Segment Information - Summarized Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Revenues	$ 2,807,259	$ 2,417,576
Operating income (loss)	119,487	75,221
Depreciation	52,216	48,719
Corporate and Non-Allocated Costs
Segment Reporting Information [Line Items]
Operating income (loss)	(82,829)	(75,731)
Depreciation	4,410	3,754
Electric Power Infrastructure Services \| Operating Segments
Segment Reporting Information [Line Items]
Revenues	1,664,023	1,568,507
Operating income (loss)	161,617	140,895
Depreciation	25,251	24,270
Pipeline and Industrial Infrastructure Services Division \| Operating Segments
Segment Reporting Information [Line Items]
Revenues	1,143,236	849,069
Operating income (loss)	40,699	10,057
Depreciation	$ 22,555	$ 20,695

The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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