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, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Summary of Significant Accounting Policies [Abstract]
Net income attributable to Tutor Perini Corporation	$ 49,405	$ 21,272	$ 24,883	$ (12,124)	$ 80,938	$ 23,584	$ 30,096	$ 13,764	$ 83,436	$ 148,382	$ 95,822
Weighted-average common shares outstanding, basic									49,952	49,647	49,150
Effect of dilutive restricted stock units and stock options									349	1,112	714
Weighted-average common shares outstanding, diluted									50,301	50,759	49,864
Net income attributable to Tutor Perini Corporation per common share: Basic	$ 0.99	$ 0.43	$ 0.50	$ (0.24)	$ 1.63	$ 0.47	$ 0.61	$ 0.28	$ 1.67	$ 2.99	$ 1.95
Net income attributable to Tutor Perini Corporation per common share: Diluted	$ 0.98	$ 0.42	$ 0.49	$ (0.24)	$ 1.60	$ 0.47	$ 0.59	$ 0.27	$ 1.66	$ 2.92	$ 1.92
Anti-dilutive securities not included above									2,670	798	1,132