Restatement of 2018 Condensed Consolidated Financial Statements - Impact of Corrections on Condensed Consolidated Statements of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 29, 2019	Dec. 30, 2018	Sep. 30, 2018	Sep. 29, 2019	Sep. 30, 2018	Dec. 30, 2018
Revenues:
Total revenues	$ 403,706	$ 395,834	$ 385,231	$ 1,201,734	$ 1,265,305	$ 1,661,139
Costs and expenses:
General and administrative expenses	53,503	58,854	55,711	153,356	134,679	193,534
Total costs and expenses	400,505	404,788	399,401	1,178,956	1,224,508	1,629,297
Operating income	4,927	(7,325)	(14,170)	24,667	38,879	31,553
Net interest expense	(4,249)	(7,926)	(6,058)	(14,797)	(16,930)	(24,856)
(Loss) income before income taxes	678	(15,252)	(20,228)	9,870	21,949	6,697
Income tax expense (benefit)	421	(2,027)	(7,367)	2,535	4,651	2,624
Net income (loss) before attribution to noncontrolling interests	257	(13,225)	(12,861)	7,335	17,298	4,073
Net income (loss) attributable to the Company	385	(12,868)	(13,300)	7,008	15,342	2,474
Net (loss) income attributable to common shareholders	$ (3,088)	$ (12,868)	$ (13,300)	$ (2,021)	$ 15,195	$ 2,474
Basic (loss) earnings per common share	$ (0.10)	$ (0.41)	$ (0.42)	$ (0.06)	$ 0.47	$ 0.08
Diluted (loss) earnings per common share	$ (0.10)	$ (0.41)	$ (0.42)	$ (0.06)	$ 0.47	$ 0.08
Domestic Company-owned restaurants
Revenues:
Total revenues	$ 165,135		$ 158,285	$ 490,594	$ 529,906
Costs and expenses:
Operating costs (excluding depreciation and amortization shown separately below):	134,037	$ 135,958	136,257	399,040	441,699	$ 577,658
Other segment
Revenues:
Total revenues	43,265	41,620	42,247	131,347	127,631	169,251
Costs and expenses:
Operating costs (excluding depreciation and amortization shown separately below):	$ 42,952	40,920	42,736	$ 129,019	127,904	168,824
As reported
Revenues:
Total revenues		373,981	364,007		1,199,335	1,573,316
Costs and expenses:
General and administrative expenses		58,648	55,462		133,903	192,551
Total costs and expenses		383,924	377,997		1,158,723	1,542,647
Operating income		(8,314)	(13,990)		38,694	30,380
Net interest expense		(7,909)	(5,963)		(16,580)	(24,489)
(Loss) income before income taxes		(16,224)	(19,953)		22,114	5,891
Income tax expense (benefit)		(2,018)	(7,359)		4,663	2,646
Net income (loss) before attribution to noncontrolling interests		(14,206)	(12,594)		17,451	3,245
Net income (loss) attributable to the Company		(13,849)	(13,033)		15,495	1,646
Net (loss) income attributable to common shareholders		$ (13,849)	$ (13,033)		$ 15,348	$ 1,646
Basic (loss) earnings per common share		$ (0.44)	$ (0.41)		$ 0.48	$ 0.05
Diluted (loss) earnings per common share		$ (0.44)	$ (0.41)		$ 0.47	$ 0.05
As reported | Domestic Company-owned restaurants
Costs and expenses:
Operating costs (excluding depreciation and amortization shown separately below):		$ 135,862	$ 135,836		$ 440,936	$ 576,799
As reported | Other segment
Revenues:
Total revenues		19,767	21,023		61,661	81,428
Costs and expenses:
Operating costs (excluding depreciation and amortization shown separately below):		20,358	22,002		63,658	84,016
Total Adjustments
Revenues:
Total revenues		21,853	21,224		65,970	87,823
Costs and expenses:
General and administrative expenses		206	249		776	983
Total costs and expenses		20,864	21,404		65,785	86,650
Operating income		989	(180)		185	1,173
Net interest expense		(17)	(95)		(350)	(367)
(Loss) income before income taxes		972	(275)		(165)	806
Income tax expense (benefit)		(9)	(8)		(12)	(22)
Net income (loss) before attribution to noncontrolling interests		981	(267)		(153)	828
Net income (loss) attributable to the Company		981	(267)		(153)	828
Net (loss) income attributable to common shareholders		$ 981	$ (267)		$ (153)	$ 828
Basic (loss) earnings per common share		$ 0.03	$ (0.01)		$ (0.01)	$ 0.03
Diluted (loss) earnings per common share		$ 0.03	$ (0.01)			$ 0.03
Total Adjustments | Domestic Company-owned restaurants
Costs and expenses:
Operating costs (excluding depreciation and amortization shown separately below):		$ 96	$ 421		$ 763	$ 859
Total Adjustments | Other segment
Revenues:
Total revenues		21,853	21,224		65,970	87,823
Costs and expenses:
Operating costs (excluding depreciation and amortization shown separately below):		$ 20,562	$ 20,734		$ 64,246	$ 84,808