Fair Value Measurements (Fair Value Assets And Liabilities Measured On Recurring and Nonrecurring Basis) (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Financial Assets:
Total available-for-sale investment securities	$ 8,638,358	$ 4,234,854
Asset derivatives	25,074	133,481
Value under fair value options	388	4,694
Financial Liabilities:
Liability derivatives	200,729	13,301
U.S. Treasury notes
Financial Assets:
Total available-for-sale investment securities	726,484	396,966
Government agency debentures
Financial Assets:
Total available-for-sale investment securities	291,203
Municipal bonds and notes
Financial Assets:
Total available-for-sale investment securities	1,830,630
Agency CMO
Financial Assets:
Total available-for-sale investment securities	71,247	90,384
Agency MBS
Financial Assets:
Total available-for-sale investment securities	2,421,333	1,593,403
Agency CMBS
Financial Assets:
Total available-for-sale investment securities	1,561,505	1,232,541
Non-agency CMBS
Financial Assets:
Total available-for-sale investment securities	929,103	886,263
CLO
Financial Assets:
Total available-for-sale investment securities	10,147	21,847
Corporate debt securities
Financial Assets:
Total available-for-sale investment securities	736,520	13,450
Private label MBS
Financial Assets:
Total available-for-sale investment securities	48,303
Other
Financial Assets:
Total available-for-sale investment securities	11,883
Fair Value, Recurring
Financial Assets:
Total available-for-sale investment securities	8,638,358	4,234,854
Alternative investments	71,074	27,732
Total financial assets	8,848,457	4,429,813
Financial Liabilities:
Liability derivatives	212,551	21,784
Fair Value, Recurring | Level 1
Financial Assets:
Total available-for-sale investment securities	726,484	396,966
Alternative investments	718	1,877
Total financial assets	740,617	402,446
Financial Liabilities:
Liability derivatives	99	141
Fair Value, Recurring | Level 2
Financial Assets:
Total available-for-sale investment securities	7,911,874	3,837,888
Alternative investments	0	0
Total financial assets	8,037,484	4,001,512
Financial Liabilities:
Liability derivatives	212,452	21,643
Fair Value, Recurring | Level 3
Financial Assets:
Total available-for-sale investment securities	0	0
Alternative investments	0	0
Total financial assets	0	0
Financial Liabilities:
Liability derivatives	0	0
Fair Value, Recurring | Derivative instruments
Financial Assets:
Asset derivatives	126,016	159,117
Fair Value, Recurring | Derivative instruments | Level 1
Financial Assets:
Asset derivatives	794	187
Fair Value, Recurring | Derivative instruments | Level 2
Financial Assets:
Asset derivatives	125,222	158,930
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	388	4,694
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	388	4,694
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	12,621	3,416
Fair Value, Recurring | Investments Held In Rabbi Trust | Level 1
Financial Assets:
Other assets	12,621	3,416
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 investment securities	726,484	396,966
Fair Value, Recurring | U.S. Treasury notes | Level 1
Financial Assets:
Total available-for-sale investment securities	726,484	396,966
Fair Value, Recurring | U.S. Treasury notes | Level 2
Financial Assets:
Total available-for-sale investment securities	0	0
Fair Value, Recurring | U.S. Treasury notes | Level 3
Financial Assets:
Total available-for-sale investment securities	0	0
Fair Value, Recurring | Government agency debentures
Financial Assets:
Total available-for-sale investment securities	291,203
Fair Value, Recurring | Government agency debentures | Level 1
Financial Assets:
Total available-for-sale investment securities	0
Fair Value, Recurring | Government agency debentures | Level 2
Financial Assets:
Total available-for-sale investment securities	291,203
Fair Value, Recurring | Government agency debentures | Level 3
Financial Assets:
Total available-for-sale investment securities	0
Fair Value, Recurring | Municipal bonds and notes
Financial Assets:
Total available-for-sale investment securities	1,830,630
Fair Value, Recurring | Municipal bonds and notes | Level 1
