Discontinued Operations - Schedule of Assets Held for Sale (Details) - Windcat Workboats Holdings Ltd - Discontinued Operations, Held-for-sale - USD ($) $ in Thousands		3 Months Ended
	Jan. 12, 2021	Mar. 31, 2021	Mar. 31, 2020
Operating Revenues:
Operating Revenues		$ 973	$ 6,076
Costs and Expenses:
Operating		578	3,885
Direct Vessel Profit		395	2,191
General and Administrative Expenses		238	1,371
Lease Expense		24	82
Depreciation			1,639
Total expenses		262	3,092
Operating Income		133	(901)
Other Income (Expense)
Interest income		2	14
Interest expense		39	264
Foreign currency translation loss		89	(645)
Other Income (Expense)		52	(895)
Operating Loss Before Equity Earnings of 50% or Less Owned Companies, Net of Tax		185	(1,796)
Income Tax Expense			(6)
Operating Loss Before Equity Earnings of 50% or Less Owned Companies		185	(1,790)
Equity in Earnings of 50% or Less Owned Companies, Net of Tax		(16)	(264)
Net (Loss) Income from Discontinued Operations	$ 200	169	(2,054)
Time Charter
Operating Revenues:
Operating Revenues		903	5,742
Other Revenue
Operating Revenues:
Operating Revenues		$ 70	$ 334