SEACOR Marine (SMHI) 10-Q 5 Nov 20 2020 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Oct. 30, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Trading Symbol	SMHI
Entity Registrant Name	SEACOR Marine Holdings Inc.
Entity Central Index Key	0001690334
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Common Stock, Shares Outstanding		23,435,254
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	1-37966
Entity Tax Identification Number	47-2564547
Entity Address, Address Line One	12121 Wickchester Lane
Entity Address, Address Line Two	Suite 500
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77079
City Area Code	346
Local Phone Number	980-1700
Entity Incorporation, State or Country Code	DE
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common stock
Security Exchange Name	NYSE
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current Assets:
Cash and cash equivalents	$ 45,179	$ 83,943
Restricted cash	3,352	3,104
Receivables:
Trade, net of allowance for credit loss accounts of $850 and $455 in 2020 and 2019, respectively	54,935	49,128
Other	17,914	18,531
Receivable from SEACOR Holdings	18,814
Tax Receivable	11,770
Inventories	573	1,228
Prepaid expenses and other	3,598	2,612
Total current assets	156,135	158,546
Property and Equipment:
Historical cost	1,078,169	976,978
Accumulated depreciation	(334,387)	(358,962)
Property and equipment	743,782	618,016
Construction in progress	56,709	74,344
Net property and equipment	800,491	692,360
Right-of-Use Asset - Operating Leases	8,327	17,313
Right-of-Use Asset - Finance Leases	137
Investments, at Equity, and Advances to 50% or Less Owned Companies	88,933	124,680
Construction Reserve Funds		12,893
Other Assets	3,152	3,401
Total assets	1,057,175	1,009,193
Current Liabilities:
Current portion of operating lease liabilities	9,632	15,099
Current Portion of financing lease liabilities	27
Current portion of long-term debt:
Recourse	46,464	17,802
Non-recourse	5,644
Accounts payable and accrued expenses	29,542	25,691
Due to SEACOR Holdings		74
Accrued wages and benefits	1,551	1,832
Accrued interest	2,887	731
Deferred revenue and unearned revenue	3,131	5,327
Accrued capital, repair and maintenance expenditures	11,164	15,997
Accrued insurance deductibles and premiums	2,315	3,564
Derivatives	4,103	3,009
Other current liabilities	5,027	5,691
Total current liabilities	121,487	94,817
Long-Term Operating Lease Liabilities	5,694	9,822
Long-Term Financing Lease Liabilities	113
Long-Term Debt:
Recourse	315,326	239,939
Non-recourse	137,638	140,312
Conversion Option Liability on Convertible Senior Notes	1	5,205
Deferred Income Taxes	36,452	33,905
Deferred Gains and Other Liabilities	3,810	6,269
Total liabilities	620,521	530,269
SEACOR Marine Holdings Inc. stockholders’ equity:
Common stock, $.01 par value, 60,000,000 shares authorized; 23,435,234 and 21,928,674 shares issued in 2020 and 2019, respectively	235	219
Additional paid-in capital	450,320	429,318
(Accumulated Deficit) Retained earnings	(13,023)	27,076
Shares held in treasury of 73,284 and 47,187, respectively, at cost	(848)	(669)
Accumulated other comprehensive gain (loss), net of tax	(380)	1,548
Total stockholders equity	436,304	457,492
Noncontrolling interests in subsidiaries	350	21,432
Total equity	436,654	478,924
Total liabilities and equity	$ 1,057,175	$ 1,009,193

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Trade receivables, allowance for credit loss	$ 850	$ 455
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	60,000,000	60,000,000
Common stock, shares issued (in shares)	23,435,234	21,928,674
Shares held in treasury (in shares)	73,284	47,187

Unaudited Condensed Consolidate

Unaudited Condensed Consolidated Statements of Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Operating Revenues	$ 45,697	$ 54,700	$ 129,318	$ 152,422
Costs and Expenses:
Operating	29,128	27,211	77,661	97,747
Administrative and general	10,155	11,462	35,480	32,798
Lease expense	1,390	4,153	6,152	12,589
Depreciation and amortization	16,613	16,091	46,927	48,600
Costs and expenses	57,286	58,917	166,220	191,734
Losses on Asset Dispositions and Impairments, Net	233	861	(15,792)	(2,719)
Operating Loss	(11,356)	(3,356)	(52,694)	(42,031)
Other Income (Expense):
Interest income	50	317	1,255	886
Interest expense	(8,598)	(7,362)	(23,231)	(22,659)
SEACOR Holdings guarantee fees	(11)	(26)	(36)	(87)
Derivative gains, net	5	3,057	5,204	734
Foreign currency losses, net	(853)	(370)	(959)	(624)
Nonoperating income expense	(9,407)	(4,384)	(17,767)	(21,750)
Loss from Continuing Operations Before Income Tax Benefit and Equity in Earnings of 50% or Less Owned Companies	(20,763)	(7,740)	(70,461)	(63,781)
Income Tax Expense (Benefit)	(3,119)	1,277	(24,868)	(5,606)
Loss from Continuing Operations Before Equity in Earnings of 50% or Less Owned Companies	(17,644)	(9,017)	(45,593)	(58,175)
Equity in Earnings Gains (Losses) of 50% or Less Owned Companies	(433)	(1,325)	1,458	(11,879)
Loss from Continuing Operations	(18,077)	(10,342)	(44,135)	(70,054)
Loss on Discontinued Operations, Net of Tax (see Note 15)		(7,899)		(6,724)
Net Loss	(18,077)	(18,241)	(44,135)	(76,778)
Net Income (Loss) Attributable to Noncontrolling Interests in Subsidiaries	4	204	(4,036)	(4,395)
Net Loss attributable to SEACOR Marine Holdings Inc.	$ (18,081)	$ (18,445)	$ (40,099)	$ (72,383)
Basic and Diluted Loss Per Common Share and Warrants of SEACOR Marine Holdings Inc.
Continuing operations	$ (0.72)	$ (0.34)	$ (1.63)	$ (2.80)
Discontinued operations		(0.44)		(0.29)
Basic and Diluted Loss Per Common Share and Warrants	$ (0.72)	$ (0.78)	$ (1.63)	$ (3.09)
Weighted Average Common Stock and Warrants Outstanding:
Basic and diluted shares	24,989,977	23,740,718	24,611,666	23,406,759

Unaudited Condensed Consolida_2

Unaudited Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Net Loss	$ (18,077)	$ (18,241)	$ (44,135)	$ (76,778)
Other Comprehensive Loss:
Foreign currency translation gains (losses)	2,068	(1,626)	(385)	(1,902)
Derivative losses on cash flow hedges	(82)	(329)	(2,028)	(2,263)
Other comprehensive income	2,161	(1,949)	(1,928)	(4,490)
Income Tax Benefit				173
Other comprehensive income, net	2,161	(1,949)	(1,928)	(4,317)
Comprehensive Loss	(15,916)	(20,190)	(46,063)	(81,095)
Comprehensive Income (Loss) Attributable to Noncontrolling Interests in Subsidiaries	4	204	(4,036)	(4,395)
Comprehensive Loss attributable to SEACOR Marine Holdings Inc.	(15,920)	(20,394)	(42,027)	(76,700)
Interest Expense
Other Comprehensive Loss:
Reclassification of derivative gains (losses) on cash flow hedges	457	158	964	357
Equity Method Investments
Other Comprehensive Loss:
Reclassification of derivative gains (losses) on cash flow hedges	$ (282)	$ (152)	$ (479)	$ (682)

Unaudited Condensed Consolida_3

Unaudited Condensed Consolidated Statements of Comprehensive Loss (Parenthetical)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Reclassification of derivative gains (losses) on cash flow hedges to equity in earnings	50.00%	50.00%	50.00%	50.00%

Unaudited Condensed Consolida_4

Unaudited Condensed Consolidated Statement of Changes In Equity - USD ($) $ in Thousands	Total	Revision of Prior Period, Accounting Standards Update, Adjustment [Member]	Previously Reported [Member]	Common Stock [Member]	Common Stock [Member]Previously Reported [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member]Previously Reported [Member]	Treasury Stock [Member]	Treasury Stock [Member]Previously Reported [Member]	Retained Earnings [Member]	Retained Earnings [Member]Revision of Prior Period, Accounting Standards Update, Adjustment [Member]	Retained Earnings [Member]Previously Reported [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Other Comprehensive Loss [Member]Previously Reported [Member]	Non-Controlling Interests In Subsidiaries [Member]	Non-Controlling Interests In Subsidiaries [Member]Previously Reported [Member]
Balance at Dec. 31, 2018	$ 565,351	$ 10,416	$ 554,935	$ 204	$ 204	$ 415,372	$ 415,372	$ (91)	$ (91)	$ 137,250	$ 10,416	$ 126,834	$ (16,788)	$ (16,788)	$ 29,404	$ 29,404
Balance (in shares) at Dec. 31, 2018				20,439,208	20,439,208			4,007	4,007
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201602Member
Issuance of Common Stock	$ 6,596			$ 7		6,589
Issuance of Common Stock (in shares)				653,872
Forfeiture of employee share awards (in shares)				(1,000)
Restricted stock grants	2			$ 2
Restricted stock grants (in shares)				211,500
Amortization of employee share awards	3,891					3,891
Exercise of options	1,081			$ 1		1,080
Exercise of options (in shares)				86,494
Exercise of Warrants	3			$ 4				$ (1)
Exercise of Warrants (in shares)				444,391				49
Restricted stock vesting	(524)					(2)		$ (522)
Restricted stock vesting (in shares)				(38,448)				38,448
Director share awards	894			$ 1		893
Director share awards (in shares)				30,197
Acquisition of consolidated joint venture	(2,114)														(2,114)
Dissolution of an entity	62									62
Net Loss	(76,778)									(72,383)					(4,395)
Other comprehensive (loss) income	(4,317)												(4,317)
Balance at Sep. 30, 2019	494,147			$ 219		427,823		$ (614)		64,929			(21,105)		22,895
Balance (in shares) at Sep. 30, 2019				21,826,214				42,504
Balance at Jun. 30, 2019	511,240			$ 218		424,549		$ (374)		83,312			(19,156)		22,691
Balance (in shares) at Jun. 30, 2019				21,765,331				25,643
Amortization of employee share awards	2,302					2,302
Exercise of options	973			$ 1		972
Exercise of options (in shares)				77,744
Restricted stock vesting	(240)							$ (240)
Restricted stock vesting (in shares)				(16,861)				16,861
Dissolution of an entity	62									62
Net Loss	(18,241)									(18,445)					204
Other comprehensive (loss) income	(1,949)												(1,949)
Balance at Sep. 30, 2019	494,147			$ 219		427,823		$ (614)		64,929			(21,105)		22,895
Balance (in shares) at Sep. 30, 2019				21,826,214				42,504
Balance at Dec. 31, 2019	$ 478,924			$ 219		429,318		$ (669)		27,076			1,548		21,432
Balance (in shares) at Dec. 31, 2019	21,928,674			21,881,487				47,187
Issuance of Common Stock	$ 3,358			$ 9		3,349
Forfeiture of employee share awards (in shares)				(8,182)
Restricted stock grants	3			$ 3
Restricted stock grants (in shares)				289,452
Amortization of employee share awards	$ 3,210					3,210
Exercise of options (in shares)	20,000
Exercise of Warrants	$ 2			$ 3				$ (1)
Exercise of Warrants (in shares)				338,320				354
Restricted stock vesting	$ (178)							$ (178)
Restricted stock vesting (in shares)	(26,097)			(25,743)				25,743
Director share awards	$ 755			$ 1		754
Director share awards (in shares)				59,900
Acquisition of consolidated joint venture	(3,357)					13,689									(17,046)
Acquisition of consolidated joint venture (in shares)				900,000
Net Loss	(44,135)									(40,099)					(4,036)
Other comprehensive (loss) income	(1,928)												(1,928)
Balance at Sep. 30, 2020	$ 436,654			$ 235		450,320		$ (848)		(13,023)			(380)		350
Balance (in shares) at Sep. 30, 2020	23,435,234			23,435,234				73,284
Balance at Jun. 30, 2020	$ 451,364			$ 232		449,116		$ (847)		5,058			(2,541)		346
Balance (in shares) at Jun. 30, 2020				23,096,914				72,930
Amortization of employee share awards	1,204					1,204
Exercise of Warrants	2			$ 3				$ (1)
Exercise of Warrants (in shares)				338,320				354
Net Loss	(18,077)									(18,081)					4
Other comprehensive (loss) income	2,161												2,161
Balance at Sep. 30, 2020	$ 436,654			$ 235		$ 450,320		$ (848)		$ (13,023)			$ (380)		$ 350
Balance (in shares) at Sep. 30, 2020	23,435,234			23,435,234				73,284

Unaudited Condensed Consolida_5

Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash Flows from Continuing Operating Activities:
Net Loss	$ (44,135)	$ (77,138)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	46,927	48,600
Deferred financing costs amortization	976	883
Amortization of employee share awards	3,210	3,891
Restricted stock vesting	(178)	(522)
Director share awards	755	894
Debt discount amortization	4,755	4,201
Bad debt recoveries	376	(404)
Loss from equipment sales, retirements or impairments	15,792	2,719
Loss from sale of Boston Putford Offshore Safety		7,085
Derivative gains	(5,204)	(734)
Cash settlement payments on derivative transactions, net	(938)	(346)
Currency losses	959	624
Deferred income taxes	2,488	(9,840)
Equity losses	(1,458)	11,879
Dividends received from equity investees	2,117	1,273
Changes in Operating Assets and Liabilities:
Accounts receivables	(37,670)	(2,198)
Other assets	6,433	344
Accounts payable and accrued liabilities	(16,255)	7,971
Net cash used in operating activities	(21,050)	(818)
Cash Flows from Continuing Investing Activities:
Purchases of property and equipment	(24,940)	(49,566)
Proceeds from disposition of property and equipment	20,674	19,765
Construction reserve funds utilized	9,148	9,900
Construction reserve funds transferred to short-term cash	3,745
Purchase of subsidiary from joint venture	(8,445)
Investments in and advances to 50% or less owned companies	(1,208)	(11,355)
Capital distributions from equity investees		413
Principal payments on notes due from equity investees	490	22
Net cash used in investing activities	(536)	(30,821)
Cash Flows from Continuing Financing Activities:
Payments on long-term debt	(16,970)	(20,075)
Proceeds from issuance of long-term debt	1,089
Purchase of subsidiary shares from noncontrolling interests		(3,392)
Proceeds from exercise of stock options and Warrants	2	1,084
Net cash used in financing activities	(15,879)	(22,383)
Effects of Exchange Rate Changes on Cash and Cash Equivalents	(1,051)	2,018
Net Decrease in Cash, Restricted Cash and Cash Equivalents	(38,516)	(52,004)
Cash Flows from Discontinued Operations:
Operating Activities	0	1,695
Investing Activities	0	(1,107)
Effects of Exchange Rate Changes on Cash, Restricted Cash and Cash Equivalents	0	(1,046)
Net Decrease in Cash, Restricted Cash and Cash Equivalents on Discontinued Operations	0	(458)
Net Decrease in Cash, Restricted Cash and Cash Equivalents	(38,516)	(52,462)
Cash, Restricted Cash and Cash Equivalents, Beginning of Period	87,047	96,852
Cash, Restricted Cash and Cash Equivalents, End of Period	48,531	44,390
Supplemental disclosures:
Cash paid for interest, including capitalized interest	(16,080)	(17,397)
Income taxes refunded, net	456	1,999
Noncash Investing and Financing Activities:
Increase in property, plant and equipment related to an acquisition	142,282
Decrease in joint venture investments related to an acquisition	22,222
Increase in long-term debt related to an acquisition	75,569
Increase in long-term debt related to asset purchases	21,252	10,626
(Decrease) Increase in capital expenditures in accounts payable and accrued liabilities	$ (5,444)	$ 538

