SEACOR Marine (SMHI) 10-Q 11 May 20 2020 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2020	May 04, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
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		23,027,225
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
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	Mar. 31, 2020	Dec. 31, 2019
Current Assets:
Cash and cash equivalents	$ 69,220	$ 83,943
Restricted cash	3,353	3,104
Receivables:
Trade, net of allowance for credit loss accounts of $375 and $455 in 2020 and 2019, respectively	48,192	49,128
Other	27,872	18,531
Inventories	1,575	1,228
Prepaid expenses and other	2,653	2,612
Total current assets	152,865	158,546
Property and Equipment:
Historical cost	930,264	976,978
Accumulated depreciation	(312,911)	(358,962)
Property and equipment	617,353	618,016
Construction in progress	55,302	74,344
Net property and equipment	672,655	692,360
Right-of-Use Asset - Operating Leases	8,990	17,313
Investments, at Equity, and Advances to 50% or Less Owned Companies	125,010	124,680
Construction Reserve Funds	3,745	12,893
Other Assets	3,270	3,401
Total assets	966,535	1,009,193
Current Liabilities:
Current portion of operating lease liabilities	13,359	15,099
Current portion of long-term debt:
Recourse	36,278	17,802
Non-recourse	806
Accounts payable and accrued expenses	32,023	25,691
Due to SEACOR Holdings	66	74
Accrued wages and benefits	1,274	1,832
Accrued interest	1,835	731
Accrued income taxes	1,143
Deferred revenue and unearned revenue	3,787	5,327
Accrued capital, repair and maintenance expenditures	10,577	15,997
Accrued insurance deductibles and premiums	2,921	3,564
Accrued professional fees	652	871
Derivatives	4,893	3,009
Other current liabilities	2,867	4,820
Total current liabilities	112,481	94,817
Long-Term Operating Lease Liabilities	7,859	9,822
Long-Term Debt:
Recourse	217,733	239,939
Non-recourse	138,996	140,312
Conversion Option Liability on Convertible Senior Notes	91	5,205
Deferred Income Taxes	26,113	33,905
Deferred Gains and Other Liabilities	7,951	6,269
Total liabilities	511,224	530,269
SEACOR Marine Holdings Inc. stockholders’ equity:
Common stock, $.01 par value, 60,000,000 shares authorized; 23,099,127 and 21,928,674 shares issued in 2020 and 2019, respectively	231	219
Additional paid-in capital	447,425	429,318
Retained earnings	11,131	27,076
Shares held in treasury of 71,902 and 47,185, respectively, at cost	844	669
Accumulated other comprehensive loss, net of tax	(2,971)	1,548
Total stockholders equity	454,972	457,492
Noncontrolling interests in subsidiaries	339	21,432
Total equity	455,311	478,924
Total liabilities and equity	$ 966,535	$ 1,009,193

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Trade receivables, allowance for credit loss	$ 375	$ 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)	23,099,127	21,928,674
Shares held in treasury (in shares)	71,902	47,185

Unaudited Condensed Consolidate

Unaudited Condensed Consolidated Statements of Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Operating Revenues	$ 41,743	$ 44,910
Costs and Expenses:
Operating	24,620	35,166
Administrative and general	10,765	10,812
Lease expense	3,407	4,137
Depreciation and amortization	15,001	16,097
Costs and expenses	53,793	66,212
Gain (loss) on Asset Dispositions and Impairments, Net	(12,572)	268
Operating Loss	(24,622)	(21,034)
Other Income (Expense):
Interest income	676	354
Interest expense	(7,638)	(7,664)
SEACOR Holdings guarantee fees	(16)	(29)
Derivative gains (losses), net	5,114	(925)
Foreign currency gains, net	65	670
Nonoperating income expense	(1,799)	(7,594)
Loss from Continuing Operations Before Income Tax Benefit and Equity in Earnings of 50% or Less Owned Companies	(26,421)	(28,628)
Income Tax Benefit	(6,668)	(3,831)
Loss from Continuing Operations Before Equity in Earnings of 50% or Less Owned Companies	(19,753)	(24,797)
Equity in Losses of 50% or Less Owned Companies	(239)	(3,476)
Loss from Continuing Operations	(19,992)	(28,273)
Net Loss	(19,992)	(28,273)
Net Loss attributable to Noncontrolling Interests in Subsidiaries	(4,047)	(2,724)
Net Loss attributable to SEACOR Marine Holdings Inc.	$ (15,945)	$ (25,549)
Basic and Diluted Loss Per Common Share and Warrants of SEACOR Marine Holdings Inc.
Continuing operations	$ (0.66)	$ (1.11)
Basic Income (Loss) Per Common Share	$ (0.66)	$ (1.11)
Weighted Average Common Shares and Warrants Outstanding:
Basic and diluted shares	23,989,029	23,090,137

Unaudited Condensed Consolida_2

Unaudited Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net Loss	$ (19,992)	$ (28,273)
Other Comprehensive Loss:
Foreign currency translation gains (losses)	(2,528)	875
Derivative losses on cash flow hedges	(2,038)	(710)
Other comprehensive income	(4,519)	(24)
Other comprehensive income, net	(4,519)	(24)
Comprehensive Loss	(24,511)	(28,297)
Comprehensive Loss attributable to Noncontrolling Interests in Subsidiaries	(4,047)	(2,724)
Comprehensive Loss attributable to SEACOR Marine Holdings Inc.	(20,464)	(25,573)
Interest Expense
Other Comprehensive Loss:
Reclassification of derivative gains (losses) on cash flow hedges	196	71
Equity Method Investments
Other Comprehensive Loss:
Reclassification of derivative gains (losses) on cash flow hedges	$ (149)	$ (260)

Unaudited Condensed Consolida_3

Unaudited Condensed Consolidated Statements of Comprehensive Loss (Parenthetical)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement Of Income And Comprehensive Income [Abstract]
Reclassification of derivative losses on cash flow hedges to equity in earnings	50.00%	50.00%

Unaudited Condensed Consolida_4

Unaudited Condensed Consolidated Statement of Changes In Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Non-Controlling Interests In Subsidiaries [Member]
Balance at Dec. 31, 2018	$ 554,935	$ 204	$ 415,372	$ (91)	$ 126,834	$ (16,788)	$ 29,404
Balance (in shares) at Dec. 31, 2018		20,439,208		4,007
Impact of adoption of accounting principle at Dec. 31, 2018	10,416				10,416
Balance at Dec. 31, 2018	565,351	$ 204	415,372	$ (91)	137,250	(16,788)	29,404
Issuance of Common Stock	6,596	$ 7	6,589
Issuance of Common Stock (in shares)		653,872
Cancellation of employee share awards	(15)		(15)
Cancellation of employee share awards (in shares)		(1,000)
Amortization of employee share awards	776		776
Exercise of options	108		108
Exercise of options (in shares)		8,750
Restricted stock vesting	(282)			$ (282)
Restricted stock vesting (in shares)		(21,551)		21,551
Acquisition of consolidated joint venture	(2,114)						(2,114)
Net Loss	(28,273)				(25,549)		(2,724)
Other comprehensive loss	(24)					(24)
Balance at Mar. 31, 2019	542,123	$ 211	422,830	$ (373)	111,701	(16,812)	24,566
Balance (in shares) at Mar. 31, 2019		21,079,279		25,558
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
Issuance of Common Stock (in shares)		900,000
Cancellation of employee share awards (in shares)		(1,497)
Restricted stock grants	3	$ 3
Restricted stock grants (in shares)		271,950
Amortization of employee share awards	1,069		1,069
Restricted stock vesting	$ (175)			$ (175)
Restricted stock vesting (in shares)	(24,715)	(24,715)		24,715
Acquisition of consolidated joint venture	$ (3,357)		13,689				(17,046)
Net Loss	(19,992)				(15,945)		(4,047)
Other comprehensive loss	(4,519)					(4,519)
Balance at Mar. 31, 2020	$ 455,311	$ 231	$ 447,425	$ (844)	$ 11,131	$ (2,971)	$ 339
Balance (in shares) at Mar. 31, 2020	23,099,127	23,027,225		71,902

Unaudited Condensed Consolida_5

Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash Flows from Continuing Operating Activities:
Net Loss	$ (19,992)	$ (28,273)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	15,001	16,097
Deferred financing costs amortization	312	320
Restricted stock amortization	1,069	761
Restricted stock vesting	(175)	(282)
Debt discount amortization	1,478	1,373
Bad debt recoveries	(80)	(404)
Loss (gain) from equipment sales, retirements or impairments	12,572	(268)
Derivative (gains) losses	(5,114)	925
Cash settlement on derivative transactions, net	(214)	(75)
Currency losses	(65)	(670)
Deferred income taxes	(7,768)	(5,160)
Equity losses	239	3,476
Dividends received from equity investees		400
Changes in Operating Assets and Liabilities:
Accounts receivables	(10,424)	(4,275)
Other assets	(855)	(2,791)
Accounts payable and accrued liabilities	5,908	13,991
Net cash used in operating activities	(8,108)	(4,855)
Cash Flows from Continuing Investing Activities:
Purchases of property and equipment	(11,244)	(20,633)
Proceeds from disposition of property and equipment	3,105	378
Net change in construction reserve fund	9,148	(48)
Investments in and advances to 50% or less owned companies	(245)	(1,951)
Net cash provided by (used in) investing activities	764	(22,254)
Cash Flows from Continuing Financing Activities:
Payments on long-term debt	(5,222)	(4,361)
Purchase of subsidiary shares from noncontrolling interests		(3,392)
Proceeds from exercise of stock options and Warrants		108
Net cash used in financing activities	(5,222)	(7,645)
Effects of Exchange Rate Changes on Cash and Cash Equivalents	(1,908)	873
Net Decrease in Cash, Restricted Cash and Cash Equivalents	(14,474)	(33,881)
Cash Flows from Discontinued Operations:
Operating Activities	0	2,888
Investing Activities	0	(376)
Effects of Exchange Rate Changes on Cash, Restricted Cash and Cash Equivalents	0	612
Net Decrease in Cash, Restricted Cash and Cash Equivalents on Discontinued Operations	0	3,124
Net Decrease in Cash, Restricted Cash and Cash Equivalents	(14,474)	(30,757)
Cash, Restricted Cash and Cash Equivalents, Beginning of Period	87,047	96,852
Cash, Restricted Cash and Cash Equivalents, End of Period	$ 72,573	$ 66,095

