Long Term Debt - Additional Information (Details) $ / shares in Units, € in Millions													1 Months Ended	12 Months Ended
	Jul. 23, 2021 USD ($)	Jun. 29, 2021 USD ($)	Jun. 24, 2021 USD ($)	Jun. 18, 2021 USD ($)	Jun. 10, 2021 USD ($) Liftboat	Dec. 18, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 03, 2020 EUR (€)	Sep. 26, 2018 USD ($)	Jul. 05, 2018 USD ($)	May 02, 2018 USD ($) $ / shares shares	Dec. 01, 2015 USD ($) $ / shares	Apr. 30, 2018 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) $ / shares	Dec. 31, 2020 USD ($)	Dec. 31, 2020 EUR (€)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jun. 29, 2020 Vessel	Oct. 31, 2018 USD ($)	May 24, 2016 EUR (€)	Apr. 21, 2016 EUR (€)
Debt Instrument [Line Items]
Repayments of long-term debt, total														$ 78,124,000	$ 22,601,000		$ 23,974,000
Gain on troubled debt restructuring, increase of basic earnings per share | $ / shares														$ 2.44
Gain on troubled debt restructuring, increase of diluted earnings per share | $ / shares														$ 2.43
Debt instrument, increase (decrease), net,									$ 30,100,000
Gain on troubled debt restructuring														$ (61,994,000)
Number of additional vessels owned | Vessel																					2
Long-term Debt Obligation
Debt Instrument [Line Items]
Letters of credit outstanding, amount														1,200,000
Carlyle Group
Debt Instrument [Line Items]
Convertible debt, total												$ 175,000,000.0
Convertible Senior Notes Converted to Warrants | Carlyle Group
Debt Instrument [Line Items]
Debt instrument, face amount											$ 1,000		$ 1,000
Debt instrument, convertible, conversion ratio											37.73		37.73
Class of warrant or right, exercise price of warrants or rights | $ / shares											$ 0.01		$ 0.01
Debt conversion, original debt, amount											$ 50,000,000		$ 50,000,000.0
Debt conversion, converted instrument, shares issued | shares											1,886,792		1,900,000
Debt instrument, convertible, conversion price | $ / shares											$ 26.50		$ 26.50
Carlyle Warrants
Debt Instrument [Line Items]
Class of warrant or right, exercise price of warrants or rights | $ / shares												$ 0.01
Warrants and rights outstanding, term											25 years
Term Loan to Acquire One Vessel
Debt Instrument [Line Items]
Debt instrument, face amount	$ 6,500,000
Term loan fixed interest percentage rate	6.00%
Debt instrument, maturity year	2025
Conditional Payoff Agreement
Debt Instrument [Line Items]
Repayments of long-term debt, total			$ 27,500,000		$ 50,000,000.0
Reimbursement amount		$ 2,500,000
Number of liftboats released from mortgages and security arrangements | Liftboat					9
Gain on restructuring of debt					$ 62,000,000.0
Conditional Payoff Agreement | Paid at Signing of Conditional Payoff Agreement
Debt Instrument [Line Items]
Repayments of long-term debt, total					25,000,000.0
Conditional Payoff Agreement | Paid Using Hull and Machinery Insurance Proceeds
Debt Instrument [Line Items]
Repayments of long-term debt, total				$ 22,500,000
Conditional Payoff Agreement | Reimbursed from Hull and Machinery Insurance Proceeds
Debt Instrument [Line Items]
Repayments of long-term debt, total			$ 2,500,000
Deferred Purchase Agreements | SEACOR Offshore Delta (f/k/a SEACOSCO)
Debt Instrument [Line Items]
Purchase price payable for equity method investment in first year							$ 1,000,000.0
Purchase price payable for equity method investment in second year							2,500,000
Purchase price payable for equity method investment in third year							2,500,000
Purchase price payable for equity method investment in fourth year							$ 13,700,000
Purchase price fixed accrued interest rate in first year							1.50%
Purchase price fixed accrued interest rate in second year							7.00%
Purchase price fixed accrued interest rate in third year							7.50%
