Revenues Financial Statement Impact of Adoption (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 28, 2018	Mar. 29, 2017	Dec. 28, 2017	Dec. 27, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid and other current assets	$ 9,048			$ 11,788
Deferred income taxes	22,294			16,945
Other current liabilities	51,707			59,246
Other noncurrent liabilities	51,561			27,951
Deficit	(340,348)			(334,661)
Franchise and license revenue	54,080	$ 34,131
Costs of franchise and license revenue	28,556	9,746
Provision for income taxes	1,829	4,744
Net income	$ 9,759	$ 8,373
Basic net income per share	$ 0.15	$ 0.12
Diluted net income per share	$ 0.15	$ 0.11
Total comprehensive income	$ 6,668	$ 7,764
Deferred income tax expense	1,118	3,225
Other current assets	2,739	3,131
Other accrued liabilities	(5,948)	(1,204)
Other noncurrent liabilities	(413)	(1,133)
Net cash flows provided by operating activities	3,450	$ 8,021
Cumulative effect adjustment			$ (20,976)	$ (15,446)
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
Deferred income taxes	(5,282)
Other current liabilities	(1,158)
Other noncurrent liabilities	(18,624)
Deficit	15,009
Franchise and license revenue	(20,307)
Costs of franchise and license revenue	(19,764)
Provision for income taxes	(140)
Net income	$ (403)
Basic net income per share	$ (0.01)
Diluted net income per share	$ (0.01)
Total comprehensive income	$ (403)
Deferred income tax expense	(140)
Other current assets	(509)
Other accrued liabilities	923
Other noncurrent liabilities	129
Net cash flows provided by operating activities	0
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	9,557
Deferred income taxes	17,012
Other current liabilities	50,549
Other noncurrent liabilities	32,937
Deficit	(325,339)
Franchise and license revenue	33,773
Costs of franchise and license revenue	8,792
Provision for income taxes	1,689
Net income	$ 9,356
Basic net income per share	$ 0.14
Diluted net income per share	$ 0.14
Total comprehensive income	$ 6,265
Deferred income tax expense	978
Other current assets	2,230
Other accrued liabilities	(5,025)
Other noncurrent liabilities	(284)
Net cash flows provided by operating activities	3,450
Initial and other fees [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment			21,000
(Deficit) [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment			100
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
Adjustments for New Accounting Pronouncement [Member] | (Deficit) [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment			$ (15,600)
Initial and other fees [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Franchise and license revenue	500
Advertising [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Franchise and license revenue	19,188
Costs of franchise and license revenue	19,188
Other Franchise Services [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Franchise and license revenue	454
Costs of franchise and license revenue	$ 454