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Investment Securities - Schedule of Amortized Cost and Estimated Fair Value of Investments Available-for-Sale by Contractual Maturity (Details) - USD ($)
$ in Thousands
Mar. 31, 2023
Dec. 31, 2022
AFS Amortized Cost [Abstract]    
Amortized Cost $ 1,763,371 $ 1,803,898
AFS Estimated Fair Value [Abstract]    
Allowance for credit losses 31 17
Estimated Fair Value 1,582,185 1,598,666
HTM Amortized Cost [Abstract]    
Allowance for credit losses 2,008 766
Amortized Cost 1,075,303 1,093,374
HTM Estimated Fair Value [Abstract]    
Allowance for credit losses 2,008 766
Investment securities, held-to-maturity, estimated fair value 965,786 968,707
Debt Securities, Available-for-Sale and Held-to-Maturity [Abstract]    
Amortized Cost 2,838,674 2,897,272
Estimated Fair Value 2,547,971 2,567,373
Allowance for credit losses 31 17
U. S. agency securities    
AFS Amortized Cost [Abstract]    
One year or less 549,420 549,137
After one year through five years 110,918 111,742
After five years through ten years 68,936 73,886
After ten years 12,420 13,012
Amortized Cost 741,694 747,777
AFS Estimated Fair Value [Abstract]    
One year or less 499,312 490,699
After one year through five years 100,911 100,297
After five years through ten years 64,008 68,180
After ten years 10,236 10,552
Allowance for credit losses 0 0
Debt Securities, Available-for-Sale and Held-to-Maturity [Abstract]    
Allowance for credit losses 0 0
After ten years 12,420 13,012
After ten years 10,236 10,552
Residential mortgage-backed securities    
AFS Amortized Cost [Abstract]    
Residential mortgage-backed securities: 905,524 937,557
Amortized Cost 905,524 937,557
AFS Estimated Fair Value [Abstract]    
Residential mortgage-backed securities: 800,242 820,503
Allowance for credit losses 0 0
HTM Amortized Cost [Abstract]    
One year or less 724,756 741,057
HTM Estimated Fair Value [Abstract]    
One year or less 647,470 652,667
Investment securities, held-to-maturity, estimated fair value 647,470 652,667
Debt Securities, Available-for-Sale and Held-to-Maturity [Abstract]    
Allowance for credit losses 0 0
Residential mortgage-backed securities: 905,524 937,557
Residential mortgage-backed securities: 800,242 820,503
Commercial mortgage-backed securities    
AFS Amortized Cost [Abstract]    
Residential mortgage-backed securities: 55,421 56,071
Amortized Cost 55,421 56,071
AFS Estimated Fair Value [Abstract]    
Residential mortgage-backed securities: 50,282 50,213
Allowance for credit losses 0 0
HTM Amortized Cost [Abstract]    
One year or less 92,141 92,557
HTM Estimated Fair Value [Abstract]    
One year or less 80,907 80,564
Investment securities, held-to-maturity, estimated fair value 80,907 80,564
Debt Securities, Available-for-Sale and Held-to-Maturity [Abstract]    
Allowance for credit losses 0 0
Residential mortgage-backed securities: 55,421 56,071
Residential mortgage-backed securities: 50,282 50,213
Municipal bonds    
AFS Amortized Cost [Abstract]    
One year or less 0 300
After one year through five years 0 1,444
After five years through ten years 8,914 8,956
After ten years 0 0
Amortized Cost 8,914 10,700
AFS Estimated Fair Value [Abstract]    
One year or less 0 300
After one year through five years 0 1,488
After five years through ten years 8,482 8,299
After ten years 0 0
Allowance for credit losses 0 0
HTM Amortized Cost [Abstract]    
One year or less 3,151 3,139
After one year through five years 35,520 35,579
After five years through ten years 77,246 77,262
After ten years 12,243 12,293
Allowance for credit losses (16)  
HTM Estimated Fair Value [Abstract]    
One year or less 3,122 3,110
After one year through five years 34,398 33,743
After five years through ten years 70,370 67,945
After ten years 11,580 11,383
Allowance for credit losses (16)  
Investment securities, held-to-maturity, estimated fair value 119,470 116,181
Debt Securities, Available-for-Sale and Held-to-Maturity [Abstract]    
Allowance for credit losses 0 0
After ten years 0 0
After ten years 0 0
Corporate bonds    
AFS Amortized Cost [Abstract]    
One year or less 0 0
After one year through five years 2,000 2,000
After five years through ten years 0 0
Amortized Cost 2,000 2,000
AFS Estimated Fair Value [Abstract]    
One year or less 0 0
After one year through five years 1,812 1,825
After five years through ten years 0 0
Allowance for credit losses 31 17
HTM Amortized Cost [Abstract]    
One year or less 23,963 23,954
After one year through five years 84,938 84,953
After five years through ten years 23,353 23,346
Allowance for credit losses (2,000)  
HTM Estimated Fair Value [Abstract]    
One year or less 21,367 20,771
After one year through five years 75,735 77,997
After five years through ten years 20,837 20,527
Allowance for credit losses (2,000)  
Investment securities, held-to-maturity, estimated fair value 117,939 119,295
Debt Securities, Available-for-Sale and Held-to-Maturity [Abstract]    
Allowance for credit losses 31 17
U.S. Treasury    
AFS Amortized Cost [Abstract]    
Residential mortgage-backed securities: 49,818 49,793
AFS Estimated Fair Value [Abstract]    
Residential mortgage-backed securities: 46,931 46,327
Debt Securities, Available-for-Sale and Held-to-Maturity [Abstract]    
Residential mortgage-backed securities: 49,818 49,793
Residential mortgage-backed securities: $ 46,931 $ 46,327