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				6 Months Ended		9 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018	Sep. 30, 2018	Dec. 30, 2018
Revenues:
Total revenues	$ 399,623	$ 395,834	$ 385,231	$ 429,952	$ 798,028	$ 880,074	$ 1,265,305	$ 1,661,139
Costs and expenses:
General and administrative expenses	48,718	58,854	55,711	38,972	99,853	78,968	134,680	193,534
Total costs and expenses	385,555	404,788	399,401	402,920	778,451	825,107	1,224,509	1,629,297
Operating income	14,231	(7,325)	(14,170)	24,910	19,740	53,049	38,879	31,553
Net interest expense	(4,272)	(7,926)	(6,058)	(5,797)	(10,548)	(10,872)	(16,930)	(25,673)
(Loss) income before income taxes	9,959	(15,252)	(20,228)	19,113	9,192	42,177	21,949	6,697
Income tax expense	1,283	(2,027)	(7,372)	7,040	2,114	12,018	4,650	2,624
Net income before attribution to noncontrolling interests	8,676	(13,225)	(12,856)	12,073	7,078	30,159	17,298	4,073
Net income attributable to the Company	8,354	(12,868)	(13,295)	11,199	6,623	28,642	15,342	2,474
Net (loss) income attributable to common shareholders	$ 4,868	$ (12,868)	$ (13,295)	$ 11,127	$ 1,067	$ 28,495	$ 15,195	$ 2,474
Basic earnings per common share	$ 0.15	$ (0.41)	$ (0.42)	$ 0.35	$ 0.03	$ 0.87	$ 0.47	$ 0.08
Diluted earnings per common share	$ 0.15	$ (0.41)	$ (0.42)	$ 0.35	$ 0.03	$ 0.87	$ 0.47	$ 0.08
Domestic Company-owned restaurants
Revenues:
Total revenues	$ 163,656			$ 181,379	$ 325,459	$ 371,621
Costs and expenses:
Operating costs (excluding depreciation and amortization shown separately below):	131,950	$ 135,958	$ 136,257	147,868	265,003	305,442	$ 441,699	$ 577,658
Other segment
Revenues:
Total revenues	43,581	41,620	42,247	42,137	88,082	85,384	127,631	169,251
Costs and expenses:
Operating costs (excluding depreciation and amortization shown separately below):	$ 41,970	40,920	42,736	42,801	$ 86,067	85,168	127,904	168,824
As reported
Revenues:
Total revenues		373,981	364,007	407,959		835,328	1,199,335	1,573,316
Costs and expenses:
General and administrative expenses		58,648	55,462	38,712		78,441	133,903	192,551
Total costs and expenses		383,924	377,997	380,470		780,726	1,158,723	1,542,647
Operating income		(8,314)	(13,990)	25,367		52,684	38,694	30,380
Net interest expense		(7,909)	(5,963)	(5,662)		(10,617)	(16,580)	(25,306)
(Loss) income before income taxes		(16,224)	(19,953)	19,705		42,067	22,114	5,891
Income tax expense		(2,018)	(7,359)	7,040		12,022	4,663	2,646
Net income before attribution to noncontrolling interests		(14,206)	(12,594)	12,665		30,045	17,451	3,245
Net income attributable to the Company		(13,849)	(13,033)	11,791		28,528	15,495	1,646
Net (loss) income attributable to common shareholders		$ (13,849)	$ (13,033)	$ 11,719		$ 28,381	$ 15,348	$ 1,646
Basic earnings per common share		$ (0.44)	$ (0.41)	$ 0.37		$ 0.87	$ 0.48	$ 0.05
Diluted earnings per common share		$ (0.44)	$ (0.41)	$ 0.36		$ 0.86	$ 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	$ 147,781		$ 305,100	$ 440,936	$ 576,799
As reported | Other segment
Revenues:
Total revenues		19,767	21,023	20,144		40,638	61,661	81,428
Costs and expenses:
Operating costs (excluding depreciation and amortization shown separately below):		20,358	22,002	20,698		41,656	63,658	84,016
Total Adjustments
Revenues:
Total revenues		21,853	21,224	21,993		44,746	65,970	87,823
Costs and expenses:
General and administrative expenses		206	249	260		527	777	983
Total costs and expenses		20,864	21,404	22,450		44,381	65,786	86,650
Operating income		989	(180)	(457)		365	185	1,173
Net interest expense		(17)	(95)	(135)		(255)	(350)	(367)
(Loss) income before income taxes		972	(275)	(592)		110	(165)	806
Income tax expense		(9)	(13)			(4)	(13)	(22)
Net income before attribution to noncontrolling interests		981	(262)	(592)		114	(153)	828
Net income attributable to the Company		981	(262)	(592)		114	(153)	828
Net (loss) income attributable to common shareholders		$ 981	$ (262)	$ (592)		$ 114	$ (153)	$ 828
Basic earnings per common share		$ 0.03	$ (0.01)	$ (0.02)			$ (0.01)	$ 0.03
Diluted earnings per common share		$ 0.03	$ (0.01)	$ (0.01)		$ 0.01		$ 0.03
Total Adjustments | Domestic Company-owned restaurants
Costs and expenses:
Operating costs (excluding depreciation and amortization shown separately below):		$ 96	$ 421	$ 87		$ 342	$ 763	$ 859
Total Adjustments | Other segment
Revenues:
Total revenues		21,853	21,224	21,993		44,746	65,970	87,823
Costs and expenses:
Operating costs (excluding depreciation and amortization shown separately below):		$ 20,562	$ 20,734	$ 22,103		$ 43,512	$ 64,246	$ 84,808