Inventories and Related Notes Payable - Floor Plan - Additional Information (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
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| Inventory Disclosure [Abstract] | |||
| Average interest rate for new vehicle floor plan facilities | 2.37% | 1.85% | 1.61% |
| Amount recognized for floor plan assistance | $ 45.3 | $ 45.0 | $ 42.1 |
| Average interest rate for used vehicle floor plan facilities | 2.61% | 1.78% | 1.72% |
| X | ||||||||||
- Definition Floor plan assistance recognized. No definition available.
|
| X | ||||||||||
- Definition Weighted average interest rate new vehicle floor plan. No definition available.
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| X | ||||||||||
- Definition Weighted average interest rate used vehicle floor plan. No definition available.
|
| X | ||||||||||
- References No definition available.
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