CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 92,926	$ 16,392	$ 153,580	$ 35,753
Other comprehensive income (loss), net of tax:
Unrealized gain (loss) on investments	38	(3)	77	14
Gain on derivatives	9,266	3,566	19,905	38,978
Foreign currency translation	(6,717)	(5,031)	(6,709)	(12,401)
Other comprehensive income (loss), net of tax	2,587	(1,468)	13,273	26,591
Total comprehensive income	95,513	14,924	166,853	62,344
Less: Comprehensive income (loss) attributable to noncontrolling interests	(1,811)	273	532	1,128
Comprehensive income attributable to McDermott International, Inc.	$ 97,324	$ 14,651	$ 166,321	$ 61,216