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ACQUISITIONS AND DIVESTITURES - Narrative (Details) $ in Millions |  | 1 Months Ended | 3 Months Ended | 9 Months Ended |
--- | --- | --- | --- | --- | ---
Jul. 21, 2025 USD ($) dealership franchise collisionCenter | Jul. 30, 2025 dealership | Sep. 30, 2025 USD ($) | Sep. 30, 2024 USD ($) business | Sep. 30, 2025 USD ($) dealership franchise | Sep. 30, 2024 USD ($) business franchise dealership | Dec. 31, 2024 USD ($)
Business Combination [Line Items] |  |  |  |  |  |  |
Goodwill | $ |  |  | $ 2,264.8 |  | $ 2,264.8 |  | $ 2,044.7
Number of businesses acquired | business |  |  |  | 0 |  | 0 |
Gain on divestitures, net | $ |  |  | 35.7 | $ 5.0 | 45.8 | $ 8.6 |
Asset impairments | $ |  |  | $ 11.7 | $ 0.0 | 26.0 | 135.4 |
Disposed of by sale | Franchises & Dealerships Sold |  |  |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |  |  |
Gain on divestitures, net | $ |  |  |  |  | $ 45.8 | $ 8.6 |
Disposed of by sale | Toyota Franchise |  |  |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |  |  |
Number of franchises, sold (in franchises) | franchise |  |  |  |  | 2 |  |
Number of dealership locations, sold (in dealership locations) | dealership |  |  |  |  | 2 |  |
Disposed of by sale | Nissan Franchise |  |  |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |  |  |
Number of franchises, sold (in franchises) | franchise |  |  |  |  | 1 |  |
Number of dealership locations, sold (in dealership locations) | dealership |  |  |  |  | 1 |  |
Disposed of by sale | Nissan Franchise | Colorado |  |  |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |  |  |
Number of franchises, sold (in franchises) | franchise |  |  |  |  |  | 1 |
Number of dealership locations, sold (in dealership locations) | dealership |  |  |  |  |  | 1 |
Disposed of by sale | Nissan Franchise | GEORGIA |  |  |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |  |  |
Number of franchises, sold (in franchises) | franchise |  |  |  |  |  | 1 |
Number of dealership locations, sold (in dealership locations) | dealership |  |  |  |  |  | 1 |
Disposed of by sale | Chrysler Jeep Dodge Ram Franchise | Colorado |  |  |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |  |  |
Number of franchises, sold (in franchises) | franchise |  |  |  |  | 1 |  |
Number of dealership locations, sold (in dealership locations) | dealership |  |  |  |  | 1 |  |
Disposed of by sale | Chrysler Jeep Dodge Ram Franchise | UTAH |  |  |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |  |  |
Number of franchises, sold (in franchises) | franchise |  |  |  |  | 2 |  |
Number of dealership locations, sold (in dealership locations) | dealership |  |  |  |  | 2 |  |
Disposed of by sale | Volvo Franchise |  |  |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |  |  |
Number of franchises, sold (in franchises) | franchise |  |  |  |  | 1 |  |
Number of dealership locations, sold (in dealership locations) | dealership |  |  |  |  | 1 |  |
Disposed of by sale | Franchises Sold in Salt Lake City, Utah |  |  |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |  |  |
Number of franchises, sold (in franchises) | franchise |  |  |  |  | 6 |  |
Disposed of by sale | Lexus Franchise |  |  |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |  |  |
Number of franchises, sold (in franchises) | franchise |  |  |  |  | 2 | 1 |
Number of dealership locations, sold (in dealership locations) | dealership |  | 2 |  |  | 2 | 1 |
Disposed of by sale | Chevrolet Franchise |  |  |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |  |  |
Number of franchises, sold (in franchises) | franchise |  |  |  |  | 1 |  |
Number of dealership locations, sold (in dealership locations) | dealership |  |  |  |  | 1 |  |
Disposed of by sale | Ford Franchise |  |  |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |  |  |
Number of franchises, sold (in franchises) | franchise |  |  |  |  | 1 |  |
Number of dealership locations, sold (in dealership locations) | dealership |  |  |  |  | 1 |  |
Disposed of by sale | General Motors |  |  |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |  |  |
Number of dealership locations, sold (in dealership locations) | dealership |  | 2 |  |  |  |  |
Herb Chambers Dealerships |  |  |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |  |  |
Payments to acquire businesses, gross | $ | $ 1,780.0 |  |  |  |  |  |
Aggregate purchase price | $ | 1,783.9 |  |  |  |  |  |
Goodwill | $ | $ 290.1 |  |  |  |  |  |
Dealerships acquired | dealership | 33 |  |  |  |  |  |
Franchises acquired | franchise | 52 |  |  |  |  |  |
Collision centers acquired | collisionCenter | 3 |  |  |  |  |  |
Acquisition related costs | $ | $ 14.7 |  |  |  |  |  |

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