Seacor (CKH) 10-K 27 Feb 19 2018 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Feb. 22, 2019	Jun. 30, 2018
Document And Entity Information [Abstract]
Entity Registrant Name	SEACOR HOLDINGS INC /NEW/
Entity Central Index Key	859,598
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		18,344,861
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 974,248,089

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 144,221	$ 239,246
Restricted cash and restricted cash equivalents	2,991	2,982
Marketable securities	30,316	42,761
Receivables:
Trade, net of allowance for doubtful accounts of $3,481 and $2,390 in 2018 and 2017, respectively	171,828	110,465
Other	38,881	33,870
Inventories	4,530	4,377
Prepaid expenses and other	5,382	6,594
Total current assets	398,149	440,295
Property and Equipment:
Historical cost	1,407,329	1,380,469
Accumulated depreciation	(560,819)	(502,544)
Net property and equipment	846,510	877,925
Investments, at Equity, and Advances to 50% or Less Owned Companies	156,886	173,441
Construction Reserve Funds	3,908	51,339
Goodwill	32,708	32,761
Intangible Assets, Net	24,551	28,106
Other Assets	8,312	9,469
Total Assets	1,471,024	1,613,336
Current Liabilities:
Current portion of long-term debt	8,497	77,842
Accounts payable and accrued expenses	59,607	44,013
Accrued wages and benefits	21,203	14,624
Accrued interest	1,184	4,209
Accrued capital, repair and maintenance expenditures	3,254	2,172
Other current liabilities	30,018	36,325
Total current liabilities	123,763	179,185
Long-Term Debt	346,128	501,505
Deferred Income Taxes	94,420	101,422
Deferred Gains and Other Liabilities	52,871	77,863
Total liabilities	617,182	859,975
SEACOR Holdings Inc. stockholders’ equity:
Preferred stock, $.01 par value, 10,000,000 shares authorized; none issued nor outstanding	0	0
Common stock, $.01 par value, 60,000,000 shares authorized; 39,001,924 and 38,656,505 shares issued in 2018 and 2017, respectively	390	387
Additional paid-in capital	1,596,642	1,573,013
Retained earnings	474,809	419,128
Shares held in treasury of 20,671,627 and 20,716,878 in 2018 and 2017, respectively, at cost	(1,366,773)	(1,368,300)
Accumulated other comprehensive loss, net of tax	(914)	(545)
Stockholders' equity attributable to SEACOR Holdings Inc.	704,154	623,683
Noncontrolling interests in subsidiaries	149,688	129,678
Total equity	853,842	753,361
Liabilities and stockholders' equity, total	$ 1,471,024	$ 1,613,336

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Trade receivables, allowance for doubtful accounts	$ 3,481	$ 2,390
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)	39,001,924	38,656,505
Treasury stock, shares (in shares)	20,671,627	20,716,878
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0

Consolidated Statements Of Inco

Consolidated Statements Of Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Operating Revenues	$ 835,750	$ 650,847	$ 524,163
Costs and Expenses:
Operating	591,848	433,837	358,953
Administrative and general	102,907	103,106	86,362
Depreciation and amortization	74,579	75,058	62,565
Total costs and expenses	769,334	612,001	507,880
Gains (Losses) on Asset Dispositions and Impairments, Net	19,583	11,637	(25,983)
Operating Income (Loss)	85,999	50,483	(9,700)
Other Income (Expense):
Interest income	8,730	8,547	15,641
Interest expense	(31,683)	(41,530)	(39,804)
Debt extinguishment gains (losses), net	(11,626)	(819)	5,184
Marketable security losses, net	(12,431)	(1,782)	(32,154)
Derivative gains (losses), net	0	19,727	(14,131)
Foreign currency gains (losses), net	(2,264)	323	1,444
Other, net	54,964	256	(18,716)
Nonoperating Income (Expense)	5,690	(15,278)	(82,536)
Income (Loss) from Continuing Operations Before Income Tax Expense (Benefit) and Equity in Earnings (Losses) of 50% or Less Owned Companies	91,689	35,205	(92,236)
Income Tax Expense (Benefit):
Current	23,928	(15,712)	12,207
Deferred	(15,513)	(51,477)	(48,932)
Income tax expense (benefit)	8,415	(67,189)	(36,725)
Income (Loss) from Continuing Operations Before Equity in Earnings (Losses) of 50% or Less Owned Companies	83,274	102,394	(55,511)
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax	(72)	2,952	(21,040)
Income (Loss) from Continuing Operations	83,202	105,346	(76,551)
Loss from Discontinued Operations, Net of Tax	0	(23,637)	(119,221)
Net Income (Loss)	83,202	81,709	(195,772)
Net Income attributable to Noncontrolling Interests in Subsidiaries	25,054	20,066	20,125
Net Income (Loss) attributable to SEACOR Holdings Inc.	58,148	61,643	(215,897)
Net Income (Loss) attributable to SEACOR Holdings Inc.:
Continuing Operations	58,148	82,849	(94,091)
Discontinued Operations	$ 0	$ (21,206)	$ (121,806)
Basic Earnings (Loss) Per Common Share of SEACOR Holdings Inc.:
Continuing Operations (in dollars per share)	$ 3.22	$ 4.77	$ (5.56)
Discontinued Operations (in dollars per share)	0	(1.22)	(7.20)
Basic Earnings (Loss) Per Common Share of SEACOR Holdings Inc. (in dollars per share)	3.22	3.55	(12.76)
Diluted Earnings (Loss) Per Common Share of SEACOR Holdings Inc.:
Continuing Operations (in dollars per share)	3.04	4.24	(5.56)
Discontinued Operations (in dollars per share)	0	(0.93)	(7.20)
Diluted Earnings (Loss) Per Common Share of SEACOR Holdings Inc. (in dollars per share)	$ 3.04	$ 3.31	$ (12.76)
Weighted Average Common Shares Outstanding:
Basic (in shares)	18,080,778	17,368,081	16,914,928
Diluted (in shares)	19,575,689	22,934,158	16,914,928

