Revenue from Contracts with Customers - Summary of Changes in Contract Assets and Contract Liabilities (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($)
Contract assets
Beginning Balance	$ 2,983
Additions	9,631
Deductions	(11,177)
Ending Balance	1,437
Contract liabilities
Beginning Balance	15,406
Additions	6,091
Deductions	(9,905)
Ending Balance	11,592
Subsea Projects [Member]
Contract assets
Beginning Balance	2,811
Additions	9,424
Deductions	(10,865)
Ending Balance	1,370
Contract liabilities
Beginning Balance	491
Additions	4,835
Deductions	(5,148)
Ending Balance	178
Research Services [Member]
Contract assets
Beginning Balance	172
Additions	207
Deductions	(312)
Ending Balance	67
Contract liabilities
Beginning Balance	138
Additions	94
Deductions	(232)
Product Revenue [Member]
Contract liabilities
Beginning Balance	4,991
Additions	1,162
Deductions	(4,294)
Ending Balance	1,859
Prepayment Liability [Member]
Contract liabilities
Beginning Balance	9,786
Deductions	(231)
Ending Balance	$ 9,555