Segment Information (Details) $ in Thousands	12 Months Ended
	Dec. 28, 2022 USD ($) segment	Dec. 29, 2021 USD ($)	Dec. 30, 2020 USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment	2
Segment Reporting Information [Line Items]
Total operating revenue	$ 456,429	$ 398,174	$ 288,605
General and administrative expenses	67,173	68,686	55,040
Depreciation and amortization	14,862	15,446	16,161
Operating (gains), losses and other charges, net	(1,005)	(46,105)	1,808
Total other operating expenses	81,030	38,027	73,009
Operating income	60,614	104,075	6,679
Interest expense, net	13,769	15,148	17,965
Other nonoperating income, net	(52,585)	(15,176)	(4,171)
Net income (loss) before income taxes	99,430	104,103	(7,115)
Provision for (benefit from) income taxes	24,718	26,030	(1,999)
Net income (loss)	74,712	78,073	(5,116)
Total assets	498,335	435,527
Operating Segments
Segment Reporting Information [Line Items]
Total operating revenue	456,429	398,174	288,605
Total restaurant-level operating margin	141,644	142,102	79,688
Total assets	498,335	435,527
Operating Segments | Denny’s
Segment Reporting Information [Line Items]
Total operating revenue	447,687	398,174	288,605
Total restaurant-level operating margin	138,555	142,102	79,688
Total assets	394,051	422,852
Operating Segments | Other
Segment Reporting Information [Line Items]
Total operating revenue	8,742	0	0
Total restaurant-level operating margin	3,089	0	$ 0
Total assets	$ 104,284	$ 12,675