Vessels - Schedule of Vessels (Detail) - Seaspan [Member] - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Net book value	$ 5,707.1	$ 5,926.3
Vessels [Member]
Property Plant And Equipment [Line Items]
Cost	8,018.5	8,004.0
Accumulated depreciation	2,311.4	2,077.7
Net book value	$ 5,707.1	$ 5,926.3

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, 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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