Restatement of 2018 Condensed Consolidated Financial Statements - Impact of Corrections on Statement of Cash Flows (Details) - USD ($) $ 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
Operating activities
Net income before attribution to noncontrolling interests	$ 8,676	$ (13,225)	$ (12,856)	$ 12,073	$ 7,078	$ 30,159	$ 17,298	$ 4,073
Changes in operating assets and liabilities:
Deferred income taxes					(3,096)	(2,511)		1,620
Accounts receivable					(1,092)	3,114	11,083	4,245
Income tax receivable					11,699	3,628	(7,423)	(12,157)
Prepaid expenses					8,899	1,285	8,097	(1,039)
Other current assets					(14,282)	3,276	3,534
Other assets and liabilities					(2,094)	(2,206)	(4,910)
Accounts payable					5,410	6,993	2,101	(400)
Income and other taxes payable					565	(1,656)
Accrued expenses and other current liabilities					(17,297)	(6,885)	23,105	25,177
Deferred revenue					(3,168)	(1,698)	(1,860)	(1,551)
Net cash provided by operating activities					32,175	73,427	105,032	92,454
Financing activities
Net (repayments) proceeds of revolving credit facility					(230,776)	119,567	121,476	163,585
Net cash used in financing activities					(15,212)	(53,688)	(75,968)	(48,097)
Change in cash and cash equivalents					(2,602)	2,767	6,631	5,367
Cash and cash equivalents at beginning of period		34,522	30,658		33,258	27,891	27,891	27,891
Cash and cash equivalents at end of period	$ 30,656	33,258	34,522	30,658	30,656	30,658	34,522	33,258
As reported
Operating activities
Net income before attribution to noncontrolling interests		(14,206)	(12,594)	12,665		30,045	17,451	3,245
Changes in operating assets and liabilities:
Deferred income taxes								1,705
Accounts receivable						(148)	7,410	1,386
Income tax receivable						3,678	(7,373)	(12,170)
Prepaid expenses						1,159	7,663	(2,165)
Other current assets						5,524	5,016
Other assets and liabilities						(2,202)	(4,899)
Accounts payable						2,511	769	(1,694)
Accrued expenses and other current liabilities						(2,506)	18,772	10,273
Deferred revenue						379	(4)	(271)
Net cash provided by operating activities						74,201	98,812	72,795
Financing activities
Net (repayments) proceeds of revolving credit facility						119,400	123,600	175,000
Net cash used in financing activities						(53,855)	(73,844)	(36,682)
Change in cash and cash equivalents						3,374	2,535	(2,877)
Cash and cash equivalents at beginning of period		24,880	25,719		19,468	22,345	22,345	22,345
Cash and cash equivalents at end of period		19,468	24,880	25,719		25,719	24,880	19,468
Total Adjustments
Operating activities
Net income before attribution to noncontrolling interests		981	(262)	(592)		114	(153)	828
Changes in operating assets and liabilities:
Deferred income taxes								(85)
Accounts receivable						3,262	3,673	2,859
Income tax receivable						(50)	(50)	13
Prepaid expenses						126	434	1,126
Other current assets						(2,248)	(1,482)
Other assets and liabilities						(4)	(11)
Accounts payable						4,482	1,332	1,294
Accrued expenses and other current liabilities						(4,379)	4,333	14,904
Deferred revenue						(2,077)	(1,856)	(1,280)
Net cash provided by operating activities						(774)	6,220	19,659
Financing activities
Net (repayments) proceeds of revolving credit facility						167	(2,124)	(11,415)
Net cash used in financing activities						167	(2,124)	(11,415)
Change in cash and cash equivalents						(607)	4,096	8,244
Cash and cash equivalents at beginning of period		9,642	4,939		$ 13,790	5,546	5,546	5,546
Cash and cash equivalents at end of period		$ 13,790	$ 9,642	$ 4,939		$ 4,939	$ 9,642	$ 13,790