Revenue from Contracts with Customers - Revenues Disaggregated by Revenue Source and Market (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 28, 2018	Mar. 29, 2017
Disaggregation of Revenue [Line Items]
Company-operated restaurant revenue	$ 94,553	$ 93,449
Franchise revenue	6,106	6,322
Franchise advertising fee revenue	5,097	0
Total revenue	105,756	$ 99,771
Core Market
Disaggregation of Revenue [Line Items]
Company-operated restaurant revenue	82,962
Franchise revenue	3,375
Franchise advertising fee revenue	2,610
Total revenue	88,947
Non-Core Market
Disaggregation of Revenue [Line Items]
Company-operated restaurant revenue	11,591
Franchise revenue	2,730
Franchise advertising fee revenue	2,488
Total revenue	$ 16,809

[Line Items] for Disaggregation of Revenue [Table]

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- Definition

Franchise Advertising Fee Revenue

+ References

No definition available.

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- Definition

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.

+ References

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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- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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- Definition

Aggregate revenue during the period from services rendered in the normal course of business, after deducting allowances and discounts.

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