The Davey 401KSOP and Employee Stock Ownership Plan (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Employee Stock Ownership Plan (ESOP) disclosures [Line Items]
Employee stock ownership plan (ESOP), initial shares in ESOP | shares	120,000
Employee stock ownership plan (ESOP), shares adjusted for stock splits | shares	23,040,000
Employee stock ownership plan (ESOP), initial value in ESOP	$ 2,700
Defined contribution plan, eligible age	21
Defined contribution plan, service requirement for eligibility (in years)	1 year
Number of put option periods	2
Duration of put option periods (in days)	60 days
Employee Stock Ownership Plan (ESOP), Fair Value of Shares Subject to Repurchase Obligation	$ 6,288	$ 3,843
Company shares held in 401KSOP and ESOP, fair value	112,761	119,677
Redeemable common shares related to 401KSOP and Employee Stock Ownership Plan (ESOP):	119,049	123,520
Employee retirement plan, employer match	$ 4,053	$ 3,794	$ 3,661
First 1% [Member]
Employee Stock Ownership Plan (ESOP) disclosures [Line Items]
Defined contribution plan, employer matching contribution, percent	100.00%
1% to 4% [Member]
Employee Stock Ownership Plan (ESOP) disclosures [Line Items]
Defined contribution plan, employer matching contribution, percent	50.00%
Minimum [Member] | 1% to 4% [Member]
Employee Stock Ownership Plan (ESOP) disclosures [Line Items]
Defined contribution plan, employer matching contribution, percent	1.00%
Maximum [Member] | First 1% [Member]
Employee Stock Ownership Plan (ESOP) disclosures [Line Items]
Defined contribution plan, employer matching contribution, percent	1.00%
Maximum [Member] | 1% to 4% [Member]
Employee Stock Ownership Plan (ESOP) disclosures [Line Items]
Defined contribution plan, employer matching contribution, percent	4.00%