Subsequent Events (Details) $ / shares in Units, $ in Millions		3 Months Ended			4 Months Ended	6 Months Ended
	May 11, 2018 USD ($) $ / shares	Jul. 08, 2018 USD ($)	Apr. 15, 2018 restaurant $ / shares	Apr. 16, 2017 restaurant $ / shares	Jan. 21, 2018 $ / shares	Apr. 15, 2018 restaurant $ / shares	Apr. 16, 2017 restaurant $ / shares
Subsequent Event [Line Items]
Cash dividends declared per common share | $ / shares			$ 0.4	$ 0.40	$ 0.40	$ 0.80	$ 0.80
Stock Repurchase Program, Authorized Amount	$ 200.0
Number of Restaurants | restaurant			2,245	2,260		2,245	2,260
Subsequent Event
Subsequent Event [Line Items]
Cash dividends declared per common share | $ / shares	$ 0.40
Disposal Group, Held-for-sale, Not Discontinued Operations [Member]
Subsequent Event [Line Items]
Number of Restaurants		25
Minimum [Member]
Subsequent Event [Line Items]
Estimated Pre-Tax Proceeds from Sale to Franchisees		$ 21.0
Maximum [Member]
Subsequent Event [Line Items]
Estimated Pre-Tax Proceeds from Sale to Franchisees		$ 23.0