Dividend Restrictions (Details) $ in Millions	12 Months Ended
Dec. 31, 2018 USD ($)
Dividend Restrictions [Line items]
Threshold dividend or distribution without the prior approval	$ 5.0
Dividends receivable	5.0
Palomar Specialty Reinsurance Company Bermuda Ltd
Dividend Restrictions [Line items]
Dividends receivable	2.9
Dividends received	$ 13.7

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

+ Details

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Period Type:	duration

- Definition

The amount of dividends and return on capital available to the company.

+ References

No definition available.

+ Details

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Namespace Prefix:	plmr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of maximum dividend or distribution that may be made without the prior approval of Oregon and California Insurance Commissioners.

+ References

No definition available.

+ Details

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Namespace Prefix:	plmr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

Dividends received on equity and other investments during the current period.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 16
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3337-108585

+ Details

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Balance Type:	debit
Period Type:	duration

- Details

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