| Document and Entity Information | Oct. 19, 2021 |
| Cover [Abstract] | |
| Entity Central Index Key | 0001761312 |
| Document Type | 8-K |
| Document Period End Date | Oct. 19, 2021 |
| Entity File Number | 001-38873 |
| Entity Registrant Name | Palomar Holdings, Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 83-3972551 |
| Entity Address, Address Line One | 7979 Ivanhoe Avenue |
| Entity Address, Adress Line Two | Suite 500 |
| Entity Address, City or Town | La Jolla |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 92037 |
| City Area Code | 619 |
| Local Phone Number | 567-5290 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $0.0001 per share |
| Trading Symbol | PLMR |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Amendment Flag | false |