Basis of Presentation and Accou

Basis of Presentation and Accounting Policies	9 Months Ended
	Sep. 30, 2020
Basis Of Presentation And Accounting Policies [Abstract]
Basis of Presentation and Accounting Policies	1. The condensed consolidated financial statements include the accounts of SEACOR Marine Holdings Inc. and its consolidated subsidiaries (the “Company”). In the opinion of management, all adjustments (consisting of normal recurring adjustments) have been made to fairly present the unaudited condensed consolidated financial statements for the periods indicated. Results of operations for the interim periods presented are not necessarily indicative of operating results for the full year or any future periods. Certain information and footnote disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles in the United States have been condensed or omitted. These condensed consolidated financial statements should be read in conjunction with the Company’s financial statements and related notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019 (the “2019 Annual Report”). Unless the context otherwise indicates, any reference in this Quarterly Report on Form 10-Q to the “Company” refers to SEACOR Marine Holdings Inc. and its consolidated subsidiaries, and any reference in this Quarterly Report on Form 10-Q to “SEACOR Marine” refers to SEACOR Marine Holdings Inc. without its consolidated subsidiaries. The outbreak of the novel coronavirus (“COVID-19”) and related significant disruptions and volatility in the global economy and marketplace during the first three quarters of 2020 have caused decreases in commodity prices resulting from oversupply and demand weakness. There remains continuing uncertainty regarding the length and severity of the impact of COVID-19 on the energy industry and the outlook for the Company’s business. While the global marketplace has shown signs of stabilizing, recent rises in infection rates may lead to additional uncertainty and volatility. The decrease in oil and natural gas prices stemming from the effects COVID-19 has had on the global economy has led to a decrease in the demand for the Company’s products and services, and a prolonged period of severely depressed oil and natural gas prices compared to historic averages could have a material adverse effect on the business. Recently Adopted Accounting Standards. On June 30, 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-13, Financial Instruments-Credit Losses (Topic 326). This ASU represents a significant change in the Accounting for Credit Losses model. This ASU introduced the Current Expected Credit Losses (“CECL”) model, which requires earlier recognition of credit losses and additional disclosures related to credit risk. The CECL model utilizes a lifetime expected credit loss measurement objective for the recognition of credit losses for loans and other receivables at the time the financial asset is originated or acquired. The expected credit losses are adjusted each period for changes in expected lifetime credit losses. The CECL model replaces the multiple existing impairment models in current U.S. generally accepted accounting principles (“GAAP”), which generally require that a loss be incurred before it is recognized. The standard applies to financial assets arising from revenue transactions such as contract assets and accounts receivables and was effective for fiscal years beginning after December 15, 2019. The adoption of the standard by the Company did not have a material impact on its consolidated financial position nor on its results of operations and cash flows. On August 29, 2018, the FASB issued ASU No. 2018-15, which requires implementation costs incurred by customers in cloud computing arrangements to be deferred and recognized over the term of the arrangement, if those costs would be capitalized by the customers in a software licensing arrangement. The guidance was effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019, with early adoption permitted. The adoption of the standard by the Company did not have a material impact on its consolidated financial position nor on its results of operations and cash flows. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820). The ASU eliminates certain disclosures as to the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy. The ASU also adds disclosure requirements for Level 3 measurements. This ASU was effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years, with early adoption permitted for any eliminated or modified disclosures. The adoption of the standard by the Company did not have a material impact on the Company ’ s disclosures. Recently Issued Accounting Standards On December 18, 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. The guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. The Company does not expect that adoption of the standard will have a material impact on its consolidated financial position nor on its results of operations and cash flows. On August 5, 2020, the FASB issued ASU 2020-06, Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging – Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity, which simplifies the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts on an entity’s own equity. The guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2021. The Company has not yet determined the impact that the adoption of the standard will have on the Company’s consolidated financial position, results of operations and disclosures. On March 12, 2020, the FASB issued ASU 2020-03, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting, the ASU provides temporary optional guidance to ease the potential burden in accounting for reference rate reform. The new guidance provides optional expedients and exceptions for applying generally accepted accounting principles to contract modifications and hedging relationships, subject to meeting certain criteria, that reference LIBOR or another reference rate expected to be discontinued. The ASU is intended to help stakeholders during the global market-wide reference rate transition period. Therefore, it will be in effect for a limited time through December 31, 2022. As of September 30, 2020, the reference rates for the Company’s existing debt and interest rate swaps have not changed as a result of any such amendment. The Company will continue to monitor changes to reference rates in applicable agreements and adopt the standard as needed. Critical Accounting Policies. Basis of Consolidation. The consolidated financial statements include the accounts of SEACOR Marine and its controlled subsidiaries. Control is generally deemed to exist if the Company has greater than 50% of the voting rights of a subsidiary. All significant intercompany accounts and transactions are eliminated in the combination and consolidation. Noncontrolling interests in consolidated subsidiaries are included in the consolidated balance sheets as a separate component of equity. The Company reports consolidated net income (loss) inclusive of both the Company’s and the noncontrolling interests’ share, as well as the amounts of consolidated net income (loss) attributable to each of the Company and the noncontrolling interests. If a subsidiary is deconsolidated upon a change in control, any retained noncontrolled equity investment in the former controlled subsidiary is measured at fair value and a gain or loss is recognized in net income (loss) based on such fair value. If a subsidiary is consolidated upon the acquisition of controlling interests by the Company, any previous noncontrolled equity investment in the subsidiary is measured at fair value and a gain or loss is recognized in net income (loss) based on such fair value. The Company employs the equity method of accounting for investments in 50% or less owned companies that it does not control but has the ability to exercise significant influence over the operating and financial policies of the business venture. Significant influence is generally deemed to exist if the Company has between 20% and 50% of the voting rights of a business venture but may exist when the Company’s ownership percentage is less than 20%. In certain circumstances, the Company may have an economic interest in excess of 50% but may not control and consolidate the business venture. Conversely, the Company may have an economic interest less than 50% but may control and consolidate the business venture. The Company reports its investments in and advances to these business ventures in the accompanying consolidated balance sheets as investments, at equity, and advances to 50% or less owned companies. The Company reports its share of earnings from investments in 50% or less owned companies in the accompanying consolidated statements of net income ( loss ) as equity in earnings (losses) of 50% or less owned companies, net of tax. The Company employs the cost method of accounting for investments in 50% or less owned companies it does not control or exercise significant influence. These investments in private companies are carried at cost and are adjusted only for capital distributions and other-than-temporary declines in fair value. Certain reclassifications were made to previously reported amounts in the consolidated financial statements and notes thereto to make them consistent with the current period presentation. Use of Estimates. The preparation of financial statements in conformity with accounting principles generally accepted in the U.S. requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Such estimates include those related to deferred revenues, allowance for credit loss accounts, useful lives of property and equipment, impairments, income tax provisions and certain accrued liabilities. Actual results could differ from estimates and those differences may be material. Revenue Recognition . Revenue is recognized when (or as) the Company transfers promised goods or services to its customers in amounts that reflect the consideration to which the Company expects to be entitled to in exchange for those goods or services, which occurs when (or as) the Company satisfies its contractual obligations and transfers over control of the promised goods or services to its customers. Costs to obtain or fulfill a contract are expensed as incurred. The Company earns revenue primarily from the time charter and bareboat charter of vessels to customers. Since the Company charges customers based upon daily rates of hire, vessel revenues are recognized on a daily basis throughout the contract period. Under a time charter, the Company provides a vessel to a customer and is responsible for all operating expenses, typically excluding fuel. Under a bareboat charter, the Company provides a vessel to a customer and the customer assumes responsibility for all operating expenses and assumes all risks of operation. In the U.S. Gulf of Mexico, time charter durations and rates are typically established in the context of master service agreements that govern the terms and conditions of the charter. Contract or charter durations may range from several days to several years. Charters vary in length from short-term to multi-year periods, many with cancellation clauses and without early termination penalties. As a result of options and frequent renewals, the stated duration of charters may have little correlation with the length of time the vessel is contracted to provide services to a particular customer. The Company also contracts with various customers to carry out management services for vessels as agents for and on behalf of ship owners. These services include crew management, technical management, commercial management, insurance arrangements, sale and purchase of vessels, provisions and bunkering. As the manager of the vessels, the Company undertakes to use its best endeavors to provide the agreed management services as agents for and on behalf of the owners in accordance with sound ship management practice and to protect and promote the interest of the owners in all matters relating to the provision of services thereunder. The Company also contracts with various customers to carry out management services regarding engineering for vessel construction and vessel conversions. The vast majority of the ship management agreements span one to three years and are typically billed on a monthly basis. The Company transfers control of the service to the customer and satisfies its performance obligation over the term of the contract, and therefore recognizes revenue over the term of the contract while related costs are expensed as incurred. Revenue that does not meet these criteria is deferred until the criteria is met and such revenue is considered a contract liability and is recognized as such. Contract liabilities, which are included in other current liabilities in the accompanying consolidated balance sheets, for the nine months ended September 30, 2020 and September 30, 2019 were as follows (in thousands): 2020 2019 Balance at beginning of period $ 4,786 $ 1,327 Revenues deferred during the period 94 5,022 Revenues recognized during the period (2,805 ) (3,046 ) Balance at end of period $ 2,075 $ 3,303 As of September 30, 2020, the Company had deferred revenues of $2.1 million primarily related to $1.2 million of prepaid vessel management fees, and $0.9 million related to the time charter of offshore support vessels to customers from which collections were not reasonably assured. Cash and Cash Equivalents. The Company considers all highly liquid investments, with an original maturity of three months or less, when purchased, to be cash equivalents. Cash from current construction reserve funds (“CRF”) is also classified as cash and cash equivalents. The balance in the current CRF at September 30, 2020 was $4.2 million. Property and Equipment. Equipment, stated at cost, is depreciated using the straight-line method over the estimated useful life of the asset to an estimated salvage value. With respect to each class of asset, the estimated useful life is based upon a newly built asset being placed into service and represents the time period beyond which it is typically not justifiable for the Company to continue to operate the asset in the same or similar manner. From time to time, the Company may acquire older assets that have already exceeded the Company’s useful life policy, in which case the Company depreciates such assets based on its best estimate of remaining useful life, typically the next survey or certification date. As of September 30, 2020, the estimated useful life (in years) of each of the Company’s major categories of new equipment was as follows: Offshore Support Vessels: Crew transfer vessels 10 All other offshore support vessels (excluding crew transfer) 20 Equipment maintenance and repair costs and the costs of routine overhauls, drydockings and inspections performed on vessels and equipment are charged to operating expense as incurred. Expenditures that extend the useful life or improve the marketing and commercial characteristics of equipment as well as major renewals and improvements to other properties are capitalized. Certain interest costs incurred during the construction of equipment are capitalized as part of the assets’ carrying values and are amortized over such assets estimated useful lives. During the three and nine months ended September 30, 2020, capitalized interest totaled $0.3 million and $0.7 million, respectively. Impairment of Long-Lived Assets. The Company performs an impairment analysis of long-lived assets used in operations, including intangible assets, when indicators of impairment are present. These indicators may include a significant decrease in the market price of a long-lived asset or asset group, a significant adverse change in the extent or manner in which a long-lived asset or asset group is being used or in its physical condition, or a current period operating or cash flow loss combined with a history of operating or cash flow losses or a forecast that demonstrates continuing losses associated with the use of a long-lived asset or asset group. If the carrying values of the assets are not recoverable, as determined by their estimated future undiscounted cash flows, the estimated fair value of the assets or asset groups are compared to their current carrying values and impairment charges are recorded if the carrying value exceeds fair value. Market conditions caused by COVID-19, including the decrease in oil and natural gas prices as well as the affect the pandemic has had on SEACOR Marine’s stock price, caused a triggering event to occur requiring the Company to test its assets for impairment. For the nine months ended September 30, 2020, the Company impaired the right-to-use assets on two of its leased liftboats. Based on the current market environment, it was determined that neither of these two vessels would return to active service during their remaining lease term s . Therefore, the Company recorded an impair ment of $ 7.4 million in total for these two leased-in vessels . The Company also r ecorded a partial impairment on four liftboat s for an aggregate of $ 3.9 million based on outside valuation s of its remaining liftboat fleet. Estimated fair values for the Company’s owned vessels were established by independent appraisers based on researched market information, replacement cost information, and other data . If market conditions further decline from the depressed utilization and rates per day worked experience d over the last three years, fair values based on future appraisals could decline significantly. In addition, the Company further impaired one specialty vessel for $ 1.2 million due to a reduced sales price for the vessel. There were no other impairments of right-to-use assets or any other assets for the nine months ended September 30, 2020 . The Company’s other vessel classes and other individual vessels in active service and cold-stacked status, for which no impairment was deemed necessary, have generally experienced a less severe decline in utilization and rates per day worked based on specific market factors. The market factors include vessels with more general utility to a broad range of customers (e.g., fast support vessels (“FSVs”)), vessels required for customers to meet regulatory mandates and operating under multiple year contracts and vessels that serve customers outside of the offshore oil and natural gas market (e.g., crew transfer vessels (“CTVs”)). For vessel classes and individual vessels with indicators of impairment as of September 30, 2020, the Company has estimated that their future undiscounted cash flows exceed their current carrying values. The Company’s estimates of future undiscounted cash flows are highly subjective as utilization and rates per day worked are uncertain, especially in light of the affect COVID-19 has had on the timing of an estimated market recovery in the offshore oil and natural gas markets and the timing and cost of reactivating cold-stacked vessels. If market conditions decline further, changes in the Company’s expectations on future cash flows may result in recognizing additional impairment charges related to its long-lived assets in future periods. Impairment of 50% Investments in 50% or less owned companies are reviewed periodically to assess whether there is an other-than-temporary decline in the carrying value of the investment. In its evaluation, the Company considers, among other items, recent and expected financial performance and returns, impairments recorded by the investee and the capital structure of the investee. When the Company determines the estimated fair value of an investment is below carrying value and the decline is other-than-temporary, the investment is written down to its estimated fair value. Actual results may vary from the Company’s estimates due to the uncertainty regarding projected financial performance, the severity and expected duration of declines in value and the available liquidity in the capital markets to support the continuing operations of the investee, among other factors. Although the Company believes its assumptions and estimates are reasonable, the investee’s actual performance compared with the estimates could produce different results and lead to additional impairment charges in future periods. During the nine months ended September 30, 2020 and 2019, the Company did not recognize any impairment charges related to its 50% or less owned companies. Income Taxes. During the nine months ended September 30, 2020, the Company’s effective income tax rate of 35.2% was primarily due to taxes on income attributable to noncontrolling interests, foreign sourced income not subject to U.S. income taxes, foreign taxes not creditable against U.S. income taxes, and an adjustment for the acquisition of the remaining minority membership interest in Falcon Global Holdings LLC (“Falcon Global Holdings”) (see “Note 10. Stockholder’s Equity”). Accumulated Other Comprehensive Income (Loss). The components of accumulated other comprehensive loss were as follows (in thousands): SEACOR Marine Holdings Inc. Stockholders’ Equity Noncontrolling Interests Foreign Currency Translation Adjustments Derivative Losses on Cash Flow Hedges, net Total Foreign Currency Translation Adjustments Derivative Income (Losses) on Cash Flow Hedges, net Other Comprehensive Loss December 31, 2019 $ 4,685 $ (3,137 ) $ 1,548 $ (1,445 ) $ (11 ) $ 6,716 Other comprehensive loss (385 ) (1,543 ) (1,928 ) — — $ (1,928 ) Balance as of September 30, 2020 $ 4,300 $ (4,680 ) $ (380 ) $ (1,445 ) $ (11 ) $ 4,788 Loss Per Share. Basic loss per common share of the Company is computed based on the weighted average number of common shares and warrants to purchase common shares at an exercise price of $0.01 per share (“Warrants”) issued and outstanding during the relevant periods. The Warrants are included in the basic loss per common share because the shares issuable upon exercise of the Warrants are issuable for de minimis cash consideration and therefore not anti-dilutive. Diluted loss per common share of the Company is computed based on the weighted average number of common shares and Warrants issued and outstanding plus the effect of other potentially dilutive securities through the application of the treasury stock method and the if-converted method that assumes all common shares have been issued and outstanding during the relevant periods pursuant to the conversion of the Convertible Senior Notes unless anti-dilutive. For both the nine months ended September 30, 2020 and 2019, diluted earnings per common share of the Company excluded 2,183,708 common shares, respectively, issuable pursuant to the Company’s Convertible Senior Notes (see “Note 5. Long-Term Debt”) as the effect of their inclusion in the computation would be anti-dilutive. In addition, for the nine months ended September 30, 2020 and 2019, diluted loss per common share of the Company excluded 469,964 and 282,050 shares of restricted stock, respectively, and 1,120,541 and 397,119 shares of stock, respectively, issuable upon exercise of outstanding stock options as the effect of their inclusion in the computation would be anti-dilutive.

Transformation, Facility Restru

Transformation, Facility Restructuring and Severance Charges	9 Months Ended
	Sep. 30, 2020
Restructuring And Related Activities [Abstract]
Transformation, Facility Restructuring and Severance Charges	2. Due to the highly competitive nature of the Company’s business and the continuing losses incurred over the last few years, the Company continues to reduce its overall cost structure and workforce to better align with current activity levels. The transformation plan, which began in the third quarter of 2019 and extended through the third quarter of 2020 (the “Transformation Plan”), included a workforce reduction, organization restructuring, facility consolidations and other cost reduction measures and efficiency initiatives across the Company’s geographic regions. The Transformation Plan was initiated due to activity levels of oil and gas exploration and production, and the Company continues to evaluate additional opportunities for further cost reductions to adapt to changing conditions caused by COVID-19. In connection with the Transformation Plan, the Company recognized restructuring and transformation charges of $1.2 million for the nine months ended September 30, 2020, which include severance charges of $1.1 The components of restructuring charges by segment for the three and nine months ended September 30, 2020 were as follows (in thousands): United States (primarily Gulf of Mexico) Africa (primarily West Africa) Middle East and Asia Latin America Europe (primarily North Sea) Total For the Three Months Ended September 30, 2020 Transformation Plan Severance Charges $ 1 $ — $ 346 $ — $ — $ 347 Other Charges (96 ) — — — — (96 ) Total Charges $ (95 ) $ — $ 346 $ — $ — $ 251 United States (primarily Gulf of Mexico) Africa (primarily West Africa) Middle East and Asia Latin America Europe (primarily North Sea) Total For the Nine Months Ended September 30, 2020 Transformation Plan Severance Charges $ 275 $ — $ 665 $ — $ 185 $ 1,125 Other Charges 31 — 31 — — 62 Total Charges $ 306 $ — $ 696 $ — $ 185 $ 1,187 The severance and other restructuring charges gave rise to certain liabilities primarily related to liabilities accrued as part of the Transformation Plan. For the nine months ended September 30, 2020, all related liabilities associated with the Transformation Plan have been recognized. The Transformation Plan was completed during the third of quarter of 2020. No material future costs related to these efforts are expected, but to the extent the Company identifies additional opportunities for further costs reductions beyond the Transformation Plan, these opportunities may give rise to restructuring charges. On a cumulative basis, the Company recognized $4.9 million in restructuring charges.

Seacosco Acquisition

Seacosco Acquisition	9 Months Ended
	Sep. 30, 2020
Business Combinations [Abstract]
Seacosco Acquisition	3 . On May 31, 2020, SEACOR Offshore Asia LLC (“SEACOR Offshore Asia”), an indirect wholly-owned subsidiary of SEACOR Marine, entered into a Sale and Purchase Agreement (“SEACOSCO SPA”) with China Shipping Fan Tai Limited, a company incorporated under the laws of the British Virgin Islands, and China Shipping Industry (Hong Kong) Co., Limited, a company incorporated under the laws of the Hong Kong Special Administrative Region (together, the “SEACOSCO Sellers”), pursuant to which SEACOR Offshore Asia agreed to acquire the 50% membership interest in SEACOSCO Offshore LLC (such remaining interest, the “SEACOSCO Interests”) held by the SEACOSCO Sellers that the Company did not already own. On June 30, 2020, SEACOR Offshore Asia completed the acquisition of the SEACOSCO Interests from the SEACOSCO Sellers (the “SEACOSCO Acquisition”). As a result of the completion of the acquisition, the Company owns 100% of the membership interests in SEACOSCO Offshore LLC. On July 14, 2020, the name of SEACOSCO Offshore LLC was changed to SEACOR Offshore Delta LLC (“SEACOR Offshore Delta”). The price payable by SEACOR Offshore Asia for the membership interests was $28.2 million (the “SEACOSCO Purchase Price”), $8.4 million of which was paid to the Sellers at the closing of the transaction, with annual installment payments of $1.0 million, $2.5 million and $2.5 million payable in the first, second and third year after the signing date (the “SEACOSCO SPA Signing Date”), respectively, and the remaining $13.7 million due four years after such signing date. The deferred portion of the SEACOSCO Purchase Price accrues interest at a fixed rate of 1.5%, 7.0%, 7.5% and 8.0% for the first through fourth years after the SEACOSCO SPA Signing Date, respectively. SEACOR Offshore Delta is the owner of eight platform supply vessels (“PSVs”) built by COSCO Shipping Heavy Industry (Guangdong) Co., Ltd. (the “COSCO (Guangdong) Shipyard” and such PSVs, the “SEACOR Delta PSVs”) . The SEACOSCO Sellers obtained a second lien mortgage on the SEACOR Delta PSVs to secure the payment of the deferred portion of the SEACOSCO Purchase Price, and SEACOR Marine provided a limited deficiency guarantee solely with respect to the short-fall in vessel collateral value, if any, in the event the SEACOSCO Sellers exercise their remedies under the mortgages. The SEACOR Delta PSVs were initially acquired by vessel owning subsidiaries (“SEACOR Delta SPVs”) of SEACOR Offshore Delta pursuant to existing deferred purchase agreements with the COSCO (Guangdong) Shipyard (“Guangdong DPAs”) under which an aggregate of approximately $100.8 million was outstanding as of June 30, 2020 (the “SEACOR Delta Shipyard Financing”). As of September 30, 2020, $97.2 million was outstanding. The Guangdong DPAs provide for amortization of the purchase price for each vessel over a period of 10 years from delivery bearing floating interest rate of three-month LIBOR plus 4.0%. SEACOR Offshore Delta has taken delivery of all eight SEACOR Delta PSVs, seven with a 2018 or 2019 year of build, and one with a 2020 year of build. The payment obligations of the SEACOR Delta SPVs under the Guangdong DPAs for each vessel is secured by a first lien mortgage on the vessel and a pledge of the SEACOR Delta SPV’s equity, and SEACOR Marine provided a limited deficiency guarantee solely with respect to the short-fall in vessel collateral value, if any, in the event the COSCO (Guangdong) Shipyard exercises its remedies under the mortgages. Purchase Price Allocation. The eight SEACOR Delta PSVs are all based on plans from the same designer, have a similar age of construction (2018-2020) and were constructed at the same shipyard. Two of the vessels are high specification diesel/electric powered PSVs. The other six vessels are all “sister” vessels with identical specifications. These six vessels are high specification diesel/electric/hybrid powered vessels. In accordance with ASU No. 2017-01-Business Combinations (Topic 805): Clarifying the Definition of a Business, due to the fact that the assets acquired have substantially all of their fair value concentrated as a group of similar assets, this acquisition qualified as an asset purchase. The allocation of the purchase price for the Company’s acquired assets for the six months ended June 30 was as follows (in thousands): Assets Acquired (In Thousands): June 30, 2020 Current Assets 7,700 Fixed Assets 142,282 Current Liabilities (23,929 ) Book Value of Debt Acquired (100,759 ) Discount on Debt Acquired 25,190 Fair Value of Debt Acquired (75,569 ) Total Cost Basis for Purchase 50,484 Purchase Price $ (28,150 ) Acquisition costs (112 ) Equity Investment In SEACOR Offshore Delta (f/k/a SEACOSCO) (22,222 ) (50,484 )

Equipment Acquisitions and Disp

Equipment Acquisitions and Dispositions	9 Months Ended
	Sep. 30, 2020
Property Plant And Equipment [Abstract]
Equipment Acquisitions and Dispositions	4. During the nine months ended September 30, 2020, capital acquisitions were $ 24.9 three During the nine months ended September 30, 2020, the Company sold two one As part of the completion of the SEACOSCO Acquisition, seven SEACOR Delta PSVs, which were previously included in the Company’s joint ventured fleet, and one SEACOR Delta PSV under construction (which has subsequently been delivered), were acquired (See “Note 3. SEACOSCO Acquisition”).