Financial Assets:
Total available-for-sale investment securities	0
Fair Value, Recurring | Municipal bonds and notes | Level 2
Financial Assets:
Total available-for-sale investment securities	1,830,630
Fair Value, Recurring | Municipal bonds and notes | Level 3
Financial Assets:
Total available-for-sale investment securities	0
Fair Value, Recurring | Agency CMO
Financial Assets:
Total available-for-sale investment securities	71,247	90,384
Fair Value, Recurring | Agency CMO | Level 1
Financial Assets:
Total available-for-sale investment securities	0	0
Fair Value, Recurring | Agency CMO | Level 2
Financial Assets:
Total available-for-sale investment securities	71,247	90,384
Fair Value, Recurring | Agency CMO | Level 3
Financial Assets:
Total available-for-sale investment securities	0	0
Fair Value, Recurring | Agency MBS
Financial Assets:
Total available-for-sale investment securities	2,421,333	1,593,403
Fair Value, Recurring | Agency MBS | Level 1
Financial Assets:
Total available-for-sale investment securities	0	0
Fair Value, Recurring | Agency MBS | Level 2
Financial Assets:
Total available-for-sale investment securities	2,421,333	1,593,403
Fair Value, Recurring | Agency MBS | Level 3
Financial Assets:
Total available-for-sale investment securities	0	0
Fair Value, Recurring | Agency CMBS
Financial Assets:
Total available-for-sale investment securities	1,561,505	1,232,541
Fair Value, Recurring | Agency CMBS | Level 1
Financial Assets:
Total available-for-sale investment securities	0	0
Fair Value, Recurring | Agency CMBS | Level 2
Financial Assets:
Total available-for-sale investment securities	1,561,505	1,232,541
Fair Value, Recurring | Agency CMBS | Level 3
Financial Assets:
Total available-for-sale investment securities	0	0
Fair Value, Recurring | Non-agency CMBS
Financial Assets:
Total available-for-sale investment securities	929,103	886,263
Fair Value, Recurring | Non-agency CMBS | Level 1
Financial Assets:
Total available-for-sale investment securities	0	0
Fair Value, Recurring | Non-agency CMBS | Level 2
Financial Assets:
Total available-for-sale investment securities	929,103	886,263
Fair Value, Recurring | Non-agency CMBS | Level 3
Financial Assets:
Total available-for-sale investment securities	0	0
Fair Value, Recurring | CLO
Financial Assets:
Total available-for-sale investment securities	10,147	21,847
Fair Value, Recurring | CLO | Level 1
Financial Assets:
Total available-for-sale investment securities	0	0
Fair Value, Recurring | CLO | Level 2
Financial Assets:
Total available-for-sale investment securities	10,147	21,847
Fair Value, Recurring | CLO | Level 3
Financial Assets:
Total available-for-sale investment securities	0	0
Fair Value, Recurring | Corporate debt securities
Financial Assets:
Total available-for-sale investment securities	736,520	13,450
Fair Value, Recurring | Corporate debt securities | Level 1
Financial Assets:
Total available-for-sale investment securities	0	0
Fair Value, Recurring | Corporate debt securities | Level 2
Financial Assets:
Total available-for-sale investment securities	736,520	13,450
Fair Value, Recurring | Corporate debt securities | Level 3
Financial Assets:
Total available-for-sale investment securities	0	$ 0
Fair Value, Recurring | Private label MBS
Financial Assets:
Total available-for-sale investment securities	48,303
Fair Value, Recurring | Private label MBS | Level 1
Financial Assets:
Total available-for-sale investment securities	0
Fair Value, Recurring | Private label MBS | Level 2
Financial Assets:
Total available-for-sale investment securities	48,303
Fair Value, Recurring | Private label MBS | Level 3
Financial Assets:
Total available-for-sale investment securities	0
Fair Value, Recurring | Other
Financial Assets:
Total available-for-sale investment securities	11,883
Fair Value, Recurring | Other | Level 1
Financial Assets:
Total available-for-sale investment securities	0
Fair Value, Recurring | Other | Level 2
Financial Assets:
Total available-for-sale investment securities	11,883
Fair Value, Recurring | Other | Level 3
Financial Assets:
Total available-for-sale investment securities	$ 0