Summary of Significant Accounting Policies (Tax Effects of Componenets of Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Summary of Significant Accounting Policies [Abstract]
Defined benefit pension plan adjustments, Before-Tax Amount		$ 1,079	$ 2,416	$ (4,452)
Defined benefit pension plan adjustments, Tax (Expense) Benefit		(308)	(992)	1,829
Defined benefit pension plan adjustments, Net-of-Tax Amount		771	1,424	(2,623)
Foreign currency translation adjustment, Before-Tax Amount		(4,067)	2,159	(439)
Foreign currency translation adjustment, Tax (Expense) Benefit		1,122	(886)	178
Foreign currency translation adjustment, Net-of-Tax Amount		(2,945)	1,273	(261)
Unrealized gain (loss) in fair value of investments, Before-Tax Amount		(1,005)	(4)	(576)
Unrealized gain (loss) in fair value of investments, Tax (Expense) Benefit		227	2	236
Unrealized gain (loss) in fair value of investments, Net-of-Tax Amount		(778)	(2)	(340)
Unrealized gain (loss) in fair value of interest rate swap, Before-Tax Amount				(45)
Unrealized gain (loss) in fair value of interest rate swap, Tax (Expense) Benefit				21
Unrealized gain (loss) in fair value of interest rate swap, Net-of-Tax Amount				(24)
Total other comprehensive income (loss), Before-Tax Amount		(3,993)	4,571	(5,512)
Total other comprehensive income (loss), Tax Benefit		1,041	(1,876)	2,264
TOTAL OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX		(2,952)	2,695	(3,248)
Less: Other comprehensive income (loss) attributable to noncontrolling interests, Before-Tax Amount	[1]	(221)
Less: Other comprehensive income (loss) attributable to noncontrolling interests, Net-of-Tax Amount	[1]	(221)
Total other comprehensive income (loss) attributable to Tutor Perini Corporation, Before-Tax Amount		(3,772)	4,571	(5,512)
Total other comprehensive income (loss) attributable to Tutor Perini Corporation, Tax (Expense) Benefit		1,041	(1,876)	2,264
TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAX		$ (2,731)	$ 2,695	$ (3,248)

[1] The only component of other comprehensive loss attributable to noncontrolling interests is foreign currency translation.