Long Term Debt

Long Term Debt	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Long Term Debt	5 . The Company’s long-term debt obligations as of September 30, 2020 and December 31, 2019 were as follows (in thousands): September 30, 2020 December 31, 2019 Recourse Long-term debt (1) Convertible Senior Notes $ 125,000 $ 125,000 SEACOR Marine Foreign Holdings Credit Facility 104,000 113,750 Sea-Cat Crewzer III Term Loan Facility 21,653 24,128 SEACOR Offshore Delta (f/k/a SEACOSCO) Acquisition Debt 19,705 — SEACOR Delta (f/k/a SEACOSCO) Shipyard Financing (2) 97,189 — SEACOR Alpine Shipyard Financing (3) 31,410 10,534 SEACOR 88/888 Term Loan 5,500 5,500 BNDES Equipment Construction Finance Notes 2,682 3,332 Total recourse Long-term debt 407,139 282,244 Non-recourse Long-term debt (4) Falcon Global USA Term Loan Facility 102,350 102,349 Falcon Global USA Revolver 15,000 15,000 Windcat Workboats Facilities 26,478 24,730 SEACOR 88/888 Term Loan 5,500 5,500 Total non-recourse Long-term debt 149,328 147,579 Total principal due for long-term debt 556,467 429,823 Current portion due within one year (52,107 ) (17,802 ) Unamortized debt discount (46,778 ) (26,343 ) Deferred financing costs (4,617 ) (5,427 ) Long-term debt, less current portion $ 452,965 $ 380,251 (1) Recourse debt represents debt issued by SEACOR Marine and/or its subsidiaries and guaranteed by SEACOR Marine as defined in the relevant debt agreements. (2) SEACOR Delta Shipyard Financing includes vessel financing on the eight vessels acquired in the SEACOSCO Acquisition (see “Note 3. SEACOSCO Acquisition”). (3) SEACOR Alpine Shipyard Financing includes vessel financing on the SEACOR Alps, the SEACOR Andes and the SEACOR Atlas vessels. (4) Non-recourse debt represents debt issued by the Company’s Consolidated Subsidiaries with no recourse to SEACOR Marine or its other non-debtor subsidiaries, other than certain limited support obligations as defined in the respective debt agreements, which in aggregate are not considered to be material to the Company’s business and financial condition. As of September 30, 2020, the Company was in compliance with all debt covenants except for a covenant included in the Sea-Cat Crewzer III Term Loan Facility, which is guaranteed by SEACOR Marine. Under the facility, SEACOR Marine is required to maintain a net financial debt to equity ratio of 70%. As of September 30, 2020, SEACOR Marine’s net financial debt to equity ratio was 101%. The Company and the lenders under this facility are in discussions to waive or otherwise modify the terms of this covenant. Sea-Cat Crewzer III LLC, an indirect wholly-owned subsidiary of SEACOR Marine and the borrower under the Sea-Cat Crewzer III Term Loan Facility, is otherwise in compliance with all financial covenants and payment obligations under this facility, as is SEACOR Marine. The aforementioned non-compliance does not cause any cross defaults under the Company’s other credit facilities or the immediate acceleration of the Sea-Cat Crewzer III Term Loan Facility. Until a waiver or modification of the terms of this guarantor covenant is received from the lenders under this facility, the Company has classified the balance of this debt as current. Falcon Global. On February 7, 2020, SEACOR Marine, Falcon Global USA LLC, an indirect wholly-owned subsidiary of SEACOR Marine (“FGUSA”), and certain subsidiaries of FGUSA, entered into a consent, agreement and an omnibus amendment (the “FGUSA Omnibus Amendment”) to that certain (i) $131.1 million term and revolving loan facility, dated as of February 8, 2018, with a syndicate of lenders administered by JP Morgan Chase Bank, N.A. (the “FGUSA Credit Facility”) and (ii) obligation guaranty issued by SEACOR Marine, dated February 8, 2018, pursuant to which SEACOR Marine guarantees certain limited obligations of FGUSA under the FGUSA Credit Facility (the “FGUSA Guaranty”). The FGUSA Omnibus Amendment provides for, among other things, (i) the extension from March 2020 to March 2021 of the commencement of monthly amortization of the term loan, with payments being the lesser of (a) $0.8 million per month and (b) the amount outstanding under the term loan and (ii) the extension of the term of the FGUSA Guaranty for an additional one year from February 8, 2020 to February 8, 2021. On April 29, 2020, FGUSA and certain subsidiaries of FGUSA, entered into a sixth consent and agreement (the “ FGUSA Sixth Consent and Agreement”) to the FGUSA Credit Facility, which provides that, among other things, (i) the deadline for delivery of the audited financial statements of FGUSA and its consolidated subsidiaries for the fiscal year ended December 31, 2019 (“FGUSA 2019 Audited Financial Statements”) was extended from April 29, 2020 to May 31, 2020, (ii) the FGUSA 2019 Audited Financial Statements are not required to be delivered without a “going concern” or like qualification, commentary or exception, and (iii) the deadline for delivery of certain physical vessel appraisals was extended to December 31, 2020. SEACOR Alpine. In 2019, the Company committed to take possession of three Rolls Royce UT1771 CDL designed diesel electric powered PSVs of 3,800 tons delivered deadweight capacity with dynamic position class 2 and firefighting class 1 notations. As part of this transaction, the shipbuilder, COSCO Shipping Heavy Industry (Zhoushan) Co. Ltd., agreed to finance 70% of the cost of each of these vessels pursuant to a deferred payment agreement. The deferred payment agreement calls for increasing quarterly payments of principal and interest payments that bear interest at an annual rate of 5% over a four-year Windcat Workboats. On March 3, 2020, Windcat Workboats Holdings Ltd, an indirect wholly-owned subsidiary of SEACOR Marine (“Windcat Workboats”), together with certain other obligors that are its subsidiaries entered into an agreement (the “RCF Amendment”) with Coöperatieve Rabobank U.A. to amend the €25 million revolving credit facility agreement, originally dated as of May 24, 2016, as amended and restated from time to time. Amended provisions included, among other things, the extension of the maturity date from December 31, 2021 to December 31, 2022. Applicable fees in the amount of €0.1 million were paid in conjunction with the RCF Amendment and will be amortized over the credit facility term. During the nine months ended September 30, 2020, the Company borrowed an additional €1.0 million under the Windcat Workboats credit facilities, resulting in a net increase in USD borrowings of $1.1 million. As of September 30, 2020, the Company has $1.5 million available under its Windcat Workboats credit facilities. SEACOR Delta (f/k/a SEACOSCO). On June 30, 2020, the Company completed the acquisition of the SEACOSCO Interests that it did not already own. The deferred portion of the SEACOSCO Purchase Price is payable in annual installment payments of $1.0 million, $2.5 million and $2.5 million in the first, second and third year after the SEACOSCO SPA Signing Date, respectively, with the remaining $13.7 million due four years after such date. The deferred portion of the SEACOSCO Purchase Price accrues interest at a fixed rate of 1.5%, 7.0%, 7.5% and 8.0% for the first through fourth years after the signing date, respectively. The Guangdong DPAs comprising the SEACOR Delta Shipyard Financing provide for amortization of the purchase price for each vessel over a period of 10 years from delivery with the unpaid amount bearing floating interest rate of three-month LIBOR plus 4.0% (see “Note 3. SEACOSCO Acquisition”). SEACOR Marine Foreign Holdings. On June 29, 2020, SEACOR Marine, SEACOR Marine Foreign Holdings Inc., a wholly owned subsidiary of SEACOR Marine (“SMFH”), and certain vessel-owning subsidiaries of SEACOR Marine, entered into Amendment No. 3 (the “SMFH Amendment”) to the $130 million loan facility with a syndicate of lenders administered by DNB Bank ASA, New York Branch, dated as of September 26, 2018 and as amended on August 6, 2019, November 26, 2019 and December 13, 2019 (the “SMFH Credit Facility”). The SMFH Amendment provides for, among other things, (i) the modification of certain financial maintenance and restrictive covenants contained in the Credit Facility or the guaranty provided by SEACOR Marine with respect thereto, including with respect to EBITDA coverage ratios, mandatory prepayment events, and the exclusion of certain indebtedness associated with the acquisition of the SEACOSCO Interests, and (ii) the placement of mortgages on two additional vessels owned by vessel-owning subsidiaries of SEACOR Marine as security for the indebtedness under the SMFH Credit Facility. BNDES. In October 2019, Oceanpact purchased from the Company the two vessels securing the BNDES Equipment Construction Finance Notes, but the transfer of title of the vessels from the Company to Oceanpact was subject to the assignment of the BNDES Equipment Construction Finance Notes to Oceanpact. On June 9, 2020, Banco Nacional de Desenvolvimento Economico e Social (“BNDES”), a Brazilian government-owned entity, provided a suspension for a period of six months, from May 11, 2020 to October 10, 2020, on the payment of principal and compensatory interest under the BNDES Equipment Construction Finance Notes, without changing the final term of the debt amortization period nor the interest rate thereunder. Collection on the receivable balance from Oceanpact was also deferred. Oceanpact continued to work with BNDES to follow through with the assignment of the loan or accept another form of guarantee provided by Oceanpact in order to obtain a debt release from BNDES. On October15, 2020, the Company’s outstanding debt balance to BNDES was paid in full and the receivable from OceanPact was paid in full. In addition, on October 23, 2020, the Company received a notification that the guarantor letter of credit had been released. The Company has no further obligations under the BNDES Equipment Construction Finance Notes. Letters of Credit . As of September 30, 2020, the Company had outstanding letters of credit of $0.5 million securing lease obligations, labor and performance guaranties.

Leases

Leases	9 Months Ended
	Sep. 30, 2020
Leases [Abstract]
Leases	6 . LEASES As of September 30, 2020, the Company leased in two AHTS vessels, two liftboats, one FSV and certain facilities and other equipment. The leases typically contain purchase and renewal options or rights of first refusal with respect to the sale or lease of the equipment. As of September 30, 2020, the remaining lease terms of the vessels have remaining durations ranging from two to 15 months. The lease terms of the other equipment range in duration from six to 315 months. As of September 30, 2020, future minimum payments for leases for the remainder of 2020 and the years ended December 31 were as follows (in thousands): Operating Leases Finance Leases Remainder of 2020 $ 3,718 $ 3 2021 7,955 39 2022 714 39 2023 727 39 2024 793 36 Years subsequent to 2024 4,982 — 18,889 156 Interest component (3,563 ) (16 ) 15,326 140 Current portion of long-term lease liabilities 9,632 27 Long-term lease liabilities $ 5,694 $ 113 For the three and nine months ended September 30, 2020 the components of lease expense were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Operating lease cost (1) $ 1,083 $ 3,446 $ 5,460 $ 10,669 Finance lease cost: Amortization of finance lease assets (1) 3 — 3 — Short-term lease costs (1) 307 725 692 1,967 $ 1,393 $ 4,171 $ 6,155 $ 12,636 (1) Included in selling, general and administrative expenses in the consolidated statements of income For the nine months ended September 30, 2020, supplemental cash flow information related to leases were as follows (in thousands): 2020 Operating cash flows from operating leases $ 11,252 Right-of-use assets obtained for operating lease liabilities 1,483 Right-of-use assets obtained for finance lease liabilities $ 140 For the nine months ended September 30, 2020, other information related to leases were as follows: 2020 Weighted average remaining lease term, in years - operating leases 6.1 Weighted average remaining lease term, in years - finance leases 4.2 Weighted average discount rate - operating leases 4.4 % Weighted average discount rate - finance leases 5.3 %

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	7 . The following table reconciles the difference between the statutory federal income tax rate for the Company and the effective income tax rate on continuing operations for the nine months ended September 30, 2020: Statutory rate 21.0 % Foreign taxes not creditable against U.S. income tax (4.3 ) Falcon Global Acquisition 4.5 Noncontrolling interests (1.3 ) CARES Act NOL Carryback 16.4 Other (1.1 ) 35.2 % On June 26, 2020, the Company entered into a Tax Refund and Indemnification Agreement (the “Tax Refund Agreement”) with SEACOR Holdings Inc. (“SEACOR Holdings”), the Company’s former parent company. The Tax Refund Agreement will enable the Company to utilize net operating losses (“NOLs”) generated in 2018 and 2019 to claim refunds for tax years prior to the Company’s spin-off from SEACOR Holdings in 2017 (at which time the Company was included in SEACOR Holdings consolidated tax returns) that are now permitted to be carried back pursuant to the provisions of the Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) and for which SEACOR Holdings needs to claim the refund on behalf of the Company. As a result, the Company expects to receive cash tax refunds of approximately $31.2 million within the next 12 months, subject to the refund schedule of the Internal Revenue Service. The Internal Revenue Service has been recently experiencing delays in processing refund claims due in part to the COVID-19 pandemic. SEACOR Holdings will retain certain of the funds to facilitate tax savings realized by SEACOR Holdings of no less than 35% of the amount of its own 2019 NOLs. Additionally, a $3.0 million transaction fee was paid to SEACOR Holdings concurrently with the signing of the agreement as consideration for its cooperation in connection with the filing of the applicable tax refund returns. As of September 30, 2020, the Tax Refund Agreement does not restrict the use of approximately $19.7 million of the refund, with the remaining approximately $11.5 million required to be deposited into an account to be used solely to satisfy certain of the Company’s obligations that remain guaranteed by SEACOR Holdings. These obligations primarily relate to vessel operating leases of approximately $10.4 million as of September 30, 2020. Two of these vessel operating leases expire in the fourth quarter of 2020, with the remaining three vessel operating leases that SEACOR Holdings guarantees expiring in 2021. During the third quarter the Company received a $1.6 million tax refund that had been withheld by the State of Qatar from vessel revenues between 2010 and 2016. Of this amount, approximately $0.3 million will be claimed as foreign tax credits by SEACOR Holdings on its U.S. tax return prior to the spin-off of SEACOR Marine in 2017. Subject to final resolution of taxes with the State of Qatar, these amounts are expected to be remitted to SEACOR Holdings Inc. The remaining amount relates to foreign taxes that were considered in computing earnings and profits and available foreign taxes of foreign subsidiaries of the Company and will require the Company to recompute its 2017 tax liability under IRC Section 965. The additional U . S . tax liability of the Company under Section 965 due to these refunds is expected to be approximately $ 0.4 million.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Strategies	9 Months Ended
	Sep. 30, 2020
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Strategies	8 . Derivative instruments are classified as either assets or liabilities based on their individual fair values. The fair values of the Company’s derivative instruments were as follows (in thousands): September 30, 2020 December 31, 2019 Derivative Asset Derivative Liability Derivative Asset Derivative Liability Derivatives designated as hedging instruments: Interest rate swap agreements (cash flow hedges) $ — $ 4,103 $ — $ 3,009 — 4,103 — 3,009 Derivatives not designated as hedging instruments: Conversion option liability on Convertible Senior Notes — 1 — 5,205 $ — $ 4,104 $ — $ 8,214 Cash Flow Hedges. The Company and certain of its 50% or less owned companies have interest rate swap agreements designated as cash flow hedges. By entering into these interest rate swap agreements, the Company and its 50% or less owned companies have converted the variable LIBOR or EURIBOR component of certain of their outstanding borrowings to a fixed interest rate. The Company recognized losses on derivative instruments designated as cash flow hedges of $1.1 million for the nine months ended September 30, 2020, and losses of $1.9 million for the nine months ended September 30, 2019 as a component of other comprehensive loss. As of September 30, 2020, the interest rate swaps held by the Company and certain of the Company’s 50% or less owned companies were as follows • Windcat Workboats had two interest rate swap agreements maturing in 2021 that call for the Company to pay a fixed rate of interest of (0.03%) plus a margin on the aggregate notional value of €15.0 million (approximately $17.6 million) and receive a variable interest rate based on EURIBOR on the aggregate notional value; • SMFH had an interest rate swap agreement maturing in 2023 that calls for SMFH to pay a fixed rate of interest of 3.32% per annum on the amortized notional value of $8.0 million and receive a variable interest rate based on LIBOR on the amortized notional value; • SMFH had an interest rate swap agreement maturing in 2023 that calls for SMFH to pay a fixed rate of interest of 3.195% per annum on the amortized notional value of $44.4 million and receive a variable interest rate based on LIBOR on the amortized notional value; • SEACOR 88 LLC and SEACOR 888 LLC, both indirect wholly-owned subsidiaries of SEACOR Marine (collectively, “SEACOR 88/888”), have an interest rate swap agreement maturing in 2023 that calls for SEACOR 88/888 to pay a fixed rate of interest of 3.175% per annum on the amortized notional value of $5.5 million and receive a variable interest rate based on LIBOR on the amortized notional value; and • Mantenimiento Express Maritimo, S.A.P.I. de C.V. (“MexMar”), in which the Company has a 49% noncontrolling interest, has five interest rate swap agreements with maturities in 2023 that call for MexMar to pay fixed rates of interest ranging from 1.71% to 2.10% per annum on the aggregate amortized notional value of $72.8 million and receive a variable interest rate based on LIBOR on the aggregate amortized notional value. Other Derivative Instruments. The Company recognized gains (losses) on derivative instruments not designated as hedging instruments for the three and nine months ended September 3 0 , as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Conversion option liability on Convertible Senior Notes $ 5 $ 3,057 $ 5,204 $ 734 $ 5 $ 3,057 $ 5,204 $ 734 The conversion option liability relates to the bifurcated embedded conversion option in the Convertible Senior Notes issued to investment funds managed and controlled by The Carlyle Group (see “Note 9. Fair Value Measurements”).