Basis of Presentation and Accou

Basis of Presentation and Accounting Policies	3 Months Ended
	Mar. 31, 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 decreases in commodity prices resulting from oversupply and demand weakness have caused significant disruptions and volatility in the global marketplace during the first quarter of 2020. These conditions have persisted into the second quarter, and there remains a continuing uncertainty regarding the length and impact of COVID-19 on the energy industry and the outlook for our business. Although the decrease in oil and natural gas prices has not led to a significant decrease in the demand for our products and services, a prolonged period of severely depressed oil and natural gas prices compared to historic averages could have a material adverse effect on our business. Recently Adopted Accounting Standards. On June 30, 2016, the FASB issued 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. This 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 is 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 an amendment to the accounting standards, 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 is 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 adds disclosure requirements for Level 3 measurements. This ASU is 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. 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 a change in control, 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 doubtful 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 hereunder. 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 over the length of 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 recognized 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. Contract liabilities, which are included in other current liabilities in the accompanying consolidated balance sheets, for the three months ended March 31 were as follows (in thousands): 2020 2019 Balance at beginning of period $ 4,786 $ 1,327 Revenues deferred during the period 5 3,409 Revenues recognized during the period (1,526 ) (1,136 ) Balance at end of period $ 3,265 $ 3,600 As of March 31, 2020, the Company had deferred revenues of $3.3 million primarily related to $1.5 million of prepaid vessel management fees, and $1.8 million related to the time charter of offshore support vessels to customers from which collections were not reasonably assured. 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 March 31, 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 months ended March 31, 2020, capitalized interest totaled $0.2 million. 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 our stock price, caused a triggering event to occur requiring us to test our assets for impairment. During the first quarter of 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 terms. Therefore, the Company recorded an impairment of $7.4 million in total for two leased-in vessels and recorded a partial impairment on one liftboat for $1.8 million based on an outside valuation 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 experienced over the last three years, fair values based on future appraisals could decline significantly. There were no other impairments of right-to-use assets or any other assets in the first quarter of 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 but not recently impaired as of March 31, 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 three months ended March 31, 2020 and 2019, the Company did not recognize any impairment charges related to its 50% or less owned companies. Income Taxes. During the three months ended March 31, 2020, the Company’s effective income tax rate of 25.2% was primarily due to taxes provided 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 the 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 (2,528 ) (1,991 ) (4,519 ) — — (4,519 ) Three months ended March 31, 2020 $ 2,157 $ (5,128 ) $ (2,971 ) $ (1,445 ) $ (11 ) $ 2,197 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. For both the three months ended March 31, 2020 and 2019, diluted earnings per common share of the Company excluded 2,183,708

Transformation, Facility Restru

Transformation, Facility Restructuring and Severance Charges	3 Months Ended
	Mar. 31, 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 the Company with current activity levels. The ongoing transformation plan, which began in the third quarter of 2019 and is expected to extend through the second quarter of 2020 (the “Transformation Plan”), includes 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 to reduce the Company’s overall cost structure to better align with current 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 $0.5 million for the three months ended March 31, 2020, which include severance charges of $0.5 million and other restructuring charges of less than $0.1 million. Other restructuring charges included contract termination costs, relocation and other associated costs. The restructuring and transformation charges are reflected in the Company’s general and administration expense. The components of restructuring charges by segment for the three months ended March 31, 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 Transformation Plan Severance Charges $ 128 $ — $ 235 $ — $ 110 $ 473 Other Charges 22 — 29 — — 51 Total Charges $ 150 $ — $ 264 $ — $ 110 $ 524 The severance and other restructuring charges gave rise to certain liabilities, the components of which are summarized in the following table (in thousands), and largely relate to liabilities accrued as part of the 2019 Transformation Plan that will be paid pursuant to the respective arrangements and statutory requirements. United States (primarily Gulf of Mexico) Africa (primarily West Africa) Middle East and Asia Latin America Europe (primarily North Sea) Total Transformation Plan Severance Liability $ 84 $ — $ — $ — $ 28 $ 112 Other Liability — — — — — — Total Liability $ 84 $ — $ — $ — $ 28 $ 112 The following table is a summary of the cumulative restructuring and reorganization cost incurred to date in operating charges and the estimated remaining restructuring and reorganization costs to be incurred as of March 31, 2020 (in thousands). Transformation Plan Cumulative restructuring costs incurred to date in operating charges $ 4,242 Estimated additional restructuring costs to be incurred 1,501 Total restructuring and reorganization costs incurred and to be incurred $ 5,743

Equipment Acquisitions and Disp

Equipment Acquisitions and Dispositions	3 Months Ended
	Mar. 31, 2020
Property Plant And Equipment [Abstract]
Equipment Acquisitions and Dispositions	3. During the three months ended March 31, 2020, capital acquisitions were $11.2 million. Equipment deliveries during the three months ended March 31, 2020 include one platform supply vessel (“PSV”). During the three months ended March 31, 2020, the Company sold two anchor handling towing supply (“AHTS”) vessels and one specialty vessel previously removed from service, two FSVs and other equipment for $3.1 million ($2.2 million cash and $0.9 million in previously received deposits) and gains of $1.1 million. In addition, the Company received $2.1 million in deposits for future sales.

Investments, at Equity, and Adv

Investments, at Equity, and Advances to 50% or Less Owned Companies	3 Months Ended
	Mar. 31, 2020
Schedule Of Investments [Abstract]
Investments, at Equity, and Advances to 50% or Less Owned Companies	4 . SEACOSCO . The Company, through SEACOR Offshore Asia LLC, an indirect wholly-owned subsidiary of SEACOR Marine (“SEACOR Offshore Asia”), owns an unconsolidated 50% interest in SEACOSCO Offshore LLC (“SEACOSCO”). China Shipping Fan Tai Limited (“CSFT”) and China Shipping Industry (Hong Kong) Co., Limited (“CSIHK”) own the other 50% interest in SEACOSCO. Effective May 31, 2019, SEACOR Offshore Asia, CSFT, CSIHK and COSCO Shipping Heavy Industry (Guangdong) Co., Ltd. (the “Shipyard”), the shipbuilder and lender under deferred payment agreements (“DPAs”) that are secured by the PSVs acquired by SEACOSCO, entered into a Memorandum of Understanding (“MOU”) pursuant to which (i) the Shipyard agreed to not take any action with respect to any existing defaults under the DPAs until August 31, 2019, (ii) SEACOR Offshore Asia was authorized to provide, in its sole discretion, shareholder loans to SEACOSCO and/or its subsidiaries, in an aggregate amount of $13.0 million, in respect of working capital or other payment obligations at an interest rate of 15% per annum and, subject to the priority of the indebtedness under the DPAs, the shareholder loans will have senior priority to any and all other debts of SEACOSCO and/or its subsidiaries, (“SEACOR Shareholder Loans”), (iii) the parties set out the non-binding principal terms and conditions for SEACOR Offshore Asia’s potential acquisition of the 50% interest in SEACOSCO owned by CSFT and CSIHK and (iv) in connection with such acquisition, SEACOR Offshore Asia or its nominee may acquire from the Shipyard two additional PSVs that had been under options held by SEACOSCO. Management remains in discussions with the Shipyard, CSFT and CSIHK with respect to the other transactions contemplated by the MOU and the ongoing funding requirements of SEACOSCO. Subject to these ongoing discussions, effective January 2020, SEACOSCO ceased all principal and interest payments in connection with DPAs and has approximately $3.7 million in outstanding payments as of May 1, 2020. As of March 31, 2020, the balance on the SEACOR Shareholder Loans was $13.0 million, which is the aggregate amount of SEACOR Shareholder Loans provided, and SEACOR Marine recognized interest income of $1.0 million. As of March 31, 2020, an additional $5.6 million was due from SEACOSCO to the Company related to a Ship Management Agreement.

Long Term Debt

Long Term Debt	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Long Term Debt	5 . The Company’s long-term debt obligations as of March 31, 2020 and December 31, 2019 were as follows (in thousands): March 31, 2020 December 31, 2019 Recourse Long-term debt (1) Convertible Senior Notes $ 125,000 $ 125,000 SEACOR Marine Foreign Holdings Syndicated Credit Facility 110,500 113,750 Sea-Cat Crewzer III Term Loan Facility 22,891 24,128 SEACOR Alps 10,440 10,534 SEACOR 88/888 Term Loan 5,500 5,500 BNDES Equipment Construction Finance Notes 2,844 3,332 Total recourse Long-term debt 277,175 282,244 Non-recourse Long-term debt (2) Falcon Global USA Term Loan Facility 102,349 102,349 Falcon Global USA Revolver 15,000 15,000 Windcat Workboats Facilities 23,919 24,730 SEACOR 88/888 Term Loan 5,500 5,500 Total non-recourse Long-term debt 146,768 147,579 Total principal due for long-term debt 423,943 429,823 Current portion due within one year (37,084 ) (17,802 ) Unamortized debt discount (24,865 ) (26,343 ) Deferred financing costs (5,265 ) (5,427 ) Long-term debt, less current portion $ 356,729 $ 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) Non-recourse debt represents debt issued by the Company’s Consolidated Subsidiaries with no recourse to SEACOR Marine, 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 March 31, 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 March 31, 2020, SEACOR Marine’s net financial debt to equity ratio was 72%. The Company and the lenders under this facility are in discussions to waive or otherwise modify the terms of this guarantor 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. The Company expects to receive such a waiver or modification in the second quarter of 2020 and upon receipt will reclassify the debt to long term. 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 “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 “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 Credit Facility (the “Guaranty”). The Omnibus Amendment provides for, among other things, (i) the extension from March 2020 to March 2021 of the commencement of monthly repayment 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 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 “Sixth Consent and Agreement”) to the 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. 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 (collectively, the “Obligors”) entered into an agreement (the “RCF Agreement”) with Coöperatieve Rabobank U.A. (the “Agent”) 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 amortized over the credit facility term. As of March 31, 2020, the Company has $2.3 million available under its Windcat Workboats credit facilities. Letters of Credit . As of March 31, 2020, the Company had outstanding letters of credit of $0.4 million securing lease obligations and labor and performance guaranties.

