The Davey 401KSOP and Employee Stock Ownership Plan (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018 USD ($) shares	Dec. 31, 2017 USD ($)
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 Split | shares	23,040,000
Employee Stock Ownership Plan (ESOP), Initial Value in ESOP	$ 2,700
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	3.00%
Defined Contribution Plan, Eligible Age	21
Defined Contribution Plan, Service Requirement for Eligibility	1 year
Number of put option periods	2
Duration of put option periods	60 days
Employee Stock Ownership Plan (ESOP), Fair Value of Shares Subject to Repurchase Obligation	$ 5,677	$ 3,843
Company shares held in 401KSOP shares, fair value	115,848	119,677
Redeemable common shares related to 401KSOP and Employee Stock Ownership Plan (ESOP); 6,169 and 6,467 shares at redemption value as of June 30, 2018 and December 31, 2017	$ 121,525	$ 123,520
Defined Contribution Plan, Tier 1 [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	100.00%
Defined Contribution Plan, Tier 2 [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	50.00%
Maximum [Member] | Defined Contribution Plan, Tier 1 [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	1.00%
Maximum [Member] | Defined Contribution Plan, Tier 2 [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	4.00%