v3.26.1
Available-for-Sale Securities (Tables)
 3 Months Ended
Mar. 31, 2026
Debt Securities, Available-for-sale [Line Items]  
Schedule of Available-for-sale Securities Reconciliation [Table Text Block] Available-for-sale securities as of March 31, 2026 were as follows (in thousands):
Amortized
Cost		Gross
 Unrealized
 Gains		Gross
Unrealized
Losses		Estimated
Fair
Value
GSE debentures$1,404,032 $6,489 $— $1,410,521 
GSE commercial MBS17,341,680 180,052 3,422 17,518,310 
Total$18,745,712 $186,541 $3,422 $18,928,831 

Available-for-sale securities as of December 31, 2025 were as follows (in thousands):
Amortized
Cost		Gross
 Unrealized
 Gains		Gross
Unrealized
Losses		Estimated
Fair
Value
GSE debentures$1,489,642 $9,189 $— $1,498,831 
GSE commercial MBS
17,635,403 176,702 2,744 17,809,361 
Total$19,125,045 $185,891 $2,744 $19,308,192 
Categories of Investments, Marketable Securities, Available-for-sale Securities [Member]  
Debt Securities, Available-for-sale [Line Items]  
Schedule of Unrealized Loss on Investments [Table Text Block]
The following table summarizes (in thousands) the available-for-sale securities with unrealized losses (all of which were GSE CMBS) as of March 31, 2026 and December 31, 2025. The unrealized losses are aggregated by length of time that individual securities have been in a continuous loss position.
 Less than 12 Months12 Months or MoreTotal
Estimated
Fair
Value		Gross
Unrealized
Losses		Estimated
Fair
Value		Gross
Unrealized
Losses		Estimated
Fair
Value		Gross
Unrealized
Losses
March 31, 2026$673,894 $1,400 $127,776 $2,022 $801,670 $3,422 
December 31, 2025$207,012 $636 $88,049 $2,108 $295,061 $2,744 
Investments Classified by Contractual Maturity Date [Table Text Block] The amortized cost and estimated fair value of available-for-sale securities by contractual maturity at March 31, 2026 and December 31, 2025 are presented below (in thousands).
 March 31, 2026December 31, 2025
MaturityAmortized
Cost		Estimated
Fair Value		Amortized
Cost		Estimated
Fair Value
Debentures
Due in one year or less$1,113,659 $1,115,739 $1,035,186 $1,037,965 
Due after one year through five years290,373 294,782 440,776 446,564 
Due after five years through ten years— — 13,680 14,302 
1,404,032 1,410,521 1,489,642 1,498,831 
GSE CMBS17,341,680 17,518,310 17,635,403 17,809,361 
Total$18,745,712 $18,928,831 $19,125,045 $19,308,192