Unaudited Condensed Consolidated Statements of Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Income Statement [Abstract]
Operating Revenues	$ 59,791	$ 43,663	$ 159,399	$ 122,974
Costs and Expenses:
Operating	44,006	33,448	127,647	92,370
Administrative and general	9,978	9,134	30,112	26,897
Lease expense	1,168	1,109	3,236	3,421
Depreciation and amortization	13,754	14,306	42,333	43,197
Costs and expenses	68,906	57,997	203,328	165,885
(Losses) Gains on Asset Dispositions and Impairments, Net	(1,783)	56	381	20,436
Operating Loss	(10,898)	(14,278)	(43,548)	(22,475)
Other Income (Expense):
Interest income	(123)	124	96	1,245
Interest expense	(7,634)	(6,403)	(21,250)	(21,731)
SEACOR Holdings guarantee fees	0	0	0	(7)
Gain on debt extinguishment	0	0	0	61,994
Derivative gains, net	1	2	0	387
Foreign currency gains (losses), net	2,314	245	4,305	(878)
Gain from return of investments in 50% or less owned companies and other, net	659	9,442	618	9,441
Nonoperating income expense	(4,783)	3,410	(16,231)	50,451
(Loss) Income from Continuing Operations Before Income Tax Expense (Benefit) and Equity in Earnings of 50% or Less Owned Companies	(15,681)	(10,868)	(59,779)	27,976
Income Tax Expense (Benefit)	8,418	(725)	4,363	12,502
(Loss) Income from Continuing Operations Before Equity in Earnings of 50% or Less Owned Companies	(24,099)	(10,143)	(64,142)	15,474
Equity in Earnings (Losses) Gains of 50% or Less Owned Companies	(254)	4,314	5,835	10,584
(Loss) Income from Continuing Operations	(24,353)	(5,829)	(58,307)	26,058
Income on Discontinued Operations, Net of Tax (see Note 13)	0	0	0	22,925
Net (Loss) Income	(24,353)	(5,829)	(58,307)	48,983
Net (Loss) Income attributable to Noncontrolling Interests in Subsidiaries	(2)	0	1	1
Net (Loss) Income attributable to SEACOR Marine Holdings Inc.	$ (24,351)	$ (5,829)	$ (58,308)	$ 48,982
Net (Loss) Income Per Common Share from Continuing Operations:
Basic	$ (0.91)	$ (0.23)	$ (2.19)	$ 1.03
Diluted	(0.91)	(0.23)	(2.19)	1.02
Net Earnings Per Share from Discontinued Operations:
Basic	0	0	0	0.90
Diluted	0	0	0	0.90
Net (Loss) Earnings Per Share:
Basic	(0.91)	(0.23)	(2.19)	1.93
Diluted	$ (0.91)	$ (0.23)	$ (2.19)	$ 1.92
Weighted Average Common Stock and Warrants Outstanding:
Basic	26,727,864	25,515,569	26,591,911	25,419,303
Diluted	26,727,864	25,515,569	26,591,911	25,430,762