Note 7 - Underwriting Information - Schedule of Gross Written Premiums (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Disaggregation of Revenue [Line Items]
Gross written premiums	$ 597,171	$ 414,977	$ 1,535,623	$ 1,168,239
Percentage of Gross Written Premiums	100.00%	100.00%	100.00%	100.00%
Palomar Specialty Insurance Company [Member]
Disaggregation of Revenue [Line Items]
Gross written premiums	$ 317,177	$ 236,624	$ 781,078	$ 652,988
Percentage of Gross Written Premiums	53.10%	57.00%	50.90%	55.90%
Palomar Excess And Surplus Insurance Company [Member]
Disaggregation of Revenue [Line Items]
Gross written premiums	$ 252,318	$ 159,305	$ 681,048	$ 472,909
Percentage of Gross Written Premiums	42.30%	38.40%	44.40%	40.50%
Laulima Insurance Company [Member]
Disaggregation of Revenue [Line Items]
Gross written premiums	$ 22,804	$ 19,048	$ 58,974	$ 42,342
Percentage of Gross Written Premiums	3.80%	4.60%	3.80%	3.60%
First Indemnity of America Insurance Company [Member]
Disaggregation of Revenue [Line Items]
Gross written premiums	$ 4,872	$ 0	$ 14,523	$ 0
Percentage of Gross Written Premiums	0.80%	0.00%	0.90%	0.00%
CALIFORNIA
Disaggregation of Revenue [Line Items]
Gross written premiums	$ 168,739	$ 170,265	$ 472,276	$ 510,879
Percentage of Gross Written Premiums	28.30%	41.00%	30.80%	43.70%
TEXAS
Disaggregation of Revenue [Line Items]
Gross written premiums	$ 38,609	$ 27,019	$ 119,308	$ 96,414
Percentage of Gross Written Premiums	6.50%	6.50%	7.80%	8.30%
HAWAII
Disaggregation of Revenue [Line Items]
Gross written premiums	$ 26,405	$ 23,171	$ 71,307	$ 53,922
Percentage of Gross Written Premiums	4.40%	5.60%	4.60%	4.60%
FLORIDA
Disaggregation of Revenue [Line Items]
Gross written premiums	$ 23,770	$ 14,433	$ 66,391	$ 58,153
Percentage of Gross Written Premiums	4.00%	3.50%	4.30%	5.00%
ILLINOIS
Disaggregation of Revenue [Line Items]
Gross written premiums	$ 20,911	$ 5,557	$ 39,548	$ 13,725
Percentage of Gross Written Premiums	3.50%	1.30%	2.60%	1.20%
NORTH DAKOTA
Disaggregation of Revenue [Line Items]
Gross written premiums	$ 20,022	$ 18,716	$ 23,709	$ 19,893
Percentage of Gross Written Premiums	3.40%	4.50%	1.50%	1.70%
NEW YORK
Disaggregation of Revenue [Line Items]
Gross written premiums	$ 19,181	$ 8,153	$ 51,240	$ 24,163
Percentage of Gross Written Premiums	3.20%	2.00%	3.30%	2.10%
WASHINGTON
Disaggregation of Revenue [Line Items]
Gross written premiums	$ 17,560	$ 16,828	$ 50,416	$ 41,893
Percentage of Gross Written Premiums	2.90%	4.10%	3.30%	3.60%
Other States [Member]
Disaggregation of Revenue [Line Items]
Gross written premiums	$ 261,974	$ 130,835	$ 641,428	$ 349,197
Percentage of Gross Written Premiums	43.80%	31.50%	41.80%	29.80%
Casualty [Member]
Disaggregation of Revenue [Line Items]
Gross written premiums	$ 152,034	$ 56,307	$ 392,473	$ 166,762
Percentage of Gross Written Premiums	25.50%	13.60%	25.60%	14.30%
Earthquake Premiums [Member]
Disaggregation of Revenue [Line Items]
Gross written premiums	$ 149,940	$ 135,329	$ 427,869	$ 376,088
Percentage of Gross Written Premiums	25.10%	32.60%	27.90%	32.20%
Crop [Member]
Disaggregation of Revenue [Line Items]
Gross written premiums	$ 119,757	$ 59,662	$ 207,440	$ 100,571
Percentage of Gross Written Premiums	20.10%	14.40%	13.50%	8.60%
Inland Marine and Other Property [Member]
Disaggregation of Revenue [Line Items]
Gross written premiums	$ 117,871	$ 78,734	$ 335,462	$ 249,147
Percentage of Gross Written Premiums	19.70%	19.00%	21.80%	21.30%
Fronting Premium [Member]
Disaggregation of Revenue [Line Items]
Gross written premiums	$ 57,569	$ 84,945	$ 172,379	$ 275,671
Percentage of Gross Written Premiums	9.60%	20.40%	11.20%	23.60%