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net Income (Loss)	$ 83,202	$ 81,709	$ (195,772)
Other Comprehensive Income (Loss):
Foreign currency translation gains (losses), net	(406)	1,965	(10,490)
Reclassification of foreign currency translation losses to foreign currency gains (losses), net	15	0	74
Derivative losses on cash flow hedges	0	(389)	(2,537)
Other	0	(11)	(44)
Other comprehensive income (loss)	(391)	1,707	(10,183)
Income tax (expense) benefit	22	(702)	3,174
Other comprehensive income (loss), net of tax	(369)	1,005	(7,009)
Comprehensive Income (Loss)	82,833	82,714	(202,781)
Comprehensive Income attributable to Noncontrolling Interests in Subsidiaries	25,054	20,227	19,010
Comprehensive Income (Loss) attributable to SEACOR Holdings Inc.	57,779	62,487	(221,791)
Interest Expense
Other Comprehensive Income (Loss):
Reclassification of derivative losses on cash flow hedges	0	33	18
Equity Method Investments
Other Comprehensive Income (Loss):
Reclassification of derivative losses on cash flow hedges	$ 0	$ 109	$ 2,796

Consolidated Statements Of Chan

Consolidated Statements Of Changes In Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss	Non - controlling Interests in Subsidiaries
Total equity, beginning balance at Dec. 31, 2015	$ 1,390,939	$ 377	$ 1,505,942	$ 1,126,620	$ (1,356,499)	$ (5,620)	$ 120,119
Issuance of common stock:
Employee Stock Purchase Plan	1,726				1,726
Exercise of stock options	4,368	1	4,367
Director stock awards	186		186
Restricted stock	(1,179)	1	(1,180)
Distribution of Dorian shares to shareholders	0
Purchase of conversion option in convertible debt, net of tax	(4,793)		(4,793)
Purchase of treasury shares	(2,396)				(2,396)
Amortization of share awards	13,951		13,951
Cancellation of restricted stock	0		162		(162)
Distributions to noncontrolling interests	(3,753)						(3,753)
Net Income (Loss)	(195,772)			(215,897)			20,125
Other comprehensive income (loss), net of tax	(7,009)					(5,894)	(1,115)
Total equity, ending balance at Dec. 31, 2016	1,196,268	379	1,518,635	910,723	(1,357,331)	(11,514)	135,376
Issuance of common stock:
Employee Stock Purchase Plan	1,443				1,443
Exercise of stock options	21,154	6	21,148
Director stock awards	83		83
Restricted stock	0	2	(2)
Exercise of conversion option in convertible debt	3		3
Distribution of SEACOR Marine stock to shareholders	(527,691)		2,656	(521,859)		10,125	(18,613)
Distribution of Dorian shares to shareholders	(31,379)			(31,379)
Purchase of conversion option in convertible debt, net of tax	(927)		(927)
Purchase of treasury shares	(12,300)				(12,300)
Amortization of share awards	32,419		32,419
Cancellation of restricted stock	0		112		(112)
Purchase of subsidiary shares from noncontrolling interests, net of tax	(3,693)		(1,114)				(2,579)
Acquisition of a subsidiary with noncontrolling interests	17,374						17,374
Disposition of subsidiary with noncontrolling interests	(14,673)						(14,673)
Distributions to noncontrolling interests	(7,434)						(7,434)
Net Income (Loss)	81,709			61,643			20,066
Other comprehensive income (loss), net of tax	1,005					844	161
Total equity, ending balance at Dec. 31, 2017	753,361	387	1,573,013	419,128	(1,368,300)	(545)	129,678
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Impact of adoption of accounting principle | Accounting Standards Update 2016-16				(2,467)
Issuance of common stock:
Employee Stock Purchase Plan	1,527				1,527
Exercise of stock options	6,883	2	6,881
Director stock awards	140		140
Restricted stock	0	1	(1)
Distribution of Dorian shares to shareholders	0
Net issuance of conversion option on exchange of convertible debt, net of tax	12,735		12,735
Purchase of conversion option in convertible debt, net of tax	(33)		(33)
Amortization of share awards	3,907		3,907
Purchase of subsidiary shares from noncontrolling interests, net of tax	(29)						(29)
Acquisition of a subsidiary with noncontrolling interests	96						96
Distributions to noncontrolling interests	(5,111)						(5,111)
Net Income (Loss)	83,202			58,148			25,054
Other comprehensive income (loss), net of tax	(369)					(369)
Total equity, ending balance at Dec. 31, 2018	$ 853,842	$ 390	$ 1,596,642	$ 474,809	$ (1,366,773)	$ (914)	$ 149,688

