v3.26.3
Investments (Tables)
 9 Months Ended
Sep. 30, 2026
Investments, Debt and Equity Securities [Abstract]  
Schedule of Investments Available for Sale
Investments available for sale consist of the following:
September 30, 2026 (In thousands)Amortized
Cost		Unrealized
Gains		Unrealized
Losses		Fair
Value
U.S. Treasury securities$329,228 $— $(11,384)$317,844 
U.S. agency mortgage-backed securities1,263,239 38 (138,112)1,125,165 
Municipal debt securities(1)630,376 37 (67,063)563,350 
Non-U.S. government securities53,425 — (11,256)42,169 
Corporate debt securities (2)2,076,515 32 (143,017)1,933,530 
Residential and commercial mortgage securities487,182 339 (30,036)457,485 
Asset-backed securities949,658 611 (21,971)928,298 
Money market funds504,150 — (8)504,142 
Total investments available for sale$6,293,773 $1,057 $(422,847)$5,871,983 
December 31, 2025 (In thousands)Amortized
Cost		Unrealized
Gains		Unrealized
Losses		Fair
Value
U.S. Treasury securities$373,567 $2,121 $(5,976)$369,712 
U.S. agency mortgage-backed securities1,243,823 7,822 (76,750)1,174,895 
Municipal debt securities (1)641,153 5,483 (36,225)610,411 
Non-U.S. government securities64,470 — (8,446)56,024 
Corporate debt securities (2)2,017,246 17,381 (54,547)1,980,080 
Residential and commercial mortgage securities486,441 1,046 (23,382)464,105 
Asset-backed securities804,501 3,832 (7,967)800,366 
Money market funds648,492 — — 648,492 
Total investments available for sale$6,279,693 $37,685 $(213,293)$6,104,085 

September 30,December 31,
(1) The following table summarizes municipal debt securities as of :20262025
Special revenue bonds81.7%81.2%
General obligation bonds18.3 18.8 
Total100.0%100.0%

September 30,December 31,
(2) The following table summarizes corporate debt securities as of :20262025
Financial40.2%40.9%
Consumer, non-cyclical18.6 18.1 
Industrial10.0 9.0 
Utilities8.7 7.9 
Consumer, cyclical4.8 6.0 
Technology5.9 6.1 
Energy4.7 4.7 
Communications4.4 4.7 
Basic Materials2.7 2.6 
Total100.0%100.0%
Schedule of Amortized Cost and Fair Value of Investments Available for Sale by Contractual Maturity
The amortized cost and fair value of investments available for sale at September 30, 2026, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Because most U.S. agency mortgage-backed securities, residential and commercial mortgage securities and asset-backed securities provide for periodic payments throughout their lives, they are listed below in separate categories.
 
(In thousands)Amortized
Cost		Fair
Value
U.S. Treasury securities:
Due in 1 year$49,900 $49,746 
Due after 1 but within 5 years241,366 234,478 
Due after 5 but within 10 years23,411 22,084 
Due after 10 years14,551 11,536 
Subtotal329,228 317,844 
Municipal debt securities:
Due in 1 year15,829 15,727 
Due after 1 but within 5 years95,418 90,373 
Due after 5 but within 10 years146,974 133,313 
Due after 10 years372,155 323,937 
Subtotal630,376 563,350 
Non-U.S. government securities:
Due in 1 year10,132 10,038 
Due after 1 but within 5 years4,301 3,998 
Due after 5 but within 10 years9,595 7,988 
Due after 10 years29,397 20,145 
Subtotal53,425 42,169 
Corporate debt securities:
Due in 1 year147,131 146,248 
Due after 1 but within 5 years633,953 599,524 
Due after 5 but within 10 years1,102,119 1,033,941 
Due after 10 years193,312 153,817 
Subtotal2,076,515 1,933,530 
U.S. agency mortgage-backed securities1,263,239 1,125,165 
Residential and commercial mortgage securities487,182 457,485 
Asset-backed securities949,658 928,298 
Money market funds504,150 504,142 
Total investments available for sale$6,293,773 $5,871,983 
Schedule of Realized Gross Gains and Losses on Sale of Investments Available for Sale
The components of realized investment (losses) gains, net on the condensed consolidated statements of comprehensive income were as follows:
 
Three Months Ended September 30,Nine Months Ended September 30,
(In thousands)2026202520262025
Realized gross gains$3 $40 $677 $59 
Realized gross losses(199)(425)(1,131)(754)
Impairments and changes in expected credit losses(1,430)(40)(1,430)(40)
Schedule of Fair Value of Investments in an Unrealized Loss Position and Related Unrealized Losses
The fair value of investments available for sale in an unrealized loss position and the related unrealized losses for which no allowance for credit loss has been recorded were as follows:
 
Less than 12 months12 months or moreTotal
September 30, 2026 (In thousands)Fair
Value		Gross
Unrealized
Losses		Fair
Value		Gross
Unrealized
Losses		Fair
Value		Gross
Unrealized
Losses
U.S. Treasury securities$250,695 $(4,748)$67,149 $(6,636)$317,844 $(11,384)
U.S. agency mortgage-backed securities651,356 (32,901)469,704 (105,211)1,121,060 (138,112)
Municipal debt securities290,809 (15,617)259,984 (51,446)550,793 (67,063)
Non-U.S. government securities— — 42,169 (11,256)42,169 (11,256)
Corporate debt securities1,346,480 (64,970)553,944 (78,047)1,900,424 (143,017)
Residential and commercial mortgage securities
135,269 (5,104)302,704 (24,932)437,973 (30,036)
Asset-backed securities575,498 (10,052)112,782 (11,919)688,280 (21,971)
Money market funds38,132 (8)— — 38,132 (8)
Total$3,288,239 $(133,400)$1,808,436 $(289,447)$5,096,675 $(422,847)
 
Less than 12 months12 months or moreTotal
December 31, 2025 (In thousands)Fair
Value		Gross
Unrealized
Losses		Fair
Value		Gross
Unrealized
Losses		Fair
Value		Gross
Unrealized
Losses
U.S. Treasury securities$1,048 $(8)$179,121 $(5,968)$180,169 $(5,976)
U.S. agency mortgage-backed securities45,415 (90)638,729 (76,660)684,144 (76,750)
Municipal debt securities74,928 (1,015)314,515 (35,210)389,443 (36,225)
Non-U.S. government securities— — 56,024 (8,446)56,024 (8,446)
Corporate debt securities196,571 (1,106)706,561 (53,441)903,132 (54,547)
Residential and commercial mortgage securities
36,552 (240)364,271 (23,142)400,823 (23,382)
Asset-backed securities103,989 (871)150,158 (7,096)254,147 (7,967)
Total$458,503 $(3,330)$2,409,379 $(209,963)$2,867,882 $(213,293)
Schedule of Net Investment Income
Net investment income consists of: 
Three Months Ended September 30,Nine Months Ended September 30,
(In thousands)2026202520262025
Fixed maturities$59,293 $54,940 $171,816 $162,372 
Short-term investments5,574 6,540 17,351 20,088 
Gross investment income64,867 61,480 189,167 182,460 
Investment expenses(1,915)(1,685)(5,348)(5,166)
Net investment income$62,952 $59,795 $183,819 $177,294