Reportable Segments - Revenue by Geographic Location (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross revenues	$ 132,598	$ 131,032	$ 127,974	$ 117,335	$ 115,344	$ 104,185	$ 104,018	$ 94,534	$ 508,938	$ 418,081	$ 333,034
INF
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross revenues									331,161	254,723
BTS
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross revenues									177,777	163,358
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross revenues									502,407	405,419
United States [Member] | INF
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross revenues									331,161	254,723
United States [Member] | BTS
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross revenues									171,246	150,696
Foreign [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross revenues									6,531	12,662
Foreign [Member] | INF
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross revenues									0	0
Foreign [Member] | BTS
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross revenues									$ 6,531	$ 12,662