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash Flows from Operating Activities of Continuing Operations:
Income (Loss) from Continuing Operations	$ 83,202	$ 105,346	$ (76,551)
Adjustments to reconcile income (loss) from continuing operations to net cash provided by operating activities of continuing operations:
Depreciation and amortization	74,579	75,058	62,565
Amortization of deferred gains on sale leaseback transactions	(12,774)	(15,035)	(15,073)
Debt discount and issuance cost amortization, net	7,829	12,997	15,901
Amortization of share awards	3,907	32,419	13,951
Director stock awards	140	83	190
Bad debt expense (income)	2,067	(175)	2,774
(Gains) losses on asset dispositions and impairments, net	(19,583)	(11,637)	25,983
Debt extinguishment (gains) losses, net	11,626	819	(5,184)
Marketable security losses, net	12,431	1,782	32,154
Purchases of marketable securities	0	(1,720)	0
Proceeds from sale of marketable securities	14	674	0
Derivative (gains) losses, net	0	(19,727)	14,131
Cash settlements on derivative transactions, net	0	255	(327)
Foreign currency (gains) losses, net	2,264	(323)	(1,444)
Deferred income tax benefit	(15,513)	(51,477)	(48,932)
Equity in (earnings) losses of 50% or less owned companies, net of tax	72	(2,952)	21,040
Dividends received from 50% or less owned companies	5,907	12,891	5,162
Other, net	(53,902)	0	19,106
Changes in operating assets and liabilities:
(Increase) decrease in receivables	(63,764)	2,195	(26,273)
Increase in prepaid expenses and other assets	(1,577)	(8,174)	(8,974)
Increase (decrease) in accounts payable, accrued expenses and other liabilities	12,503	(25,724)	9,607
Net cash provided by operating activities of continuing operations	49,428	107,575	39,806
Cash Flows from Investing Activities of Continuing Operations:
Purchases of property and equipment	(50,272)	(114,595)	(252,806)
Proceeds from disposition of property and equipment	16,100	164,789	143,028
Investments in and advances to 50% or less owned companies	(20,586)	(9,663)	(8,094)
Return of investments and advances from 50% or less owned companies	8,988	15,568	9,519
Proceeds on sale of 50% or less owned companies	78,015	0	0
Proceeds on sale of a controlling interest in a subsidiary	0	5,000	0
Net repayments on revolving credit line to 50% or less owned companies	0	0	2,397
(Issuances of) payments received on third party leases and notes receivable, net	506	24,485	(2,707)
Deposits into construction reserve funds	0	(13,807)	(1,586)
Withdrawals from construction reserve funds	47,431	38,221	42,626
Business acquisitions, net of cash acquired	310	5,868	(20,539)
Net cash provided by (used in) investing activities of continuing operations	80,492	115,866	(88,162)
Cash Flows from Financing Activities of Continuing Operations:
Payments on long-term debt	(225,541)	(303,485)	(168,599)
Proceeds from issuance of long-term debt, net of offering costs	(2,495)	44,900	94,379
Purchase of conversion option in convertible debt	(33)	(1,354)	(7,374)
Common stock acquired for treasury	0	(12,300)	(2,396)
Proceeds and tax benefits from share award plans	8,410	22,597	4,911
Purchase of subsidiary shares from noncontrolling interests	(29)	0	0
Distributions to noncontrolling interests	(5,111)	(4)	(248)
Net cash used in financing activities of continuing operations	(224,799)	(249,646)	(79,327)
Effects of Exchange Rate Changes on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	(137)	956	(2,928)
Net Decrease in Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents from Continuing Operations	(95,016)	(25,249)	(130,611)
Cash Flows from Discontinued Operations:
Operating Activities	0	12,811	41,206
Investing Activities	0	2,720	(21,581)
Financing Activities	0	(7,149)	12,290
Effect of Exchange Rate Changes on Cash and Cash Equivalents	0	208	437
Net Increase in Cash and Cash Equivalents from Discontinued Operations	0	8,590	32,352
Net Decrease in Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	(95,016)	(16,659)	(98,259)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Beginning of Year	242,228	258,887	357,146
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, End of Year	147,212	242,228	258,887
Restricted Cash and Restricted Cash Equivalents, End of Year	2,991	2,982	2,249
Cash and Cash Equivalents, End of Year	$ 144,221	$ 239,246	$ 256,638

