Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	$ 1,149,598	$ 879,989
Short-term investments	0	9,997
Total investments	1,149,598	889,986
U.S. government and government agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	91,302	204,412
State and municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	109,452	67,784
Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	127,595	82,438
Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	281,275	192,103
Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	120,013	120,577
Corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	419,961	212,675
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	91,302	204,412
Short-term investments	0	9,997
Total investments	91,302	214,409
Level 1 \| U.S. government and government agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	91,302	204,412
Level 1 \| State and municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	0	0
Level 1 \| Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	0	0
Level 1 \| Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	0	0
Level 1 \| Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	0	0
Level 1 \| Corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	1,058,296	675,577
Short-term investments	0	0
Total investments	1,058,296	675,577
Level 2 \| U.S. government and government agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	0	0
Level 2 \| State and municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	109,452	67,784
Level 2 \| Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	127,595	82,438
Level 2 \| Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	281,275	192,103
Level 2 \| Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	120,013	120,577
Level 2 \| Corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	419,961	212,675
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	0	0
Short-term investments	0	0
Total investments	0	0
Level 3 \| U.S. government and government agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	0	0
Level 3 \| State and municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	0	0
Level 3 \| Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	0	0
Level 3 \| Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	0	0
Level 3 \| Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	0	0
Level 3 \| Corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturity securities	$ 0	$ 0

Bowhead Specialty Holdings Inc. 10-Q