Quarterly Data - Unaudited, in Thousands, except Per Share Data (Details)	3 Months Ended								12 Months Ended
	Dec. 25, 2016 USD ($) $ / shares	Sep. 25, 2016 USD ($) $ / shares	Jun. 26, 2016 USD ($) $ / shares	Mar. 27, 2016 USD ($) $ / shares	Dec. 27, 2015 USD ($) $ / shares	Sep. 27, 2015 USD ($) $ / shares	Jun. 28, 2015 USD ($) $ / shares	Mar. 29, 2015 USD ($) $ / shares	Dec. 25, 2016 USD ($) item $ / shares	Dec. 27, 2015 USD ($) item $ / shares	Dec. 28, 2014 USD ($) $ / shares
Quarterly Data - Unaudited, in Thousands, except Per Share Data
Total revenues | $	$ 439,619,000	$ 422,442,000	$ 422,964,000	$ 428,595,000	$ 416,816,000	$ 389,284,000	$ 398,991,000	$ 432,284,000	$ 1,713,620,000	$ 1,637,375,000	$ 1,598,149,000
Operating income | $	51,411,000	33,383,000	36,831,000	42,898,000	40,229,000	27,437,000	30,996,000	37,645,000	164,523,000	136,307,000	117,630,000
Net income attributable to the Company | $	$ 32,630,000	$ 21,467,000	$ 22,541,000	$ 26,182,000	$ 24,695,000	$ 17,971,000	$ 10,780,000	$ 22,236,000	$ 102,820,000	$ 75,682,000	$ 73,315,000
Basic earnings per common share | $ / shares	$ 0.89	$ 0.57	$ 0.61	$ 0.69	$ 0.63	$ 0.46	$ 0.27	$ 0.56	$ 2.76	$ 1.91	$ 1.78
Diluted earnings per common share | $ / shares	0.88	0.57	0.61	0.69	0.62	0.45	0.27	0.55	2.74	1.89	1.75
Dividends declared per common share | $ / shares	$ 0.200	$ 0.200	$ 0.175	$ 0.175	$ 0.175	$ 0.175	$ 0.140	$ 0.140	$ 0.75	$ 0.63	$ 0.53
Number of weeks in quarter | item									13	13
After tax gain from the sale of a domestic Company-owned market to a franchisee | $	$ 7,300,000
Impact on basic and diluted EPS from the sale of a domestic Company-owned market to a franchisee | $ / shares	$ 0.19
After tax loss from impairment related to company-owned stores in China currently for sale | $	$ 900,000
Unfavorable impact on basic and diluted EPS from impairment related to Company-owned stores in China currently for sale | $ / shares	$ 0.02
After tax gain related to a legal settlement | $	$ 600,000
Favorable impact on basic and diluted EPS related to a legal settlement | $ / shares	$ 0.02
Tax legal settlement expense | $							$ 8,000,000		$ (898,000)	$ 12,278,000
Impact on basic and diluted earnings per share due to legal settlement expense | $ / shares							$ (0.20)