Revenues Financial Statement Impact of Adoption (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 26, 2018		Sep. 26, 2018		Jun. 27, 2018		Mar. 28, 2018		Dec. 27, 2017		Sep. 27, 2017		Jun. 28, 2017		Mar. 29, 2017		Dec. 26, 2018	Dec. 27, 2017		Dec. 28, 2016		Dec. 28, 2017	Dec. 29, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid and other current assets	$ 10,866								$ 11,788								$ 10,866	$ 11,788
Deferred income taxes	17,333								16,945								17,333	16,945
Other current liabilities	61,790								59,246								61,790	59,246
Other noncurrent liabilities	48,087								27,951								48,087	27,951
Deficit	(306,414)								(334,661)								(306,414)	(334,661)
Revenue from contract with customer, excluding assessed tax	159,549	[1]	$ 158,023	[1]	$ 157,334	[1]	$ 155,273	[1]	135,499		$ 132,384		$ 133,376		$ 127,910		630,179	529,169	[2]	$ 506,948	[2]
Costs of franchise and license revenue	28,517																114,296	39,294		40,805
Provision for income taxes	1,340																8,557	17,207		16,474
Net income	$ 11,503		$ 10,805		$ 11,626		$ 9,759		$ 13,147		$ 9,325		$ 8,749		$ 8,373		$ 43,693	$ 39,594		$ 19,402
Basic net income per share	$ 0.19	[3]	$ 0.17	[3]	$ 0.18	[3]	$ 0.15	[3]	$ 0.20	[4]	$ 0.14	[4]	$ 0.13	[4]	$ 0.12	[4]	$ 0.69	$ 0.58		$ 0.26
Diluted net income per share	$ 0.18	[3]	$ 0.16	[3]	$ 0.18	[3]	$ 0.15	[3]	$ 0.19	[4]	$ 0.13	[4]	$ 0.12	[4]	$ 0.11	[4]	$ 0.67	$ 0.56		$ 0.25
Total comprehensive income	$ 4,816																$ 41,863	$ 38,685		$ 41,772
Deferred income tax expense																	6,193	10,271		8,844
Other current assets																	921	(2,380)		4,622
Other accrued liabilities																	(1,676)	135		(10,217)
Other noncurrent liabilities																	(4,418)	(3,113)		30
Net cash provided by operating activities																	73,690	78,269		71,162
Cumulative effect adjustment																						$ (15,446)	$ 9,139
Franchise [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue from contract with customer, excluding assessed tax	55,160	[1]	$ 54,414	[1]	$ 54,593	[1]	$ 54,080	[1]	$ 35,196		$ 34,469		$ 35,021		$ 34,131		218,247	$ 138,817		$ 139,638
Deferred franchise revenue [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment																						20,976
(Deficit) [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment																						100
(Deficit) [Member] | Adjustments for New Accounting Pronouncement [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment																						(15,600)
Deferred Tax Asset [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment																						(5,400)
Other Liabilities [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment																						(600)
Other Current Liabilities [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment																						$ 500
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid and other current assets	509																509
Deferred income taxes	(4,988)																(4,988)
Other current liabilities	(407)																(407)
Other noncurrent liabilities	(18,370)																(18,370)
Deficit	14,298																14,298
Costs of franchise and license revenue	(20,962)																(81,268)
Provision for income taxes	(52)																(400)
Net income	$ (148)																$ (1,147)
Basic net income per share	$ (0.01)																$ (0.02)
Diluted net income per share	$ 0.00																$ (0.02)
Total comprehensive income	$ (148)																$ (1,147)
Deferred income tax expense																	(400)
Other current assets																	(509)
Other accrued liabilities																	573
Other noncurrent liabilities																	1,483
Net cash provided by operating activities																	0
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Franchise [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue from contract with customer, excluding assessed tax	(21,162)																(82,815)
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Advertising [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue from contract with customer, excluding assessed tax	19,900																78,300
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Deferred franchise revenue [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue from contract with customer, excluding assessed tax	200																1,500
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Other Franchise Services [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue from contract with customer, excluding assessed tax	1,000																3,000
Costs of franchise and license revenue	1,000																3,000
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid and other current assets	11,375																11,375
Deferred income taxes	12,345																12,345
Other current liabilities	61,383																61,383
Other noncurrent liabilities	29,717																29,717
Deficit	(292,116)																(292,116)
Costs of franchise and license revenue	7,555																33,028
Provision for income taxes	1,288																8,157
Net income	$ 11,355																$ 42,546
Basic net income per share	$ 0.18																$ 0.67
Diluted net income per share	$ 0.18																$ 0.65
Total comprehensive income	$ 4,668																$ 40,716
Deferred income tax expense																	5,793
Other current assets																	412
Other accrued liabilities																	(1,103)
Other noncurrent liabilities																	(2,935)
Net cash provided by operating activities																	73,690
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Franchise [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue from contract with customer, excluding assessed tax	$ 33,998																$ 135,432

[1] During 2018, we adopted ASU 2014-09, which clarifies the principles used to recognize revenue. We elected to apply the modified retrospective method of adoption; therefore, results for reporting periods after December 28, 2017 are presented under the new guidance and prior period amounts have not been adjusted. The increase in operating revenue was primarily the result of recognizing advertising revenue on a gross basis versus recording it on a net basis as previously reported. See Note 3 to our Consolidated Financial Statements for details.

[2] As disclosed in Note 2, prior period amounts have not been adjusted under the modified retrospective method of adoption of Topic 606.

[3] Per share amounts do not necessarily sum to the total year amounts due to changes in shares outstanding and rounding

[4] Per share amounts do not necessarily sum to the total year amounts due to changes in shares outstanding and rounding.