Restructuring - Roll Forward of Accrued Liabilities Associated with Restructuring Activities (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2015 USD ($)
Restructuring Reserve [Line Items]
Beginning balance	$ 4,048
Accruals	3,418
Payments	(1,657)
Ending balance	5,809
Morgan City environmental reserve [Member]
Restructuring Reserve [Line Items]
Beginning balance	3,675
Payments	(1,374)
Ending balance	2,301
Morgan City yard-related expenses and Other [Member]
Restructuring Reserve [Line Items]
Beginning balance	373
Accruals	338
Payments	(283)
Ending balance	428
MPI related accruals [Member]
Restructuring Reserve [Line Items]
Accruals	3,080
Ending balance	$ 3,080