Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018
Disaggregation of revenue [Line Items]
Revenue from contract with customer	$ 247,889	$ 208,651
United States
Disaggregation of revenue [Line Items]
Revenue from contract with customer	230,906	193,550
Canada
Disaggregation of revenue [Line Items]
Revenue from contract with customer	16,983	15,101
Tree and plant care [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	163,802	142,728
Grounds maintenance [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	27,942	22,802
Storm damage services [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	2,697	4,113
Consulting and other [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	53,448	39,008
Utility [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	140,469	118,687
Utility [Member] | United States
Disaggregation of revenue [Line Items]
Revenue from contract with customer	129,882	110,453
Utility [Member] | Canada
Disaggregation of revenue [Line Items]
Revenue from contract with customer	10,587	8,234
Utility [Member] | Tree and plant care [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	103,386	86,316
Utility [Member] | Grounds maintenance [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	0	0
Utility [Member] | Storm damage services [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	1,072	3,214
Utility [Member] | Consulting and other [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	36,011	29,157
Residential commercial [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	107,395	89,345
Residential commercial [Member] | United States
Disaggregation of revenue [Line Items]
Revenue from contract with customer	100,999	82,478
Residential commercial [Member] | Canada
Disaggregation of revenue [Line Items]
Revenue from contract with customer	6,396	6,867
Residential commercial [Member] | Tree and plant care [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	60,427	56,397
Residential commercial [Member] | Grounds maintenance [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	27,942	22,802
Residential commercial [Member] | Storm damage services [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	1,625	899
Residential commercial [Member] | Consulting and other [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	17,401	9,247
All other [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	25	619
All other [Member] | United States
Disaggregation of revenue [Line Items]
Revenue from contract with customer	25	619
All other [Member] | Canada
Disaggregation of revenue [Line Items]
Revenue from contract with customer	0	0
All other [Member] | Tree and plant care [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	(11)	15
All other [Member] | Grounds maintenance [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	0	0
All other [Member] | Storm damage services [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	0	0
All other [Member] | Consulting and other [Member]
Disaggregation of revenue [Line Items]
Revenue from contract with customer	$ 36	$ 604