Nature Of Operations And Accoun

Nature Of Operations And Accounting Policies	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Nature Of Operations And Accounting Policies	1. NATURE OF OPERATIONS AND ACCOUNTING POLICIES Nature of Operations and Segmentation. SEACOR Holdings Inc. (“SEACOR”) and its subsidiaries (collectively referred to as the “Company”) are a diversified holding company with interests in domestic and international transportation and logistics, risk management consultancy and other businesses. Accounting standards require public business enterprises to report information about each of their operating business segments that exceed certain quantitative thresholds or meet certain other reporting requirements. Operating business segments have been defined as a component of an enterprise about which separate financial information is available and is evaluated regularly by the chief operating decision maker in deciding how to allocate resources and in assessing performance. The Company has identified the following reporting segments: Ocean Transportation & Logistics Services (“Ocean Services”). Ocean Services owns and operates a diversified fleet of bulk transportation, port and infrastructure, and logistics assets, including U.S. coastwise eligible vessels and vessels trading internationally. Ocean Services has a 51% controlling interest in certain subsidiaries (collectively “SEA-Vista”) that operate U.S.-flag petroleum and chemical carriers servicing the U.S. coastwise crude oil, petroleum products and chemical trades. Ocean Services’ dry bulk vessels also operate in the U.S. coastwise trade. Ocean Services’ port and infrastructure services include a wholly owned harbor and offshore towing subsidiary assisting deep-sea vessels docking in U.S. Gulf and East Coast ports, providing ocean towing services between U.S. ports and providing oil terminal support and bunkering operations in St. Eustatius and the Bahamas. Ocean Services’ logistics services include U.S.-flag Pure Car/Truck Carriers (“PCTCs”) operating globally under the U.S. Maritime Security Program (“MSP”) and liner, short-sea, rail car and project cargo transportation and logistics solutions to and from ports in the Southeastern United States, the Caribbean (including Puerto Rico), the Bahamas and Mexico. Ocean Services also provides technical ship management services for third-party vessel owners. Ocean Services contributed 50% , 54% and 44% of consolidated operating revenues during the years ended December 31, 2018 , 2017 and 2016 , respectively. Inland Transportation & Logistics Services (“Inland Services”). Inland Services markets and operates domestic river transportation equipment, and owns fleeting and high-speed multi-modal terminal locations adjacent to and along the U.S. Inland Waterways, primarily in the St. Louis, Memphis and Baton Rouge areas. Inland Services’ barges are primarily used for moving agricultural and industrial commodities and containers on the U.S. Inland Waterways, the Mississippi River, Illinois River, Tennessee River, Ohio River and their tributaries and the Gulf Intracoastal Waterways. Internationally, Inland Services also owns inland river liquid tank barges that operate on the Magdalena River in Colombia. These barges primarily transport petroleum products. Inland Services also has a 50% interest in dry-cargo barge operations on the Parana-Paraguay River Waterways in Brazil, Bolivia, Paraguay, Argentina and Uruguay primarily transporting agricultural and industrial commodities, a 57% interest in towboat operations on the U.S. Inland Waterways and a 50% interest in grain terminals/elevators along the U.S. Inland waterways. Inland Services contributed 34% , 38% and 48% of consolidated operating revenues during the years ended December 31, 2018 , 2017 and 2016 , respectively. Witt O’Brien’s. Witt O’Brien’s provides crisis and emergency management services for both the public and private sectors. These services strengthen clients’ resilience and assist their response to natural and man-made disasters by enhancing their ability to prepare for, respond to and recover from such disasters, while mitigating the impact of future disruptions on operations and helping communities build back stronger. Witt O’Brien’s contributed 16% , 8% and 8% of consolidated operating revenues during the years ended December 31, 2018 , 2017 and 2016 , respectively. During the year ended December 31, 2018 , one Witt O’Brien’s customer (Virgin Islands Public Finance Authority) accounted for $91.3 million , or 11% , of consolidated operating revenues. Other. The Company’s Other business segment includes CLEANCOR Energy Solutions LLC (“Cleancor”), a full service provider that delivers clean fuel to end users, displacing legacy petroleum-based fuels (see Note 2). Cleancor primarily earns revenues from the sale of liquefied natural gas (“LNG”) (see Note 17). Other also has activities, which primarily include lending and leasing activities and noncontrolling investments in various other businesses, primarily sales, storage, and maintenance support for general aviation in Asia and an agricultural commodity trading and logistics business that is primarily focused on the global origination, and trading and merchandising of sugar. Discontinued Operations. The Company reports the historical financial position, results of operations and cash flows of disposed businesses as discontinued operations when it has no continuing interest in the business. On June 1, 2017, the Company completed the spin-off of SEACOR Marine Holdings Inc. (“SEACOR Marine”), the company that operated SEACOR’s Offshore Marine Services business segment, by means of a dividend of all the issued and outstanding common stock of SEACOR Marine to SEACOR’s shareholders (the “Spin-off”). SEACOR Marine is now an independent company whose common stock is listed on the New York Stock Exchange under the symbol “SMHI.” For all periods presented herein, the Company has reported the historical results of operations and cash flows of SEACOR Marine as discontinued operations (see Note 18). On July 3, 2017, the Company completed the sale of its 70% interest in Illinois Corn Processing LLC (“ICP”), the company that operated SEACOR’s Illinois Corn Processing business segment. The Company received $21.0 million in cash and a note from the buyer for $32.8 million , after working capital adjustments, resulting in a gain of $10.9 million , net of tax. On September 15, 2017, the Company received payment of the outstanding balance of the note, including accrued and unpaid interest. For all periods presented herein, the Company has reported the historical results of operations and cash flows of ICP as discontinued operations (see Note 18). Basis of Consolidation. The consolidated financial statements include the accounts of SEACOR 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 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 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 or losses from investments in 50% or less owned companies in the accompanying consolidated statements of 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. Use of Estimates. The preparation of financial statements in conformity with accounting principles generally accepted in the United States 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 allowance for doubtful accounts, useful lives of property and equipment, impairments, income tax provisions and certain accrued liabilities. Actual results could differ from those estimates and those differences may be material. Adoption of New Accounting Standards. On January 1, 2018, the Company adopted Financial Accounting Standard Board (“FASB”) Topic 606, Revenue from Contracts with Customers (“Topic 606”). As a consequence of adopting Topic 606, the Company now recognizes all of the operating revenues and expenses associated with the dry-cargo barge pools it manages along with additional operating expenses reflective of barge pool earnings attributable to third-party barge owners and not the Company in its capacity as manager. Under Topic 606, the Company determined it was a principal with respect to the third-party barge owners. Previously, the Company recognized operating revenues and expenses only for its proportionate share of the barge pools in which it participated, as it acted as an agent. All prior periods have been adjusted to reflect the retrospective adoption of Topic 606, which resulted in additional revenues and operating expenses of $73.0 million and $83.7 million for the years ended December 31, 2017 and 2016 , respectively. The adoption of Topic 606 had no impact on previously reported balance sheets, operating income (loss), net income (loss) or earnings (loss) per share. On January 1, 2018, the Company adopted ASU 2016-16, Intra-Entity Transfers of Assets Other Than Inventory , which eliminates the deferral of the tax effects of intercompany asset sales other than inventory until the transferred assets are sold to a third party or recovered through use. As a result of the adoption of the standard, the deferred tax charges previously recognized from those sales resulted in a decrease in deferred tax assets and a cumulative adjustment to retained earnings of $2.5 million in the consolidated balance sheets and statements of changes in equity as of January 1, 2018. 