Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2017	Dec. 28, 2016	Dec. 30, 2015	Dec. 28, 2017
Accounting Policies [Abstract]
Short-term investments	$ 1,900	$ 500
Net gain on investments	1,600	900	$ 100
Deferred compensation plan investments	12,700	11,200
Cash overdrafts	2,200	4,100
Discounted insurance liabilities	$ 16,900	$ 19,200
Self insurance liabilities, discount rate	2.00%	1.50%
Undiscounted insurance liabilities	$ 18,100	$ 20,000
Revenue recognized in breakage on gift cards	300	300	300
Deferred fees	1,600	2,100
Advertising expense	14,300	13,100	12,500
Advertising contributions from franchisees	79,700	76,500	72,500
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment		9,139		$ (21,000)
Initial and other franchise fees	2,500	2,700	2,500
Other franchise fees	$ 2,900	3,600	$ 2,900
Other Noncurrent Assets [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment		(200)
Excess Tax Benefits [Member] | Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment		9,000
Estimated Forfeitures [Member] | Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment		(400)
Paid-in Capital [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment		$ 551