Purchase price fixed accrued interest rate in fourth year							8.00%
Deferred Purchase Agreements | SEACOR Offshore Delta (f/k/a SEACOSCO) | Platform Supply Vessels
Debt Instrument [Line Items]
Equity method investment, amortization of purchase price							10 years
Debt instrument, description of floating interest rate basis							three-month LIBOR plus 4.0%
Debt instrument, basis spread on floating interest rate							4.00%
Tax Refund Agreement
Debt Instrument [Line Items]
Estimated tax refund receivable						$ 31,200,000
SEACOR Offshore OSV
Debt Instrument [Line Items]
Line of credit facility assumed and guaranteed														$ 18,100,000
Credit facility, frequency of payments														quarterly
Credit facility quarterly principal payments														$ 500,000
Credit facility, interest rate														4.68%
Credit facility, maturity date														Dec. 31, 2023
Term and Revolving Loan Facility | Conditional Payoff Agreement
Debt Instrument [Line Items]
Principal outstanding under Credit Facility					$ 117,300,000
SEACOR Alpine Shipyard Financing
Debt Instrument [Line Items]
Debt instrument, interest rate																	5.00%
Percentage of amount of loan financed																	70.00%
Debt instrument, term of delivery																	4 years
Windcat Workboats Facilities
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity | €																							€ 25.0
Debt instrument, maturity date								Dec. 31, 2021
Debt instrument, extended maturity date								Dec. 31, 2022
Application fee paid in conjunction with amendment and amortized over credit facility term | €								€ 0.1
Proceeds from lines of credit | €																€ 1.0
Debt instrument, increase (decrease), net,															$ 1,100,000
Loan Facility With DNB Bank ASA
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity									$ 130,000.0
Debt instrument, interest rate, effective percentage									3.90%
Debt instrument, maturity period									2023
Debt instrument, periodic payment, principal									$ 3,300,000
Loan Facility With DNB Bank ASA | Interest Rate Swap
Debt Instrument [Line Items]
Derivative, notional amount																						$ 65,000,000.0
Other DNB Credit Facilities
Debt Instrument [Line Items]
Repayments of lines of credit									101,300,000
Long-term debt, total									99,900,000
Interest payable									1,400,000
Gain on troubled debt restructuring									$ 600,000
Convertible Senior Notes 3.75%
Debt Instrument [Line Items]
Debt instrument, face amount												$ 1,000
Debt instrument, interest rate											4.25%	3.75%	4.25%	3.75%
Convertible debt, total											$ 125,000,000.0	$ 175,000,000.0	$ 125,000,000.0
Debt instrument, convertible, conversion ratio												23.26
Three Point Seven Five Percentage Convertible Notes
Debt Instrument [Line Items]
Debt instrument, interest rate, effective percentage												7.95%
Embedded derivative, fair value of embedded derivative liability												$ 27,300,000
Sea-Cat Crewzer III
Debt Instrument [Line Items]
Debt instrument, face amount | €																								€ 27.6
Repayments of long-term debt, total																		$ 3,100,000
Debt instrument, interest rate, effective percentage																			2.76%
Proceeds from issuance of debt																			$ 7,100,000	$ 22,800,000
Debt issuance costs, gross																				$ 2,700,000
Term Loan to Acquire Two Vessels
Debt Instrument [Line Items]
Debt instrument, face amount										$ 11,000,000.0
Debt instrument, maturity year														2023
Debt instrument, interest rate, effective percentage										3.75%
Claims recoverable amount under borrowings										$ 5,500,000
Claims recoverable under borrowings percentage of obligations outstanding										50.00%
Term Loan to Acquire Two Vessels | Interest Rate Swap
Debt Instrument [Line Items]
Derivative, notional amount																						$ 5,500,000