Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Disaggregation of revenue [Line Items]
Revenue from contract with customer	$ 337,453	$ 307,473	$ 944,980	$ 856,796
United States
Disaggregation of revenue [Line Items]
Revenue from contract with customer	317,617	286,602	892,094	797,918
Canada
Disaggregation of revenue [Line Items]
Revenue from contract with customer	19,836	20,871	52,886	58,878
Tree and plant care [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	225,060	204,475	642,060	567,556
Grounds maintenance [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	36,296	40,721	100,352	114,320
Storm damage services [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	11,130	3,259	14,134	7,096
Consulting and other [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	64,967	59,018	188,434	167,824
Utility [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	185,500	160,088	547,984	451,749
Utility [Member] | United States
Disaggregation of revenue [Line Items]
Revenue from contract with customer	176,528	150,118	522,094	420,701
Utility [Member] | Canada
Disaggregation of revenue [Line Items]
Revenue from contract with customer	8,972	9,970	25,890	31,048
Utility [Member] | Tree and plant care [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	135,021	119,449	408,371	335,658
Utility [Member] | Grounds maintenance [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	0	0	0	0
Utility [Member] | Storm damage services [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	7,061	1,709	8,087	2,933
Utility [Member] | Consulting and other [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	43,418	38,930	131,526	113,158
Residential commercial [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	151,435	146,769	396,293	404,134
Residential commercial [Member] | United States
Disaggregation of revenue [Line Items]
Revenue from contract with customer	140,571	135,868	369,297	376,304
Residential commercial [Member] | Canada
Disaggregation of revenue [Line Items]
Revenue from contract with customer	10,864	10,901	26,996	27,830
Residential commercial [Member] | Tree and plant care [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	90,049	85,112	233,810	231,988
Residential commercial [Member] | Grounds maintenance [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	36,296	40,721	100,352	114,320
Residential commercial [Member] | Storm damage services [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	4,069	1,550	6,047	4,163
Residential commercial [Member] | Consulting and other [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	21,021	19,386	56,084	53,663
All other [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	518	616	703	913
All other [Member] | United States
Disaggregation of revenue [Line Items]
Revenue from contract with customer	518	616	703	913
All other [Member] | Canada
Disaggregation of revenue [Line Items]
Revenue from contract with customer	0	0	0	0
All other [Member] | Tree and plant care [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	(10)	(86)	(121)	(90)
All other [Member] | Grounds maintenance [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	0	0	0	0
All other [Member] | Storm damage services [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	0	0	0	0
All other [Member] | Consulting and other [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	$ 528	$ 702	$ 824	$ 1,003