Independent Investigation of the Audit Committee and Related Restatements (Restated Condensed Unaudited Consolidated Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 24,059	$ 7,067	$ 15,924	$ 9,261	$ 22,927	$ 26,767	$ 20,280
Accounts receivable, net of allowance	1,303,552	1,385,678	1,280,250	1,185,236	1,134,693
Inventories, net	112,804	105,038	115,627	89,146	70,185
Prepaid expenses and other current assets, including discontinued operations	91,336	71,944	70,809	66,352	79,221
Total current assets	1,531,751	1,569,727	1,482,610	1,349,995	1,307,026
Property and equipment, net	623,118	614,359	618,672	509,585	488,132
Goodwill	1,082,466	1,000,024	983,133	912,885	902,044	826,600
Other intangible assets, net	250,373	222,212	230,592	171,562	165,606	137,000
Other long-term assets, including discontinued operations	76,272	59,579	73,821	61,439	60,390
Total assets	3,563,980	3,465,901	3,388,828	3,005,466	2,923,198	2,416,300
Current liabilities:
Current maturities of long-term debt	73,631	71,798	76,914	52,949	51,376
Accounts payable	485,347	481,840	494,090	440,423	424,917
Accrued salaries and wages	60,528	82,083	63,945	68,055	66,455
Other accrued expenses	89,343	82,952	69,401	60,453	71,448
Acquisition-related contingent consideration, current	49,798	39,126	36,479	71,500	67,226
Billings in excess of costs and earnings	155,674	129,732	108,968	109,370	121,641
Other current liabilities	66,527	17,665	13,890	20,431	26,162
Total current liabilities	980,848	905,196	863,687	823,181	829,225
Acquisition-related contingent consideration, net of current portion	103,515	115,649	116,929	112,950	112,370
Long-term debt	1,061,159	1,088,289	1,088,666	841,335	765,425
Long-term deferred tax liabilities, net	203,476	180,449	186,538	154,151	154,763
Other long-term liabilities	66,907	45,978	43,949	40,929	40,357
Total liabilities	$ 2,415,905	$ 2,335,561	$ 2,299,769	$ 1,972,546	$ 1,902,140
Commitments and contingencies
Equity:
Preferred stock, $1.00 par value: authorized shares - 5,000,000; issued and outstanding shares - none	$ 0	$ 0	$ 0	$ 0	$ 0
Common stock, $0.10 par value: authorized shares - 145,000,000	8,762	8,711	8,704	8,700	8,672
Capital surplus	756,688	781,400	776,301	827,863	822,836
Contributed shares	0	6,002	6,002	6,002	6,002
Retained earnings	457,788	436,671	387,685	353,961	341,865
Accumulated other comprehensive loss	(34,004)	(23,897)	(10,946)	(18,622)	(13,286)	(5,501)	(7,946)
Treasury stock, at cost	(45,573)	(83,385)	(83,385)	(150,000)	(150,000)
Total MasTec, Inc. shareholders' equity	1,143,661	1,125,502	1,084,361	1,027,904	1,016,089
Non-controlling interests	4,414	4,838	4,698	5,016	4,969
Total equity	1,148,075	1,130,340	1,089,059	1,032,920	1,021,058	$ 861,875	$ 811,207
Total liabilities and equity	$ 3,563,980	3,465,901	3,388,828	3,005,466	2,923,198
As Reported [Member]
Current assets:
Cash and cash equivalents		7,067	15,924	9,261	22,927
Accounts receivable, net of allowance		1,389,903	1,288,672	1,195,603
Inventories, net		105,038	115,627	89,146
Prepaid expenses and other current assets, including discontinued operations		71,944	69,429	63,926
Total current assets		1,573,952	1,489,652	1,357,936	1,306,000
Property and equipment, net		614,359	618,672	509,585
Goodwill		1,000,024	983,133	912,885	899,400
Other intangible assets, net		222,212	230,592	171,562