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	9 . The fair value of an asset or liability is the price that would be received to sell an asset or transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The Company utilizes a fair value hierarchy that maximizes the use of observable inputs and minimizes the use of unobservable inputs when measuring fair value and defines three levels of inputs that may be used to measure fair value. Level Level Level Level The Company’s financial assets and liabilities as of September 30, 2020 and December 31, 2019 that are measured at fair value on a recurring basis were as follows (in thousands): September 30, 2020 Level 1 Level 2 Level 3 LIABILITIES Derivative instruments — 4,103 — Conversion Option Liability on Convertible Senior Notes — — 1 December 31, 2019 ASSETS Construction reserve funds $ 12,893 $ — $ — LIABILITIES Derivative instruments — 3,009 — Conversion Option Liability on Convertible Senior Notes — — 5,205 Level 3 . The fair value of the conversion option liability embedded in the Convertible Senior Notes is estimated with significant inputs that are both observable and unobservable in the market and therefore is considered a Level 3 fair value measurement. The Company used a binomial lattice model that assumes the holders will maximize their value by finding the optimal decision between redeeming at the redemption price or converting into shares of Common Stock. This model estimates the fair value of the conversion option as the differential in the fair value of the notes including the conversion option compared with the fair value of the notes excluding the conversion option. The significant observable inputs used in the fair value measurement include the price of Common Stock and the risk-free interest rate. The significant unobservable inputs are the estimated Company credit spread and Common Stock volatility, which were based on comparable companies in the transportation and energy industries. The estimated fair values of the Company’s other financial assets and liabilities as of September 30, 2020 and December 31, 2019 were as follows (in thousands): Estimated Fair Value September 30, 2020 Carrying Amount Level 1 Level 2 Level 3 ASSETS Cash, cash equivalents and restricted cash $ 48,531 $ 48,531 $ — $ — Investments, at cost, in 50% or less owned companies (included in other assets) 132 see below LIABILITIES Long-term debt, including current portion 505,072 — 477,430 — December 31, 2019 ASSETS Cash, cash equivalents and restricted cash $ 87,047 $ 87,047 $ — $ — Investments, at cost, in 50% or less owned companies (included in other assets) 132 see below LIABILITIES Long-term debt, including current portion 398,053 — 380,815 — The carrying value of cash, cash equivalents and restricted cash approximates fair value. The fair value of the Company’s long-term debt was estimated based upon quoted market prices or by using discounted cash flow analysis based on estimated current rates for similar types of arrangements. It was not practicable to estimate the fair value of certain of the Company’s investments, at cost, in 50% or less owned companies because of the lack of quoted market prices and the inability to estimate fair value without incurring excessive costs. Considerable judgment was required in developing certain of the estimates of fair value including the consideration of the recent COVID-19 pandemic that has caused significant volatility in U.S. and international markets, and, accordingly, the estimates presented herein are not necessarily indicative of the amounts that the Company could realize in a current market exchange. The Company’s other assets and liabilities that were measured at fair value during the nine months ended September 30, 2020 and the year ended December 31, 2019 were as follows (in thousands): September 30, 2020 Level 1 Level 2 Level 3 ASSETS Property and equipment: Liftboats $ — $ 36,602 $ — December 31, 2019 ASSETS Property and equipment: AHTS $ — $ 520 $ — FSVs — 1,858 — Property and equipment . During the three months ended September 30, 2020, the Company recognized no impairment charges and during the nine months ended September 30, 2020 the Company recognized impairment charges of $12.5 million, associated with liftboat and specialty vessel impairments. During the three months ended September 30, 2020 the Company sold its only remaining specialty vessel. The Level 2 fair values were determined based on ordinary liquidation value and indicative sales price.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Stockholders' Equity	1 0 . On March 20, 2020, SEACOR LB Holdings LLC, an indirect wholly-owned subsidiary of SEACOR Marine (“SEACOR LB Holdings”), entered into a membership interest purchase agreement with SEACOR Marine, Montco Offshore, LLC (“Montco”) and Lee Orgeron, the principal of Montco, pursuant to which SEACOR LB Holdings purchased the 28% minority equity interest in Falcon Global Holdings held by Montco in exchange for 900,000 shares of SEACOR Marine Common Stock issued to Montco as consideration in a private placement. The purchase resulted in the Company owning 100% of Falcon Global Holdings. The Company has previously registered 2,174,000 shares of Common Stock (“Common Shares”) for issuance under the SEACOR Marine Holdings Inc. 2017 Equity Incentive Plan (the “2017 Equity Incentive Plan”). The Company’s shareholders approved the SEACOR Marine Holdings Inc. 2020 Equity Incentive Plan (the “2020 Equity Incentive Plan”) at the annual meeting of shareholders held on June 9, 2020 (the “Approval Date”), which authorized the issuance of 2,080,000 Common Shares under the 2020 Equity Incentive Plan. On June 9, 2020 the Company filed a registration statement on Form S-8 with the Securities and Exchange Commission (“SEC”) with respect to the registration of 2,114,821 Common Shares, representing the 2,080,000 Common Shares approved by the Company’s shareholders for issuance under the 2020 Equity Incentive Plan, plus 24,821 Common Shares remaining available for issuance under the 2017 Equity Incentive Plan as of the Approval Date that will be available for issuance under the 2020 Equity Incentive Plan, plus Common Shares subject to awards outstanding under the 2017 Equity Incentive Plan, that pursuant to the terms of the 2017 Equity Incentive Plan and the 2020 Equity Incentive Plan, may be available for future issuance under the 2020 Equity Incentive Plan. On September 1, 2020 and September 18, 2020, 255,307 and 83,367 Warrants were exercised, respectfully, for a penny per share resulting in 1,488,292 Warrants outstanding at September 30, 2020. In connection with the exercise of Warrants on September 18, 2020, 354 Common Shares were withheld as payment for the exercise price of the exercised Warrants.

Noncontrolling Interests in Sub

Noncontrolling Interests in Subsidiaries	9 Months Ended
	Sep. 30, 2020
Noncontrolling Interest [Abstract]
Noncontrolling Interests in Subsidiaries	1 1 . Noncontrolling interests in the Company’s consolidated subsidiaries were as follows (in thousands): Noncontrolling Interests September 30, 2020 December 31, 2019 Falcon Global Holdings 0% (1) — $ 21,119 Other 1.8-3.0% 350 313 $ 350 $ 21,432 (1) Before March 20, 2020, noncontrolling interest was 28%. Falcon Global Holdings. Prior to March 20, 2020, the Company held 72% of the equity interest in Falcon Global Holdings. On March 20, 2020, the Company completed the acquisition of the remaining 28% minority interest in Falcon Global Holdings, resulting in the Company’s 100% ownership of Falcon Global Holdings. Consideration paid by the Company was 900,000 shares of Common Stock issued in a private placement to the seller of the minority interest, Montco. Prior to the acquisition of the remaining noncontrolling interest in Falcon Global Holdings the net loss attributable to Falcon Global was $16.6 million, of which $4.6 million was attributable to noncontrolling interest.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	1 2 . COMMITMENTS AND CONTINGENCIES As of September 30, 2020, the Company’s unfunded capital commitments were $13.1 million for two PSVs, one CTV and miscellaneous vessel equipment. Of the amount of unfunded capital commitments, $1.5 million is payable during the remainder of 2020 and $11.6 million is payable during 2021. The Company has indefinitely deferred an additional $9.6 million of orders with respect to one FSV that the Company had previously reported unfunded capital commitments. In December 2015, the Brazilian Federal Revenue Office issued a tax-deficiency notice to Seabulk Offshore do Brasil Ltda, an indirect wholly-owned subsidiary of SEACOR Marine (“Seabulk Offshore do Brasil”), with respect to certain profit participation contributions (also known as “PIS”) and social security financing contributions (also known as “COFINS”) requirements alleged to be due from Seabulk Offshore do Brasil (“Deficiency Notice”) in respect of the period of January 2011 until December 2012. In January 2016, the Company administratively appealed the Deficiency Notice on the basis that, among other arguments, (i) such contributions were not applicable in the circumstances of a 70%/30% cost allocation structure, and (ii) the tax inspector had incorrectly determined that values received from outside of Brazil could not be classified as expense refunds. The initial appeal was dismissed by the Brazilian Federal Revenue Office and the Company appealed such dismissal and is currently awaiting an administrative trial. Recently, a local Brazilian law was enacted that supports the Company’s position that such contribution requirements are not applicable, but it is uncertain whether such law will be taken into consideration with respect to administrative proceedings commenced prior to the enactment of the law. Accordingly, the success of Seabulk Offshore do Brasil in the administrative proceedings cannot be assured and the matter may need to be addressed through judicial court proceedings. The potential levy arising from the Deficiency Notice is R$18.05 million based on a historical potential levy of R$12.87 million (USD $3.2 million and USD $2.3 million, respectively, based on the exchange rate as of September 30, 2020). As of September 30, 2020, SEACOR Holdings has guaranteed $10.4 million on behalf of the Company for performance obligations under sale-leaseback arrangements. Pursuant to a Distribution Agreement with SEACOR Holdings, SEACOR Holdings charges the Company a fee of 0.5% per annum on outstanding guaranteed amounts which declines as the obligations are settled by the Company. In the normal course of its business, the Company becomes involved in various other litigation matters including, among others, claims by third parties for alleged property damages and personal injuries. Management has used estimates in determining the Company’s potential exposure to these matters and has recorded reserves in its financial statements related thereto where appropriate. It is possible that a change in the Company’s estimates of that exposure could occur, but the Company does not expect such changes in estimated costs would have a material effect on the Company’s consolidated financial position, results of operations or cash flows.

Stock Based Compensation

Stock Based Compensation	9 Months Ended
	Sep. 30, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Based Compensation	1 3 . STOCK BASED COMPENSATION Transactions in connection with the Company’s Equity Incentive Plans during the nine months ended September 30, 2020 were as follows: Restricted Stock Activity: Outstanding as of December 31, 2019 303,609 Granted 289,452 Vested (115,185 ) Forfeited (8,182 ) Outstanding as of September 30, 2020 469,694 Stock Option Activity: Outstanding as of December 31, 2019 913,569 Granted 261,972 Exercised (20,000 ) Forfeited (35,000 ) Outstanding as of September 30, 2020 1,120,541 For the nine months ended September 30, 2020, the Company acquired for treasury 26,097 shares of Common Stock for an aggregate purchase price of 0.2 million from its employees to cover their tax withholding obligations upon the lapsing of restrictions on share awards. These shares were purchased in accordance with the terms of the Company’s 2017 Equity Incentive Plan. On June 9, 2020, the Company filed a registration statement on Form S-8 with the SEC pursuant to which it registered 2,114,821 Common Shares in connection with the approval by the shareholders of the Company of the 2020 Equity Incentive Plan. Refer to “Note 10. Stockholders’ Equity” for discussion of the Common Share registration under both the 2017 Equity Incentive Plan and the 2020 Equity Incentive Plan.

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Segment Information	14. SEGMENT INFORMATION The Company’s segment presentation and basis of measurement of segment profit or loss are as previously described in the 2019 Annual Report. Certain reclassifications of prior period information have been made to conform the current period’s reportable segment presentation as a result of the Company’s presentation of Discontinued Operations (see “Note 15. Discontinued Operations”). The following tables summarize the operating results, capital expenditures and assets of the Company’s reportable segments for the periods indicated (in thousands): United States (primarily Gulf of Mexico) Africa (primarily West Africa) Middle East and Asia Latin America Europe (primarily North Sea) Total For the Three Months Ended September 30, 2020 Operating Revenues: Time charter $ 1,668 $ 7,641 $ 13,672 $ 8,621 $ 11,984 $ 43,586 Bareboat charter 731 — — — (55 ) 676 Other marine services 473 (385 ) 296 212 839 1,435 2,872 7,256 13,968 8,833 12,768 45,697 Direct Costs and Expenses: Operating: Personnel 2,481 2,597 5,171 2,342 3,922 16,513 Repairs and maintenance 338 1,066 1,564 704 967 4,639 Drydocking — 481 104 — — 585 Insurance and loss reserves 778 267 451 138 239 1,873 Fuel, lubes and supplies 251 994 482 307 354 2,388 Other 85 686 1,771 444 144 3,130 3,933 6,091 9,543 3,935 5,626 29,128 Direct Vessel Profit $ (1,061 ) $ 1,165 $ 4,425 $ 4,898 $ 7,142 16,569 Other Costs and Expenses: Lease expense $ 716 $ 430 $ 46 $ 9 $ 189 1,390 Administrative and general 10,155 Depreciation and amortization 4,961 2,667 4,379 1,708 2,898 16,613 28,158 Loss on Asset Dispositions, Net 233 Operating Loss $ (11,356 ) United States (primarily Gulf of Mexico) Africa (primarily West Africa) Middle East and Asia Latin America Europe, Continuing Operations Total For the Nine Months Ended September 30, 2020 Operating Revenues: Time charter $ 7,521 $ 28,680 $ 39,044 $ 16,268 $ 31,170 $ 122,683 Bareboat charter 2,178 — — — (55 ) 2,123 Other marine services 1,628 (698 ) 1,230 529 1,823 4,512 11,327 27,982 40,274 16,797 32,938 129,318 Direct Costs and Expenses: Operating: Personnel 7,693 7,838 12,777 4,934 10,355 43,597 Repairs and maintenance 1,269 3,880 4,390 1,351 2,864 13,754 Drydocking 1,167 745 718 (114 ) — 2,516 Insurance and loss reserves 1,267 648 1,220 312 954 4,401 Fuel, lubes and supplies 964 2,193 2,102 574 917 6,750 Other 257 1,822 3,273 872 419 6,643 12,617 17,126 24,480 7,929 15,509 77,661 Direct Vessel Profit $ (1,290 ) $ 10,856 $ 15,794 $ 8,868 $ 17,429 51,657 Other Costs and Expenses: Lease expense $ 3,595 $ 1,973 $ 123 $ 27 $ 434 6,152 Administrative and general 35,480 Depreciation and amortization 15,573 8,160 12,090 3,557 7,547 46,927 88,559 Gain on Asset Dispositions and Impairments (15,792 ) Operating Loss $ (52,694 ) As of September 30, 2020 Property and Equipment: Historical Cost 258,710 203,890 365,049 109,802 140,718 1,078,169 Accumulated Depreciation (128,390 ) (57,861 ) (75,013 ) (11,545 ) (61,578 ) (334,387 ) $ 130,320 $ 146,029 $ 290,036 $ 98,257 $ 79,140 $ 743,782 Total Assets (1) $ 172,218 $ 156,551 $ 312,622 $ 175,164 $ 121,428 $ 937,983 (1) Total assets by region does not include corporate assets of $119,192 as of September 30, 2020 . United States (primarily Gulf of Mexico) Africa (primarily West Africa) Middle East and Asia Latin America Europe (primarily North Sea) Total For the Three Months Ended September 30, 2019 Operating Revenues: Time charter $ 10,914 $ 11,738 $ 14,798 $ 1,951 $ 10,346 $ 49,747 Bareboat charter 597 - - 1,168 - 1,765 Other marine services 838 129 414 221 1,586 3,188 12,349 11,867 15,212 3,340 11,932 54,700 Direct Costs and Expenses: Operating: Personnel 4,353 3,308 4,023 846 3,349 15,879 Repairs and maintenance 1,508 1,323 1,387 298 979 5,495 Drydocking 547 (53 ) 20 - 1 515 Insurance and loss reserves 371 230 333 31 233 1,198 Fuel, lubes and supplies 739 961 701 187 322 2,910 Other 88 499 567 (87 ) 147 1,214 7,606 6,268 7,031 1,275 5,031 27,211 Direct Vessel Profit $ 4,743 $ 5,599 $ 8,181 $ 2,065 $ 6,901 $ 27,489 Other Costs and Expenses: Lease expense $ 2,758 $ 761 $ 43 $ — $ 591 $ 4,153 Administrative and general 11,462 Depreciation and amortization 5,634 2,681 3,914 1,573 2,289 16,091 31,706 Loss on Asset Dispositions, Net 861 Operating Loss $ (3,356 ) United States (primarily Gulf of Mexico) Africa (primarily West Africa) Middle East and Asia Latin America Europe, Continuing Operations Total For the Nine Months Ended September 30, 2019 Operating Revenues: Time charter $ 31,547 $ 32,911 $ 40,472 $ 8,919 $ 23,987 $ 137,836 Bareboat charter 830 — — 3,467 — 4,297 Other 3,290 245 991 1,129 4,634 10,289 35,667 33,156 41,463 13,515 28,621 152,422 Direct Costs and Expenses: Operating: Personnel 14,059 10,603 12,569 3,378 9,807 50,416 Repairs and maintenance 6,801 3,459 6,209 1,114 3,103 20,686 Drydocking 4,342 237 454 47 2 5,082 Insurance and loss reserves 1,804 682 1,041 232 616 4,375 Fuel, lubes and supplies 2,529 2,654 2,135 929 671 8,918 Other 291 3,378 2,460 994 1,147 8,270 29,826 21,013 24,868 6,694 15,346 97,747 Direct Vessel Profit, from Continuing Operations $ 5,841 $ 12,143 $ 16,595 $ 6,821 $ 13,275 $ 54,675 Other Costs and Expenses: Lease expense $ 8,611 $ 2,333 $ 131 $ 1 $ 1,513 $ 12,589 Administrative and general — — — — — 32,798 Depreciation and amortization 16,473 7,796 12,437 5,168 6,726 48,600 93,987 Loss on Asset Dispositions and Impairments (2,719 ) Operating Loss, for Continuing Operations $ (42,031 ) As of September 30, 2019 Property and Equipment: Historical Cost 329,913 221,080 297,735 108,224 113,422 1,070,374 Accumulated Depreciation (161,315 ) (64,748 ) (74,225 ) (50,928 ) (49,412 ) (400,628 ) $ 168,598 $ 156,332 $ 223,510 $ 57,296 $ 64,010 $ 669,746 Total Assets (1) $ 251,547 $ 167,714 $ 257,294 $ 125,138 $ 92,861 $ 894,554 (1) Total assets by region does not include corporate assets of $145,952 as of September 30, 2019. The Company’s investments in 50% or less owned companies, which are accounted for under the equity method, also contribute to its consolidated results of operations. As of September 30, 2020, and 2019, the Company’s investments, at equity and advances to 50% or less owned companies in its other 50% or less owned companies were $88.9 million and $118.2 million, respectively. Equity in gains (losses) earnings of 50% or less owned companies for the nine months ended September 30, 2020 and 2019 were $1.5 million and ($11.9) million, respectively.

