Discontinued Operations - Schedule of Assets Held for Sale (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 12, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Assets from Discontinued Operations:
Current assets			$ 50,235
Assets from discontinued operations			50,200	$ 45,700
Liability from Discontinued Operations:
Liabilities held for sale			30,927
Boston Putford Offshore Safety | Discontinued Operations, Held-for-sale
Assets from Discontinued Operations:
Current assets			10,138
Net property and equipment			34,580
Non-current assets			5,517
Assets from discontinued operations			50,235
Liability from Discontinued Operations:
Liabilities held for sale			2,418
Long-term liabilities			28,509
Disposal Group, Including Discontinued Operation, Liabilities			30,927
Operating Revenues:
Operating Revenues				41,259
Costs and Expenses:
Operating				33,836
Direct Vessel Profit				7,423
General and Administrative Expenses				4,207
Lease Expense				60
Depreciation				3,504
Gain on Asset Dispositions and Impairments, Net				91
Operating Income (Loss)				(257)
Other Income (Expense)
Interest income				11
Interest expense				(210)
Foreign currency translation (loss)				(75)
Other Income (Expense)				(274)
Operating Income Before Equity Earnings of 50% or Less Owned Companies, Net of Tax				(531)
Income Tax Benefit				(2)
Operating Income Before Equity Earnings of 50% or Less Owned Companies				(529)
Equity in Earnings of 50% or Less Owned Companies, Net of Tax				168
Net Income from Discontinued Operations				(361)
Boston Putford Offshore Safety | Discontinued Operations, Held-for-sale | Time Charter
Operating Revenues:
Operating Revenues				41,214
Boston Putford Offshore Safety | Discontinued Operations, Held-for-sale | Other Revenue
Operating Revenues:
Operating Revenues				45
Windcat Workboats Holdings Ltd | Discontinued Operations, Held-for-sale
Operating Revenues:
Operating Revenues		$ 973	31,688	27,039
Costs and Expenses:
Operating		578	17,334	14,202
Direct Vessel Profit		395	14,354	12,837
General and Administrative Expenses		238	5,516	4,935
Lease Expense		24	628	318
Depreciation			6,166	6,846
Gain on Asset Dispositions and Impairments, Net				1,064
Operating Income (Loss)		133	2,044	1,802
Other Income (Expense)
Interest income		2	59	56
Interest expense		(39)	(1,115)	(1,100)
Foreign currency translation (loss)		89	(750)	880
Other, net			19
Other Income (Expense)		52	(1,787)	(164)
Operating Income Before Equity Earnings of 50% or Less Owned Companies, Net of Tax		185	257	1,638
Income Tax Benefit			(86)	57
Operating Income Before Equity Earnings of 50% or Less Owned Companies		185	343	1,581
Equity in Earnings of 50% or Less Owned Companies, Net of Tax		(16)	21	155
Net Income from Discontinued Operations	$ 200	169	364	1,736
Windcat Workboats Holdings Ltd | Discontinued Operations, Held-for-sale | Time Charter
Operating Revenues:
Operating Revenues		903	29,383	25,249
Windcat Workboats Holdings Ltd | Discontinued Operations, Held-for-sale | Other Revenue
Operating Revenues:
Operating Revenues		$ 70	$ 2,305	$ 1,790