Leases

Leases	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Leases	6 . LEASES As of March 31, 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 March 31, 2020, the remaining lease terms of the vessels have remaining durations ranging from eight to 20 months. The lease terms of the other equipment range in duration from two to 321 months. As of March 31, 2020, future minimum payments for operating leases for the remainder of 2020 and the years ended December 31 were as follows (in thousands): Remainder of 2020 $ 11,489 2021 7,127 2022 669 2023 622 2024 697 Years subsequent to 2024 4,439 25,043 Interest component (3,825 ) 21,218 Current portion of long-term operating lease liabilities 13,359 Long-term operating lease liabilities $ 7,859 For the three months ended March 31, the components of lease expense were as follows (in thousands): 2020 2019 Operating lease expense $ 3,275 $ 3,612 Short-term lease expense (lease duration of twelve months or less at lease commencement) 132 525 $ 3,407 $ 4,137 For the three months ended March 31, 2020, other information related to operating leases were as follows (in thousands except weighted average data): 2020 Operating cash flows from operating leases $ 3,838 Right-of-use assets obtained for operating lease liabilities $ 9 Weighted average remaining lease term, in years 4.9 Weighted average discount rate 4.2 %

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 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 three months ended March 31, 2020: Statutory rate 21.0 % Foreign taxes not creditable against U.S. income tax (3.7 ) Falcon Global Acquisition 12.0 Noncontrolling interests (3.4 ) Other (0.7 ) 25.2 % In response to the COVID-19 pandemic, in March 2020, the Coronavirus Aid, Relief, and Economic Security Act (the “CARES Act”) was passed by the U.S. Congress and signed into law by the president. The CARES Act includes a number of provisions that amended the current U.S. tax regime applicable to the Company, including allowing net operating losses generated in 2018 through 2020 to be carried back for up to five years. The Company continues to assess the changes to U.S. tax laws included in the CARES Act but believes the changes included in the CARES Act may result in the recognition of a meaningful U.S. tax asset.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Strategies	3 Months Ended
	Mar. 31, 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): March 31, 2020 December 31, 2019 Derivative Asset Derivative Liability Derivative Asset Derivative Liability Derivatives designated as hedging instruments: Interest rate swap agreements (cash flow hedges) $ — $ 4,893 $ — $ 3,009 — 4,893 — 3,009 Derivatives not designated as hedging instruments: Conversion option liability on Convertible Senior Notes — 91 — 5,205 $ — $ 4,984 $ — $ 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 immaterial losses on derivative instruments designated as cash flow hedges during the three months ended March 31, 2020. As of March 31, 2020, the interest rate swaps held by the Company and its 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 margin on the aggregate notional value of €15.0 million (approximately $16.5 million) and receive a variable interest rate based on EURIBOR on the aggregate notional value; • SEACOR Marine Foreign Holdings • 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 $48.5 million and receive a variable interest rate based on LIBOR on the amortized notional value; and • 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 3.2% 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. Other Derivative Instruments. The Company recognized gains (losses) on derivative instruments not designated as hedging instruments for the three months ended March 31, 2020 as follows (in thousands): 2020 2019 Conversion option liability on Convertible Senior Notes $ 5,114 $ (925 ) Interest rate swap agreements — — $ 5,114 $ (925 ) 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 (“Carlyle”). See “Note 9. Fair Value Measurements”. The Company and certain of its 50% or less owned companies have entered into interest rate swap agreements that did not qualify as cash flow hedges for the general purpose of providing protection against increases in interest rates, which might lead to higher interest costs. As of March 31, 2020, these interest rate swaps held by the Company or its 50% or less owned companies were as follows: • SEACOR OSV Partners I LP (“OSV Partners”) has two interest rate swap agreements with maturities in 2020 that call for OSV Partners to pay a fixed rate of interest ranging from 1.89% to 2.27% per annum on the aggregate amortized notional value of $22.0 million and receive a variable interest rate based on LIBOR on the aggregate amortized notional value; and • Mantenimiento Express Maritimo, S.A.P.I. de (“

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 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 March 31, 2020 that are measured at fair value on a recurring basis were as follows (in thousands): Level 1 Level 2 Level 3 March 31, 2020 ASSETS Construction reserve funds $ 3,745 $ — $ — LIABILITIES Derivative instruments — 4,893 — Conversion Option Liability on Convertible Senior Notes — — 91 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 on 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 March 31, 2020 were as follows (in thousands): Estimated Fair Value Carrying Amount Level 1 Level 2 Level 3 March 31, 2020 ASSETS Cash, cash equivalents and restricted cash $ 72,573 $ 72,573 $ — $ — Investments, at cost, in 50% or less owned companies (included in other assets) 132 see below LIABILITIES Long-term debt, including current portion 393,813 — 350,081 — 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 three months ended March 31, 2020 were as follows (in thousands); 2020 Level 1 Level 2 Level 3 ASSETS Property and equipment: Liftboats $ — $ 8,100 $ — 2019 ASSETS Property and equipment: AHTS $ — $ 520 $ — FSVs — 1,858 — Property and equipment . During the three months ended March 31, 2020, the Company recognized impairment charges of $9.2 million primarily associated with certain vessels. The Level 2 fair values were determined based on the sales prices of similar property and equipment as scrap value.

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 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, par value $0.01 per share, issued to Montco as purchase consideration in a private placement. The purchase resulted in the Company owning 100% of Falcon Global Holdings.

Noncontrolling Interests in Sub

Noncontrolling Interests in Subsidiaries	3 Months Ended
	Mar. 31, 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 March 31, 2020 December 31, 2019 Falcon Global Holdings 0% (1) — $ 21,119 Other 1.8% 339 313 $ 339 $ 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 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. During the three months ended March 31, 2020, the net loss of Falcon Global Holdings was $14.5 million, including non-cash impairment charges of $9.2 million. These charges were recognized concurrently with the acquisition of the minority interest with $4.1 million of net loss attributable to noncontrolling interest.

Commitment and Contingencies

Commitment and Contingencies	3 Months Ended
	Mar. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	1 2 . COMMITMENTS AND CONTINGENCIES As of March 31, 2020, the Company’s unfunded capital commitments were $34.2 million for three PSVs and two CTVs. All of the unfunded capital commitments are payable during the remainder of 2020. The Company has indefinitely deferred an additional $16.3 million of orders with respect to two FSVs that the Company had previously reported unfunded capital commitments. On April 20, 2020, the vessel SEACOR Andes was delivered, which is the second vessel of a purchase of three vessels that was contracted in January 2019. The vessel SEACOR Alps was delivered in September 2019. The third contracted vessel, the SEACOR Atlas, is expected to be delivered in the second quarter of 2020. On April 17, 2020, Hull 488, which was under construction at the Gulf Craft Shipyard, was sold by the Company for $14.5 million resulting in a gain of $2.1 million, which will be recognized in the second quarter of 2020. In 2015, the Brazilian Federal Revenue Office issued a tax-deficiency notice to Seabulk Offshore do Brasil Ltda (“Seabulk Offshore do Brasil”), an indirect wholly-owned subsidiary of SEACOR Marine, with respect to certain profit participation contributions (“PIS”) and social security financing contributions (“COFINS”) requirements alleged to be due from Seabulk Offshore do Brasil (“Deficiency Notice”). In February 2015, Company deposited with the relevant Brazilian court an amount equal to USD $1.2 million and appealed the Deficiency Notice on the basis that such contributions were not applicable in the circumstances of a 70%/30% cost allocation structure. The case was remitted to the second instance and is currently awaiting 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. The potential range of levies arising from the Deficiency Notice is R$12.8 million - R$17.5 million (USD $2.3 million – USD $3.2 million based on the exchange rate as of March 31, 2020). 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	3 Months Ended
	Mar. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Based Compensation	1 3 . STOCK BASED COMPENSATION Transactions in connection with the Company’s 2017 Equity Incentive Plan during the three months ended March 31, 2020 were as follows: Restricted Stock Activity: Outstanding as of December 31, 2019 303,609 Granted 271,950 Vested 112,699 Forfeited 1,497 Outstanding as of March 31, 2020 461,363 Stock Option Activity: Outstanding as of December 31, 2019 913,569 Granted 37,500 Exercised — Forfeited 30,000 Outstanding as of March 31, 2020 921,069 For the three months ended March 31, 2020, the Company acquired for treasury 24,715 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.

