Other Comprehensive Income (Loss) (Schedule Of Changes In AOCI Balances By Component (After-Tax)) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Attributable to Tutor Perini Corporation:
Balance at the beginning of the period			$ 1,440,142
Other comprehensive income (loss) before reclassifications	$ 579	$ (97)	1,268	$ 2,181
Amounts reclassified from AOCI	202	333	1,016	974
Total other comprehensive income (loss)	781	236	2,284	3,155
Balance at the end of the period	1,523,356		1,523,356
Defined Benefit Pension Plan
Attributable to Tutor Perini Corporation:
Balance at the beginning of the period	(36,979)	(38,009)	(37,826)	(38,670)
Other comprehensive income (loss) before reclassifications	0	0	0	0
Amounts reclassified from AOCI	424	331	1,271	992
Total other comprehensive income (loss)	424	331	1,271	992
Balance at the end of the period	(36,555)	(37,678)	(36,555)	(37,678)
Foreign Currency Translation
Attributable to Tutor Perini Corporation:
Balance at the beginning of the period	(6,563)	(5,416)	(5,371)	(6,315)
Other comprehensive income (loss) before reclassifications	582	(351)	(610)	548
Amounts reclassified from AOCI	0	0	0	0
Total other comprehensive income (loss)	582	(351)	(610)	548
Balance at the end of the period	(5,981)	(5,767)	(5,981)	(5,767)
Unrealized Gain (Loss) in Fair Value of Investments, Net
Attributable to Tutor Perini Corporation:
Balance at the beginning of the period	2,945	895	1,097	(464)
Other comprehensive income (loss) before reclassifications	(3)	254	1,878	1,633
Amounts reclassified from AOCI	(222)	2	(255)	(18)
Total other comprehensive income (loss)	(225)	256	1,623	1,615
Balance at the end of the period	2,720	1,151	2,720	1,151
Accumulated Other Comprehensive Income (Loss)
Attributable to Tutor Perini Corporation:
Balance at the beginning of the period	(40,597)	(42,530)	(42,100)	(45,449)
Balance at the end of the period	$ (39,816)	$ (42,294)	$ (39,816)	$ (42,294)