Discontinued Operations

Discontinued Operations	9 Months Ended
	Sep. 30, 2020
Discontinued Operations And Disposal Groups [Abstract]
Discontinued Operations	15. On December 2, 2019, the Company completed the sale of its North Sea standby safety business, which was previously classified as assets held for sale. Following the completion of the sale, the Company has no continuing involvement in this business, which is considered a strategic shift in the Company’s operations. Summarized selected operating result of the Company’s assets, previously classified as held for sale were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2019 2019 Boston Putford Offshore Safety Ltd Operating Revenues: Time charter $ 11,223 $ 34,034 Other revenue (11 ) 50 11,212 34,084 Costs and Expenses: Operating 9,847 27,113 Direct Vessel Profit 1,365 6,971 General and Administrative Expenses 1,047 3,350 Lease Expense 18 47 Depreciation 1,035 3,213 2,100 6,610 (Loss) on Asset Dispositions and Impairments, Net - 91 Operating Income (735 ) 452 Other Income (Expense) Interest income — 10 Interest expense (55 ) (184 ) Foreign currency translation loss (42 ) (82 ) (97 ) (256 ) Operating Loss Before Equity Earnings of 50% or Less Owned Companies, Net of Tax $ (832 ) $ 196 Income Tax Expense — 4 Operating Loss Before Equity Earnings of 50% or Less Owned Companies $ (832 ) $ 192 Loss on the Sale of Boston Putford Offshore Safety Ltd (7,084 ) (7,084 ) Equity in Earnings of 50% or Less Owned Companies, Net of Tax 17 168 Net (Loss) Income from Discontinued Operations $ (7,899 ) $ (6,724 )

Basis of Presentation and Acc_2

Basis of Presentation and Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Recently Adopted Accounting Standards	Recently Adopted Accounting Standards. On June 30, 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-13, Financial Instruments-Credit Losses (Topic 326). This ASU represents a significant change in the Accounting for Credit Losses model. This ASU introduced the Current Expected Credit Losses (“CECL”) model, which requires earlier recognition of credit losses and additional disclosures related to credit risk. The CECL model utilizes a lifetime expected credit loss measurement objective for the recognition of credit losses for loans and other receivables at the time the financial asset is originated or acquired. The expected credit losses are adjusted each period for changes in expected lifetime credit losses. The CECL model replaces the multiple existing impairment models in current U.S. generally accepted accounting principles (“GAAP”), which generally require that a loss be incurred before it is recognized. The standard applies to financial assets arising from revenue transactions such as contract assets and accounts receivables and was effective for fiscal years beginning after December 15, 2019. The adoption of the standard by the Company did not have a material impact on its consolidated financial position nor on its results of operations and cash flows. On August 29, 2018, the FASB issued ASU No. 2018-15, which requires implementation costs incurred by customers in cloud computing arrangements to be deferred and recognized over the term of the arrangement, if those costs would be capitalized by the customers in a software licensing arrangement. The guidance was effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019, with early adoption permitted. The adoption of the standard by the Company did not have a material impact on its consolidated financial position nor on its results of operations and cash flows. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820). The ASU eliminates certain disclosures as to the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy. The ASU also adds disclosure requirements for Level 3 measurements. This ASU was effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years, with early adoption permitted for any eliminated or modified disclosures. The adoption of the standard by the Company did not have a material impact on the Company ’ s disclosures.
Recently Issued Accounting Standards	Recently Issued Accounting Standards On December 18, 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. The guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. The Company does not expect that adoption of the standard will have a material impact on its consolidated financial position nor on its results of operations and cash flows. On August 5, 2020, the FASB issued ASU 2020-06, Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging – Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity, which simplifies the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts on an entity’s own equity. The guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2021. The Company has not yet determined the impact that the adoption of the standard will have on the Company’s consolidated financial position, results of operations and disclosures. On March 12, 2020, the FASB issued ASU 2020-03, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting, the ASU provides temporary optional guidance to ease the potential burden in accounting for reference rate reform. The new guidance provides optional expedients and exceptions for applying generally accepted accounting principles to contract modifications and hedging relationships, subject to meeting certain criteria, that reference LIBOR or another reference rate expected to be discontinued. The ASU is intended to help stakeholders during the global market-wide reference rate transition period. Therefore, it will be in effect for a limited time through December 31, 2022. As of September 30, 2020, the reference rates for the Company’s existing debt and interest rate swaps have not changed as a result of any such amendment. The Company will continue to monitor changes to reference rates in applicable agreements and adopt the standard as needed.
Basis of Consolidation	Basis of Consolidation. The consolidated financial statements include the accounts of SEACOR Marine and its controlled subsidiaries. Control is generally deemed to exist if the Company has greater than 50% of the voting rights of a subsidiary. All significant intercompany accounts and transactions are eliminated in the combination and consolidation. Noncontrolling interests in consolidated subsidiaries are included in the consolidated balance sheets as a separate component of equity. The Company reports consolidated net income (loss) inclusive of both the Company’s and the noncontrolling interests’ share, as well as the amounts of consolidated net income (loss) attributable to each of the Company and the noncontrolling interests. If a subsidiary is deconsolidated upon a change in control, any retained noncontrolled equity investment in the former controlled subsidiary is measured at fair value and a gain or loss is recognized in net income (loss) based on such fair value. If a subsidiary is consolidated upon the acquisition of controlling interests by the Company, any previous noncontrolled equity investment in the subsidiary is measured at fair value and a gain or loss is recognized in net income (loss) based on such fair value. The Company employs the equity method of accounting for investments in 50% or less owned companies that it does not control but has the ability to exercise significant influence over the operating and financial policies of the business venture. Significant influence is generally deemed to exist if the Company has between 20% and 50% of the voting rights of a business venture but may exist when the Company’s ownership percentage is less than 20%. In certain circumstances, the Company may have an economic interest in excess of 50% but may not control and consolidate the business venture. Conversely, the Company may have an economic interest less than 50% but may control and consolidate the business venture. The Company reports its investments in and advances to these business ventures in the accompanying consolidated balance sheets as investments, at equity, and advances to 50% or less owned companies. The Company reports its share of earnings from investments in 50% or less owned companies in the accompanying consolidated statements of net income ( loss ) as equity in earnings (losses) of 50% or less owned companies, net of tax. The Company employs the cost method of accounting for investments in 50% or less owned companies it does not control or exercise significant influence. These investments in private companies are carried at cost and are adjusted only for capital distributions and other-than-temporary declines in fair value. Certain reclassifications were made to previously reported amounts in the consolidated financial statements and notes thereto to make them consistent with the current period presentation.
Use of Estimates	Use of Estimates. The preparation of financial statements in conformity with accounting principles generally accepted in the U.S. requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Such estimates include those related to deferred revenues, allowance for credit loss accounts, useful lives of property and equipment, impairments, income tax provisions and certain accrued liabilities. Actual results could differ from estimates and those differences may be material.
Revenue Recognition	Revenue Recognition . Revenue is recognized when (or as) the Company transfers promised goods or services to its customers in amounts that reflect the consideration to which the Company expects to be entitled to in exchange for those goods or services, which occurs when (or as) the Company satisfies its contractual obligations and transfers over control of the promised goods or services to its customers. Costs to obtain or fulfill a contract are expensed as incurred. The Company earns revenue primarily from the time charter and bareboat charter of vessels to customers. Since the Company charges customers based upon daily rates of hire, vessel revenues are recognized on a daily basis throughout the contract period. Under a time charter, the Company provides a vessel to a customer and is responsible for all operating expenses, typically excluding fuel. Under a bareboat charter, the Company provides a vessel to a customer and the customer assumes responsibility for all operating expenses and assumes all risks of operation. In the U.S. Gulf of Mexico, time charter durations and rates are typically established in the context of master service agreements that govern the terms and conditions of the charter. Contract or charter durations may range from several days to several years. Charters vary in length from short-term to multi-year periods, many with cancellation clauses and without early termination penalties. As a result of options and frequent renewals, the stated duration of charters may have little correlation with the length of time the vessel is contracted to provide services to a particular customer. The Company also contracts with various customers to carry out management services for vessels as agents for and on behalf of ship owners. These services include crew management, technical management, commercial management, insurance arrangements, sale and purchase of vessels, provisions and bunkering. As the manager of the vessels, the Company undertakes to use its best endeavors to provide the agreed management services as agents for and on behalf of the owners in accordance with sound ship management practice and to protect and promote the interest of the owners in all matters relating to the provision of services thereunder. The Company also contracts with various customers to carry out management services regarding engineering for vessel construction and vessel conversions. The vast majority of the ship management agreements span one to three years and are typically billed on a monthly basis. The Company transfers control of the service to the customer and satisfies its performance obligation over the term of the contract, and therefore recognizes revenue over the term of the contract while related costs are expensed as incurred. Revenue that does not meet these criteria is deferred until the criteria is met and such revenue is considered a contract liability and is recognized as such. Contract liabilities, which are included in other current liabilities in the accompanying consolidated balance sheets, for the nine months ended September 30, 2020 and September 30, 2019 were as follows (in thousands): 2020 2019 Balance at beginning of period $ 4,786 $ 1,327 Revenues deferred during the period 94 5,022 Revenues recognized during the period (2,805 ) (3,046 ) Balance at end of period $ 2,075 $ 3,303 As of September 30, 2020, the Company had deferred revenues of $2.1 million primarily related to $1.2 million of prepaid vessel management fees, and $0.9 million related to the time charter of offshore support vessels to customers from which collections were not reasonably assured.
Cash and Cash Equivalents	Cash and Cash Equivalents. The Company considers all highly liquid investments, with an original maturity of three months or less, when purchased, to be cash equivalents. Cash from current construction reserve funds (“CRF”) is also classified as cash and cash equivalents. The balance in the current CRF at September 30, 2020 was $4.2 million.
Property and Equipment	Property and Equipment. Equipment, stated at cost, is depreciated using the straight-line method over the estimated useful life of the asset to an estimated salvage value. With respect to each class of asset, the estimated useful life is based upon a newly built asset being placed into service and represents the time period beyond which it is typically not justifiable for the Company to continue to operate the asset in the same or similar manner. From time to time, the Company may acquire older assets that have already exceeded the Company’s useful life policy, in which case the Company depreciates such assets based on its best estimate of remaining useful life, typically the next survey or certification date. As of September 30, 2020, the estimated useful life (in years) of each of the Company’s major categories of new equipment was as follows: Offshore Support Vessels: Crew transfer vessels 10 All other offshore support vessels (excluding crew transfer) 20 Equipment maintenance and repair costs and the costs of routine overhauls, drydockings and inspections performed on vessels and equipment are charged to operating expense as incurred. Expenditures that extend the useful life or improve the marketing and commercial characteristics of equipment as well as major renewals and improvements to other properties are capitalized. Certain interest costs incurred during the construction of equipment are capitalized as part of the assets’ carrying values and are amortized over such assets estimated useful lives. During the three and nine months ended September 30, 2020, capitalized interest totaled $0.3 million and $0.7 million, respectively.
Impairment of Long-Lived Assets and Impairment of 50% or Less Owned Companies	Impairment of Long-Lived Assets. The Company performs an impairment analysis of long-lived assets used in operations, including intangible assets, when indicators of impairment are present. These indicators may include a significant decrease in the market price of a long-lived asset or asset group, a significant adverse change in the extent or manner in which a long-lived asset or asset group is being used or in its physical condition, or a current period operating or cash flow loss combined with a history of operating or cash flow losses or a forecast that demonstrates continuing losses associated with the use of a long-lived asset or asset group. If the carrying values of the assets are not recoverable, as determined by their estimated future undiscounted cash flows, the estimated fair value of the assets or asset groups are compared to their current carrying values and impairment charges are recorded if the carrying value exceeds fair value. Market conditions caused by COVID-19, including the decrease in oil and natural gas prices as well as the affect the pandemic has had on SEACOR Marine’s stock price, caused a triggering event to occur requiring the Company to test its assets for impairment. For the nine months ended September 30, 2020, the Company impaired the right-to-use assets on two of its leased liftboats. Based on the current market environment, it was determined that neither of these two vessels would return to active service during their remaining lease term s . Therefore, the Company recorded an impair ment of $ 7.4 million in total for these two leased-in vessels . The Company also r ecorded a partial impairment on four liftboat s for an aggregate of $ 3.9 million based on outside valuation s of its remaining liftboat fleet. Estimated fair values for the Company’s owned vessels were established by independent appraisers based on researched market information, replacement cost information, and other data . If market conditions further decline from the depressed utilization and rates per day worked experience d over the last three years, fair values based on future appraisals could decline significantly. In addition, the Company further impaired one specialty vessel for $ 1.2 million due to a reduced sales price for the vessel. There were no other impairments of right-to-use assets or any other assets for the nine months ended September 30, 2020 . The Company’s other vessel classes and other individual vessels in active service and cold-stacked status, for which no impairment was deemed necessary, have generally experienced a less severe decline in utilization and rates per day worked based on specific market factors. The market factors include vessels with more general utility to a broad range of customers (e.g., fast support vessels (“FSVs”)), vessels required for customers to meet regulatory mandates and operating under multiple year contracts and vessels that serve customers outside of the offshore oil and natural gas market (e.g., crew transfer vessels (“CTVs”)). For vessel classes and individual vessels with indicators of impairment as of September 30, 2020, the Company has estimated that their future undiscounted cash flows exceed their current carrying values. The Company’s estimates of future undiscounted cash flows are highly subjective as utilization and rates per day worked are uncertain, especially in light of the affect COVID-19 has had on the timing of an estimated market recovery in the offshore oil and natural gas markets and the timing and cost of reactivating cold-stacked vessels. If market conditions decline further, changes in the Company’s expectations on future cash flows may result in recognizing additional impairment charges related to its long-lived assets in future periods. Impairment of 50% Investments in 50% or less owned companies are reviewed periodically to assess whether there is an other-than-temporary decline in the carrying value of the investment. In its evaluation, the Company considers, among other items, recent and expected financial performance and returns, impairments recorded by the investee and the capital structure of the investee. When the Company determines the estimated fair value of an investment is below carrying value and the decline is other-than-temporary, the investment is written down to its estimated fair value. Actual results may vary from the Company’s estimates due to the uncertainty regarding projected financial performance, the severity and expected duration of declines in value and the available liquidity in the capital markets to support the continuing operations of the investee, among other factors. Although the Company believes its assumptions and estimates are reasonable, the investee’s actual performance compared with the estimates could produce different results and lead to additional impairment charges in future periods. During the nine months ended September 30, 2020 and 2019, the Company did not recognize any impairment charges related to its 50% or less owned companies.
Income Taxes	Income Taxes. During the nine months ended September 30, 2020, the Company’s effective income tax rate of 35.2% was primarily due to taxes on income attributable to noncontrolling interests, foreign sourced income not subject to U.S. income taxes, foreign taxes not creditable against U.S. income taxes, and an adjustment for the acquisition of the remaining minority membership interest in Falcon Global Holdings LLC (“Falcon Global Holdings”) (see “Note 10. Stockholder’s Equity”).
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss). The components of accumulated other comprehensive loss were as follows (in thousands): SEACOR Marine Holdings Inc. Stockholders’ Equity Noncontrolling Interests Foreign Currency Translation Adjustments Derivative Losses on Cash Flow Hedges, net Total Foreign Currency Translation Adjustments Derivative Income (Losses) on Cash Flow Hedges, net Other Comprehensive Loss December 31, 2019 $ 4,685 $ (3,137 ) $ 1,548 $ (1,445 ) $ (11 ) $ 6,716 Other comprehensive loss (385 ) (1,543 ) (1,928 ) — — $ (1,928 ) Balance as of September 30, 2020 $ 4,300 $ (4,680 ) $ (380 ) $ (1,445 ) $ (11 ) $ 4,788
Loss Per Share	Loss Per Share. Basic loss per common share of the Company is computed based on the weighted average number of common shares and warrants to purchase common shares at an exercise price of $0.01 per share (“Warrants”) issued and outstanding during the relevant periods. The Warrants are included in the basic loss per common share because the shares issuable upon exercise of the Warrants are issuable for de minimis cash consideration and therefore not anti-dilutive. Diluted loss per common share of the Company is computed based on the weighted average number of common shares and Warrants issued and outstanding plus the effect of other potentially dilutive securities through the application of the treasury stock method and the if-converted method that assumes all common shares have been issued and outstanding during the relevant periods pursuant to the conversion of the Convertible Senior Notes unless anti-dilutive. For both the nine months ended September 30, 2020 and 2019, diluted earnings per common share of the Company excluded 2,183,708 common shares, respectively, issuable pursuant to the Company’s Convertible Senior Notes (see “Note 5. Long-Term Debt”) as the effect of their inclusion in the computation would be anti-dilutive. In addition, for the nine months ended September 30, 2020 and 2019, diluted loss per common share of the Company excluded 469,964 and 282,050 shares of restricted stock, respectively, and 1,120,541 and 397,119 shares of stock, respectively, issuable upon exercise of outstanding stock options as the effect of their inclusion in the computation would be anti-dilutive.

Basis of Presentation and Acc_3

Basis of Presentation and Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2020
Basis Of Presentation And Accounting Policies [Abstract]
Schedule of Deferred Revenues	Revenue that does not meet these criteria is deferred until the criteria is met and such revenue is considered a contract liability and is recognized as such. Contract liabilities, which are included in other current liabilities in the accompanying consolidated balance sheets, for the nine months ended September 30, 2020 and September 30, 2019 were as follows (in thousands): 2020 2019 Balance at beginning of period $ 4,786 $ 1,327 Revenues deferred during the period 94 5,022 Revenues recognized during the period (2,805 ) (3,046 ) Balance at end of period $ 2,075 $ 3,303
Schedule of Property and Equipment Useful Life	As of September 30, 2020, the estimated useful life (in years) of each of the Company’s major categories of new equipment was as follows: Offshore Support Vessels: Crew transfer vessels 10 All other offshore support vessels (excluding crew transfer) 20
Schedule of Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss). The components of accumulated other comprehensive loss were as follows (in thousands): SEACOR Marine Holdings Inc. Stockholders’ Equity Noncontrolling Interests Foreign Currency Translation Adjustments Derivative Losses on Cash Flow Hedges, net Total Foreign Currency Translation Adjustments Derivative Income (Losses) on Cash Flow Hedges, net Other Comprehensive Loss December 31, 2019 $ 4,685 $ (3,137 ) $ 1,548 $ (1,445 ) $ (11 ) $ 6,716 Other comprehensive loss (385 ) (1,543 ) (1,928 ) — — $ (1,928 ) Balance as of September 30, 2020 $ 4,300 $ (4,680 ) $ (380 ) $ (1,445 ) $ (11 ) $ 4,788

Transformation, Facility Rest_2

Transformation, Facility Restructuring and Severance Charges (Tables)	9 Months Ended
	Sep. 30, 2020
Restructuring And Related Activities [Abstract]
Schedule of Components of Restructuring Charges By Segment	The components of restructuring charges by segment for the three and nine months ended September 30, 2020 were as follows (in thousands): United States (primarily Gulf of Mexico) Africa (primarily West Africa) Middle East and Asia Latin America Europe (primarily North Sea) Total For the Three Months Ended September 30, 2020 Transformation Plan Severance Charges $ 1 $ — $ 346 $ — $ — $ 347 Other Charges (96 ) — — — — (96 ) Total Charges $ (95 ) $ — $ 346 $ — $ — $ 251 United States (primarily Gulf of Mexico) Africa (primarily West Africa) Middle East and Asia Latin America Europe (primarily North Sea) Total For the Nine Months Ended September 30, 2020 Transformation Plan Severance Charges $ 275 $ — $ 665 $ — $ 185 $ 1,125 Other Charges 31 — 31 — — 62 Total Charges $ 306 $ — $ 696 $ — $ 185 $ 1,187

Seacosco Acquisition (Tables)

Seacosco Acquisition (Tables)	9 Months Ended
	Sep. 30, 2020
Business Combinations [Abstract]
Summary of Purchase Price Allocation of Acquired Assets	The allocation of the purchase price for the Company’s acquired assets for the six months ended June 30 was as follows (in thousands): Assets Acquired (In Thousands): June 30, 2020 Current Assets 7,700 Fixed Assets 142,282 Current Liabilities (23,929 ) Book Value of Debt Acquired (100,759 ) Discount on Debt Acquired 25,190 Fair Value of Debt Acquired (75,569 ) Total Cost Basis for Purchase 50,484 Purchase Price $ (28,150 ) Acquisition costs (112 ) Equity Investment In SEACOR Offshore Delta (f/k/a SEACOSCO) (22,222 ) (50,484 )

Long-term Debt (Tables)

Long-term Debt (Tables)	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Schedule of Long-term Debt Obligations	The Company’s long-term debt obligations as of September 30, 2020 and December 31, 2019 were as follows (in thousands): September 30, 2020 December 31, 2019 Recourse Long-term debt (1) Convertible Senior Notes $ 125,000 $ 125,000 SEACOR Marine Foreign Holdings Credit Facility 104,000 113,750 Sea-Cat Crewzer III Term Loan Facility 21,653 24,128 SEACOR Offshore Delta (f/k/a SEACOSCO) Acquisition Debt 19,705 — SEACOR Delta (f/k/a SEACOSCO) Shipyard Financing (2) 97,189 — SEACOR Alpine Shipyard Financing (3) 31,410 10,534 SEACOR 88/888 Term Loan 5,500 5,500 BNDES Equipment Construction Finance Notes 2,682 3,332 Total recourse Long-term debt 407,139 282,244 Non-recourse Long-term debt (4) Falcon Global USA Term Loan Facility 102,350 102,349 Falcon Global USA Revolver 15,000 15,000 Windcat Workboats Facilities 26,478 24,730 SEACOR 88/888 Term Loan 5,500 5,500 Total non-recourse Long-term debt 149,328 147,579 Total principal due for long-term debt 556,467 429,823 Current portion due within one year (52,107 ) (17,802 ) Unamortized debt discount (46,778 ) (26,343 ) Deferred financing costs (4,617 ) (5,427 ) Long-term debt, less current portion $ 452,965 $ 380,251 (1) Recourse debt represents debt issued by SEACOR Marine and/or its subsidiaries and guaranteed by SEACOR Marine as defined in the relevant debt agreements. (2) SEACOR Delta Shipyard Financing includes vessel financing on the eight vessels acquired in the SEACOSCO Acquisition (see “Note 3. SEACOSCO Acquisition”). (3) SEACOR Alpine Shipyard Financing includes vessel financing on the SEACOR Alps, the SEACOR Andes and the SEACOR Atlas vessels. (4) Non-recourse debt represents debt issued by the Company’s Consolidated Subsidiaries with no recourse to SEACOR Marine or its other non-debtor subsidiaries, other than certain limited support obligations as defined in the respective debt agreements, which in aggregate are not considered to be material to the Company’s business and financial condition.

