Update to Significant Accounting Policies - Impact of Corrections on Statement of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Apr. 01, 2018
Operating activities
Net income before attribution to noncontrolling interests	$ (1,598)	$ 18,086
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	(3,443)	2,675
Income tax receivable	10,715	3,899
Prepaid expenses	7,888	555
Other current assets	(13,855)	(1,264)
Other assets and liabilities	(3,258)	475
Accounts payable	8,108	2,563
Income and other taxes payable	746	(466)
Accrued expenses and other current liabilities	(11,003)	(3,759)
Deferred revenue	(2,170)	(3,474)
Net cash provided by operating activities	13,813	36,731
Financing activities
Net proceeds (repayments) of revolving credit facility	(240,026)	140,308
Net cash used in financing activities	(9,627)	(13,814)
Change in cash and cash equivalents	(3,985)	18,593
Cash and cash equivalents at beginning of period	33,258	27,891
Cash and cash equivalents at end of period	$ 29,273	46,484
As reported
Operating activities
Net income before attribution to noncontrolling interests		17,380
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable		86
Income tax receivable		3,903
Prepaid expenses		(217)
Other current assets		5,097
Other assets and liabilities		(514)
Accounts payable		1,209
Income and other taxes payable		(466)
Accrued expenses and other current liabilities		(3,103)
Deferred revenue		220
Net cash provided by operating activities		41,036
Financing activities
Net proceeds (repayments) of revolving credit facility		127,000
Net cash used in financing activities		(27,122)
Change in cash and cash equivalents		9,590
Cash and cash equivalents at beginning of period		22,345
Cash and cash equivalents at end of period		31,935
Total Adjustments
Operating activities
Net income before attribution to noncontrolling interests		706
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable		2,589
Income tax receivable		(4)
Prepaid expenses		772
Other current assets		(6,361)
Other assets and liabilities		989
Accounts payable		1,354
Accrued expenses and other current liabilities		(656)
Deferred revenue		(3,694)
Net cash provided by operating activities		(4,305)
Financing activities
Net proceeds (repayments) of revolving credit facility		13,308
Net cash used in financing activities		13,308
Change in cash and cash equivalents		9,003
Cash and cash equivalents at beginning of period		5,546
Cash and cash equivalents at end of period		$ 14,549