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 control of the promised goods or services to its customers. Costs to obtain or fulfill a contract are expensed as incurred. Revenue from Contracts with Customers. Ocean Services primarily earns revenues from voyage charters, contracts of affreightment, tariff based port and infrastructure services, unit freight logistics services, and technical ship management agreements with vessel owners (see Note 17). Ocean Services transfers control of the service to the customer and satisfies its performance obligation over the term of the contract, and therefore recognizes revenue over the term of the contract while related costs are expensed as incurred. Voyage charters are contracts to carry cargoes on a single voyage basis for a predetermined price, regardless of time to complete. Contracts of affreightment are contracts for cargoes that are committed on a multi-voyage basis for various periods of time, with minimum and maximum cargo tonnages specified over the period at a fixed or escalating rate per ton. Tariff based port and infrastructure services typically include operating harbor tugs alongside oceangoing vessels to escort them to their berth, assisting with the docking and undocking of these oceangoing vessels and escorting them back out to sea. They are contracted using prevailing port tariff terms on a per-use basis. In the unit freight logistics trade, transportation services typically include transporting shipping containers, rail cars, project cargoes, automobiles and U.S. military vehicles and are generally contracted on a per unit basis for the specified cargo and destination, typically in accordance with a publicly available tariff rate or based on a negotiated rate when moving larger volumes over an extended period. Managed services include technical ship management agreements whereby Ocean Services provides technical ship management services to third-party customers for a predetermined price over a specified period of time, typically a year or more. Inland Services primarily earns revenues from contracts of affreightment, terminal operations, fleeting operations and repair and maintenance services (see Note 17). Inland Services transfers control of the service to the customer and satisfies its performance obligation over the term of the contract, and therefore recognizes revenue over the term of the contract while related costs are expensed as incurred. Contracts of affreightment are contracts whereby customers are charged an established rate per ton to transport cargo from point-to-point. Terminal operations includes tank farms and dry bulk and container handling facilities that are marketed under contractual rates and terms driven by throughput volume. Fleeting operations includes fleeting services whereby barges are held in fleeting areas for an agreed-upon day rate and shifting services whereby harbor boats are used to pick up and drop off barges to assist in assembling tows and to move barges to and from the dock for loading and unloading at predetermined per-shift fees. Other operations primarily include a machine shop specializing in towboat and barge cleaning, repair and maintenance services that are charged on an hourly or a fixed fee basis depending on the scope and nature of the work. Witt O’Brien’s primarily earns revenues from time and material and retainer contracts (see Note 17). Witt O’Brien’s transfers control of the service to the customer and satisfies its performance obligation over the term of the contract, and therefore recognizes revenue over the term of the contract while related costs are expensed as incurred. Time and material contracts primarily relate to emergency response, debris management or consulting services that Witt O’Brien’s performs for a predetermined fee. Retainer contracts, which are nearly all with vessel services operators and oil companies, are contracted based on agreed-upon rates. The Company’s Other business segment includes Cleancor, which primarily earns revenues from the sale of liquefied natural gas (see Note 17). Under these arrangements, control of the goods are transfered to the customer and performance obligations are satisfied at a point in time, and therefore revenue is recognized upon delivery while any related costs are expensed as incurred. Contract liabilities from contracts with customers arise when the Company has received consideration prior to performance and are included in other current liabilities in the accompanying consolidated balance sheets. The Company’s contract liability activity for the year ended December 31 was a follows (in thousands): 2018 Balance at beginning of period $ 983 Contract liabilities arising during the period 968 Revenue recognized upon completion of prior period performance obligations (983 ) Balance at end of period $ 968 Lease Revenues. The Company’s lease revenues are primarily from time charters, bareboat charters and non-vessel rental agreements that are recognized ratably over the lease term as services are provided, typically on a per day basis. Under a time charter, the Company provides a vessel to a customer for a set term and is responsible for all operating expenses, typically excluding fuel. Under a bareboat charter, the Company provides a vessel to a customer for a set term and the customer assumes responsibility for all operating expenses and risks of operation. Under a non-vessel rental agreement, the Company provides non-vessel property or equipment to a customer for a set term and the customer assumes responsibility for all operating expenses and risks of operation. Cash Equivalents. The Company considers all highly liquid investments with an original maturity of three months or less when purchased to be cash equivalents. Cash equivalents consist of U.S. treasury securities, money market instruments, time deposits and overnight investments. Restricted Cash and Restricted Cash Equivalents. Restricted cash and restricted cash equivalents primarily relates to cash collateral for letters of credit and banking facility requirements. Marketable Securities. Marketable equity securities with readily determinable fair values and debt securities are reported in the accompanying consolidated balance sheets as marketable securities. These investments are stated at fair value, as determined by their market observable prices, with both realized and unrealized gains and losses reported in the accompanying consolidated statements of income (loss) as marketable security losses, net. Short sales of marketable securities are stated at fair value in the accompanying consolidated balance sheets with both realized and unrealized gains and losses reported in the accompanying consolidated statements of income (loss) as marketable security losses, net. Long and short marketable security positions are primarily in energy, marine, transportation and other related businesses. Marketable securities are classified as trading securities for financial reporting purposes with gains and losses reported as operating activities in the accompanying consolidated statements of cash flows. The Company’s most significant marketable security position is its investment in 5,200,000 shares of Dorian LPG Ltd. (“Dorian”), a publicly traded company listed on the New York Stock Exchange under the symbol “LPG” (see Note 11). Dorian’s closing share price was $5.83 and $8.22 as of December 31, 2018 and 2017 , respectively. The Company’s cost basis in Dorian is $13.66 per share. Trade Receivables. Customers of Ocean Services are primarily multinational oil companies, refining companies, oil trading companies, major gasoline retailers, large industrial consumers of crude, petroleum and chemicals, trading houses, pools, major automobile manufacturers and shippers, the U.S. Government and regional power utilities. Customers of Inland Services are primarily major agricultural companies, fertilizer companies, trading companies and industrial companies. Customers of Witt O’Brien’s are primarily governments, energy companies, ship managers and owners, healthcare providers, universities and school systems. Customers of the Company’s other business activities primarily include agricultural and feed companies, asphalt producers and municipalities and government agencies. All customers are granted credit on a short-term basis and related credit risks are considered minimal. The Company routinely reviews its trade receivables and makes provisions for probable doubtful accounts; however, those provisions are estimates and actual results could differ from those estimates and those differences may be material. Trade receivables are deemed uncollectible and removed from accounts receivable and the allowance for doubtful accounts when collection efforts have been exhausted. Other Receivables. Other receivables primarily consists of income tax and insurance claim receivables. Other receivables also includes amounts due from certain of the Company’s 50% or less owned companies for working capital in excess of working capital advances, which are typically settled monthly in arrears. Derivative Instruments. The Company accounts for derivatives through the use of a fair value concept whereby all of the Company’s derivative positions are stated at fair value in the accompanying consolidated balance sheets. Realized and unrealized gains and losses on derivatives not designated as hedges are reported in the accompanying consolidated statements of income (loss) as derivative gains (losses), net. Realized and unrealized gains and losses on derivatives designated as fair value hedges are recognized as corresponding increases or decreases in the fair value of the underlying hedged item to the extent they are effective, with any ineffective portion reported in the accompanying consolidated statements of income (loss) as derivative gains (losses), net. Realized and unrealized gains and losses on derivatives designated as cash flow hedges are reported as a component of other comprehensive income (loss) in the accompanying consolidated statements of comprehensive income (loss) to the extent they are effective and reclassified into earnings on the same line item associated with the hedged transaction and in the same period the hedged transaction affects earnings. Any ineffective portions of cash flow hedges are reported in the accompanying consolidated statements of income (loss) as derivative gains (losses), net. Realized and unrealized gains and losses on derivatives designated as cash flow hedges that are entered into by the Company’s 50% or less owned companies are also reported as a component of the Company’s other comprehensive income (loss) in proportion to the Company’s ownership percentage, with reclassifications and ineffective portions being included in equity in earnings (losses) of 50% or less owned companies, net of tax, in the accompanying consolidated statements of income (loss). Concentrations of Credit Risk. The Company is exposed to concentrations of credit risk associated with its cash, cash equivalents, restricted cash and restricted cash equivalents, construction reserve funds and derivative instruments. The Company minimizes its credit risk relating to these positions by monitoring the financial condition of the financial institutions and counterparties involved and by primarily conducting business with large, well-established financial institutions and diversifying its counterparties. The Company does not currently anticipate nonperformance of its significant counterparties. The Company is also exposed to concentrations of credit risk relating to its receivables due from customers in the industries described above. The Company does not generally require collateral or other security to support its outstanding receivables. The Company minimizes its credit risk relating to receivables by performing ongoing credit evaluations and, to date, credit losses have not been material. Inventories. Inventories are stated at the lower of cost (using the first-in, first-out method) or market. Inventories consist primarily of fuel and fuel oil consumed by the Company’s vessels in its Ocean Services and Inland Services business segments. The Company records write-downs, as needed, to adjust the carrying amount of inventories to the lower of cost or market. During the years ended December 31, 2018 , 2017 and 2016 , the Company had no market write-downs of inventory. 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 typically based upon a newly built asset being placed into service and represents the point at 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 their useful life as set forth in 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 December 31, 2018 , the estimated useful life (in years) of each of the Company’s major classes of new equipment was as follows: Petroleum and chemical carriers - U.S.-flag 25 Harbor and offshore tugs 25 Ocean liquid tank barges 25 Short-sea container/RORO (1) vessels 20 Bulk carriers - U.S.-flag 25 Inland river dry-cargo and specialty barges 20 Inland river liquid tank barges 25 Inland river towboats and harbor boats 25 Terminal and fleeting facilities 20 ______________________ (1) Roll On/Roll Off. The Company’s major classes of property and equipment as of December 31 were as follows (in thousands): Historical Cost (1) Accumulated Depreciation Net Book Value 2018 Ocean Services: Petroleum and chemical carriers - U.S.-flag $ 649,795 $ (241,604 ) $ 408,191 Harbor and offshore tugs - U.S.-flag 132,697 (41,764 ) 90,933 Harbor tugs - Foreign-flag 45,379 (13,822 ) 31,557 Ocean liquid tank barges - U.S.-flag 39,238 (14,649 ) 24,589 Short-sea container/RORO - Foreign-flag 29,846 (10,644 ) 19,202 Bulk carriers - U.S.-flag 13,000 (9,800 ) 3,200 Other (2) 20,073 (9,716 ) 10,357 Construction in Progress 202 — 202 930,230 (341,999 ) 588,231 Inland Services: Dry-cargo barges 222,539 (106,157 ) 116,382 Specialty barges 3,828 (1,904 ) 1,924 Liquid tank barges 20,011 (3,054 ) 16,957 Towboats 43,998 (3,294 ) 40,704 Harbor boats 18,695 (8,047 ) 10,648 Terminal and fleeting facilities 99,696 (62,274 ) 37,422 Other (2) 22,213 (10,364 ) 11,849 Construction in Progress 7,868 — 7,868 438,848 (195,094 ) 243,754 Witt O’Brien’s: Other (2) 1,227 (1,031 ) 196 Other: Other (3) 6,892 (490 ) 6,402 Corporate and Eliminations: Other (2) 30,132 (22,205 ) 7,927 $ 1,407,329 $ (560,819 ) $ 846,510 ______________________ (1) Includes property and equipment acquired in business acquisitions at acquisition date fair value. (2) Includes land and buildings, leasehold improvements, fixed-wing aircraft, vehicles and other property and equipment. (3) Includes LNG Equipment and other property and equipment. Historical Cost (1) Accumulated Depreciation Net Book Value 2017 Ocean Services: Petroleum and chemical carriers - U.S.-flag $ 652,985 $ (215,057 ) $ 437,928 Harbor and offshore tugs - U.S.-flag 84,155 (38,984 ) 45,171 Harbor tugs - Foreign-flag 45,338 (11,575 ) 33,763 Ocean liquid tank barges - U.S.-flag 39,238 (13,126 ) 26,112 Short-sea container/RORO - Foreign-flag 20,954 (8,178 ) 12,776 Bulk carriers - U.S.-flag 13,000 (4,733 ) 8,267 Other (2) 19,420 (7,875 ) 11,545 Construction in Progress 25,986 — 25,986 901,076 (299,528 ) 601,548 Inland Services: Dry-cargo barges 233,734 (101,087 ) 132,647 Specialty barges 4,180 (1,781 ) 2,399 Liquid tank barges 21,802 (2,684 ) 19,118 Towboats 44,555 (1,765 ) 42,790 Harbor boats 18,158 (6,956 ) 11,202 Terminal and fleeting facilities 95,926 (55,899 ) 40,027 Other (2) 26,938 (11,401 ) 15,537 Construction in Progress 2,742 — 2,742 448,035 (181,573 ) 266,462 Witt O’Brien’s: Other (2) 1,227 (938 ) 289 Corporate and Eliminations: Other (2) 30,131 (20,505 ) 9,626 $ 1,380,469 $ (502,544 ) $ 877,925 ______________________ (1) Includes property and equipment acquired in business acquisitions at acquisition date fair value. (2) Includes land and buildings, leasehold improvements, fixed-wing aircraft, vehicles and other property and equipment. During the years ended December 31, 2018 , 2017 and 2016 , depreciation expense totaled $69.9 million , $72.1 million , and $60.2 million , respectively. Equipment maintenance and repair costs and the costs of routine overhauls, dry-dockings 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 years ended December 31, 2018 , 2017 and 2016 capitalized interest totaled $0.2 million , $2.7 million and $11.5 million , respectively. As of December 31, 2018, the Company’s construction in progress totaling $8.1 million primarily consisted of the construction of and upgrades to inland river towboats and the construction of other Inland Services equipment, and is included in historical cost in the accompanying consolidated balance sheets. Intangible Assets. The Company’s intangible assets primarily arose from business acquisitions (see Note 2) and consist of trademarks and tradenames, customer relationships and acquired contractual rights. These intangible assets are amortized over their estimated useful lives generally ranging from one to 15 years. During the years ended December 31, 2018 , 2017 and 2016 , the Company recognized amortization expense of $4.7 million , $2.9 million and $2.4 million , respectively. The Company’s intangible assets by type were as follows (in thousands): Trademark/ Tradenames Customer Relationships Acquired Contractual Rights Total Gross Carrying Value Year Ended December 31, 2016 $ 3,324 $ 15,365 $ 8,416 $ 27,105 Acquired intangible assets — — 10,957 10,957 Foreign currency translation — — 2 2 Fully amortized intangible assets — — (1,017 ) (1,017 ) Year Ended December 31, 2017 3,324 15,365 18,358 37,047 Acquired intangible assets — 1,120 — 1,120 Fully amortized intangible assets — (1,120 ) — (1,120 ) Year Ended December 31, 2018 $ 3,324 $ 15,365 $ 18,358 $ 37,047 Accumulated Amortization Year Ended December 31, 2016 $ (1,648 ) $ (3,867 ) $ (1,512 ) $ (7,027 ) Amortization expense (332 ) (1,279 ) (1,320 ) (2,931 ) Fully amortized intangible assets — — 1,017 1,017 Year Ended December 31, 2017 (1,980 ) (5,146 ) (1,815 ) (8,941 ) Amortization expense (332 ) (2,402 ) (1,941 ) (4,675 ) Fully amortized intangible assets — 1,120 — 1,120 Year Ended December 31, 2018 $ (2,312 ) $ (6,428 ) $ (3,756 ) $ (12,496 ) Weighted average remaining contractual life, in years 3.0 8.0 8.0 7.8 Future amortization expense of intangible assets for each of the years ended December 31 is as follows (in thousands): 2019 $ 3,555 2020 3,555 2021 3,571 2022 2,866 2023 2,852 Years subsequent to 2023 8,152 $ 24,551 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 the estimated 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. The Company performs its testing on an asset or asset group basis. Generally, fair value is determined using valuation techniques, such as expected discounted cash flows or appraisals, as appropriate. During the year ended December 31, 2018 , the Company did not recognize any impairment ch

