Stockholders' Equity - Schedule of Other Ownership Interests (Details) - shares	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
THG units held by Hagerty, Inc.
Class of Stock [Roll Forward]
Ending balance (in shares)	346,135,977	345,219,009
Beginning of period	29.10%	26.10%
End of period	29.20%	26.10%
Common stock, shares, issued (in shares)	346,135,977	345,219,009
THG units held by other unit holders
Class of Stock [Roll Forward]
Beginning balance (in shares)	245,420,794	255,178,346
Ending balance (in shares)	245,050,694	255,154,346
Beginning of period	70.90%	73.90%
End of period	70.80%	73.90%
Class A Common Stock
Class of Stock [Roll Forward]
Beginning balance (in shares)	100,706,893
Ending balance (in shares)	101,085,283
Common stock, shares, issued (in shares)	101,085,283		100,706,893
Class A Common Stock | THG units held by Hagerty, Inc.
Class of Stock [Roll Forward]
Beginning balance (in shares)	100,706,893	90,032,391
Issuance of shares under employee plans (in shares)	8,290	8,272
Exchange of THG units for Class A Common Stock (in shares)	(370,100)	(24,000)
Ending balance (in shares)	101,085,283	90,064,663
Class A Common Stock | THG units held by other unit holders
Class of Stock [Roll Forward]
Exchange of THG units for Class A Common Stock (in shares)	(370,100)	(24,000)