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2020
Segment Reporting [Abstract]
Segment Information	14. 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, Continuing Operations Total For the Three Months Ended March 31, 2020 Operating Revenues: Time charter $ 4,375 $ 11,095 $ 11,767 $ 3,396 $ 8,657 $ 39,290 Bareboat charter 724 — — — — 724 Other marine services 642 167 420 149 351 1,729 5,741 11,262 12,187 3,545 9,008 41,743 Direct Costs and Expenses: Operating: Personnel 2,928 2,695 3,811 1,215 3,057 13,706 Repairs and maintenance 617 1,435 1,246 392 1,114 4,804 Drydocking 1,057 8 414 (114 ) - 1,365 Insurance and loss reserves 135 193 339 69 203 939 Fuel, lubes and supplies 524 472 665 135 271 2,067 Other 79 571 683 305 101 1,739 5,340 5,374 7,158 2,002 4,746 24,620 Direct Vessel Profit $ 401 $ 5,888 $ 5,029 $ 1,543 $ 4,262 17,123 Other Costs and Expenses: Lease expense $ 2,138 $ 1,126 $ 45 $ 9 $ 89 3,407 Administrative and general 10,765 Depreciation and amortization 5,358 2,604 3,790 899 2,350 15,001 29,173 Gain on Asset Dispositions and Impairments (12,572 ) Operating Loss $ (24,622 ) As of March 31, 2020 Property and Equipment: Historical Cost 256,059 199,242 281,767 74,308 118,888 930,264 Accumulated Depreciation (120,599 ) (52,225 ) (67,829 ) (17,271 ) (54,987 ) (312,911 ) $ 135,460 $ 147,017 $ 213,938 $ 57,037 $ 63,901 $ 617,353 Total Assets (1) $ 191,611 $ 158,660 $ 245,279 $ 134,171 $ 106,412 $ 836,133 (1) Total assets by region does not include corporate assets of $130,403 as of March 31, 2020 . United States (primarily Gulf of Mexico) Africa (primarily West Africa) Middle East and Asia Latin America Europe, Continuing Operations Total For the Three Months Ended March 31, 2019 Operating Revenues: Time charter $ 8,005 $ 10,773 $ 12,499 $ 4,922 $ 4,620 $ 40,819 Bareboat charter — — — 1,143 — 1,143 Other 1,132 (637 ) 228 635 1,590 2,948 9,137 10,136 12,727 6,700 6,210 44,910 Direct Costs and Expenses: Operating: Personnel 4,503 3,867 4,254 1,556 2,443 16,623 Repairs and maintenance 2,778 1,184 2,193 335 1,094 7,584 Drydocking 1,994 338 159 79 - 2,570 Insurance and loss reserves 592 213 327 135 147 1,414 Fuel, lubes and supplies 683 754 709 428 232 2,806 Other 90 2,106 1,100 521 352 4,169 10,640 8,462 8,742 3,054 4,268 35,166 Direct Vessel Profit, from Continuing Operations $ (1,503 ) $ 1,674 $ 3,985 $ 3,646 $ 1,942 $ 9,744 Other Costs and Expenses: Lease expense $ 2,911 $ 785 $ 46 $ 1 $ 394 $ 4,137 Administrative and general 10,812 Depreciation and amortization 5,498 2,356 4,249 1,936 2,058 16,097 31,046 Loss on Asset Dispositions and Impairments 268 Operating Loss, for Continuing Operations $ (21,034 ) As of March 31, 2019 Property and Equipment: Historical Cost 416,559 207,167 310,297 119,699 114,382 1,168,104 Accumulated Depreciation (223,720 ) (59,652 ) (85,627 ) (60,444 ) (48,796 ) (478,239 ) $ 192,839 $ 147,515 $ 224,670 $ 59,255 $ 65,586 $ 689,865 Total Assets (1) $ 330,938 $ 160,624 $ 266,007 $ 128,421 $ 91,047 $ 977,037 (1) Total assets by region does not include corporate assets of $135,312 as of March 31, 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 March 31, 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 $125.0 million and $124.7 million, respectively. Equity in (losses) earnings of 50% or less owned companies for the three months ended March 31, 2020 and 2019 were ($0.2) million and ($3.4) million, respectively.

Discontinued Operations

Discontinued Operations	3 Months Ended
	Mar. 31, 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 March 31, 2019 Boston Putford Offshore Safety Ltd Operating Revenues: Time charter $ 11,308 Other revenue 31 11,339 Costs and Expenses: Operating 9,111 Direct Vessel Profit 2,228 General and Administrative Expenses 1,188 Lease Expense 11 Depreciation 1,096 2,295 Gain on Asset Dispositions and Impairments, Net 91 Operating Income 24 Other Income (Expense) Interest income 3 Interest expense (71 ) Foreign currency translation loss (35 ) (103 ) Operating Loss Before Equity Earnings of 50% or Less Owned Companies, Net of Tax (79 ) Income Tax Expense — Operating Loss Before Equity Earnings of 50% or Less Owned Companies (79 ) Equity in Earnings of 50% or Less Owned Companies, Net of Tax 79 Net (Loss) Income from Discontinued Operations $ —

Basis of Presentation and Acc_2

Basis of Presentation and Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Recently Adopted Accounting Standards	Recently Adopted Accounting Standards. On June 30, 2016, the FASB issued 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. This 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 is 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 an amendment to the accounting standards, 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 is 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 adds disclosure requirements for Level 3 measurements. This ASU is 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.
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 a change in control, 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 doubtful 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 hereunder. 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 over the length of 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 recognized 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. Contract liabilities, which are included in other current liabilities in the accompanying consolidated balance sheets, for the three months ended March 31 were as follows (in thousands): 2020 2019 Balance at beginning of period $ 4,786 $ 1,327 Revenues deferred during the period 5 3,409 Revenues recognized during the period (1,526 ) (1,136 ) Balance at end of period $ 3,265 $ 3,600 As of March 31, 2020, the Company had deferred revenues of $3.3 million primarily related to $1.5 million of prepaid vessel management fees, and $1.8 million related to the time charter of offshore support vessels to customers from which collections were not reasonably assured.
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 March 31, 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 months ended March 31, 2020, capitalized interest totaled $0.2 million.
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 our stock price, caused a triggering event to occur requiring us to test our assets for impairment. During the first quarter of 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 terms. Therefore, the Company recorded an impairment of $7.4 million in total for two leased-in vessels and recorded a partial impairment on one liftboat for $1.8 million based on an outside valuation 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 experienced over the last three years, fair values based on future appraisals could decline significantly. There were no other impairments of right-to-use assets or any other assets in the first quarter of 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 but not recently impaired as of March 31, 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 three months ended March 31, 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 three months ended March 31, 2020, the Company’s effective income tax rate of 25.2% was primarily due to taxes provided 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 the 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 (2,528 ) (1,991 ) (4,519 ) — — (4,519 ) Three months ended March 31, 2020 $ 2,157 $ (5,128 ) $ (2,971 ) $ (1,445 ) $ (11 ) $ 2,197
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. For both the three months ended March 31, 2020 and 2019, diluted earnings per common share of the Company excluded 2,183,708

Basis of Presentation and Acc_3

Basis of Presentation and Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 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. Contract liabilities, which are included in other current liabilities in the accompanying consolidated balance sheets, for the three months ended March 31 were as follows (in thousands): 2020 2019 Balance at beginning of period $ 4,786 $ 1,327 Revenues deferred during the period 5 3,409 Revenues recognized during the period (1,526 ) (1,136 ) Balance at end of period $ 3,265 $ 3,600
Schedule of Property and Equipment Useful Life	As of March 31, 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 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 (2,528 ) (1,991 ) (4,519 ) — — (4,519 ) Three months ended March 31, 2020 $ 2,157 $ (5,128 ) $ (2,971 ) $ (1,445 ) $ (11 ) $ 2,197

Transformation, Facility Rest_2

Transformation, Facility Restructuring and Severance Charges (Tables)	3 Months Ended
	Mar. 31, 2020
Restructuring And Related Activities [Abstract]
Schedule of Components of Restructuring Charges By Segment	The components of restructuring charges by segment for the three months ended March 31, 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 Transformation Plan Severance Charges $ 128 $ — $ 235 $ — $ 110 $ 473 Other Charges 22 — 29 — — 51 Total Charges $ 150 $ — $ 264 $ — $ 110 $ 524
Schedule of Severance and Other Restructuring Charges	The severance and other restructuring charges gave rise to certain liabilities, the components of which are summarized in the following table (in thousands), and largely relate to liabilities accrued as part of the 2019 Transformation Plan that will be paid pursuant to the respective arrangements and statutory requirements. United States (primarily Gulf of Mexico) Africa (primarily West Africa) Middle East and Asia Latin America Europe (primarily North Sea) Total Transformation Plan Severance Liability $ 84 $ — $ — $ — $ 28 $ 112 Other Liability — — — — — — Total Liability $ 84 $ — $ — $ — $ 28 $ 112
Schedule of Cumulative Restructuring and Reorganization Cost Incurred to Date, Estimated Remaining and to be Incurred	The following table is a summary of the cumulative restructuring and reorganization cost incurred to date in operating charges and the estimated remaining restructuring and reorganization costs to be incurred as of March 31, 2020 (in thousands). Transformation Plan Cumulative restructuring costs incurred to date in operating charges $ 4,242 Estimated additional restructuring costs to be incurred 1,501 Total restructuring and reorganization costs incurred and to be incurred $ 5,743

Long-term Debt (Tables)

