Employee Benefit Plans (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) Participant	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Employee Benefits Plans [Line Items]
Defined Contribution Plan, Maximum Annual Contribution Per Employee, Percent	50.00%
Defined Contribution Plan, Employer Matching Contribution, Percent	6.00%
Defined Contribution Plan, Cost	$ 13,400	$ 12,100	$ 11,000
Number of Participants in Non Qualified Deferred Compensation Plan | Participant	56
Deferred Compensation Liability, Current and Noncurrent	$ 25,200	24,700
Multiemployer Plan, Contributions by Employer	$ 43,911	36,784	33,082
Multiemployer Plans, Maximum Percent Funded Status for Red Zone	65.00%
Multiemployer Plans, Maximum Percent Funded Status for Yellow Zone and Minmum Percent for Green Zone	80.00%
Locals 302 and 612 Operating Engineers Employers Retirement Fund [Member]
Employee Benefits Plans [Line Items]
Multiemployer Plan, Contributions by Employer	$ 4,726	3,646	3,113
Pension Trust Fund for Operating Engineers Pension Plan [Member]
Employee Benefits Plans [Line Items]
Multiemployer Plan, Contributions by Employer	11,363	10,431	9,266
Operating Engineers Pension Trust Fund [Member]
Employee Benefits Plans [Line Items]
Multiemployer Plan, Contributions by Employer	4,251	4,692	5,357
Laborers Pension Trust Fund for Northern California [Member] [Member]
Employee Benefits Plans [Line Items]
Multiemployer Plan, Contributions by Employer	3,009	2,464	2,215
Laborers Pension Trust Fund for Northern California [Member] [Member] [Member]
Employee Benefits Plans [Line Items]
Multiemployer Plan, Contributions by Employer	2,110	2,002	2,095
Laborers Pension Fund [Member]
Employee Benefits Plans [Line Items]
Multiemployer Plan, Contributions by Employer	$ 2,458	3,208	2,328
All Other Pension Trust Funds [Member]
Employee Benefits Plans [Line Items]
Number of Participants in Non Qualified Deferred Compensation Plan | Participant	44
Multiemployer Plan, Contributions by Employer	$ 15,994	10,341	8,708
Layne Christensen Company [Member]
Employee Benefits Plans [Line Items]
Plan obligations assumed from acquisitions	3,600
Liabilities of supplemental retirement benefits assumed with acquisition	5,000
Deferred Profit Sharing [Member]
Employee Benefits Plans [Line Items]
Defined Contribution Plan, Cost	$ 0	$ 0	$ 0