Impairment and closure (Details) $ in Thousands |
3 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
|
Sep. 30, 2018
USD ($)
|
Dec. 30, 2018
USD ($)
Restaurant
|
Dec. 31, 2017
USD ($)
|
Dec. 25, 2016
USD ($)
Restaurant
|
|
| Impairment and Closure Costs [Abstract] | ||||
| Impairment and closure costs | $ | $ 12,336 | $ 12,336 | $ 0 | $ 1,517 |
| Closure Costs, Number of Restaurants | 1 | |||
| Impairment charges, number of restaurants | 6 | |||
| X | ||||||||||
- Definition Closure Costs, Number of Restaurants No definition available.
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| X | ||||||||||
- Definition Impairment Charges, Number of Restaurants No definition available.
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| X | ||||||||||
- Definition Impairment and Closure Costs [Abstract] No definition available.
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| X | ||||||||||
- Definition Amount of restructuring charges, remediation cost, and asset impairment loss. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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