Independent Investigation of the Audit Committee and Related Restatements (Restated Condensed Unaudited Consolidated Statement of Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2014	Sep. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income	$ 49,125	$ 33,589	$ 12,142	$ 45,730	$ 94,855	$ 115,549	$ 141,216	$ 107,416
Other comprehensive (loss) income:
Foreign currency translation adjustments, net of tax	(12,951)	7,676	(5,336)	2,340	(10,611)	(20,718)	(7,893)	1,924
Comprehensive income	36,174	41,265	6,806	48,070	84,244	94,831	133,431	109,861
Comprehensive income (loss) attributable to non-controlling interests	139	(136)	45	(91)	48	(374)	266	(10)
Comprehensive income attributable to MasTec, Inc.	36,035	41,401	6,761	48,161	84,196	$ 95,205	$ 133,165	$ 109,871
As Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income	45,410	31,914	16,068	47,982	93,392
Other comprehensive (loss) income:
Foreign currency translation adjustments, net of tax	(12,944)	7,678	(5,335)	2,343	(10,601)
Comprehensive income	32,466	39,592	10,733	50,325	82,791
Comprehensive income (loss) attributable to non-controlling interests	139	(136)	45	(91)	48
Comprehensive income attributable to MasTec, Inc.	32,327	39,728	10,688	50,416	82,743
Adjustments [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income	3,715	1,675	(3,926)	(2,252)	1,463
Other comprehensive (loss) income:
Foreign currency translation adjustments, net of tax	(7)	(2)	(1)	(3)	(10)
Comprehensive income	3,708	1,673	(3,927)	(2,255)	1,453
Comprehensive income (loss) attributable to non-controlling interests	0	0	0	0	0
Comprehensive income attributable to MasTec, Inc.	$ 3,708	$ 1,673	$ (3,927)	$ (2,255)	$ 1,453