Business Acquisitions

Business Acquisitions	12 Months Ended
	Dec. 31, 2018
Business Combinations [Abstract]
Business Acquisitions	2. BUSINESS ACQUISITIONS Cleancor . On June 1, 2018, the Company acquired a controlling interest in Cleancor, a full service solution provider that delivers clean fuel to end users displacing legacy petroleum-based fuels, through the acquisition of its partners’ 50% equity interest for $3.2 million in cash. In addition, immediately prior to consolidation, the Company contributed as capital $1.9 million of notes receivable due from Cleancor. The Company performed a fair value analysis and the purchase price was allocated to the acquired assets and liabilities based on their fair value resulting in no goodwill being recorded. SCA. On March 1, 2018, the Company acquired Strategic Crisis Advisors LLC (“SCA”) for $1.5 million to be paid in two installments. The purchase price includes $0.9 million in contingent consideration that is dependent upon SCA meeting predetermined revenue targets for the twelve months following the acquisition date. The Company performed a fair value analysis and the purchase price was allocated to the acquired assets and liabilities based on their fair value resulting in no goodwill being recorded. ISH. On July 3, 2017, International Shipholding Corporation (“ISH”) emerged from bankruptcy pursuant to its chapter 11 plan of reorganization (the “Plan”) confirmed by the U.S. Bankruptcy Court for the Southern District of New York (the “ISH Acquisition”). Pursuant to the Plan, SEACOR Ocean Transport Inc., a wholly-owned subsidiary of SEACOR, acquired all of the equity of the reorganized ISH. Under the terms of the Plan, the Company paid consideration consisting of $10.5 million in cash, converted $18.1 million of debtor-in-possession financing into equity and assumed $28.7 million of debt primarily from a new credit facility that is secured by the assets and equity of ISH and is non-recourse to SEACOR and its subsidiaries other than ISH (see Note 7). ISH, through its subsidiaries, operates a diversified fleet of U.S. and foreign-flag vessels including four leased-in PCTCs and two owned U.S.-flag bulk carriers that provide worldwide and domestic maritime transportation services to commercial and governmental customers. In addition, ISH has investments in two 50% or less owned companies that operate two foreign-flag rail ferries and a railcar repair and maintenance facility. The Company has excluded pro forma financial information with respect to the ISH Acquisition as financial information for the specific assets acquired under the Plan were not material or reasonably attainable. The Company performed a fair value analysis and the purchase price was allocated to the acquired assets and liabilities based on their fair value resulting in no goodwill being recorded. CCM. On October 31, 2016, the Company acquired certain assets from Central Contracting & Marine, Inc. (“CCM”) consisting primarily of terminal and fleeting assets, including five inland river harbor boats, for $18.1 million in cash. The Company performed a fair value analysis and the purchase price was allocated to the acquired assets based on their fair values resulting in no goodwill being recorded. SeaJon II. On December 2, 2016, the Company acquired a controlling interest in SeaJon II LLC (“SeaJon II”), which owns one U.S.-flag offshore tug, through the acquisition of its partner’s 50% equity interest for $3.4 million in cash (see Note 4). The Company performed a fair value analysis and the purchase price was allocated to the acquired assets and liabilities based on their fair values resulting in no goodwill being recorded. Purchase Price Allocation. The allocation of the purchase price for the Company’s acquisitions for the years ended December 31 was as follows (in thousands): 2018 2017 2016 Restricted cash and restricted cash equivalents $ — $ 13 $ — Trade and other receivables 1,264 15,823 937 Other current assets 170 2,054 150 Investments, at Equity, and Advances to 50% or Less Owned Companies (5,123 ) 10,000 (3,437 ) Property and Equipment 4,382 15,190 15,765 Intangible Assets 1,120 10,957 7,098 Other Assets (1) 7 (17,863 ) — Accounts payable and other accrued liabilities (2) (1,609 ) — 39 Other current liabilities (439 ) (17,214 ) (13 ) Long-Term Debt — (28,725 ) — Deferred Income Taxes — 3,939 — Other Liabilities — (42 ) — Noncontrolling interests in subsidiaries (82 ) — — Purchase price (3) $ (310 ) $ (5,868 ) $ 20,539 ______________________ (1) Net of debtor-in-possession financing converted into equity of $18.1 million , in 2017. (2) Includes $1.5 million of consideration to be paid in two installments. (3) Purchase price is net of cash acquired totaling $3.6 million , $16.4 million and $0.9 million in 2018 , 2017 and 2016 , respectively.

