale securities	43,050	44,249
Fair Value, Recurring | Private label MBS | Level 3
Financial Assets:
Total available-for-sale securities	0	0
Fair Value, Recurring | Other
Financial Assets:
Total available-for-sale securities	8,906	12,198
Fair Value, Recurring | Other | Level 1
Financial Assets:
Total available-for-sale securities	0	0
Fair Value, Recurring | Other | Level 2
Financial Assets:
Total available-for-sale securities	8,906	12,198
Fair Value, Recurring | Other | Level 3
Financial Assets:
Total available-for-sale securities	$ 0	$ 0