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2020
Leases [Abstract]
Summary of Future Minimum Payments For Leases	As of September 30, 2020, future minimum payments for leases for the remainder of 2020 and the years ended December 31 were as follows (in thousands): Operating Leases Finance Leases Remainder of 2020 $ 3,718 $ 3 2021 7,955 39 2022 714 39 2023 727 39 2024 793 36 Years subsequent to 2024 4,982 — 18,889 156 Interest component (3,563 ) (16 ) 15,326 140 Current portion of long-term lease liabilities 9,632 27 Long-term lease liabilities $ 5,694 $ 113
Summary of Components of Leases Expense	For the three and nine months ended September 30, 2020 the components of lease expense were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Operating lease cost (1) $ 1,083 $ 3,446 $ 5,460 $ 10,669 Finance lease cost: Amortization of finance lease assets (1) 3 — 3 — Short-term lease costs (1) 307 725 692 1,967 $ 1,393 $ 4,171 $ 6,155 $ 12,636 (1) Included in selling, general and administrative expenses in the consolidated statements of income
Summary of Supplemental Cash Flow Information Related to Leases	For the nine months ended September 30, 2020, supplemental cash flow information related to leases were as follows (in thousands): 2020 Operating cash flows from operating leases $ 11,252 Right-of-use assets obtained for operating lease liabilities 1,483 Right-of-use assets obtained for finance lease liabilities $ 140
Summary of Other Information Related to Leases	For the nine months ended September 30, 2020, other information related to leases were as follows: 2020 Weighted average remaining lease term, in years - operating leases 6.1 Weighted average remaining lease term, in years - finance leases 4.2 Weighted average discount rate - operating leases 4.4 % Weighted average discount rate - finance leases 5.3 %

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Schedule of Effective Income Tax Rate Reconciliation	The following table reconciles the difference between the statutory federal income tax rate for the Company and the effective income tax rate on continuing operations for the nine months ended September 30, 2020: Statutory rate 21.0 % Foreign taxes not creditable against U.S. income tax (4.3 ) Falcon Global Acquisition 4.5 Noncontrolling interests (1.3 ) CARES Act NOL Carryback 16.4 Other (1.1 ) 35.2 %

Derivative Instruments and He_2

Derivative Instruments and Hedging Strategies (Tables)	9 Months Ended
	Sep. 30, 2020
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Schedule of Fair Value of Derivative Assets and Liabilities	The fair values of the Company’s derivative instruments were as follows (in thousands): September 30, 2020 December 31, 2019 Derivative Asset Derivative Liability Derivative Asset Derivative Liability Derivatives designated as hedging instruments: Interest rate swap agreements (cash flow hedges) $ — $ 4,103 $ — $ 3,009 — 4,103 — 3,009 Derivatives not designated as hedging instruments: Conversion option liability on Convertible Senior Notes — 1 — 5,205 $ — $ 4,104 $ — $ 8,214
Schedule of Gains (Losses) on Derivative Instruments not Designated as Hedging Instruments	The Company recognized gains (losses) on derivative instruments not designated as hedging instruments for the three and nine months ended September 3 0 , as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Conversion option liability on Convertible Senior Notes $ 5 $ 3,057 $ 5,204 $ 734 $ 5 $ 3,057 $ 5,204 $ 734

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis	The Company’s financial assets and liabilities as of September 30, 2020 and December 31, 2019 that are measured at fair value on a recurring basis were as follows (in thousands): September 30, 2020 Level 1 Level 2 Level 3 LIABILITIES Derivative instruments — 4,103 — Conversion Option Liability on Convertible Senior Notes — — 1 December 31, 2019 ASSETS Construction reserve funds $ 12,893 $ — $ — LIABILITIES Derivative instruments — 3,009 — Conversion Option Liability on Convertible Senior Notes — — 5,205
Schedule of Estimated Fair Values of Financial Assets and Liabilities	The estimated fair values of the Company’s other financial assets and liabilities as of September 30, 2020 and December 31, 2019 were as follows (in thousands): Estimated Fair Value September 30, 2020 Carrying Amount Level 1 Level 2 Level 3 ASSETS Cash, cash equivalents and restricted cash $ 48,531 $ 48,531 $ — $ — Investments, at cost, in 50% or less owned companies (included in other assets) 132 see below LIABILITIES Long-term debt, including current portion 505,072 — 477,430 — December 31, 2019 ASSETS Cash, cash equivalents and restricted cash $ 87,047 $ 87,047 $ — $ — Investments, at cost, in 50% or less owned companies (included in other assets) 132 see below LIABILITIES Long-term debt, including current portion 398,053 — 380,815 —
Schedule of Other Assets and Liabilities Measured at Fair Value	The Company’s other assets and liabilities that were measured at fair value during the nine months ended September 30, 2020 and the year ended December 31, 2019 were as follows (in thousands): September 30, 2020 Level 1 Level 2 Level 3 ASSETS Property and equipment: Liftboats $ — $ 36,602 $ — December 31, 2019 ASSETS Property and equipment: AHTS $ — $ 520 $ — FSVs — 1,858 —

Noncontrolling Interests in S_2

Noncontrolling Interests in Subsidiaries (Tables)	9 Months Ended
	Sep. 30, 2020
Noncontrolling Interest [Abstract]
Schedule of Noncontrolling Interests in the Company's Consolidated Subsidiaries	Noncontrolling interests in the Company’s consolidated subsidiaries were as follows (in thousands): Noncontrolling Interests September 30, 2020 December 31, 2019 Falcon Global Holdings 0% (1) — $ 21,119 Other 1.8-3.0% 350 313 $ 350 $ 21,432 (1) Before March 20, 2020, noncontrolling interest was 28%.

Stock Based Compensation (Table

Stock Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Transactions in Connection with Equity Incentive Plans	Transactions in connection with the Company’s Equity Incentive Plans during the nine months ended September 30, 2020 were as follows: Restricted Stock Activity: Outstanding as of December 31, 2019 303,609 Granted 289,452 Vested (115,185 ) Forfeited (8,182 ) Outstanding as of September 30, 2020 469,694 Stock Option Activity: Outstanding as of December 31, 2019 913,569 Granted 261,972 Exercised (20,000 ) Forfeited (35,000 ) Outstanding as of September 30, 2020 1,120,541

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	The following tables summarize the operating results, capital expenditures and assets of the Company’s reportable segments for the periods indicated (in thousands): United States (primarily Gulf of Mexico) Africa (primarily West Africa) Middle East and Asia Latin America Europe (primarily North Sea) Total For the Three Months Ended September 30, 2020 Operating Revenues: Time charter $ 1,668 $ 7,641 $ 13,672 $ 8,621 $ 11,984 $ 43,586 Bareboat charter 731 — — — (55 ) 676 Other marine services 473 (385 ) 296 212 839 1,435 2,872 7,256 13,968 8,833 12,768 45,697 Direct Costs and Expenses: Operating: Personnel 2,481 2,597 5,171 2,342 3,922 16,513 Repairs and maintenance 338 1,066 1,564 704 967 4,639 Drydocking — 481 104 — — 585 Insurance and loss reserves 778 267 451 138 239 1,873 Fuel, lubes and supplies 251 994 482 307 354 2,388 Other 85 686 1,771 444 144 3,130 3,933 6,091 9,543 3,935 5,626 29,128 Direct Vessel Profit $ (1,061 ) $ 1,165 $ 4,425 $ 4,898 $ 7,142 16,569 Other Costs and Expenses: Lease expense $ 716 $ 430 $ 46 $ 9 $ 189 1,390 Administrative and general 10,155 Depreciation and amortization 4,961 2,667 4,379 1,708 2,898 16,613 28,158 Loss on Asset Dispositions, Net 233 Operating Loss $ (11,356 ) United States (primarily Gulf of Mexico) Africa (primarily West Africa) Middle East and Asia Latin America Europe, Continuing Operations Total For the Nine Months Ended September 30, 2020 Operating Revenues: Time charter $ 7,521 $ 28,680 $ 39,044 $ 16,268 $ 31,170 $ 122,683 Bareboat charter 2,178 — — — (55 ) 2,123 Other marine services 1,628 (698 ) 1,230 529 1,823 4,512 11,327 27,982 40,274 16,797 32,938 129,318 Direct Costs and Expenses: Operating: Personnel 7,693 7,838 12,777 4,934 10,355 43,597 Repairs and maintenance 1,269 3,880 4,390 1,351 2,864 13,754 Drydocking 1,167 745 718 (114 ) — 2,516 Insurance and loss reserves 1,267 648 1,220 312 954 4,401 Fuel, lubes and supplies 964 2,193 2,102 574 917 6,750 Other 257 1,822 3,273 872 419 6,643 12,617 17,126 24,480 7,929 15,509 77,661 Direct Vessel Profit $ (1,290 ) $ 10,856 $ 15,794 $ 8,868 $ 17,429 51,657 Other Costs and Expenses: Lease expense $ 3,595 $ 1,973 $ 123 $ 27 $ 434 6,152 Administrative and general 35,480 Depreciation and amortization 15,573 8,160 12,090 3,557 7,547 46,927 88,559 Gain on Asset Dispositions and Impairments (15,792 ) Operating Loss $ (52,694 ) As of September 30, 2020 Property and Equipment: Historical Cost 258,710 203,890 365,049 109,802 140,718 1,078,169 Accumulated Depreciation (128,390 ) (57,861 ) (75,013 ) (11,545 ) (61,578 ) (334,387 ) $ 130,320 $ 146,029 $ 290,036 $ 98,257 $ 79,140 $ 743,782 Total Assets (1) $ 172,218 $ 156,551 $ 312,622 $ 175,164 $ 121,428 $ 937,983 (1) Total assets by region does not include corporate assets of $119,192 as of September 30, 2020 . United States (primarily Gulf of Mexico) Africa (primarily West Africa) Middle East and Asia Latin America Europe (primarily North Sea) Total For the Three Months Ended September 30, 2019 Operating Revenues: Time charter $ 10,914 $ 11,738 $ 14,798 $ 1,951 $ 10,346 $ 49,747 Bareboat charter 597 - - 1,168 - 1,765 Other marine services 838 129 414 221 1,586 3,188 12,349 11,867 15,212 3,340 11,932 54,700 Direct Costs and Expenses: Operating: Personnel 4,353 3,308 4,023 846 3,349 15,879 Repairs and maintenance 1,508 1,323 1,387 298 979 5,495 Drydocking 547 (53 ) 20 - 1 515 Insurance and loss reserves 371 230 333 31 233 1,198 Fuel, lubes and supplies 739 961 701 187 322 2,910 Other 88 499 567 (87 ) 147 1,214 7,606 6,268 7,031 1,275 5,031 27,211 Direct Vessel Profit $ 4,743 $ 5,599 $ 8,181 $ 2,065 $ 6,901 $ 27,489 Other Costs and Expenses: Lease expense $ 2,758 $ 761 $ 43 $ — $ 591 $ 4,153 Administrative and general 11,462 Depreciation and amortization 5,634 2,681 3,914 1,573 2,289 16,091 31,706 Loss on Asset Dispositions, Net 861 Operating Loss $ (3,356 ) United States (primarily Gulf of Mexico) Africa (primarily West Africa) Middle East and Asia Latin America Europe, Continuing Operations Total For the Nine Months Ended September 30, 2019 Operating Revenues: Time charter $ 31,547 $ 32,911 $ 40,472 $ 8,919 $ 23,987 $ 137,836 Bareboat charter 830 — — 3,467 — 4,297 Other 3,290 245 991 1,129 4,634 10,289 35,667 33,156 41,463 13,515 28,621 152,422 Direct Costs and Expenses: Operating: Personnel 14,059 10,603 12,569 3,378 9,807 50,416 Repairs and maintenance 6,801 3,459 6,209 1,114 3,103 20,686 Drydocking 4,342 237 454 47 2 5,082 Insurance and loss reserves 1,804 682 1,041 232 616 4,375 Fuel, lubes and supplies 2,529 2,654 2,135 929 671 8,918 Other 291 3,378 2,460 994 1,147 8,270 29,826 21,013 24,868 6,694 15,346 97,747 Direct Vessel Profit, from Continuing Operations $ 5,841 $ 12,143 $ 16,595 $ 6,821 $ 13,275 $ 54,675 Other Costs and Expenses: Lease expense $ 8,611 $ 2,333 $ 131 $ 1 $ 1,513 $ 12,589 Administrative and general — — — — — 32,798 Depreciation and amortization 16,473 7,796 12,437 5,168 6,726 48,600 93,987 Loss on Asset Dispositions and Impairments (2,719 ) Operating Loss, for Continuing Operations $ (42,031 ) As of September 30, 2019 Property and Equipment: Historical Cost 329,913 221,080 297,735 108,224 113,422 1,070,374 Accumulated Depreciation (161,315 ) (64,748 ) (74,225 ) (50,928 ) (49,412 ) (400,628 ) $ 168,598 $ 156,332 $ 223,510 $ 57,296 $ 64,010 $ 669,746 Total Assets (1) $ 251,547 $ 167,714 $ 257,294 $ 125,138 $ 92,861 $ 894,554 (1) Total assets by region does not include corporate assets of $145,952 as of September 30, 2019.

Discontinued Operations (Tables

Discontinued Operations (Tables)	9 Months Ended
	Sep. 30, 2020
Discontinued Operations And Disposal Groups [Abstract]
Schedule of Assets Held for Sale	Summarized selected operating result of the Company’s assets, previously classified as held for sale were as follows (in thousands) Three Months Ended September 30, Nine Months Ended September 30, 2019 2019 Boston Putford Offshore Safety Ltd Operating Revenues: Time charter $ 11,223 $ 34,034 Other revenue (11 ) 50 11,212 34,084 Costs and Expenses: Operating 9,847 27,113 Direct Vessel Profit 1,365 6,971 General and Administrative Expenses 1,047 3,350 Lease Expense 18 47 Depreciation 1,035 3,213 2,100 6,610 (Loss) on Asset Dispositions and Impairments, Net - 91 Operating Income (735 ) 452 Other Income (Expense) Interest income — 10 Interest expense (55 ) (184 ) Foreign currency translation loss (42 ) (82 ) (97 ) (256 ) Operating Loss Before Equity Earnings of 50% or Less Owned Companies, Net of Tax $ (832 ) $ 196 Income Tax Expense — 4 Operating Loss Before Equity Earnings of 50% or Less Owned Companies $ (832 ) $ 192 Loss on the Sale of Boston Putford Offshore Safety Ltd (7,084 ) (7,084 ) Equity in Earnings of 50% or Less Owned Companies, Net of Tax 17 168 Net (Loss) Income from Discontinued Operations $ (7,899 ) $ (6,724 )

Basis of Presentation and Acc_4

Basis of Presentation and Accounting Policies - Additional Information (Details) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Basis Of Presentation And Accounting Policies [Line Items]
Contract with customer, liability	$ 2,075,000	$ 2,075,000	$ 3,303,000	$ 4,786,000	$ 1,327,000
Prepaid management fees	3,131,000	3,131,000		$ 5,327,000
Construction reserve funds, current	4,200,000	4,200,000
Capitalized interest costs, including allowance for funds used during construction, total	$ 300,000	700,000
Impairment of long-lived assets right-to-use		7,400,000
Partial impairment of right to use assets		3,900,000
Additional impairment of right-to-use assets		1,200,000
Equity method investment, other than temporary impairment		$ 0	$ 0
Effective income tax rate reconciliation, percent, total		35.20%
Class of warrant or right, exercise price of warrants or rights	$ 0.01	$ 0.01
Incremental common shares attributable to conversion of debt securities, total		2,183,708	2,183,708
Restricted Stock
Basis Of Presentation And Accounting Policies [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount		469,964	282,050
Employee Stock Option
Basis Of Presentation And Accounting Policies [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount		1,120,541	397,119
Prepaid Vessel Management Fees
Basis Of Presentation And Accounting Policies [Line Items]
Prepaid management fees	$ 1,200,000	$ 1,200,000
Geographic Distribution, Domestic
Basis Of Presentation And Accounting Policies [Line Items]
Contract with customer, liability	2,100,000	2,100,000
Geographic Distribution, Foreign
Basis Of Presentation And Accounting Policies [Line Items]
Contract with customer, liability	$ 900,000	$ 900,000
Minimum
Basis Of Presentation And Accounting Policies [Line Items]
Equity method investment, ownership percentage	20.00%	20.00%
Minimum | SEACOR Marine Foreign Holdings
Basis Of Presentation And Accounting Policies [Line Items]
Equity method investment, ownership percentage	50.00%	50.00%
Maximum
Basis Of Presentation And Accounting Policies [Line Items]
Equity method investment, ownership percentage	50.00%	50.00%	50.00%

Basis of Presentation and Acc_5

Basis of Presentation and Accounting Policies - Schedule of Deferred Revenues (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Basis Of Presentation And Accounting Policies [Abstract]
Balance at beginning of period	$ 4,786	$ 1,327
Revenues deferred during the period	94	5,022
Revenues recognized during the period	(2,805)	(3,046)
Balance at end of period	$ 2,075	$ 3,303

Basis of Presentation and Acc_6

Basis of Presentation and Accounting Policies - Schedule of Property and Equipment Useful Life (Details)	9 Months Ended
	Sep. 30, 2020
Crew Transfer Vessels
Property Plant And Equipment [Line Items]
Estimated useful life (Year)	10 years
All Other Offshore Support Vessels
Property Plant And Equipment [Line Items]
Estimated useful life (Year)	20 years

