Segment information - Revenues by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 30, 2017	Sep. 30, 2017	Jul. 01, 2017	Apr. 01, 2017	Dec. 31, 2016	Sep. 24, 2016	Jun. 25, 2016	Mar. 26, 2016	Dec. 30, 2017	Dec. 31, 2016	Dec. 26, 2015
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	$ 227,139	$ 224,168	$ 218,522	$ 190,672	$ 215,705	$ 207,099	$ 216,309	$ 189,776	$ 860,501	$ 828,889	$ 810,933
Other									34,148	31,495	32,682
Operating segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues									826,353	797,394	778,251
Operating segments | Dunkin Donuts | United States
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues									641,896	607,964	591,062
Operating segments | Dunkin’ Donuts International | United States
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues									20,573	22,903	22,973
Operating segments | Baskin Robbins | United States
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues									49,204	47,512	47,140
Operating segments | Baskin-Robbins International | United States
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues									$ 114,680	$ 119,015	$ 117,076