Summary of Properties and Equipment (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Property Plant And Equipment [Abstract]
Vessels and related equipment	$ 969,360	$ 1,051,558
Other properties and equipment	16,234	13,119
Properties and equipment, gross	985,594	1,064,677
Less accumulated depreciation and amortization	145,682	125,716
Properties and equipment, net	$ 839,912	$ 938,961

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation of tangible personal property used to produce goods and services, including, but is not limited to, tools, dies and molds, computer and office equipment.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Amount before accumulated depreciation, depletion and amortization of other physical assets used in the normal conduct of business to produce goods and services and not intended for resale.

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