Basis of Presentation and Acc_7

Basis of Presentation and Accounting Policies - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	$ 451,364	$ 511,240	$ 478,924	$ 565,351
Other comprehensive loss	2,161	(1,949)	(1,928)	(4,490)
Balance	436,654	494,147	436,654	494,147
Foreign Currency Translation Adjustments Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Balance			4,685
Other comprehensive loss			(385)
Balance	4,300		4,300
Derivative Losses on Cash Flow Hedges, net Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Balance			(3,137)
Other comprehensive loss			(1,543)
Balance	(4,680)		(4,680)
AOCI Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(2,541)	(19,156)	1,548	(16,788)
Other comprehensive loss			(1,928)
Balance	(380)	$ (21,105)	(380)	$ (21,105)
Foreign Currency Translation Adjustments Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income Loss [Line Items]
Balance			(1,445)
Balance	(1,445)		(1,445)
Derivative Losses on Cash Flow Hedges, net Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income Loss [Line Items]
Balance			(11)
Balance	(11)		(11)
AOCI Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income Loss [Line Items]
Balance			6,716
Other comprehensive loss			(1,928)
Balance	$ 4,788		$ 4,788

Transformation, Facility Rest_3

Transformation, Facility Restructuring and Severance Charges - Additional Information (Details) - Transformation Plan - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020
Restructuring Cost And Reserve [Line Items]
Restructuring and related activities, description		The transformation plan, which began in the third quarter of 2019 and extended through the third quarter of 2020 (the “Transformation Plan”), included a workforce reduction, organization restructuring, facility consolidations and other cost reduction measures and efficiency initiatives across the Company’s geographic regions. The Transformation Plan was initiated due to activity levels of oil and gas exploration and production, and the Company continues to evaluate additional opportunities for further cost reductions to adapt to changing conditions caused by COVID-19.
Restructuring and transformation charges	$ 251	$ 1,187
Severance charges		1,100
Other restructuring charges	$ (96)	62
Restructuring charges		$ 4,900

Transformation, Facility Rest_4

Transformation, Facility Restructuring and Severance Charges - Schedule of Components of Restructuring Charges By Segment (Details) - Transformation Plan - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020
Restructuring Cost And Reserve [Line Items]
Severance Charges	$ 347	$ 1,125
Other Charges	(96)	62
Total Charges	251	1,187
UNITED STATES
Restructuring Cost And Reserve [Line Items]
Severance Charges	1	275
Other Charges	(96)	31
Total Charges	(95)	306
Middle East and Asia
Restructuring Cost And Reserve [Line Items]
Severance Charges	346	665
Other Charges		31
Total Charges	$ 346	696
Europe
Restructuring Cost And Reserve [Line Items]
Severance Charges		185
Total Charges		$ 185

Seacosco Acquisition - Addition

Seacosco Acquisition - Additional Information (Details) - SEACOR Offshore Delta LLC $ in Millions	Jun. 30, 2020USD ($)Vessel	Sep. 30, 2020USD ($)Vessel	May 31, 2020
Sale And Purchase Agreement
Business Acquisition [Line Items]
Percentage of membership interests acquired	100.00%
Purchase price payable for membership interest	$ 28.2
Purchase price payable to sellers at closing of transaction	8.4
Purchase price for membership interests annual installment payment in first year	1
Purchase price for membership interests annual installment payment in second year	2.5
Purchase price for membership interests annual installment payment in third year	2.5
Purchase price for membership interests annual installment payment in fourth year	$ 13.7
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%
Sale And Purchase Agreement | Platform Supply Vessels
Business Acquisition [Line Items]
Number of vessels owned | Vessel	8
Number of vessels owned with high specification | Vessel		2
Number of vessels owned with identical specification | Vessel		6
Deferred Purchase Agreements | Platform Supply Vessels
Business Acquisition [Line Items]
Business acquisition, aggregate amount outstanding	$ 100.8	$ 97.2
Business acquisition, amortization period 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%
Number of vessels delivered to the company | Vessel	8
SEACOR Offshore Asia | Sale And Purchase Agreement
Business Acquisition [Line Items]
Percentage of membership interests acquired			50.00%

Seacosco Acquisition - Summary

Seacosco Acquisition - Summary of Purchase Price Allocation of Acquired Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jun. 30, 2020
Business Acquisition [Line Items]
Equity Investment In SEACOR Offshore Delta (f/k/a SEACOSCO)	$ (88,900)
SEACOR Offshore Delta LLC
Business Acquisition [Line Items]
Current Assets		$ 7,700
Fixed Assets		142,282
Current Liabilities		(23,929)
Book Value of Debt Acquired		(100,759)
Discount on Debt Acquired		25,190
Fair Value of Debt Acquired		(75,569)
Total Cost Basis for Purchase		50,484
Purchase Price		(28,150)
Acquisition costs		(112)
Equity Investment In SEACOR Offshore Delta (f/k/a SEACOSCO)		(22,222)
Total Cost Basis for Purchase		$ (50,484)

Equipment Acquisitions and Di_2

Equipment Acquisitions and Dispositions - Additional Information (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)Vessel	Sep. 30, 2019USD ($)
Property Plant And Equipment [Line Items]
Payments to acquire property, plant, and equipment, including fair value hedges | $	$ 24,900
Proceeds from property, plant, and equipment, including deposits and gain on sale | $	21,600
Proceeds from disposition of property and equipment | $	20,674	$ 19,765
Proceeds from deposits | $	900
Gain (loss) on disposition of property, plant and equipment | $	1,200
Cash
Property Plant And Equipment [Line Items]
Proceeds from disposition of property and equipment | $	$ 20,700
Platform Supply Vessels
Property Plant And Equipment [Line Items]
Number of equipment acquired | Vessel	3
Crew Transfer Vessels
Property Plant And Equipment [Line Items]
Number of equipment acquired | Vessel	2
Anchor Handling Towing Supply Vessel
Property Plant And Equipment [Line Items]
Number of equipment sold | Vessel	2
Fast Support Vessels
Property Plant And Equipment [Line Items]
Number of equipment sold | Vessel	4
Specialty Vessel
Property Plant And Equipment [Line Items]
Number of equipment sold | Vessel	1
Vessel Under Construction
Property Plant And Equipment [Line Items]
Number of equipment sold | Vessel	1

Long Term Debt - Schedule of Lo

Long Term Debt - Schedule of Long-term Debt Obligations (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 556,467	$ 429,823
Current portion due within one year	(52,107)	(17,802)
Unamortized debt discount	(46,778)	(26,343)
Deferred financing costs	(4,617)	(5,427)
Long-term debt, less current portion	452,965	380,251
Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	407,139	282,244
Recourse Long-Term Debt | Convertible Senior Notes
Debt Instrument [Line Items]
Long-term Debt, Gross	125,000	125,000
Recourse Long-Term Debt | SEACOR Marine Foreign Holdings Credit Facility
Debt Instrument [Line Items]
Long-term Debt, Gross	104,000	113,750
Recourse Long-Term Debt | Sea-Cat Crewzer III Term Loan Facility
Debt Instrument [Line Items]
Long-term Debt, Gross	21,653	24,128
Recourse Long-Term Debt | SEACOR Offshore Delta (f/k/a SEACOSCO) Acquisition Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	19,705
Recourse Long-Term Debt | SEACOR Delta (f/k/a SEACOSCO) Shipyard Financing
Debt Instrument [Line Items]
Long-term Debt, Gross	97,189
Recourse Long-Term Debt | SEACOR Alpine Shipyard Financing
Debt Instrument [Line Items]
Long-term Debt, Gross	31,410	10,534
Recourse Long-Term Debt | SEACOR 88/888 Term Loan
Debt Instrument [Line Items]
Long-term Debt, Gross	5,500	5,500
Recourse Long-Term Debt | BNDES Equipment Construction Finance Notes
Debt Instrument [Line Items]
Long-term Debt, Gross	2,682	3,332
Non-Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	149,328	147,579
Non-Recourse Long-Term Debt | SEACOR 88/888 Term Loan
Debt Instrument [Line Items]
Long-term Debt, Gross	5,500	5,500
Non-Recourse Long-Term Debt | Falcon Global USA Term Loan Facility
Debt Instrument [Line Items]
Long-term Debt, Gross	102,350	102,349
Non-Recourse Long-Term Debt | Falcon Global USA Revolver
Debt Instrument [Line Items]
Long-term Debt, Gross	15,000	15,000
Non-Recourse Long-Term Debt | Windcat Workboats Facilities
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 26,478	$ 24,730

Long Term Debt - Schedule of _2

Long Term Debt - Schedule of Long-term Debt Obligations (Parenthetical) (Details)	9 Months Ended
	Sep. 30, 2020Vessel
SEACOR Delta Shipyard Financing | SEACOSCO Offshore LLC
Debt Instrument [Line Items]
Number of vessels acquired	8

Long Term Debt - Additional Inf

Long Term Debt - Additional Information (Details) € in Millions	Mar. 03, 2020EUR (€)	Feb. 07, 2020USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2020EUR (€)	Sep. 30, 2019USD ($)	Dec. 31, 2019	Jun. 29, 2020USD ($)Vessel	Oct. 31, 2019Vessel	Feb. 08, 2018USD ($)	May 24, 2016EUR (€)
Debt Instrument [Line Items]
Net financial debt to equity ratio			101.00%
Repayments of long-term debt, total			$ 16,970,000		$ 20,075,000
Number of additional vessels owned | Vessel							2
Lease Obligations, Labor and Performance Guaranties
Debt Instrument [Line Items]
Letters of credit outstanding, amount			500,000
FGUSA Omnibus Amendment
Debt Instrument [Line Items]
Repayment terms		the extension from March 2020 to March 2021 of the commencement of monthly amortization of the term loan, with payments being the lesser of (a) $0.8 million per month and (b) the amount outstanding under the term loan
Repayments of long-term debt, total		$ 800,000
Extension term of Guaranty		1 year
Deferred Purchase Agreements | SEACOR Delta (f/k/a SEACOSCO)
Debt Instrument [Line Items]
Purchase price payable for equity method investment in first year			1,000,000
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 Delta (f/k/a SEACOSCO) | Platform Supply Vessels
Debt Instrument [Line Items]
Equity method investment, amortization of purchase price			10 years	10 years
Debt instrument, description of floating interest rate basis			three-month LIBOR plus 4.0%	three-month LIBOR plus 4.0%
Debt instrument, basis spread on floating interest rate			4.00%	4.00%
Sea-Cat Crewzer III Term Loan Facility
Debt Instrument [Line Items]
Net financial debt to equity ratio			70.00%
Term and Revolving Loan Facility | FGUSA Omnibus Amendment
Debt Instrument [Line Items]
Debt agreement maximum borrowing capacity									$ 131,100,000
SEACOR Alpine Shipyard Financing
Debt Instrument [Line Items]
Debt instrument, interest rate						5.00%
Percentage of amount of loan to be 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
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
Debt instrument, increase (decrease), net,			$ 1,100,000
Line of credit facility, amount available under credit facilities			$ 1,500,000
Loan Facility With DNB Bank ASA
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity							$ 130,000,000
BNDES Equipment Construction Finance Notes
Debt Instrument [Line Items]
Number of vessels purchased from the company | Vessel								2

Leases - Additional Information

Leases - Additional Information (Details)	9 Months Ended
	Sep. 30, 2020Vessel
Anchor Handling Towing Supply
Lessee Lease Description [Line Items]
Number of operating leases on equipment	2
Liftboats
Lessee Lease Description [Line Items]
Number of operating leases on equipment	2
Fast Support Vessels
Lessee Lease Description [Line Items]
Number of operating leases on equipment	1
Vessels | Minimum
Lessee Lease Description [Line Items]
Operating lease, lease terms (in duration)	2 months
Vessels | Maximum
Lessee Lease Description [Line Items]
Operating lease, lease terms (in duration)	15 months
Other Equipment | Minimum
Lessee Lease Description [Line Items]
Operating lease, lease terms (in duration)	6 months
Other Equipment | Maximum
Lessee Lease Description [Line Items]
Operating lease, lease terms (in duration)	315 months

Leases - Summary of Future Mini

Leases - Summary of Future Minimum Payments For Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Operating Leases
Remainder of 2020	$ 3,718
2021	7,955
2022	714
2023	727
2024	793
Years subsequent to 2024	4,982
Operating lease payments due	18,889
Interest component	(3,563)
Total operating leases	15,326
Current portion of operating lease liabilities	9,632	$ 15,099
Long-Term Operating Lease Liabilities	5,694	$ 9,822
Finance Leases
Remainder of 2020	3
2021	39
2022	39
2023	39
2024	36
Total finance leases	156
Interest component	(16)
Finance Leases	140
Current Portion of financing lease liabilities	27
Long-Term Financing Lease Liabilities	$ 113

Leases - Summary of Components

Leases - Summary of Components of Leases Expense (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Leases [Abstract]
Operating lease cost	[1]	$ 1,083	$ 3,446	$ 5,460	$ 10,669
Finance lease cost:
Amortization of finance lease assets	[1]	3		3
Short-term lease costs	[1]	307	725	692	1,967
Total Lease expense		$ 1,393	$ 4,171	$ 6,155	$ 12,636
[1]	Included in selling, general and administrative expenses in the consolidated statements of income

Leases - Summary of Supplementa

Leases - Summary of Supplemental Cash Flow Information Related to Leases (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)
Leases [Abstract]
Operating cash flows from operating leases	$ 11,252
Right-of-use assets obtained for operating lease liabilities	1,483
Right-of-use assets obtained for finance lease liabilities	$ 140

Leases - Summary of Other Infor

Leases - Summary of Other Information Related to Leases (Details)	Sep. 30, 2020
Leases [Abstract]
Weighted average remaining lease term, in years - operating leases	6 years 1 month 6 days
Weighted average remaining lease term, in years - finance leases	4 years 2 months 12 days
Weighted average discount rate - operating leases	4.40%
Weighted average discount rate - finance leases	5.30%

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details)	9 Months Ended
	Sep. 30, 2020
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Statutory rate	21.00%
Foreign taxes not creditable against U.S. income tax	(4.30%)
Falcon Global Acquisition	4.50%
Noncontrolling interests	(1.30%)
CARES Act NOL Carryback	16.40%
Other	(1.10%)
Effective income tax rate reconciliation, percent, total	35.20%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Millions	Jun. 26, 2020	Sep. 30, 2020	Sep. 30, 2020
Income Taxes [Line Items]
Income tax refunds		$ 1.6
Foreign tax credits		0.3
Expected tax refund		0.4	$ 0.4
Tax Refund Agreement
Income Taxes [Line Items]
Expected to cash tax refunds receivable	$ 31.2
Percentage of net operating losses facilitate tax savings	35.00%
Cash tax refunds receivable without restrict to use			19.7
Cash tax refunds receivable with restrict to use			11.5
Tax refunds restricted cash		$ 10.4	$ 10.4
Transaction fee	$ 3

Derivative Instruments and He_3

Derivative Instruments and Hedging Strategies - Schedule of Fair Value of Derivative Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Designated as Hedging Instrument | Cash Flow Hedging
Derivative [Line Items]
Derivative Liability	$ 4,103	$ 3,009
Designated as Hedging Instrument | Interest Rate Swap | Cash Flow Hedging
Derivative [Line Items]
Derivative Liability	4,103	3,009
Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative Liability	4,104	8,214
Conversion option liability on Convertible Senior Notes	$ 1	$ 5,205

Derivative Instruments and He_4

Derivative Instruments and Hedging Strategies - Additional Information (Details) $ in Thousands, € in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020EUR (€)
Derivative [Line Items]
Derivative losses on cash flow hedges	$ (82)	$ (329)	$ (2,028)	$ (2,263)
Maximum
Derivative [Line Items]
Equity method investment, ownership percentage	50.00%	50.00%	50.00%	50.00%	50.00%
Minimum
Derivative [Line Items]
Equity method investment, ownership percentage	20.00%		20.00%		20.00%
Minimum | SEACOR Marine Foreign Holdings
Derivative [Line Items]
Equity method investment, ownership percentage	50.00%		50.00%		50.00%
Cash Flow Hedging
Derivative [Line Items]
Derivative losses on cash flow hedges			$ (1,100)	$ (1,900)
Cash Flow Hedging | Interest Rate Swap | Designated as Hedging Instrument | Windcat Workboats
Derivative [Line Items]
Derivative, number of instruments held, total	2		2		2
Derivative, fixed interest rate	0.03%		0.03%		0.03%
Derivative, notional amount	$ 17,600		$ 17,600		€ 15
Cash Flow Hedging | Interest Rate Swap | Designated as Hedging Instrument | SEACOR 88/888
Derivative [Line Items]
Derivative, fixed interest rate	3.175%		3.175%		3.175%
Derivative, notional amount	$ 5,500		$ 5,500
Cash Flow Hedging | Interest Rate Swap | Designated as Hedging Instrument | MexMar
Derivative [Line Items]
Equity method investment, ownership percentage	49.00%		49.00%		49.00%
Derivative, number of instruments held, total	5		5		5
Derivative, notional amount	$ 72,800		$ 72,800
Cash Flow Hedging | 3.32% Interest Rate Swap Agreement | Designated as Hedging Instrument | SEACOR Marine Foreign Holdings
Derivative [Line Items]
Derivative, fixed interest rate	3.32%		3.32%		3.32%
Derivative, notional amount	$ 8,000		$ 8,000
Cash Flow Hedging | 3.195% Interest Rate Swap Agreement | Designated as Hedging Instrument | SEACOR Marine Foreign Holdings
Derivative [Line Items]
Derivative, fixed interest rate	3.195%		3.195%		3.195%
Derivative, notional amount	$ 44,400		$ 44,400
Cash Flow Hedging | Maximum | Interest Rate Swap | Designated as Hedging Instrument | MexMar
Derivative [Line Items]
Derivative, fixed interest rate	2.10%		2.10%		2.10%
Cash Flow Hedging | Minimum | Interest Rate Swap | Designated as Hedging Instrument | MexMar
Derivative [Line Items]
Derivative, fixed interest rate	1.71%		1.71%		1.71%

Derivative Instruments and He_5

Derivative Instruments and Hedging Strategies - Schedule of Gains (Losses) on Derivative Instruments not Designated as Hedging Instruments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative [Line Items]
Gains (losses) on derivative instruments	$ 5	$ 3,057	$ 5,204	$ 734
Embedded Derivative Financial Instruments
Derivative [Line Items]
Gains (losses) on derivative instruments	$ 5	$ 3,057	$ 5,204	$ 734

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Inputs, Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Construction reserve funds		$ 12,893
Fair Value, Inputs, Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative Liability	$ 4,103	3,009
Fair Value, Inputs, Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Conversion Option Liability on Convertible Senior Notes	$ 1	$ 5,205

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Estimated Fair Values of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Reported Value Measurement
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash, cash equivalents and restricted cash	$ 48,531	$ 87,047
Investments, at cost, in 50% or less owned companies (included in other assets)	132	132
Long-term debt, including current portion	505,072	398,053
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 1
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash, cash equivalents and restricted cash	48,531	87,047
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, including current portion	$ 477,430	$ 380,815

Fair Value Measurements - Sch_3

Fair Value Measurements - Schedule of Other Assets and Liabilities Measured at Fair Value (Details) - Fair Value, Inputs, Level 2 - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Liftboats
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Property and equipment	$ 36,602
Anchor Handling Towing Supply
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Property and equipment		$ 520
Fast Support Vessels
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Property and equipment		$ 1,858

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020
Liftboat and Specialty
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Impairment charges	$ 0	$ 12.5

