Schedule of Balances with Unconsolidated Affiliates (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Due to related parties:
Due from related parties, net of due to related parties	$ 78,804	$ 97,979
Sonatide Marine, Ltd. \| ANGOLA
Due from related parties:
Total due from related parties	92,202	109,176
Due to related parties:
Total due to related parties	29,611	29,347
DTDW Holdings, Ltd. \| NIGERIA
Due from related parties:
Total due from related parties	26,847	23,775
Due to related parties:
Total due to related parties	$ 10,634	$ 5,625

The aggregate amount of receivables to be collected from related parties where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth, at the financial statement date. which are usually due within one year (or one business cycle).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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-Name Accounting Standards Codification
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Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant