Fair Value Measurements - Summarizes Carrying Value and Estimated Fair Values of Financial Instruments not Carried at Fair Value (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Carrying value	$ 19,500	$ 20,200
Surplus Note [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Carrying value	19,485	20,221
Term Loan [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Carrying value	17,991
Level 3 [Member] \| Surplus Note [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Estimated fair value	17,235	18,057
Level 3 [Member] \| Term Loan [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Estimated fair value	$ 17,991

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

No definition available.

+ Details

Name:	us-gaap_LongTermDebtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of loans payable (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LongTermLoansPayable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of notes payable (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion.

+ References

+ Details

Name:	us-gaap_LongTermNotesPayable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	uve_FairValueInputsAssetsLiabilitiesQuantitativeInformationLineItems
Namespace Prefix:	uve_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration