Stockholders' Equity - Schedule of Ownership (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Class of Stock [Roll Forward]
Ending balance (in shares)	345,815,692	341,070,926	345,815,692	341,070,926
THG units held by Hagerty, Inc.
Class of Stock [Roll Forward]
Beginning of period	26.10%	24.90%	26.10%	24.90%
End of period	26.20%	25.10%	26.20%	25.10%
THG units held by other unit holders
Class of Stock [Roll Forward]
Beginning balance (in shares)	255,154,346	255,499,164	255,178,346	255,499,164
Ending balance (in shares)	255,100,044	255,367,640	255,100,044	255,367,640
Beginning of period	73.90%	75.10%	73.90%	75.10%
End of period	73.80%	74.90%	73.80%	74.90%
Class A Common Stock
Class of Stock [Roll Forward]
Beginning balance (in shares)			90,032,391
Ending balance (in shares)	90,715,648		90,715,648
Class A Common Stock \| THG units held by Hagerty, Inc.
Class of Stock [Roll Forward]
Beginning balance (in shares)	90,064,663	84,655,539	90,032,391	84,588,536
Issuance of shares under employee plans (in shares)	596,683	916,223	604,955	983,226
Exchange of THG units for Class A Common Stock (in shares)	(54,302)	(131,524)	(78,302)	(131,524)
Ending balance (in shares)	90,715,648	85,703,286	90,715,648	85,703,286
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)	(54,302)	(131,524)	(78,302)	(131,524)