Leases - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 27, 2017	Dec. 28, 2016	Dec. 30, 2015
Property Subject to or Available for Operating Lease [Line Items]
Initial term of lease	20 years
Sublease income, contingent rental income	$ 800	$ 1,000	$ 1,100
Franchise revenue	$ 25,086	24,655	23,017
Minimum
Property Subject to or Available for Operating Lease [Line Items]
Lessor, term of contract	3 years
Maximum
Property Subject to or Available for Operating Lease [Line Items]
Lessor, term of contract	9 years
Rental Income
Property Subject to or Available for Operating Lease [Line Items]
Franchise revenue	$ 500	$ 500	$ 400

Revenue earned during the period from consideration (often a percentage of the franchisee's sales) received for the right to operate a business using the entity's name, merchandise, services, methodologies, promotional support, marketing, and supplies.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(e))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 952
-SubTopic 605
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=68058139&loc=d3e68564-108043

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Period Type:	duration

- Definition

Term of the lessee's leasing arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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- Definition

Term of the lessor's leasing arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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- Definition

Amount of contingent rental revenue recognized for the period under lease, based on the occurrences of an event or condition.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6454179&loc=d3e41551-112718

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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