Long-term Debt (Tables)	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Schedule of Long-term Debt Obligations	The Company’s long-term debt obligations as of March 31, 2020 and December 31, 2019 were as follows (in thousands): March 31, 2020 December 31, 2019 Recourse Long-term debt (1) Convertible Senior Notes $ 125,000 $ 125,000 SEACOR Marine Foreign Holdings Syndicated Credit Facility 110,500 113,750 Sea-Cat Crewzer III Term Loan Facility 22,891 24,128 SEACOR Alps 10,440 10,534 SEACOR 88/888 Term Loan 5,500 5,500 BNDES Equipment Construction Finance Notes 2,844 3,332 Total recourse Long-term debt 277,175 282,244 Non-recourse Long-term debt (2) Falcon Global USA Term Loan Facility 102,349 102,349 Falcon Global USA Revolver 15,000 15,000 Windcat Workboats Facilities 23,919 24,730 SEACOR 88/888 Term Loan 5,500 5,500 Total non-recourse Long-term debt 146,768 147,579 Total principal due for long-term debt 423,943 429,823 Current portion due within one year (37,084 ) (17,802 ) Unamortized debt discount (24,865 ) (26,343 ) Deferred financing costs (5,265 ) (5,427 ) Long-term debt, less current portion $ 356,729 $ 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) Non-recourse debt represents debt issued by the Company’s Consolidated Subsidiaries with no recourse to SEACOR Marine, 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)	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Summary of Future Minimum Payments For Operating Leases	As of March 31, 2020, future minimum payments for operating leases for the remainder of 2020 and the years ended December 31 were as follows (in thousands): Remainder of 2020 $ 11,489 2021 7,127 2022 669 2023 622 2024 697 Years subsequent to 2024 4,439 25,043 Interest component (3,825 ) 21,218 Current portion of long-term operating lease liabilities 13,359 Long-term operating lease liabilities $ 7,859
Summary of Components of Leases Expense	For the three months ended March 31, the components of lease expense were as follows (in thousands): 2020 2019 Operating lease expense $ 3,275 $ 3,612 Short-term lease expense (lease duration of twelve months or less at lease commencement) 132 525 $ 3,407 $ 4,137
Summary of Other Information Related to Operating Leases	For the three months ended March 31, 2020, other information related to operating leases were as follows (in thousands except weighted average data): 2020 Operating cash flows from operating leases $ 3,838 Right-of-use assets obtained for operating lease liabilities $ 9 Weighted average remaining lease term, in years 4.9 Weighted average discount rate 4.2 %

Income Taxes (Tables)

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 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 three months ended March 31, 2020: Statutory rate 21.0 % Foreign taxes not creditable against U.S. income tax (3.7 ) Falcon Global Acquisition 12.0 Noncontrolling interests (3.4 ) Other (0.7 ) 25.2 %

Derivative Instruments and He_2

Derivative Instruments and Hedging Strategies (Tables)	3 Months Ended
	Mar. 31, 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): March 31, 2020 December 31, 2019 Derivative Asset Derivative Liability Derivative Asset Derivative Liability Derivatives designated as hedging instruments: Interest rate swap agreements (cash flow hedges) $ — $ 4,893 $ — $ 3,009 — 4,893 — 3,009 Derivatives not designated as hedging instruments: Conversion option liability on Convertible Senior Notes — 91 — 5,205 $ — $ 4,984 $ — $ 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 months ended March 31, 2020 as follows (in thousands): 2020 2019 Conversion option liability on Convertible Senior Notes $ 5,114 $ (925 ) Interest rate swap agreements — — $ 5,114 $ (925 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2020 that are measured at fair value on a recurring basis were as follows (in thousands): Level 1 Level 2 Level 3 March 31, 2020 ASSETS Construction reserve funds $ 3,745 $ — $ — LIABILITIES Derivative instruments — 4,893 — Conversion Option Liability on Convertible Senior Notes — — 91 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 March 31, 2020 were as follows (in thousands): Estimated Fair Value Carrying Amount Level 1 Level 2 Level 3 March 31, 2020 ASSETS Cash, cash equivalents and restricted cash $ 72,573 $ 72,573 $ — $ — Investments, at cost, in 50% or less owned companies (included in other assets) 132 see below LIABILITIES Long-term debt, including current portion 393,813 — 350,081 — 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 three months ended March 31, 2020 were as follows (in thousands); 2020 Level 1 Level 2 Level 3 ASSETS Property and equipment: Liftboats $ — $ 8,100 $ — 2019 ASSETS Property and equipment: AHTS $ — $ 520 $ — FSVs — 1,858 —

Noncontrolling Interests in S_2

Noncontrolling Interests in Subsidiaries (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2020 December 31, 2019 Falcon Global Holdings 0% (1) — $ 21,119 Other 1.8% 339 313 $ 339 $ 21,432 (1) Before March 20, 2020, noncontrolling interest was 28%.

Stock Based Compensation (Table

Stock Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Transactions in Connection with 2017 Equity Incentive Plan	Transactions in connection with the Company’s 2017 Equity Incentive Plan during the three months ended March 31, 2020 were as follows: Restricted Stock Activity: Outstanding as of December 31, 2019 303,609 Granted 271,950 Vested 112,699 Forfeited 1,497 Outstanding as of March 31, 2020 461,363 Stock Option Activity: Outstanding as of December 31, 2019 913,569 Granted 37,500 Exercised — Forfeited 30,000 Outstanding as of March 31, 2020 921,069

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 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, Continuing Operations Total For the Three Months Ended March 31, 2020 Operating Revenues: Time charter $ 4,375 $ 11,095 $ 11,767 $ 3,396 $ 8,657 $ 39,290 Bareboat charter 724 — — — — 724 Other marine services 642 167 420 149 351 1,729 5,741 11,262 12,187 3,545 9,008 41,743 Direct Costs and Expenses: Operating: Personnel 2,928 2,695 3,811 1,215 3,057 13,706 Repairs and maintenance 617 1,435 1,246 392 1,114 4,804 Drydocking 1,057 8 414 (114 ) - 1,365 Insurance and loss reserves 135 193 339 69 203 939 Fuel, lubes and supplies 524 472 665 135 271 2,067 Other 79 571 683 305 101 1,739 5,340 5,374 7,158 2,002 4,746 24,620 Direct Vessel Profit $ 401 $ 5,888 $ 5,029 $ 1,543 $ 4,262 17,123 Other Costs and Expenses: Lease expense $ 2,138 $ 1,126 $ 45 $ 9 $ 89 3,407 Administrative and general 10,765 Depreciation and amortization 5,358 2,604 3,790 899 2,350 15,001 29,173 Gain on Asset Dispositions and Impairments (12,572 ) Operating Loss $ (24,622 ) As of March 31, 2020 Property and Equipment: Historical Cost 256,059 199,242 281,767 74,308 118,888 930,264 Accumulated Depreciation (120,599 ) (52,225 ) (67,829 ) (17,271 ) (54,987 ) (312,911 ) $ 135,460 $ 147,017 $ 213,938 $ 57,037 $ 63,901 $ 617,353 Total Assets (1) $ 191,611 $ 158,660 $ 245,279 $ 134,171 $ 106,412 $ 836,133 (1) Total assets by region does not include corporate assets of $130,403 as of March 31, 2020 . United States (primarily Gulf of Mexico) Africa (primarily West Africa) Middle East and Asia Latin America Europe, Continuing Operations Total For the Three Months Ended March 31, 2019 Operating Revenues: Time charter $ 8,005 $ 10,773 $ 12,499 $ 4,922 $ 4,620 $ 40,819 Bareboat charter — — — 1,143 — 1,143 Other 1,132 (637 ) 228 635 1,590 2,948 9,137 10,136 12,727 6,700 6,210 44,910 Direct Costs and Expenses: Operating: Personnel 4,503 3,867 4,254 1,556 2,443 16,623 Repairs and maintenance 2,778 1,184 2,193 335 1,094 7,584 Drydocking 1,994 338 159 79 - 2,570 Insurance and loss reserves 592 213 327 135 147 1,414 Fuel, lubes and supplies 683 754 709 428 232 2,806 Other 90 2,106 1,100 521 352 4,169 10,640 8,462 8,742 3,054 4,268 35,166 Direct Vessel Profit, from Continuing Operations $ (1,503 ) $ 1,674 $ 3,985 $ 3,646 $ 1,942 $ 9,744 Other Costs and Expenses: Lease expense $ 2,911 $ 785 $ 46 $ 1 $ 394 $ 4,137 Administrative and general 10,812 Depreciation and amortization 5,498 2,356 4,249 1,936 2,058 16,097 31,046 Loss on Asset Dispositions and Impairments 268 Operating Loss, for Continuing Operations $ (21,034 ) As of March 31, 2019 Property and Equipment: Historical Cost 416,559 207,167 310,297 119,699 114,382 1,168,104 Accumulated Depreciation (223,720 ) (59,652 ) (85,627 ) (60,444 ) (48,796 ) (478,239 ) $ 192,839 $ 147,515 $ 224,670 $ 59,255 $ 65,586 $ 689,865 Total Assets (1) $ 330,938 $ 160,624 $ 266,007 $ 128,421 $ 91,047 $ 977,037 (1) Total assets by region does not include corporate assets of $135,312 as of March 31, 2019 .

