Long Term Debt - Schedule of Long-term Debt Obligations (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 513,575	$ 521,877
Current portion due within one year	(34,888)	(32,377)
Unamortized debt discount	(42,972)	(44,864)
Deferred financing costs	(3,866)	(4,126)
Long-term debt, less current portion	431,849	440,510
Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	390,726	399,028
Non-Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	122,849	122,849
Convertible Senior Notes \| Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	125,000	125,000
SEACOR Marine Foreign Holdings Credit Facility \| Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	96,220	100,750
Sea-Cat Crewzer III Term Loan Facility \| Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	20,415	21,653
SEACOR Offshore Delta (f/k/a SEACOSCO) Acquisition Debt \| Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	19,705	19,705
SEACOR Delta (f/k/a SEACOSCO) Shipyard Financing \| Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	93,094	95,317
SEACOR Alpine Shipyard Financing \| Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	30,792	31,103
SEACOR 88/888 Term Loan \| Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	5,500	5,500
SEACOR 88/888 Term Loan \| Non-Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	5,500	5,500
Falcon Global USA Term Loan Facility \| Non-Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	102,349	102,349
Falcon Global USA Revolver \| Non-Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 15,000	$ 15,000

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Amount, after accumulated amortization, of debt discount.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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