v3.26.1
Debt Securities Held-to-maturity - Weighted average yield and contractual maturities of debt securities HTM (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Amortized cost    
Amortized cost $ 7,208,328 $ 7,620,074
Book Value    
Book Value 6,962,659 7,327,529
Allowance for credit losses    
Allowance for credit losses 5,900 5,812
Net of Allowance    
Net of Allowance 6,956,759 7,321,717
Gross unrecognized gains    
Gross Unrealized Gains 8,596 44,085
Gross unrealized losses    
Gross Unrealized Losses 2,132 2,215
Fair Value    
Fair value $ 6,963,223 $ 7,363,587
Weighted Average Yield    
Weighted Average Yield 1.25% 1.29%
US Treasury Securities    
Amortized cost    
Amortized cost - Within 1 year $ 2,755,510 $ 2,558,293
Amortized cost - After 1 to 5 year 4,403,161 5,003,219
Amortized cost 7,158,671 7,561,512
Book Value    
Book Value - within 1 year 2,717,438 2,519,071
Book Value - Within 1 to 5 years 4,195,564 4,749,896
Book Value 6,913,002 7,268,967
Allowance for credit losses    
Allowance for credit losses - Within 1 Year 0 0
Allowance for credit losses - After 1 to 5 years 0 0
Allowance for credit losses 0 0
Net of Allowance    
Net of Allowance - Within 1 Year 2,717,438 2,519,071
Net of Allowance - After 1 to 5 Years 4,195,564 4,749,896
Net of Allowance 6,913,002 7,268,967
Gross unrecognized gains    
Gross unrealized gains - Within 1 year 1,757 5,224
Gross unrealized gains - After 1 to 5 years 4,137 35,910
Gross Unrealized Gains 5,894 41,134
Gross unrealized losses    
Gross unrealized losses - Within 1 year 139 110
Gross unrealized losses - After 1 to 5 years 0 0
Gross Unrealized Losses 139 110
Fair Value    
Fair Value - within 1 year 2,719,056 2,524,185
Fair Value - After 1 to 5 years 4,199,701 4,785,806
Fair value $ 6,918,757 $ 7,309,991
Weighted Average Yield    
Weighted average yield - Within 1 Year 1.15% 1.31%
Weighted average yield - After 1 to 5 years 1.30% 1.27%
Weighted Average Yield 1.24% 1.28%
Obligations of Puerto Rico, States and political subdivisions    
Amortized cost    
Amortized cost - Within 1 year $ 2,720 $ 2,605
Amortized cost - After 1 to 5 year 3,910 12,508
Amortized cost - After 5 to 10 years 450 450
Amortized cost - After 10 years 35,126 35,544
Amortized cost 42,206 51,107
Book Value    
Book Value - within 1 year 2,720 2,605
Book Value - Within 1 to 5 years 3,910 12,508
Book Value - After 5 to 10 years 450 450
Book Value - After 10 years 35,126 35,544
Book Value 42,206 51,107
Allowance for credit losses    
Allowance for credit losses - Within 1 Year 13 5
Allowance for credit losses - After 1 to 5 years 27 39
Allowance for credit losses - After 5 to 10 years 14 15
Allowance for credit losses - After 10 years 5,846 5,753
Allowance for credit losses 5,900 5,812
Net of Allowance    
Net of Allowance - Within 1 Year 2,707 2,600
Net of Allowance - After 1 to 5 Years 3,883 12,469
Net of Allowance - After 5 to 10 Years 436 435
Net of Allowance - After 10 Years 29,280 29,791
Net of Allowance 36,306 45,295
Gross unrecognized gains    
Gross unrealized gains - Within 1 year 11 4
Gross unrealized gains - After 1 to 5 years 12 24
Gross unrealized gains - After 5 to 10 years 7 15
Gross unrealized gains - After 10 years 2,672 2,908
Gross Unrealized Gains 2,702 2,951
Gross unrealized losses    
Gross unrealized losses - Within 1 year 0 0
Gross unrealized losses - After 1 to 5 years 8 87
Gross unrealized losses - After 5 to 10 years 0 0
Gross unrealized losses - After 10 years 1,795 1,829
Gross Unrealized Losses 1,803 1,916
Fair Value    
Fair Value - within 1 year 2,718 2,604
Fair Value - After 1 to 5 years 3,887 12,406
Fair Value - After 5 to 10 years 443 450
Fair Value - After 10 years 30,157 30,870
Fair value $ 37,205 $ 46,330
Weighted Average Yield    
Weighted average yield - Within 1 Year 6.45% 6.43%
Weighted average yield - After 1 to 5 years 1.84% 3.49%
Weighted average yield - After 5 to 10 years 5.81% 5.81%
Weighted average yield - After 10 years 1.43% 1.43%
Weighted Average Yield 1.83% 2.22%
Collateralized Mortgage Obligations - Federal agencies    
Amortized cost    
Amortized cost - After 10 years $ 1,491 $ 1,495
Amortized cost 1,491 1,495
Book Value    
Book Value - After 10 years 1,491 1,495
Book Value 1,491 1,495
Allowance for credit losses    
Allowance for credit losses - After 10 years 0 0
Allowance for credit losses 0 0
Net of Allowance    
Net of Allowance - After 10 Years 1,491 1,495
Net of Allowance 1,491 1,495
Gross unrecognized gains    
Gross unrealized gains - After 10 years 0 0
Gross Unrealized Gains 0 0
Gross unrealized losses    
Gross unrealized losses - After 10 years 190 189
Gross Unrealized Losses 190 189
Fair Value    
Fair Value - After 10 years 1,301 1,306
Fair value $ 1,301 $ 1,306
Weighted Average Yield    
Weighted average yield - After 10 years 2.87% 2.87%
Weighted Average Yield 2.87% 2.87%
Securities in wholly owned statutory business trusts    
Amortized cost    
Amortized cost - After 5 to 10 years $ 5,960 $ 5,960
Amortized cost 5,960 5,960
Book Value    
Book Value - After 5 to 10 years 5,960 5,960
Book Value 5,960 5,960
Allowance for credit losses    
Allowance for credit losses - After 5 to 10 years 0 0
Allowance for credit losses 0 0
Net of Allowance    
Net of Allowance - After 5 to 10 Years 5,960 5,960
Net of Allowance 5,960 5,960
Gross unrecognized gains    
Gross unrealized gains - After 5 to 10 years 0 0
Gross Unrealized Gains 0 0
Gross unrealized losses    
Gross unrealized losses - After 5 to 10 years 0 0
Gross Unrealized Losses 0 0
Fair Value    
Fair Value - After 5 to 10 years 5,960 5,960
Fair value $ 5,960 $ 5,960
Weighted Average Yield    
Weighted average yield - After 5 to 10 years 6.33% 6.33%
Weighted Average Yield 6.33% 6.33%