Discontinued Operations (Tables

Discontinued Operations (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2019 Boston Putford Offshore Safety Ltd Operating Revenues: Time charter $ 11,308 Other revenue 31 11,339 Costs and Expenses: Operating 9,111 Direct Vessel Profit 2,228 General and Administrative Expenses 1,188 Lease Expense 11 Depreciation 1,096 2,295 Gain on Asset Dispositions and Impairments, Net 91 Operating Income 24 Other Income (Expense) Interest income 3 Interest expense (71 ) Foreign currency translation loss (35 ) (103 ) Operating Loss Before Equity Earnings of 50% or Less Owned Companies, Net of Tax (79 ) Income Tax Expense — Operating Loss Before Equity Earnings of 50% or Less Owned Companies (79 ) Equity in Earnings of 50% or Less Owned Companies, Net of Tax 79 Net (Loss) Income from Discontinued Operations $ —

Basis of Presentation and Acc_4

Basis of Presentation and Accounting Policies - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Basis Of Presentation And Accounting Policies [Line Items]
Contract with customer, liability	$ 3,265,000	$ 3,600,000	$ 4,786,000	$ 1,327,000
Prepaid management fees	3,787,000		$ 5,327,000
Capitalized interest costs, including allowance for funds used during construction, total	200,000
Impairment of long-lived assets right-to-use	7,400,000
Partial impairment of right to use assets	1,800,000
Equity method investment, other than temporary impairment	$ 0	$ 0
Effective income tax rate reconciliation, percent, total	25.20%
Class of warrant or right, exercise price of warrants or rights	$ 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	461,363	129,080
Employee Stock Option
Basis Of Presentation And Accounting Policies [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	921,069	791,816
Prepaid Vessel Management Fees
Basis Of Presentation And Accounting Policies [Line Items]
Prepaid management fees	$ 1,500,000
Geographic Distribution, Domestic
Basis Of Presentation And Accounting Policies [Line Items]
Contract with customer, liability	3,300,000
Geographic Distribution, Foreign
Basis Of Presentation And Accounting Policies [Line Items]
Contract with customer, liability	$ 1,800,000
Minimum
Basis Of Presentation And Accounting Policies [Line Items]
Equity method investment, ownership percentage	20.00%
Minimum | SEACOR Marine Foreign Holdings
Basis Of Presentation And Accounting Policies [Line Items]
Equity method investment, ownership percentage	50.00%
Maximum
Basis Of Presentation And Accounting Policies [Line Items]
Equity method investment, ownership percentage	50.00%	50.00%

Basis of Presentation and Acc_5

Basis of Presentation and Accounting Policies - Schedule of Deferred Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Basis Of Presentation And Accounting Policies [Abstract]
Balance at beginning of period	$ 4,786	$ 1,327
Revenues deferred during the period	5	3,409
Revenues recognized during the period	(1,526)	(1,136)
Balance at end of period	$ 3,265	$ 3,600

Basis of Presentation and Acc_6

Basis of Presentation and Accounting Policies - Schedule of Property and Equipment Useful Life (Details)	3 Months Ended
	Mar. 31, 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 Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	$ 478,924	$ 554,935
Other comprehensive loss	(4,519)	(24)
Balance	455,311	542,123
Accumulated Foreign Currency Adjustment Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	4,685
Other comprehensive loss	(2,528)
Balance	2,157
Accumulated Loss, Net, Cash Flow Hedge, Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(3,137)
Other comprehensive loss	(1,991)
Balance	(5,128)
AOCI Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	1,548	(16,788)
Other comprehensive loss	(4,519)
Balance	(2,971)	$ (16,812)
Accumulated Foreign Currency Adjustment Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(1,445)
Balance	(1,445)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Noncontrolling Interest
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(11)
Balance	(11)
AOCI Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	6,716
Other comprehensive loss	(4,519)
Balance	$ 2,197

Transformation, Facility Rest_3

Transformation, Facility Restructuring and Severance Charges - Additional Information (Details) - Transformation Plan $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)
Restructuring Cost And Reserve [Line Items]
Restructuring and related activities, description	The ongoing transformation plan, which began in the third quarter of 2019 and is expected to extend through the second quarter of 2020 (the “Transformation Plan”), includes 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 to reduce the Company’s overall cost structure and workforce to better align with current activity levels of oil and gas exploration and production.
Restructuring and transformation charges	$ 524
Severance charges	473
Other restructuring charges	51
Maximum
Restructuring Cost And Reserve [Line Items]
Other restructuring charges	$ 100

Transformation, Facility Rest_4

Transformation, Facility Restructuring and Severance Charges - Schedule of Components of Restructuring Charges By Segment (Details) - Transformation Plan $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)
Restructuring Cost And Reserve [Line Items]
Severance Charges	$ 473
Other Charges	51
Total Charges	524
UNITED STATES
Restructuring Cost And Reserve [Line Items]
Severance Charges	128
Other Charges	22
Total Charges	150
Middle East and Asia
Restructuring Cost And Reserve [Line Items]
Severance Charges	235
Other Charges	29
Total Charges	264
Europe
Restructuring Cost And Reserve [Line Items]
Severance Charges	110
Total Charges	$ 110

Transformation, Facility Rest_5

Transformation, Facility Restructuring and Severance Charges - Schedule of Severance and Other Restructuring Charges (Details) - Transformation Plan $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)
Restructuring Cost And Reserve [Line Items]
Restructuring liability	$ 112
Severance Liability
Restructuring Cost And Reserve [Line Items]
Restructuring liability	112
UNITED STATES
Restructuring Cost And Reserve [Line Items]
Restructuring liability	84
UNITED STATES | Severance Liability
Restructuring Cost And Reserve [Line Items]
Restructuring liability	84
Europe
Restructuring Cost And Reserve [Line Items]
Restructuring liability	28
Europe | Severance Liability
Restructuring Cost And Reserve [Line Items]
Restructuring liability	$ 28

Transformation, Facility Rest_6

Transformation, Facility Restructuring and Severance Charges - Schedule of Cumulative Restructuring and Reorganization Cost Incurred to Date, Estimated Remaining and to be Incurred (Details) - Transformation Plan $ in Thousands	Mar. 31, 2020USD ($)
Restructuring Cost And Reserve [Line Items]
Cumulative restructuring costs incurred to date in operating charges	$ 4,242
Estimated additional restructuring costs to be incurred	1,501
Total restructuring and reorganization costs incurred and to be incurred	$ 5,743

Equipment Acquisitions and Di_2

Equipment Acquisitions and Dispositions - Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)Vessel	Mar. 31, 2019USD ($)
Property Plant And Equipment [Line Items]
Payments to acquire property, plant, and equipment, including fair value hedges	$ 11,200
Proceeds from property, plant, and equipment, including deposits and gain on sale	3,100
Proceeds from disposition of property and equipment	3,105	$ 378
Proceeds from deposits	900
Gain (loss) on disposition of property, plant and equipment	1,100
Increase (decrease) in contract with customer, liability	2,100
Cash
Property Plant And Equipment [Line Items]
Proceeds from disposition of property and equipment	$ 2,200
Platform Supply Vessels
Property Plant And Equipment [Line Items]
Number of equipment acquired | Vessel	1
Anchor Handling Towing Supply
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	2
Specialty Vessel
Property Plant And Equipment [Line Items]
Number of equipment sold | Vessel	1

Investments, at Equity, and A_2

Investments, at Equity, and Advances to 50% or Less Owned Companies - Additional Information (Details) $ in Thousands	May 31, 2019USD ($)Vessel	May 01, 2020USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Schedule Of Investments [Line Items]
Due to affiliate			$ 66	$ 74
SeaCosco Offshore LLC | MOU
Schedule Of Investments [Line Items]
Agreement standstill date	Aug. 31, 2019
Loans receivable, interest rate	15.00%
Shareholder loans in respect of working capital	$ 13,000		13,000
Interest income recognized on shareholder loans in respect of working capital			1,000
SeaCosco Offshore LLC | MOU | Scenario Forecast
Schedule Of Investments [Line Items]
Principal and interest outstanding		$ 3,700
SeaCosco Offshore LLC | MOU | Platform Supply Vessels
Schedule Of Investments [Line Items]
Number of vessels acquired | Vessel	2
SeaCosco Offshore LLC | Ship Management Agreement
Schedule Of Investments [Line Items]
Due to affiliate			$ 5,600
SeaCosco Offshore LLC | SEACOR Offshore Asia
Schedule Of Investments [Line Items]
Equity method investment, ownership percentage			50.00%
SeaCosco Offshore LLC | CSFT and CSIHK
Schedule Of Investments [Line Items]
Equity method investment, ownership percentage			50.00%
SeaCosco Offshore LLC | CSFT and CSIHK | MOU
Schedule Of Investments [Line Items]
Equity method investment, ownership percentage	50.00%

Long Term Debt - Schedule of Lo

Long Term Debt - Schedule of Long-term Debt Obligations (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 423,943	$ 429,823
Current portion due within one year	(37,084)	(17,802)
Unamortized debt discount	(24,865)	(26,343)
Deferred financing costs	(5,265)	(5,427)
Long-term debt, less current portion	356,729	380,251
Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	277,175	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 Syndicated Credit Facility
Debt Instrument [Line Items]
Long-term Debt, Gross	110,500	113,750
Recourse Long-Term Debt | Sea-Cat Crewzer III Term Loan Facility
Debt Instrument [Line Items]
Long-term Debt, Gross	22,891	24,128
Recourse Long-Term Debt | SEACOR Alps
Debt Instrument [Line Items]
Long-term Debt, Gross	10,440	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	2,844	3,332
Non-Recourse Long-Term Debt
Debt Instrument [Line Items]
Long-term Debt, Gross	146,768	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	102,349	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	$ 23,919	$ 24,730

Long Term Debt - Additional Inf

Long Term Debt - Additional Information (Details) $ in Thousands, € in Millions	Mar. 03, 2020EUR (€)	Feb. 07, 2020USD ($)	Mar. 31, 2020USD ($)	Mar. 31, 2019USD ($)	Feb. 08, 2018USD ($)	May 24, 2016EUR (€)
Debt Instrument [Line Items]
Net financial debt to equity ratio			72.00%
Repayments of long-term debt, total			$ 5,222	$ 4,361
Lease Obligations and Labor and Performance Guaranties
Debt Instrument [Line Items]
Letters of credit outstanding, amount			$ 400
Omnibus Amendment
Debt Instrument [Line Items]
Repayment terms		the extension from March 2020 to March 2021 of the commencement of monthly repayment 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
Extension term of Guaranty		1 year
Sea-Cat Crewzer III Term Loan Facility
Debt Instrument [Line Items]
Net financial debt to equity ratio			70.00%
Term and Revolving Loan Facility | Omnibus Amendment
Debt Instrument [Line Items]
Debt agreement maximum borrowing capacity					$ 131,100
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
Line of credit facility, amount available under credit facilities			$ 2,300

