Note 9 - Reserve for Losses and Loss Adjustment Expenses (Details Textual) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Loss and Loss Adjustment Expense Reserve Redundancy	$ (2.2)	$ (2.4)	$ 3.6

Represents the amount of loss and loss adjustment expense reserve redundancy.

No definition available.

Name:	plmr_LossAndLossAdjustmentExpenseReserveRedundancy
Namespace Prefix:	plmr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration