The following tables present information about industry segments and geographic areas for the three and six months ended June 30, 2019 and 2018 (in thousands): For the three months ended June 30, 2019 2018 Revenues from unrelated entities: United States electrical construction and facilities services $ 569,402 $ 479,542 United States mechanical construction and facilities services 823,086 723,882 United States building services 523,698 461,033 United States industrial services 295,460 183,922 Total United States operations 2,211,646 1,848,379 United Kingdom building services 112,556 105,507 Total worldwide operations $ 2,324,202 $ 1,953,886 Total revenues: United States electrical construction and facilities services $ 570,077 $ 481,379 United States mechanical construction and facilities services 827,952 733,551 United States building services 541,911 476,775 United States industrial services 302,977 184,643 Less intersegment revenues (31,271 ) (27,969 ) Total United States operations 2,211,646 1,848,379 United Kingdom building services 112,556 105,507 Total worldwide operations $ 2,324,202 $ 1,953,886 For the six months ended June 30, 2019 2018 Revenues from unrelated entities: United States electrical construction and facilities services $ 1,097,472 $ 934,294 United States mechanical construction and facilities services 1,575,495 1,408,632 United States building services 1,035,777 915,785 United States industrial services 554,105 383,166 Total United States operations 4,262,849 3,641,877 United Kingdom building services 220,081 212,397 Total worldwide operations $ 4,482,930 $ 3,854,274 Total revenues: United States electrical construction and facilities services $ 1,099,059 $ 938,548 United States mechanical construction and facilities services 1,587,716 1,425,334 United States building services 1,072,507 946,874 United States industrial services 562,252 384,460 Less intersegment revenues (58,685 ) (53,339 ) Total United States operations 4,262,849 3,641,877 United Kingdom building services 220,081 212,397 Total worldwide operations $ 4,482,930 $ 3,854,274 For the three months ended June 30, 2019 2018 Operating income (loss): United States electrical construction and facilities services $ 43,799 $ 35,985 United States mechanical construction and facilities services 53,954 57,417 United States building services 28,001 22,430 United States industrial services 16,012 1,234 Total United States operations 141,766 117,066 United Kingdom building services 5,476 4,601 Corporate administration (27,110 ) (20,730 ) Restructuring expenses (173 ) (374 ) Impairment loss on identifiable intangible assets  (907 ) Total worldwide operations 119,959 99,656 Other corporate items: Net periodic pension (cost) income 400 717 Interest expense, net (3,231 ) (2,823 ) Income from continuing operations before income taxes $ 117,128 $ 97,550 For the six months ended June 30, 2019 2018 Operating income (loss): United States electrical construction and facilities services $ 86,750 $ 71,836 United States mechanical construction and facilities services 94,939 97,037 United States building services 55,484 39,507 United States industrial services 25,648 4,675 Total United States operations 262,821 213,055 United Kingdom building services 9,617 8,371 Corporate administration (49,721 ) (42,395 ) Restructuring expenses (448 ) (464 ) Impairment loss on identifiable intangible assets  (907 ) Total worldwide operations 222,269 177,660 Other corporate items: Net periodic pension (cost) income 806 1,454 Interest expense, net (6,054 ) (5,275 ) Income from continuing operations before income taxes $ 217,021 $ 173,839 June 30, 2019 December 31, 2018 Total assets: United States electrical construction and facilities services $ 810,170 $ 702,112 United States mechanical construction and facilities services 1,201,345 1,080,829 United States building services 994,117 846,221 United States industrial services 919,376 864,622 Total United States operations 3,925,008 3,493,784 United Kingdom building services 168,835 146,379 Corporate administration 299,735 448,644 Total worldwide operations $ 4,393,578 $ 4,088,807