Other long-term assets, including discontinued operations		59,579	73,821	61,439
Total assets		3,470,126	3,395,870	3,013,407
Current liabilities:
Current maturities of long-term debt		71,798	76,914	52,949
Accounts payable		481,840	494,090	440,152
Accrued salaries and wages		82,083	63,845	68,055
Other accrued expenses		82,054	69,401	60,581
Acquisition-related contingent consideration, current		39,126	36,479	64,694
Billings in excess of costs and earnings		130,997	109,805	109,370
Other current liabilities		22,976	17,940	24,588
Total current liabilities		910,874	868,474	820,389	825,500
Acquisition-related contingent consideration, net of current portion		115,649	116,929	119,756
Long-term debt		1,088,289	1,088,666	841,335
Long-term deferred tax liabilities, net		180,449	186,538	154,151	154,900
Other long-term liabilities		45,978	43,949	40,929
Total liabilities		$ 2,341,239	2,304,556	$ 1,976,560
Commitments and contingencies
Equity:
Preferred stock, $1.00 par value: authorized shares - 5,000,000; issued and outstanding shares - none		$ 0	0	$ 0
Common stock, $0.10 par value: authorized shares - 145,000,000		8,711	8,704	8,700
Capital surplus		781,400	776,301	827,863
Contributed shares		6,002	6,002	6,002
Retained earnings		435,208	389,937	357,887
Accumulated other comprehensive loss		(23,887)	(10,943)	(18,621)
Treasury stock, at cost		(83,385)	(83,385)	(150,000)
Total MasTec, Inc. shareholders' equity		1,124,049	1,086,616	1,031,831
Non-controlling interests		4,838	4,698	5,016
Total equity		1,128,887	1,091,314	1,036,847
Total liabilities and equity		3,470,126	3,395,870	3,013,407
Adjustments [Member]
Current assets:
Cash and cash equivalents		0	0	0	$ 0
Accounts receivable, net of allowance		(4,225)	(8,422)	(10,367)
Inventories, net		0	0	0
Prepaid expenses and other current assets, including discontinued operations		0	1,380	2,426
Total current assets		(4,225)	(7,042)	(7,941)
Property and equipment, net		0	0	0
Goodwill		0	0	0
Other intangible assets, net		0	0	0
Other long-term assets, including discontinued operations		0	0	0
Total assets		(4,225)	(7,042)	(7,941)
Current liabilities:
Current maturities of long-term debt		0	0	0
Accounts payable		0	0	271
Accrued salaries and wages		0	100	0
Other accrued expenses		898	0	(128)
Acquisition-related contingent consideration, current		0	0	6,806
Billings in excess of costs and earnings		(1,265)	(837)	0
Other current liabilities		(5,311)	(4,050)	(4,157)
Total current liabilities		(5,678)	(4,787)	2,792
Acquisition-related contingent consideration, net of current portion		0	0	(6,806)
Long-term debt		0	0	0
Long-term deferred tax liabilities, net		0	0	0
Other long-term liabilities		0	0	0
Total liabilities		$ (5,678)	(4,787)	$ (4,014)
Commitments and contingencies
Equity:
Preferred stock, $1.00 par value: authorized shares - 5,000,000; issued and outstanding shares - none		$ 0	0	$ 0
Common stock, $0.10 par value: authorized shares - 145,000,000		0	0	0
Capital surplus		0	0	0
Contributed shares		0	0	0
Retained earnings		1,463	(2,252)	(3,926)
Accumulated other comprehensive loss		(10)	(3)	(1)
Treasury stock, at cost		0	0	0
Total MasTec, Inc. shareholders' equity		1,453	(2,255)	(3,927)
Non-controlling interests		0	0	0
Total equity		1,453	(2,255)	(3,927)
Total liabilities and equity		$ (4,225)	$ (7,042)	$ (7,941)