Summary of Significant Accounting Policies (Calculations of Basic and Diluted EPS) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summary of Significant Accounting Policies [Abstract]
Net income attributable to Tutor Perini Corporation	$ 80,938	$ 23,584	$ 30,096	$ 13,764	$ 30,260	$ 28,801	$ 21,361	$ 15,400	$ 148,382	$ 95,822	$ 45,292
Weighted-average common shares outstanding, basic									49,647	49,150	48,981
Effect of dilutive stock options and unvested restricted stock									1,112	714	685
Weighted-average common shares outstanding, diluted									50,759	49,864	49,666
Net income attributable to Tutor Perini Corporation per common share: Basic	$ 1.63	$ 0.47	$ 0.61	$ 0.28	$ 0.62	$ 0.59	$ 0.43	$ 0.31	$ 2.99	$ 1.95	$ 0.92
Net income attributable to Tutor Perini Corporation per common share: Diluted	$ 1.60	$ 0.47	$ 0.59	$ 0.27	$ 0.60	$ 0.57	$ 0.43	$ 0.31	$ 2.92	$ 1.92	$ 0.91
Anti-dilutive securities not included above									798	1,132	1,372