Stockholders' Equity - Narrative (Details) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended
	Jun. 30, 2025 USD ($)	Jun. 30, 2024 USD ($)	Mar. 31, 2026 USD ($) vote $ / shares shares	Sep. 30, 2025 shares	Mar. 31, 2025 USD ($) shares	Dec. 31, 2025 $ / shares shares
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)			20,000,000
Non-controlling interest | $			$ 700		$ 200
Non-controlling interest unit holders | $			359		24,676
THG LLC
Class of Stock [Line Items]
Dividends, preferred stock, cash | $	$ 5,600	$ 5,600
Non-controlling interest unit holders | $			400		24,700
THG LLC | Hagerty, Inc.
Class of Stock [Line Items]
Non-controlling interest unit holders | $			$ 200		$ 9,700
Class A Common Stock
Class of Stock [Line Items]
Common stock, shares authorized (in shares)			500,000,000			500,000,000
Common stock, par value (in dollars per share) | $ / shares			$ 0.0001			$ 0.0001
Common stock, votes per share | vote			1
Units owned (in shares)			101,085,283			100,706,893
Common stock, shares, issued (in shares)			101,085,283			100,706,893
Stock issued during period, shares, new issues				9,481,750
Class A Common Stock | 2021 Stock Incentive Plan
Class of Stock [Line Items]
Stock issued during period, shares, new issues			8,290		8,272
Class V Common Stock
Class of Stock [Line Items]
Common stock, shares authorized (in shares)			300,000,000			300,000,000
Common stock, par value (in dollars per share) | $ / shares			$ 0.0001			$ 0.0001
Common stock, votes per share | vote			10
Units owned (in shares)			241,552,156			241,552,156
Common stock, shares, issued (in shares)			241,552,156			241,552,156
Common stock, conversion ratio			1
Stock issued during period, shares, new issues			370,100	9,481,750	24,000
Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share) | $ / shares			$ 0.0001
Series A Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares issued (in shares)			8,483,561			8,483,561
Preferred stock, shares outstanding (in shares)			8,483,561			8,483,561
Dividends, preferred stock, cash | $	$ 5,600	$ 5,600