CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (31,081)	$ (9,662)
Other comprehensive loss, net of tax:
Net unrealized (loss) gain on derivatives	(598)	620
Less: reclassification for net gains included in interest expense	(173)	(40)
Net change	(771)	580
Foreign currency translation adjustments, net	894	(17)
Other comprehensive income	123	563
Comprehensive loss	(30,958)	(9,099)
Non-controlling interests in comprehensive loss	(3,493)	(1,761)
Comprehensive loss attributable to Granite Construction Incorporated	$ (34,451)	$ (10,860)