| Summary of information about reportable segments |
We aggregate our operating segments into two reportable segments, as the operating segments meet all of the aggregation criteria. The following tables present information about our reportable segments (in thousands): | | | | | | | | | | | | | | | Mechanical Segment | | Electrical Segment | | Corporate | | Consolidated | Total assets at September 30, 2026 | | $ | 4,918,736 | | $ | 2,724,730 | | $ | 2,161,817 | | $ | 9,805,283 | Total assets at December 31, 2025 | | $ | 3,683,678 | | $ | 1,765,570 | | $ | 991,921 | | $ | 6,441,169 |
| | | | | | | | | | | | | | | Three Months Ended September 30, 2026 | | | Mechanical Segment | | Electrical Segment | | Corporate | | Consolidated | Revenue | | $ | 2,582,889 | | $ | 1,183,413 | | $ | — | | $ | 3,766,302 | Cost of services | | | 1,935,615 | | | 896,205 | | | — | | | 2,831,820 | Gross profit | | | 647,274 | | | 287,208 | | | — | | | 934,482 | Selling, general and administrative expenses | | | 181,701 | | | 113,846 | | | 18,618 | | | 314,165 | Gain on sale of assets | | | (4,015) | | | (238) | | | — | | | (4,253) | Operating income (loss) | | $ | 469,588 | | $ | 173,600 | | $ | (18,618) | | $ | 624,570 | Reconciliation to income before income taxes: | | | | | | | | | | | | | Other income (expense) | | | | | | | | | | | | 10,486 | Income before income taxes | | | | | | | | | | | $ | 635,056 | | | | | | | | | | | | | | Amortization of identifiable intangible assets | | $ | 10,831 | | $ | 14,860 | | $ | — | | $ | 25,691 | Depreciation expense | | $ | 17,885 | | $ | 3,612 | | $ | 353 | | $ | 21,850 | Capital expenditures | | $ | 196,538 | | $ | 13,511 | | $ | 551 | | $ | 210,600 |
| | | | | | | | | | | | | | | Three Months Ended September 30, 2025 | | | Mechanical Segment | | Electrical Segment | | Corporate | | Consolidated | Revenue | | $ | 1,810,462 | | $ | 640,507 | | $ | — | | $ | 2,450,969 | Cost of services | | | 1,370,687 | | | 472,411 | | | — | | | 1,843,098 | Gross profit | | | 439,775 | | | 168,096 | | | — | | | 607,871 | Selling, general and administrative expenses | | | 152,442 | | | 60,021 | | | 17,116 | | | 229,579 | Gain on sale of assets | | | (418) | | | (164) | | | — | | | (582) | Operating income (loss) | | $ | 287,751 | | $ | 108,239 | | $ | (17,116) | | $ | 378,874 | Reconciliation to income before income taxes: | | | | | | | | | | | | | Other income (expense) | | | | | | | | | | | | (8,416) | Income before income taxes | | | | | | | | | | | $ | 370,458 | | | | | | | | | | | | | | Amortization of identifiable intangible assets | | $ | 14,001 | | $ | 5,525 | | $ | — | | $ | 19,526 | Depreciation expense | | $ | 13,048 | | $ | 2,600 | | $ | 400 | | $ | 16,048 | Capital expenditures | | $ | 28,881 | | $ | 5,787 | | $ | 664 | | $ | 35,332 |
| | | | | | | | | | | | | | | Nine Months Ended September 30, 2026 | | | Mechanical Segment | | Electrical Segment | | Corporate | | Consolidated | Revenue | | $ | 6,940,178 | | $ | 2,957,112 | | $ | — | | $ | 9,897,290 | Cost of services | | | 5,150,117 | | | 2,214,051 | | | — | | | 7,364,168 | Gross profit | | | 1,790,061 | | | 743,061 | | | — | | | 2,533,122 | Selling, general and administrative expenses | | | 500,613 | | | 295,525 | | | 74,070 | | | 870,208 | Gain on sale of assets | | | (4,988) | | | (352) | | | — | | | (5,340) | Operating income (loss) | | $ | 1,294,436 | | $ | 447,888 | | $ | (74,070) | | $ | 1,668,254 | Reconciliation to income before income taxes: | | | | | | | | | | | | | Other income (expense) | | | | | | | | | | | | 15,191 | Income before income taxes | | | | | | | | | | | $ | 1,683,445 | | | | | | | | | | | | | | Amortization of identifiable intangible assets | | $ | 32,037 | | $ | 37,322 | | $ | — | | $ | 69,359 | Depreciation expense | | $ | 49,529 | | $ | 9,813 | | $ | 1,110 | | $ | 60,452 | Capital expenditures | | $ | 468,570 | | $ | 29,325 | | $ | 1,542 | | $ | 499,437 |
| | | | | | | | | | | | | | | Nine Months Ended September 30, 2025 | | | Mechanical Segment | | Electrical Segment | | Corporate | | Consolidated | Revenue | | $ | 4,851,349 | | $ | 1,604,225 | | $ | — | | $ | 6,455,574 | Cost of services | | | 3,732,449 | | | 1,201,941 | | | — | | | 4,934,390 | Gross profit | | | 1,118,900 | | | 402,284 | | | — | | | 1,521,184 | Selling, general and administrative expenses | | | 421,786 | | | 159,302 | | | 53,831 | | | 634,919 | Gain on sale of assets | | | (1,141) | | | (439) | | | — | | | (1,580) | Operating income (loss) | | $ | 698,255 | | $ | 243,421 | | $ | (53,831) | | $ | 887,845 | Reconciliation to income before income taxes: | | | | | | | | | | | | | Other income (expense) | | | | | | | | | | | | (12,891) | Income before income taxes | | | | | | | | | | | $ | 874,954 | | | | | | | | | | | | | | Amortization of identifiable intangible assets | | $ | 42,857 | | $ | 16,575 | | $ | — | | $ | 59,432 | Depreciation expense | | $ | 36,545 | | $ | 7,361 | | $ | 1,008 | | $ | 44,914 | Capital expenditures | | $ | 72,179 | | $ | 15,419 | | $ | 1,215 | | $ | 88,813 |
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