The following tables present information about industry segments and geographic areas for the years ended December 31, 2016, 2015 and 2014 (in thousands):



	2016			2015			2014
Revenues from unrelated entities:
United States electrical construction and facilities services	$	1,704,403		$	1,367,142		$	1,311,988
United States mechanical construction and facilities services	2,661,763			2,312,763			2,201,212
United States building services	1,791,787			1,739,259			1,721,341
United States industrial services	1,067,315			922,085			839,980
Total United States operations	7,225,268			6,341,249			6,074,521
United Kingdom building services	326,256			377,477			350,444
Total worldwide operations	$	7,551,524		$	6,718,726		$	6,424,965

Total revenues:
United States electrical construction and facilities services	$	1,728,920		$	1,378,620		$	1,326,547
United States mechanical construction and facilities services	2,680,542			2,326,683			2,219,886
United States building services	1,846,382			1,794,086			1,762,697
United States industrial services	1,068,662			923,648			842,040
Less intersegment revenues	(99,238		)	(81,788		)	(76,649		)
Total United States operations	7,225,268			6,341,249			6,074,521
United Kingdom building services	326,256			377,477			350,444
Total worldwide operations	$	7,551,524		$	6,718,726		$	6,424,965



Operating income (loss):
United States electrical construction and facilities services	$	101,761		$	82,225		$	90,873
United States mechanical construction and facilities services	133,742			138,688			114,418
United States building services	75,770			70,532			65,885
United States industrial services	77,845			56,469			63,159
Total United States operations	389,118			347,914			334,335
United Kingdom building services	11,946			11,634			15,011
Corporate administration	(88,740		)	(71,642		)	(68,578		)
Restructuring expenses	(1,438		)	(824		)	(1,168		)
Impairment loss on identifiable intangible assets	(2,428		)	—			(1,471		)
Gain on sale of building	—			—			11,749
Total worldwide operations	308,458			287,082			289,878
Other corporate items:
Interest expense	(12,627		)	(8,932		)	(9,075		)
Interest income	663			673			842
Income from continuing operations before income taxes	$	296,494		$	278,823		$	281,645



	2016		2015		2014
Capital expenditures:
United States electrical construction and facilities services	$	5,294	$	6,063	$	6,671
United States mechanical construction and facilities services	8,004		5,345		8,631
United States building services	10,748		7,233		10,589
United States industrial services	10,065		11,073		9,139
Total United States operations	34,111		29,714		35,030
United Kingdom building services	4,523		5,298		1,935
Corporate administration	1,014		448		1,070
Total worldwide operations	$	39,648	$	35,460	$	38,035

Depreciation and amortization of Property, plant and equipment:
United States electrical construction and facilities services	$	6,318	$	4,676	$	4,237
United States mechanical construction and facilities services	7,594		7,624		7,600
United States building services	10,191		9,834		10,660
United States industrial services	10,394		9,629		9,839
Total United States operations	34,497		31,763		32,336
United Kingdom building services	3,560		3,603		3,305
Corporate administration	824		928		883
Total worldwide operations	$	38,881	$	36,294	$	36,524



Costs and estimated earnings in excess of billings on uncompleted contracts:
United States electrical construction and facilities services	$	46,193	$	39,116	$	32,464
United States mechanical construction and facilities services	47,437		46,220		43,443
United States building services	27,350		20,959		18,555
United States industrial services	2,572		3,358		281
Total United States operations	123,552		109,653		94,743
United Kingdom building services	7,145		8,081		8,458
Total worldwide operations	$	130,697	$	117,734	$	103,201

Billings in excess of costs and estimated earnings on uncompleted contracts:
United States electrical construction and facilities services	$	163,794	$	139,857	$	114,422
United States mechanical construction and facilities services	272,978		238,463		199,983
United States building services	49,379		44,476		38,059
United States industrial services	1,823		1,170		1,516
Total United States operations	487,974		423,966		353,980
United Kingdom building services	1,268		5,269		14,575
Total worldwide operations	$	489,242	$	429,235	$	368,555



	2016		2015		2014
Long-lived assets:
United States electrical construction and facilities services	$	183,632	$	20,139	$	18,792
United States mechanical construction and facilities services	289,676		296,633		288,161
United States building services	399,222		378,367		392,364
United States industrial services	709,267		730,413		750,101
Total United States operations	1,581,797		1,425,552		1,449,418
United Kingdom building services	11,446		10,927		6,899
Corporate administration	1,734		1,543		2,023
Total worldwide operations	$	1,594,977	$	1,438,022	$	1,458,340



Total assets:
United States electrical construction and facilities services	$	631,581	$	372,525	$	332,150
United States mechanical construction and facilities services	960,748		894,366		793,056
United States building services	747,319		721,653		737,082
United States industrial services	850,434		883,338		954,018
Total United States operations	3,190,082		2,871,882		2,816,306
United Kingdom building services	105,081		133,782		130,340
Corporate administration	599,007		536,993		437,201
Total worldwide operations	$	3,894,170	$	3,542,657	$	3,383,847