Restructuring - Restructuring Costs Incurred and Future Cost Expected to be Incurred (Detail) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Incurred for the period	$ 2,484,000	$ 0	$ 8,851,000
Incurred from inception to June 30, 2017		99,321,000
Americas Restructuring [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Incurred for the period	(1,500,000)		(1,500,000)
Incurred from inception to June 30, 2017		44,194,000
McDermott Profitability Initiative [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Incurred for the period	2,582,000		4,083,000
Incurred from inception to June 30, 2017		46,962,000
McDermott Profitability Initiative [Member] | Severance and other personnel-related costs [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Incurred for the period	992,000		1,425,000
Incurred from inception to June 30, 2017		17,807,000
McDermott Profitability Initiative [Member] | Asset impairment and disposal [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Incurred from inception to June 30, 2017		7,471,000
McDermott Profitability Initiative [Member] | Legal and other advisor fees [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Incurred for the period	49,000		222,000
Incurred from inception to June 30, 2017		11,639,000
McDermott Profitability Initiative [Member] | Other Charges [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Incurred for the period	1,541,000		2,436,000
Incurred from inception to June 30, 2017		10,045,000
Additional Overhead Reduction [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Incurred for the period	1,402,000		6,268,000
Incurred from inception to June 30, 2017		8,165,000
Additional Overhead Reduction [Member] | Severance and other personnel-related costs [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Incurred for the period	1,073,000		4,044,000
Incurred from inception to June 30, 2017		5,012,000
Additional Overhead Reduction [Member] | Legal and other advisor fees [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Incurred for the period	240,000		1,968,000
Incurred from inception to June 30, 2017		2,768,000
Additional Overhead Reduction [Member] | Other Charges [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Incurred for the period	$ 89,000		$ 256,000
Incurred from inception to June 30, 2017		$ 385,000