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - shares	Sep. 18, 2020	Sep. 01, 2020	Mar. 20, 2020	Sep. 30, 2020	Jun. 09, 2020
Class Of Stock [Line Items]
Class of warrant or right, exercised during period	83,367	255,307
Exchange Warrants
Class Of Stock [Line Items]
Class of warrant or right, outstanding				1,488,292
Number of shares withheld in an exercise to purchase warrants as payment for the exercise	354
2017 Equity Incentive Plan
Class Of Stock [Line Items]
Common shares registered for issuance				2,174,000
Common shares remaining available for issuance					24,821
2020 Equity Incentive Plan
Class Of Stock [Line Items]
Common shares registered for issuance					2,114,821
Common shares authorized for issuance					2,080,000
Falcon Global Holdings
Class Of Stock [Line Items]
Business acquisition, percentage of voting interests acquired			28.00%
Business acquisition, exchange for consideration			900,000
Ownership percentage by parent			100.00%

Noncontrolling Interests in S_3

Noncontrolling Interests in Subsidiaries - Schedule of Noncontrolling Interests in the Company's Consolidated Subsidiaries (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Mar. 19, 2020	Dec. 31, 2019
Minority Interest [Line Items]
Noncontrolling interest	$ 350		$ 21,432
Falcon Global
Minority Interest [Line Items]
Noncontrolling interest, ownership percentage by noncontrolling owners	0.00%	28.00%
Noncontrolling interest			21,119
Other Noncontrolling Interests
Minority Interest [Line Items]
Noncontrolling interest	$ 350		$ 313
Other Noncontrolling Interests | Minimum
Minority Interest [Line Items]
Noncontrolling interest, ownership percentage by noncontrolling owners	1.80%
Other Noncontrolling Interests | Maximum
Minority Interest [Line Items]
Noncontrolling interest, ownership percentage by noncontrolling owners	3.00%

Noncontrolling Interests in S_4

Noncontrolling Interests in Subsidiaries - Schedule of Noncontrolling Interests in the Company's Consolidated Subsidiaries (Parenthetical) (Details)	Sep. 30, 2020	Mar. 19, 2020
Falcon Global
Minority Interest [Line Items]
Noncontrolling interest, ownership percentage by noncontrolling owners	0.00%	28.00%

Noncontrolling Interests in S_5

Noncontrolling Interests in Subsidiaries - Additional Information (Details) - USD ($) $ in Thousands	Mar. 20, 2020	Mar. 19, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Minority Interest [Line Items]
Net income (loss), including portion attributable to noncontrolling interest, total			$ (18,077)	$ (18,241)	$ (44,135)	$ (76,778)
Net income (loss) attributable to noncontrolling interest, total			$ 4	$ 204	$ (4,036)	$ (4,395)
Falcon Global Holdings
Minority Interest [Line Items]
Business acquisition, percentage of voting interests acquired	100.00%
Falcon Global Holdings | Common Stock
Minority Interest [Line Items]
Business acquisition, exchange for consideration	900,000
Falcon Global Holdings
Minority Interest [Line Items]
Noncontrolling Interest, ownership percentage by parent	28.00%	72.00%
Business acquisition, percentage of voting interests acquired	28.00%
Business acquisition, exchange for consideration	900,000
Net income (loss), including portion attributable to noncontrolling interest, total		$ 16,600
Net income (loss) attributable to noncontrolling interest, total		$ 4,600

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) R$ in Thousands, $ in Millions	9 Months Ended
	Sep. 30, 2020USD ($)	Sep. 30, 2020BRL (R$)
Commitments And Contingencies [Line Items]
Remaining capital commitment	$ 13.1
Unrecorded unconditional purchase obligation due within four years	9.6
Unrecorded unconditional purchase obligation, due in remainder of fiscal year	1.5
Unrecorded unconditional purchase obligation, due within two years	11.6
Amount guaranteed under arrangement	$ 10.4
SEACOR Holdings
Commitments And Contingencies [Line Items]
Related party transaction, rate	0.50%
Deficiency Notice
Commitments And Contingencies [Line Items]
Cost allocation percentage	70.00%
Deficiency Notice | Seabulk Overseas
Commitments And Contingencies [Line Items]
Cost allocation percentage	30.00%
Minimum | Deficiency Notice
Commitments And Contingencies [Line Items]
Potential range of levies	$ 3.2	R$ 18050
Maximum | Deficiency Notice
Commitments And Contingencies [Line Items]
Potential range of levies	$ 2.3	R$ 12870
Platform Supply Vessels
Commitments And Contingencies [Line Items]
Unrecorded unconditional purchase obligation, maximum quantity	2	2
Crew Transfer Vessels
Commitments And Contingencies [Line Items]
Unrecorded unconditional purchase obligation, maximum quantity	1	1
FSV Offshore Support Vessels
Commitments And Contingencies [Line Items]
Unrecorded unconditional purchase obligation, maximum quantity	1	1

Stock Based Compensation - Summ

Stock Based Compensation - Summary of Transactions in Connection with Equity Incentive Plans (Details)	9 Months Ended
	Sep. 30, 2020shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding as of the beginning of year (in shares)	913,569
Granted (in shares)	261,972
Exercised (in shares)	(20,000)
Forfeited (in shares)	(35,000)
Outstanding as of the end of year (in shares)	1,120,541
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding as of the beginning of year (in shares)	303,609
Granted (in shares)	289,452
Vested (in shares)	(115,185)
Forfeited (in shares)	(8,182)
Outstanding as of the end of year (in shares)	469,694

Stock Based Compensation - Addi

Stock Based Compensation - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jun. 09, 2020
Class Of Stock [Line Items]
Treasury stock, shares acquired		26,097
Treasury stock, value acquired cost method	$ 240	$ 178	$ 524
2020 Equity Incentive Plan
Class Of Stock [Line Items]
Common shares registered for issuance				2,114,821

Segment Information - Schedule

Segment Information - Schedule of Segment Reporting Information, by Segment (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2020		Sep. 30, 2019		Sep. 30, 2020		Sep. 30, 2019		Dec. 31, 2019
Segment Reporting Information [Line Items]
Operating Revenues	$ 45,697		$ 54,700		$ 129,318		$ 152,422
Direct Costs and Expenses	29,128		27,211		77,661		97,747
Direct Vessel Profit	16,569		27,489		51,657		54,675
Lease expense	1,390		4,153		6,152		12,589
Administrative and general	10,155		11,462		35,480		32,798
Depreciation and amortization	16,613		16,091		46,927		48,600
Other Costs and Expenses	28,158		31,706		88,559		93,987
Gain (Loss) on Asset Dispositions and Impairments	233		861		(15,792)		(2,719)
Operating Loss	(11,356)		(3,356)		(52,694)		(42,031)
Historical cost	1,078,169		1,070,374		1,078,169		1,070,374		$ 976,978
Accumulated depreciation	(334,387)		(400,628)		(334,387)		(400,628)		(358,962)
Property and equipment	743,782		669,746		743,782		669,746		$ 618,016
Total Assets	937,983	[1]	894,554	[2]	937,983	[1]	894,554	[2]
Time Charter
Segment Reporting Information [Line Items]
Operating Revenues	43,586		49,747		122,683		137,836
Bareboat Charter
Segment Reporting Information [Line Items]
Operating Revenues	676		1,765		2,123		4,297
Other Marine Services
Segment Reporting Information [Line Items]
Operating Revenues	1,435		3,188		4,512		10,289
Personnel
Segment Reporting Information [Line Items]
Direct Costs and Expenses	16,513		15,879		43,597		50,416
Repairs and Maintenance
Segment Reporting Information [Line Items]
Direct Costs and Expenses	4,639		5,495		13,754		20,686
Drydocking
Segment Reporting Information [Line Items]
Direct Costs and Expenses	585		515		2,516		5,082
Insurance and Loss Reserves
Segment Reporting Information [Line Items]
Direct Costs and Expenses	1,873		1,198		4,401		4,375
Fuel, Lubes and Supplies
Segment Reporting Information [Line Items]
Direct Costs and Expenses	2,388		2,910		6,750		8,918
Other Direct Costs and Expenses
Segment Reporting Information [Line Items]
Direct Costs and Expenses	3,130		1,214		6,643		8,270
UNITED STATES
Segment Reporting Information [Line Items]
Operating Revenues	2,872		12,349		11,327		35,667
Direct Costs and Expenses	3,933		7,606		12,617		29,826
Direct Vessel Profit	(1,061)		4,743		(1,290)		5,841
Lease expense	716		2,758		3,595		8,611
Depreciation and amortization	4,961		5,634		15,573		16,473
Historical cost	258,710		329,913		258,710		329,913
Accumulated depreciation	(128,390)		(161,315)		(128,390)		(161,315)
Property and equipment	130,320		168,598		130,320		168,598
Total Assets	172,218	[1]	251,547	[2]	172,218	[1]	251,547	[2]
UNITED STATES | Time Charter
Segment Reporting Information [Line Items]
Operating Revenues	1,668		10,914		7,521		31,547
UNITED STATES | Bareboat Charter
Segment Reporting Information [Line Items]
Operating Revenues	731		597		2,178		830
UNITED STATES | Other Marine Services
Segment Reporting Information [Line Items]
Operating Revenues	473		838		1,628		3,290
UNITED STATES | Personnel
Segment Reporting Information [Line Items]
Direct Costs and Expenses	2,481		4,353		7,693		14,059
UNITED STATES | Repairs and Maintenance
Segment Reporting Information [Line Items]
Direct Costs and Expenses	338		1,508		1,269		6,801
UNITED STATES | Drydocking
Segment Reporting Information [Line Items]
Direct Costs and Expenses			547		1,167		4,342
UNITED STATES | Insurance and Loss Reserves
Segment Reporting Information [Line Items]
Direct Costs and Expenses	778		371		1,267		1,804
UNITED STATES | Fuel, Lubes and Supplies
Segment Reporting Information [Line Items]
Direct Costs and Expenses	251		739		964		2,529
UNITED STATES | Other Direct Costs and Expenses
Segment Reporting Information [Line Items]
Direct Costs and Expenses	85		88		257		291
Africa
Segment Reporting Information [Line Items]
Operating Revenues	7,256		11,867		27,982		33,156
Direct Costs and Expenses	6,091		6,268		17,126		21,013
Direct Vessel Profit	1,165		5,599		10,856		12,143
Lease expense	430		761		1,973		2,333
Depreciation and amortization	2,667		2,681		8,160		7,796
Historical cost	203,890		221,080		203,890		221,080
Accumulated depreciation	(57,861)		(64,748)		(57,861)		(64,748)
Property and equipment	146,029		156,332		146,029		156,332
Total Assets	156,551	[1]	167,714	[2]	156,551	[1]	167,714	[2]
Africa | Time Charter
Segment Reporting Information [Line Items]
Operating Revenues	7,641		11,738		28,680		32,911
Africa | Other Marine Services
Segment Reporting Information [Line Items]
Operating Revenues	(385)		129		(698)		245
Africa | Personnel
Segment Reporting Information [Line Items]
Direct Costs and Expenses	2,597		3,308		7,838		10,603
Africa | Repairs and Maintenance
Segment Reporting Information [Line Items]
Direct Costs and Expenses	1,066		1,323		3,880		3,459
Africa | Drydocking
Segment Reporting Information [Line Items]
Direct Costs and Expenses	481		(53)		745		237
Africa | Insurance and Loss Reserves
Segment Reporting Information [Line Items]
Direct Costs and Expenses	267		230		648		682
Africa | Fuel, Lubes and Supplies
Segment Reporting Information [Line Items]
Direct Costs and Expenses	994		961		2,193		2,654
Africa | Other Direct Costs and Expenses
Segment Reporting Information [Line Items]
Direct Costs and Expenses	686		499		1,822		3,378
Middle East and Asia
Segment Reporting Information [Line Items]
Operating Revenues	13,968		15,212		40,274		41,463
Direct Costs and Expenses	9,543		7,031		24,480		24,868
Direct Vessel Profit	4,425		8,181		15,794		16,595
Lease expense	46		43		123		131
Depreciation and amortization	4,379		3,914		12,090		12,437
Historical cost	365,049		297,735		365,049		297,735
Accumulated depreciation	(75,013)		(74,225)		(75,013)		(74,225)
Property and equipment	290,036		223,510		290,036		223,510
Total Assets	312,622	[1]	257,294	[2]	312,622	[1]	257,294	[2]
Middle East and Asia | Time Charter
Segment Reporting Information [Line Items]
Operating Revenues	13,672		14,798		39,044		40,472
Middle East and Asia | Other Marine Services
Segment Reporting Information [Line Items]
Operating Revenues	296		414		1,230		991
Middle East and Asia | Personnel
Segment Reporting Information [Line Items]
Direct Costs and Expenses	5,171		4,023		12,777		12,569
Middle East and Asia | Repairs and Maintenance
Segment Reporting Information [Line Items]
Direct Costs and Expenses	1,564		1,387		4,390		6,209
Middle East and Asia | Drydocking
Segment Reporting Information [Line Items]
Direct Costs and Expenses	104		20		718		454
Middle East and Asia | Insurance and Loss Reserves
Segment Reporting Information [Line Items]
Direct Costs and Expenses	451		333		1,220		1,041
Middle East and Asia | Fuel, Lubes and Supplies
Segment Reporting Information [Line Items]
Direct Costs and Expenses	482		701		2,102		2,135
Middle East and Asia | Other Direct Costs and Expenses
Segment Reporting Information [Line Items]
Direct Costs and Expenses	1,771		567		3,273		2,460
Latin America
Segment Reporting Information [Line Items]
Operating Revenues	8,833		3,340		16,797		13,515
Direct Costs and Expenses	3,935		1,275		7,929		6,694
Direct Vessel Profit	4,898		2,065		8,868		6,821
Lease expense	9				27		1
Depreciation and amortization	1,708		1,573		3,557		5,168
Historical cost	109,802		108,224		109,802		108,224
Accumulated depreciation	(11,545)		(50,928)		(11,545)		(50,928)
Property and equipment	98,257		57,296		98,257		57,296
Total Assets	175,164	[1]	125,138	[2]	175,164	[1]	125,138	[2]
Latin America | Time Charter
Segment Reporting Information [Line Items]
Operating Revenues	8,621		1,951		16,268		8,919
Latin America | Bareboat Charter
Segment Reporting Information [Line Items]
Operating Revenues			1,168				3,467
Latin America | Other Marine Services
Segment Reporting Information [Line Items]
Operating Revenues	212		221		529		1,129
Latin America | Personnel
Segment Reporting Information [Line Items]
Direct Costs and Expenses	2,342		846		4,934		3,378
Latin America | Repairs and Maintenance
Segment Reporting Information [Line Items]
Direct Costs and Expenses	704		298		1,351		1,114
Latin America | Drydocking
Segment Reporting Information [Line Items]
Direct Costs and Expenses					(114)		47
Latin America | Insurance and Loss Reserves
Segment Reporting Information [Line Items]
Direct Costs and Expenses	138		31		312		232
Latin America | Fuel, Lubes and Supplies
Segment Reporting Information [Line Items]
Direct Costs and Expenses	307		187		574		929
Latin America | Other Direct Costs and Expenses
Segment Reporting Information [Line Items]
Direct Costs and Expenses	444		(87)		872		994
Europe, Continuing Operations
Segment Reporting Information [Line Items]
Operating Revenues	12,768		11,932		32,938		28,621
Direct Costs and Expenses	5,626		5,031		15,509		15,346
Direct Vessel Profit	7,142		6,901		17,429		13,275
Lease expense	189		591		434		1,513
Depreciation and amortization	2,898		2,289		7,547		6,726
Historical cost	140,718		113,422		140,718		113,422
Accumulated depreciation	(61,578)		(49,412)		(61,578)		(49,412)
Property and equipment	79,140		64,010		79,140		64,010
Total Assets	121,428	[1]	92,861	[2]	121,428	[1]	92,861	[2]
Europe, Continuing Operations | Time Charter
Segment Reporting Information [Line Items]
Operating Revenues	11,984		10,346		31,170		23,987
Europe, Continuing Operations | Bareboat Charter
Segment Reporting Information [Line Items]
Operating Revenues	(55)				(55)
Europe, Continuing Operations | Other Marine Services
Segment Reporting Information [Line Items]
Operating Revenues	839		1,586		1,823		4,634
Europe, Continuing Operations | Personnel
Segment Reporting Information [Line Items]
Direct Costs and Expenses	3,922		3,349		10,355		9,807
Europe, Continuing Operations | Repairs and Maintenance
Segment Reporting Information [Line Items]
Direct Costs and Expenses	967		979		2,864		3,103
Europe, Continuing Operations | Drydocking
Segment Reporting Information [Line Items]
Direct Costs and Expenses			1				2
Europe, Continuing Operations | Insurance and Loss Reserves
Segment Reporting Information [Line Items]
Direct Costs and Expenses	239		233		954		616
Europe, Continuing Operations | Fuel, Lubes and Supplies
Segment Reporting Information [Line Items]
Direct Costs and Expenses	354		322		917		671
Europe, Continuing Operations | Other Direct Costs and Expenses
Segment Reporting Information [Line Items]
Direct Costs and Expenses	$ 144		$ 147		$ 419		$ 1,147
[1]	Total assets by region does not include corporate assets of $119,192 as of September 30, 2020
[2]	Total assets by region does not include corporate assets of $145,952 as of September 30, 2019

Segment Information - Schedul_2

Segment Information - Schedule of Segment Reporting Information, by Segment (Parenthetical) (Details) - USD ($)	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Segment Reporting Information [Line Items]
Assets, Total	$ 1,057,175,000	$ 1,009,193,000
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Assets, Total	$ 119,192		$ 145,952

Segment Information - Additiona

Segment Information - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Segment Information [Line Items]
Equity method investments	$ 88.9
Equity in Gains (Losses) Earnings of 50% or Less Owned Companies	$ 1.5	$ (11.9)
Maximum
Segment Information [Line Items]
Equity method investment, ownership percentage	50.00%	50.00%
Minimum
Segment Information [Line Items]
Equity method investment, ownership percentage	20.00%
Other Offshore Marine Services Joint Ventures
Segment Information [Line Items]
Equity method investments		$ 118.2
Other Offshore Marine Services Joint Ventures | Maximum
Segment Information [Line Items]
Equity method investment, ownership percentage		50.00%

Discontinued Operations - Sched

Discontinued Operations - Schedule of Assets Held for Sale (Details) - BPOS - Discontinued Operations, Held-for-sale - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Operating Revenues:
Operating Revenues	$ 11,212	$ 34,084
Costs and Expenses:
Operating	9,847	27,113
Direct Vessel Profit	1,365	6,971
General and Administrative Expenses	1,047	3,350
Lease Expense	18	47
Depreciation	1,035	3,213
Total expenses	2,100	6,610
(Loss) on Asset Dispositions and Impairments, Net		91
Operating Income	(735)	452
Other Income (Expense)
Interest income		10
Interest expense	55	184
Foreign currency translation loss	(42)	(82)
Other Income (Expense)	(97)	(256)
Operating Loss Before Equity Earnings of 50% or Less Owned Companies, Net of Tax	(832)	196
Income Tax Expense		4
Operating Loss Before Equity Earnings of 50% or Less Owned Companies	(832)	192
Loss on the Sale of Boston Putford Offshore Safety Ltd	(7,084)	(7,084)
Equity in Earnings of 50% or Less Owned Companies, Net of Tax	17	168
Net (Loss) Income from Discontinued Operations	(7,899)	(6,724)
Time Charter
Operating Revenues:
Operating Revenues	11,223	34,034
Other Revenue
Operating Revenues:
Operating Revenues	$ (11)	$ 50