Earnings Per Share (Schedule of Earnings Per Share Information) (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net income attributable to MasTec:
Net income - basic (in dollars)	$ 100,900	$ 128,600	$ 119,700	$ 43,100	$ 31,900	$ 120,700	$ 80,500	$ 26,600	$ 392,334	$ 259,659	$ 347,213
Net income - diluted (in dollars)									$ 392,334	$ 259,659	$ 347,213
Weighted average shares outstanding:
Weighted average shares outstanding - basic									75,185	78,695	80,903
Dilutive common stock equivalents (in shares)									661	1,077	1,422
Weighted average shares outstanding - diluted									75,846	79,772	82,325