Leases - Additional Information

Leases - Additional Information (Details)	3 Months Ended
	Mar. 31, 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)	8 months
Vessels | Maximum
Lessee Lease Description [Line Items]
Operating lease, lease terms (in duration)	20 months
Other Equipment | Minimum
Lessee Lease Description [Line Items]
Operating lease, lease terms (in duration)	2 months
Other Equipment | Maximum
Lessee Lease Description [Line Items]
Operating lease, lease terms (in duration)	321 months

Leases - Summary of Future Mini

Leases - Summary of Future Minimum Payments For Operating Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Remainder of 2020	$ 11,489
2021	7,127
2022	669
2023	622
2024	697
Years subsequent to 2024	4,439
Operating lease payments due	25,043
Interest component	(3,825)
Total operating leases	21,218
Current portion of long-term operating lease liabilities	13,359	$ 15,099
Long-term operating lease liabilities	$ 7,859	$ 9,822

Leases - Summary of Components

Leases - Summary of Components of Leases Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Leases [Abstract]
Operating lease expense	$ 3,275	$ 3,612
Short-term lease expense (lease duration of twelve months or less at lease commencement)	132	525
Total Lease expense	$ 3,407	$ 4,137

Leases - Summary of Other Infor

Leases - Summary of Other Information Related to Operating Leases (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)
Leases [Abstract]
Operating cash flows from operating leases	$ 3,838
Right-of-use assets obtained for operating lease liabilities	$ 9
Weighted average remaining lease term, in years	4 years 10 months 24 days
Weighted average discount rate	4.20%

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details)	3 Months Ended
	Mar. 31, 2020
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Statutory rate	21.00%
Foreign taxes not creditable against U.S. income tax	(3.70%)
Falcon Global Acquisition	12.00%
Noncontrolling interests	(3.40%)
Other	(0.70%)
Effective income tax rate reconciliation, percent, total	25.20%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details)	3 Months Ended
	Mar. 31, 2020
U.S. Tax Laws
Income Taxes [Line Items]
Operating loss carryforwards, expiration period	5 years

Derivative Instruments and He_3

Derivative Instruments and Hedging Strategies - Schedule of Fair Value of Derivative Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Designated as Hedging Instrument | Cash Flow Hedging
Derivative [Line Items]
Derivative Liability	$ 4,893	$ 3,009
Designated as Hedging Instrument | Interest Rate Swap | Cash Flow Hedging
Derivative [Line Items]
Derivative Liability	4,893	3,009
Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative Liability	4,984	8,214
Conversion option liability on Convertible Senior Notes	$ 91	$ 5,205

Derivative Instruments and He_4

Derivative Instruments and Hedging Strategies - Additional Information (Details) € in Millions, $ in Millions	Mar. 31, 2020USD ($)	Mar. 31, 2020EUR (€)	Mar. 31, 2019
Minimum
Derivative [Line Items]
Equity method investment, ownership percentage	20.00%	20.00%
Maximum
Derivative [Line Items]
Equity method investment, ownership percentage	50.00%	50.00%	50.00%
SEACOR Marine Foreign Holdings | Minimum
Derivative [Line Items]
Equity method investment, ownership percentage	50.00%	50.00%
Interest Rate Swap | OSV Partners
Derivative [Line Items]
Derivative, number of instruments held, total	2	2
Derivative, notional amount	$ 22
Interest Rate Swap | OSV Partners | Minimum
Derivative [Line Items]
Derivative, fixed interest rate	1.89%	1.89%
Interest Rate Swap | OSV Partners | Maximum
Derivative [Line Items]
Derivative, fixed interest rate	2.27%	2.27%
Cash Flow Hedging | Interest Rate Swap | Designated as Hedging Instrument | Windcat Workboats
Derivative [Line Items]
Derivative, number of instruments held, total	2	2
Derivative, fixed interest rate	0.03%	0.03%
Derivative, notional amount	$ 16.5	€ 15
Cash Flow Hedging | Interest Rate Swap | Designated as Hedging Instrument | SEACOR 88/888
Derivative [Line Items]
Derivative, fixed interest rate	3.20%	3.20%
Derivative, notional amount	$ 5.5
Cash Flow Hedging | Interest Rate Swap | Designated as Hedging Instrument | MexMar
Derivative [Line Items]
Derivative, number of instruments held, total	5	5
Derivative, notional amount	$ 79.7
Equity method investment, ownership percentage	49.00%	49.00%
Cash Flow Hedging | Interest Rate Swap | Designated as Hedging Instrument | MexMar | Minimum
Derivative [Line Items]
Derivative, fixed interest rate	1.71%	1.71%
Cash Flow Hedging | Interest Rate Swap | Designated as Hedging Instrument | MexMar | Maximum
Derivative [Line Items]
Derivative, fixed interest rate	2.10%	2.10%
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%
Derivative, notional amount	$ 8.5
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%
Derivative, notional amount	$ 48.5

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	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Derivative [Line Items]
Gains (losses) on derivative instruments	$ 5,114	$ (925)
Embedded Derivative Financial Instruments
Derivative [Line Items]
Gains (losses) on derivative instruments	$ 5,114	$ (925)

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	Mar. 31, 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	$ 3,745	$ 12,893
Fair Value, Inputs, Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative Liability	4,893	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	$ 91	$ 5,205

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Estimated Fair Values of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Reported Value Measurement
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash, cash equivalents and restricted cash	$ 72,573	$ 87,047
Investments, at cost, in 50% or less owned companies (included in other assets)	132	132
Long-term debt, including current portion	393,813	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	72,573	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	$ 350,081	$ 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	Mar. 31, 2020	Dec. 31, 2019
Liftboats
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Property and equipment	$ 8,100
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) $ in Millions	3 Months Ended
	Mar. 31, 2020USD ($)
Fair Value Disclosures [Abstract]
Impairment charges	$ 9.2

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - Falcon Global Holdings	Mar. 20, 2020shares
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	Mar. 31, 2020	Mar. 19, 2020	Dec. 31, 2019
Minority Interest [Line Items]
Noncontrolling interest	$ 339		$ 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, ownership percentage by noncontrolling owners	1.80%
Noncontrolling interest	$ 339		$ 313

Noncontrolling Interests in S_4

Noncontrolling Interests in Subsidiaries - Schedule of Noncontrolling Interests in the Company's Consolidated Subsidiaries (Parenthetical) (Details)	Mar. 31, 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	Mar. 31, 2020	Mar. 31, 2019
Minority Interest [Line Items]
Net income (loss), including portion attributable to noncontrolling interest, total			$ (19,992)	$ (28,273)
Non-cash impairment charges			7,400
Net income (loss) attributable to noncontrolling interest, total			(4,047)	$ (2,724)
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			14,500
Non-cash impairment charges			$ 9,200
Net income (loss) attributable to noncontrolling interest, total		$ 4,100

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) R$ in Millions, $ in Millions	Apr. 17, 2020USD ($)	Feb. 28, 2015USD ($)	Mar. 31, 2020USD ($)	Mar. 31, 2020BRL (R$)
Commitments And Contingencies [Line Items]
Remaining capital commitment			$ 34.2
Unrecorded unconditional purchase obligation due within four years			16.3
Gain (loss) on disposition of property, plant and equipment			$ 1.1
Deficiency Notice
Commitments And Contingencies [Line Items]
Cost allocation percentage			70.00%
Deposited with Court		$ 1.2
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			$ 2.3	R$ 12.8
Maximum | Deficiency Notice
Commitments And Contingencies [Line Items]
Potential range of levies			$ 3.2	R$ 17.5
Platform Supply Vessels
Commitments And Contingencies [Line Items]
Unrecorded unconditional purchase obligation, maximum quantity			3	3
Crew Transfer Vessels
Commitments And Contingencies [Line Items]
Unrecorded unconditional purchase obligation, maximum quantity			2	2
FSV Offshore Support Vessels
Commitments And Contingencies [Line Items]
Unrecorded unconditional purchase obligation, maximum quantity			2	2
Under Construction | Subsequent Event
Commitments And Contingencies [Line Items]
Sale of vessel	$ 14.5
Gain (loss) on disposition of property, plant and equipment	$ 2.1

Stock Based Compensation - Summ

Stock Based Compensation - Summary of Transactions in Connection with 2017 Equity Incentive Plan (Details)	3 Months Ended
	Mar. 31, 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)	37,500
Forfeited (in shares)	30,000
Outstanding as of the end of year (in shares)	921,069
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)	271,950
Vested (in shares)	112,699
Forfeited (in shares)	1,497
Outstanding as of the end of year (in shares)	461,363

Stock Based Compensation - Addi

Stock Based Compensation - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Treasury stock, shares acquired	24,715
Treasury stock, value acquired cost method	$ 175	$ 282

