Quarterly Information (Unaudited) (Schedule of Quarterly Financial Information (Unaudited)) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Selected Quarterly Financial Information [Abstract]
Revenue	$ 1,636,800	$ 1,698,300	$ 1,569,300	$ 1,416,600	$ 1,709,300	$ 2,016,600	$ 1,939,000	$ 1,518,300	$ 6,320,975	$ 7,183,188	$ 6,909,417
Costs of revenue, excluding depreciation and amortization	1,322,200	1,380,500	1,341,800	1,226,300	1,434,200	1,690,600	1,633,400	1,312,000	5,270,879	6,070,244	5,939,308
Net income	112,900	116,900	56,800	36,100	100,700	130,100	120,200	43,100	322,699	394,096	259,231
Net income attributable to MasTec, Inc.	$ 113,100	$ 116,500	$ 57,000	$ 36,200	$ 100,900	$ 128,600	$ 119,700	$ 43,100	$ 322,848	$ 392,334	$ 259,659
Earnings per share:
Basic (in dollars per share)	$ 1.56	$ 1.61	$ 0.79	$ 0.48	$ 1.34	$ 1.71	$ 1.59	$ 0.57	$ 4.43	$ 5.22	$ 3.30
Diluted (in dollars per share)	$ 1.54	$ 1.59	$ 0.78	$ 0.48	$ 1.33	$ 1.69	$ 1.58	$ 0.57	$ 4.38	$ 5.17	$ 3.26