Nature of Operations and Accounting Policies - Summary of Property and Equipment from Continuing Operations (Details) - USD ($) $ in Thousands |
Dec. 31, 2022 |
Dec. 31, 2021 |
Dec. 31, 2020 |
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Historical cost | $ 967,683 | [1] | $ 1,008,080 | [1] | $ 1,012,873 | ||||||||||
Accumulated depreciation | (310,778) | (302,328) | (291,538) | ||||||||||||
Net book value | 656,905 | 705,752 | $ 721,335 | ||||||||||||
Offshore Support Vessels, Anchor Handling Towing Supply | |||||||||||||||
Historical cost | [1],[2] | 27,281 | 49,632 | ||||||||||||
Accumulated depreciation | [2] | (18,139) | (33,200) | ||||||||||||
Net book value | [2] | 9,142 | 16,432 | ||||||||||||
Fast Support Vessels | |||||||||||||||
Historical cost | [1],[3] | 354,473 | 362,309 | ||||||||||||
Accumulated depreciation | [3] | (130,599) | (116,878) | ||||||||||||
Net book value | [3] | 223,874 | 245,431 | ||||||||||||
Platform Supply Vessels | |||||||||||||||
Historical cost | [1],[4] | 295,875 | 282,243 | ||||||||||||
Accumulated depreciation | [4] | (36,112) | (20,613) | ||||||||||||
Net book value | [4] | 259,763 | 261,630 | ||||||||||||
Offshore Support Vessels, Specialty | |||||||||||||||
Historical cost | [1] | 3,163 | 3,163 | ||||||||||||
Accumulated depreciation | (3,138) | (3,138) | |||||||||||||
Net book value | 25 | 25 | |||||||||||||
Offshore Support Vessels, Liftboats | |||||||||||||||
Historical cost | [1] | 264,142 | 289,283 | ||||||||||||
Accumulated depreciation | (102,156) | (108,364) | |||||||||||||
Net book value | 161,986 | 180,919 | |||||||||||||
General Machinery and Spares | |||||||||||||||
Historical cost | [1] | 10,148 | 8,814 | ||||||||||||
Accumulated depreciation | (8,565) | (8,463) | |||||||||||||
Net book value | 1,583 | 351 | |||||||||||||
Property, Plant and Equipment, Other Types | |||||||||||||||
Historical cost | [1],[5] | 12,601 | 12,636 | ||||||||||||
Accumulated depreciation | [5] | (12,069) | (11,672) | ||||||||||||
Net book value | [5] | $ 532 | $ 964 | ||||||||||||
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