Segment Information - Schedule

Segment Information - Schedule of Segment Reporting Information, by Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020		Mar. 31, 2019		Dec. 31, 2019
Segment Reporting Information [Line Items]
Operating Revenues	$ 41,743		$ 44,910
Direct Costs and Expenses	24,620		35,166
Direct Vessel Profit, from Continuing Operations	17,123		9,744
Lease expense	3,407		4,137
Administrative and general	10,765		10,812
Depreciation and amortization	15,001		16,097
Other Costs and Expenses	29,173		31,046
Gain (Loss) on Asset Dispositions and Impairments	(12,572)		268
Operating Loss, for Continuing Operations	(24,622)		(21,034)
Historical cost	930,264		1,168,104		$ 976,978
Accumulated depreciation	(312,911)		(478,239)		(358,962)
Property and equipment	617,353		689,865		$ 618,016
Total Assets	836,133	[1]	977,037	[2]
Time Charter
Segment Reporting Information [Line Items]
Operating Revenues	39,290		40,819
Bareboat Charter
Segment Reporting Information [Line Items]
Operating Revenues	724		1,143
Other Marine Services
Segment Reporting Information [Line Items]
Operating Revenues	1,729		2,948
Personnel
Segment Reporting Information [Line Items]
Direct Costs and Expenses	13,706		16,623
Repairs and Maintenance
Segment Reporting Information [Line Items]
Direct Costs and Expenses	4,804		7,584
Drydocking
Segment Reporting Information [Line Items]
Direct Costs and Expenses	1,365		2,570
Insurance and Loss Reserves
Segment Reporting Information [Line Items]
Direct Costs and Expenses	939		1,414
Fuel, Lubes and Supplies
Segment Reporting Information [Line Items]
Direct Costs and Expenses	2,067		2,806
Other Direct Costs and Expenses
Segment Reporting Information [Line Items]
Direct Costs and Expenses	1,739		4,169
UNITED STATES
Segment Reporting Information [Line Items]
Operating Revenues	5,741		9,137
Direct Costs and Expenses	5,340		10,640
Direct Vessel Profit, from Continuing Operations	401		(1,503)
Lease expense	2,138		2,911
Depreciation and amortization	5,358		5,498
Historical cost	256,059		416,559
Accumulated depreciation	(120,599)		(223,720)
Property and equipment	135,460		192,839
Total Assets	191,611	[1]	330,938	[2]
UNITED STATES | Time Charter
Segment Reporting Information [Line Items]
Operating Revenues	4,375		8,005
UNITED STATES | Bareboat Charter
Segment Reporting Information [Line Items]
Operating Revenues	724
UNITED STATES | Other Marine Services
Segment Reporting Information [Line Items]
Operating Revenues	642		1,132
UNITED STATES | Personnel
Segment Reporting Information [Line Items]
Direct Costs and Expenses	2,928		4,503
UNITED STATES | Repairs and Maintenance
Segment Reporting Information [Line Items]
Direct Costs and Expenses	617		2,778
UNITED STATES | Drydocking
Segment Reporting Information [Line Items]
Direct Costs and Expenses	1,057		1,994
UNITED STATES | Insurance and Loss Reserves
Segment Reporting Information [Line Items]
Direct Costs and Expenses	135		592
UNITED STATES | Fuel, Lubes and Supplies
Segment Reporting Information [Line Items]
Direct Costs and Expenses	524		683
UNITED STATES | Other Direct Costs and Expenses
Segment Reporting Information [Line Items]
Direct Costs and Expenses	79		90
Africa
Segment Reporting Information [Line Items]
Operating Revenues	11,262		10,136
Direct Costs and Expenses	5,374		8,462
Direct Vessel Profit, from Continuing Operations	5,888		1,674
Lease expense	1,126		785
Depreciation and amortization	2,604		2,356
Historical cost	199,242		207,167
Accumulated depreciation	(52,225)		(59,652)
Property and equipment	147,017		147,515
Total Assets	158,660	[1]	160,624	[2]
Africa | Time Charter
Segment Reporting Information [Line Items]
Operating Revenues	11,095		10,773
Africa | Other Marine Services
Segment Reporting Information [Line Items]
Operating Revenues	167		(637)
Africa | Personnel
Segment Reporting Information [Line Items]
Direct Costs and Expenses	2,695		3,867
Africa | Repairs and Maintenance
Segment Reporting Information [Line Items]
Direct Costs and Expenses	1,435		1,184
Africa | Drydocking
Segment Reporting Information [Line Items]
Direct Costs and Expenses	8		338
Africa | Insurance and Loss Reserves
Segment Reporting Information [Line Items]
Direct Costs and Expenses	193		213
Africa | Fuel, Lubes and Supplies
Segment Reporting Information [Line Items]
Direct Costs and Expenses	472		754
Africa | Other Direct Costs and Expenses
Segment Reporting Information [Line Items]
Direct Costs and Expenses	571		2,106
Middle East and Asia
Segment Reporting Information [Line Items]
Operating Revenues	12,187		12,727
Direct Costs and Expenses	7,158		8,742
Direct Vessel Profit, from Continuing Operations	5,029		3,985
Lease expense	45		46
Depreciation and amortization	3,790		4,249
Historical cost	281,767		310,297
Accumulated depreciation	(67,829)		(85,627)
Property and equipment	213,938		224,670
Total Assets	245,279	[1]	266,007	[2]
Middle East and Asia | Time Charter
Segment Reporting Information [Line Items]
Operating Revenues	11,767		12,499
Middle East and Asia | Other Marine Services
Segment Reporting Information [Line Items]
Operating Revenues	420		228
Middle East and Asia | Personnel
Segment Reporting Information [Line Items]
Direct Costs and Expenses	3,811		4,254
Middle East and Asia | Repairs and Maintenance
Segment Reporting Information [Line Items]
Direct Costs and Expenses	1,246		2,193
Middle East and Asia | Drydocking
Segment Reporting Information [Line Items]
Direct Costs and Expenses	414		159
Middle East and Asia | Insurance and Loss Reserves
Segment Reporting Information [Line Items]
Direct Costs and Expenses	339		327
Middle East and Asia | Fuel, Lubes and Supplies
Segment Reporting Information [Line Items]
Direct Costs and Expenses	665		709
Middle East and Asia | Other Direct Costs and Expenses
Segment Reporting Information [Line Items]
Direct Costs and Expenses	683		1,100
Latin America
Segment Reporting Information [Line Items]
Operating Revenues	3,545		6,700
Direct Costs and Expenses	2,002		3,054
Direct Vessel Profit, from Continuing Operations	1,543		3,646
Lease expense	9		1
Depreciation and amortization	899		1,936
Historical cost	74,308		119,699
Accumulated depreciation	(17,271)		(60,444)
Property and equipment	57,037		59,255
Total Assets	134,171	[1]	128,421	[2]
Latin America | Time Charter
Segment Reporting Information [Line Items]
Operating Revenues	3,396		4,922
Latin America | Bareboat Charter
Segment Reporting Information [Line Items]
Operating Revenues			1,143
Latin America | Other Marine Services
Segment Reporting Information [Line Items]
Operating Revenues	149		635
Latin America | Personnel
Segment Reporting Information [Line Items]
Direct Costs and Expenses	1,215		1,556
Latin America | Repairs and Maintenance
Segment Reporting Information [Line Items]
Direct Costs and Expenses	392		335
Latin America | Drydocking
Segment Reporting Information [Line Items]
Direct Costs and Expenses	(114)		79
Latin America | Insurance and Loss Reserves
Segment Reporting Information [Line Items]
Direct Costs and Expenses	69		135
Latin America | Fuel, Lubes and Supplies
Segment Reporting Information [Line Items]
Direct Costs and Expenses	135		428
Latin America | Other Direct Costs and Expenses
Segment Reporting Information [Line Items]
Direct Costs and Expenses	305		521
Europe, Continuing Operations
Segment Reporting Information [Line Items]
Operating Revenues	9,008		6,210
Direct Costs and Expenses	4,746		4,268
Direct Vessel Profit, from Continuing Operations	4,262		1,942
Lease expense	89		394
Depreciation and amortization	2,350		2,058
Historical cost	118,888		114,382
Accumulated depreciation	(54,987)		(48,796)
Property and equipment	63,901		65,586
Total Assets	106,412	[1]	91,047	[2]
Europe, Continuing Operations | Time Charter
Segment Reporting Information [Line Items]
Operating Revenues	8,657		4,620
Europe, Continuing Operations | Other Marine Services
Segment Reporting Information [Line Items]
Operating Revenues	351		1,590
Europe, Continuing Operations | Personnel
Segment Reporting Information [Line Items]
Direct Costs and Expenses	3,057		2,443
Europe, Continuing Operations | Repairs and Maintenance
Segment Reporting Information [Line Items]
Direct Costs and Expenses	1,114		1,094
Europe, Continuing Operations | Insurance and Loss Reserves
Segment Reporting Information [Line Items]
Direct Costs and Expenses	203		147
Europe, Continuing Operations | Fuel, Lubes and Supplies
Segment Reporting Information [Line Items]
Direct Costs and Expenses	271		232
Europe, Continuing Operations | Other Direct Costs and Expenses
Segment Reporting Information [Line Items]
Direct Costs and Expenses	$ 101		$ 352
[1]	Total assets by region does not include corporate assets of $130,403 as of March 31, 2020.
[2]	Total assets by region does not include corporate assets of $135,312 as of March 31, 2019.

Segment Information - Schedul_2

Segment Information - Schedule of Segment Reporting Information, by Segment (Parenthetical) (Details) - USD ($)	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Segment Reporting Information [Line Items]
Assets, Total	$ 966,535,000	$ 1,009,193,000
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Assets, Total	$ 130,403		$ 135,312

Segment Information - Additiona

Segment Information - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Information [Line Items]
Equity method investments	$ 125
Equity in (Losses) Earnings of 50% or Less Owned Companies	$ (0.2)	$ (3.4)
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		$ 124.7
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 $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Operating Revenues:
Operating Revenues	$ 11,339
Costs and Expenses:
Operating	9,111
Direct Vessel Profit	2,228
General and Administrative Expenses	1,188
Lease Expense	11
Depreciation	1,096
Total expenses	2,295
Gain on Asset Dispositions and Impairments, Net	91
Operating Income	24
Other Income (Expense)
Interest income	3
Interest expense	71
Foreign currency translation loss	(35)
Other Income (Expense)	(103)
Operating Loss Before Equity Earnings of 50% or Less Owned Companies, Net of Tax	(79)
Operating Loss Before Equity Earnings of 50% or Less Owned Companies	(79)
Equity in Earnings of 50% or Less Owned Companies, Net of Tax	79
Time Charter
Operating Revenues:
Operating Revenues	11,308
Other Revenue
Operating Revenues:
Operating Revenues	$ 31