Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Property and equipment
Gross property and equipment	$ 774,903	$ 732,720
Less: accumulated depreciation and amortization	(399,015)	(356,836)
Property and equipment, net	$ 375,888	375,884
Minimum
Property and equipment
Useful Life	3 years
Maximum
Property and equipment
Useful Life	30 years
Land and buildings
Property and equipment
Gross property and equipment	$ 125,047	101,170
Useful Life	30 years
Leasehold improvements
Property and equipment
Gross property and equipment	$ 15,399	13,438
Office equipment
Property and equipment
Gross property and equipment	$ 12,379	9,669
Office equipment \| Minimum
Property and equipment
Useful Life	3 years
Office equipment \| Maximum
Property and equipment
Useful Life	5 years
Construction equipment
Property and equipment
Gross property and equipment	$ 443,285	439,875
Construction equipment \| Minimum
Property and equipment
Useful Life	3 years
Construction equipment \| Maximum
Property and equipment
Useful Life	7 years
Transportation equipment
Property and equipment
Gross property and equipment	$ 122,082	112,170
Transportation equipment \| Minimum
Property and equipment
Useful Life	3 years
Transportation equipment \| Maximum
Property and equipment
Useful Life	18 years
Solar equipment
Property and equipment
Gross property and equipment	$ 23,552	21,304
Useful Life	25 years
Construction in progress
Property and equipment
Gross property and equipment	$ 33,159	$ 35,094

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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