Segment Information (Details) $ in Thousands	12 Months Ended
	Dec. 25, 2024 USD ($) segment	Dec. 27, 2023 USD ($)	Dec. 28, 2022 USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment	2
Revenues
Revenue recognized	$ 452,334	$ 463,922	$ 456,429
Costs and expenses
Product costs	53,931	55,789	53,617
Payroll and benefits	80,605	80,666	76,412
Occupancy costs	18,129	16,809	15,154
Utilities	6,954	7,848	7,273
Repairs and maintenance	4,023	3,661	3,874
Marketing	7,850	5,603	5,294
Legal settlements	1,700	2,302	4,224
Pre-opening costs	1,548	288
Other direct costs	15,004	14,633	13,610
Total costs of company restaurant sales, excluding depreciation and amortization	189,744	187,599	179,458
Costs of franchise and license revenue, excluding depreciation and amortization:
Costs of franchise and license revenue	120,226	122,452	135,327
Total restaurant-level operating margin	142,364	153,871	141,644
Reconciliation of restaurant-level operating margin to net income
General and administrative expenses	80,197	77,770	67,173
Depreciation and amortization	14,857	14,385	14,862
Goodwill impairment charges	20	6,363	0
Operating (gains), losses and other charges, net	1,974	2,530	(1,005)
Total operating costs and expenses, net	97,048	101,048	81,030
Operating income	45,316	52,823	60,614
Interest expense, net	17,974	17,597	13,769
Other nonoperating (income) expense, net	(1,907)	8,288	(52,585)
Net income before income taxes	29,249	26,938	99,430
Provision for income taxes	7,678	6,993	24,718
Net income	21,571	19,945	74,712
Total assets	496,274	464,818
Company restaurant sales
Revenues
Revenue recognized	211,781	215,532	199,753
Royalties
Revenues
Revenue recognized	118,705	120,131	113,891
Advertising costs
Revenues
Revenue recognized	79,973	78,494	75,926
Costs of franchise and license revenue, excluding depreciation and amortization:
Costs of franchise and license revenue	79,973	78,494	75,926
Initial and other fees
Revenues
Revenue recognized	8,711	13,882	28,262
Occupancy costs
Revenues
Revenue recognized	33,164	35,883	38,597
Costs of franchise and license revenue, excluding depreciation and amortization:
Costs of franchise and license revenue	20,539	22,160	24,090
Franchise and license revenue
Revenues
Revenue recognized	240,553	248,390	256,676
Other direct costs
Costs of franchise and license revenue, excluding depreciation and amortization:
Costs of franchise and license revenue	19,714	21,798	35,311
Denny’s
Revenues
Revenue recognized	426,994	443,106	447,687
Costs and expenses
Product costs	48,976	51,939	51,705
Payroll and benefits	72,828	75,407	74,157
Occupancy costs	15,680	14,875	14,310
Utilities	6,404	7,418	7,075
Repairs and maintenance	3,806	3,486	3,803
Marketing	7,098	5,524	5,294
Legal settlements	1,670	2,302	4,224
Pre-opening costs	0	0
Other direct costs	13,267	13,452	13,243
Total costs of company restaurant sales, excluding depreciation and amortization	169,729	174,403	173,811
Costs of franchise and license revenue, excluding depreciation and amortization:
Costs of franchise and license revenue	117,318	121,870	135,321
Total restaurant-level operating margin	139,947	146,833	138,555
Reconciliation of restaurant-level operating margin to net income
Total assets	344,986	340,136
Denny’s | Company restaurant sales
Revenues
Revenue recognized	193,572	201,175	193,576
Denny’s | Royalties
Revenues
Revenue recognized	113,804	115,004	111,718
Denny’s | Advertising costs
Revenues
Revenue recognized	78,192	77,932	75,926
Costs of franchise and license revenue, excluding depreciation and amortization:
Costs of franchise and license revenue	78,192	77,932	75,926
Denny’s | Initial and other fees
Revenues
Revenue recognized	8,351	13,112	27,870
Denny’s | Occupancy costs
Revenues
Revenue recognized	33,075	35,883	38,597
Costs of franchise and license revenue, excluding depreciation and amortization:
Costs of franchise and license revenue	20,451	22,160	24,090
Denny’s | Franchise and license revenue
Revenues
Revenue recognized	233,422	241,931	254,111
Denny’s | Other direct costs
Costs of franchise and license revenue, excluding depreciation and amortization:
Costs of franchise and license revenue	18,675	21,778	35,305
Other
Revenues
Revenue recognized	25,340	20,816	8,742
Costs and expenses
Product costs	4,955	3,850	1,912
Payroll and benefits	7,777	5,259	2,255
Occupancy costs	2,449	1,934	844
Utilities	550	430	198
Repairs and maintenance	217	175	71
Marketing	752	79	0
Legal settlements	30	0	0
Pre-opening costs	1,548	288
Other direct costs	1,737	1,181	367
Total costs of company restaurant sales, excluding depreciation and amortization	20,015	13,196	5,647
Costs of franchise and license revenue, excluding depreciation and amortization:
Costs of franchise and license revenue	2,908	582	6
Total restaurant-level operating margin	2,417	7,038	3,089
Reconciliation of restaurant-level operating margin to net income
Total assets	151,288	124,682
Other | Company restaurant sales
Revenues
Revenue recognized	18,209	14,357	6,177
Other | Royalties
Revenues
Revenue recognized	4,901	5,127	2,173
Other | Advertising costs
Revenues
Revenue recognized	1,781	562	0
Costs of franchise and license revenue, excluding depreciation and amortization:
Costs of franchise and license revenue	1,781	562	0
Other | Initial and other fees
Revenues
Revenue recognized	360	770	392
Other | Occupancy costs
Revenues
Revenue recognized	89	0	0
Costs of franchise and license revenue, excluding depreciation and amortization:
Costs of franchise and license revenue	88	0	0
Other | Franchise and license revenue
Revenues
Revenue recognized	7,131	6,459	2,565
Other | Other direct costs
Costs of franchise and license revenue, excluding depreciation and amortization:
Costs of franchise and license revenue	$ 1,039	$ 20	$ 6