Equipment Acquisitions And Disp

Equipment Acquisitions And Dispositions	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Equipment Acquisitions And Dispositions	3. EQUIPMENT ACQUISITIONS AND DISPOSITIONS Equipment Additions. The Company’s capital expenditures were $50.3 million , $114.6 million and $252.8 million during the years ended December 31, 2018 , 2017 , and 2016 , respectively. Major owned equipment placed in service for the years ended December 31 were as follows: 2018 2017 (1) 2016 (2) Petroleum and chemical carriers - U.S.-flag — 3 3 Short-sea container\RORO - Foreign-flag 2 — — Harbor tugs - U.S.-flag 5 1 1 Harbor tugs - Foreign-flag — 2 — Inland river dry-cargo barges — — 46 Inland river liquid tank barges — 2 — Inland river towboats — 3 2 ______________________ (1) Excludes two U.S.-flag bulk carriers acquired in the ISH acquisition (see Note 2). (2) Excludes five inland river harbor boats acquired in the CCM acquisition and one U.S.-flag offshore tug acquired in the SeaJon II acquisition (see Note 2). Equipment Dispositions. During the year ended December 31, 2018 , the Company sold property and equipment for net proceeds of $16.1 million and gains of $6.6 million . In addition, the Company recognized previously deferred gains of $13.0 million . During the year ended December 31, 2017 , the Company sold property and equipment for net proceeds of $164.8 million and gains of $23.3 million , of which $10.0 million were recognized currently and $13.3 million were deferred (see Note 1). Equipment dispositions included the sale-leaseback of one U.S.-flag petroleum and chemical carrier for $134.9 million , with leaseback terms of 104 months and 50 dry-cargo barges for $12.5 million with leaseback terms of 84 months. Gains of $13.3 million related to the sale-leasebacks were deferred and are being amortized over the respective minimum lease periods. In addition, the Company recognized previously deferred gains of $2.3 million . The Company also recognized a loss of $0.3 million related to the total loss of one inland river specialty barge. During the year ended December 31, 2016 , the Company sold property and equipment for net proceeds of $153.0 million ( $143.0 million in cash, $8.0 million in seller financing and one U.S.-flag harbor tug valued at $2.0 million ) and gains of $11.3 million , of which $2.3 million were recognized currently and $9.0 million were deferred (see Note 1). Equipment dispositions included the sale-leaseback of one U.S.-flag petroleum and chemical carrier for $61.0 million , with leaseback terms of 76 months. Gains of $8.2 million related to the sale-leaseback were deferred and are being amortized over the minimum lease period. In addition, the Company recognized previously deferred gains of $2.4 million . Major equipment dispositions for the years ended December 31 were as follows: 2018 2017 2016 Petroleum and chemical carriers - U.S.-flag 1 1 1 Harbor tugs - U.S.-flag 1 — 2 Inland river dry-cargo barges 32 50 — Inland river liquid tank barges — — 19 Inland river specialty barges 2 2 — Inland river towboats — 2 14

Investments, At Equity, And Adv

Investments, At Equity, And Advances To 50% Or Less Owned Companies	12 Months Ended
	Dec. 31, 2018
Equity Method Investment, Summarized Financial Information [Abstract]
Investments, At Equity, And Advances To 50% Or Less Owned Companies	4. INVESTMENTS, AT EQUITY, AND ADVANCES TO 50% OR LESS OWNED COMPANIES Investments, at equity, and advances to 50% or less owned companies as of December 31 were as follows (in thousands): Ownership 2018 2017 Ocean Services: Trailer Bridge (1) 55.3% $ 56,364 $ 47,324 RF Vessel Holdings 50.0% 10,826 2,378 Golfo de Mexico 50.0% 5,272 2,500 KSM 50.0% 1,478 (199 ) 73,940 52,003 Inland Services: SCFCo 50.0% 37,219 42,126 Bunge-SCF Grain 50.0% 14,738 16,166 SCF Bunge Marine (1) 57.0% 3,144 5,404 Other 50.0% 2,796 2,783 57,897 66,479 Witt O’Brien’s: O’Brien’s do Brazil 50.0% 472 777 Other: Hawker Pacific 34.2% — 21,681 VA&E 41.3% 13,073 13,596 Avion 39.1% 10,290 11,400 Cleancor 50.0% — 5,134 Other 34.0% – 47.5 % 1,214 2,371 24,577 54,182 $ 156,886 $ 173,441 ______________________ (1) The Company’s ownership percentage represents its economic interest in the joint venture. Combined Condensed Financial Information. Summarized financial information for the Company’s investments, at equity, excluding SCFCo and Trailer Bridge, as of and for the years ended December 31 was as follows (in thousands): 2018 2017 Current assets $ 184,704 $ 523,343 Noncurrent assets 77,929 124,733 Current liabilities 113,784 407,812 Noncurrent liabilities 46,503 81,899 2018 2017 2016 Operating Revenues $ 786,717 $ 1,068,190 $ 1,019,658 Costs and Expenses: Operating and administrative 771,324 1,035,952 951,019 Depreciation 7,216 11,810 24,936 778,540 1,047,762 975,955 Gains (Losses) on Asset Dispositions and Impairments, Net 38 16,115 (6,339 ) Operating Income $ 8,215 $ 36,543 $ 37,364 Net Income $ 3,967 $ 23,383 $ 4,961 As of December 31, 2018 and 2017 , cumulative undistributed net losses of 50% or less owned companies accounted for by the equity method and included in the Company’s consolidated retained earnings were $65.0 million and $40.1 million , respectively. Trailer Bridge. Trailer Bridge, Inc. (“Trailer Bridge”), an operator of U.S.-flag RORO and deck barges, provides marine transportation services between Jacksonville, Florida, San Juan, Puerto Rico and Puerto Plata, Dominican Republic. In December 2016, the Company and other major investors recapitalized Trailer Bridge by agreeing to exchange outstanding subordinated debt for equity. As a consequence of the recapitalization, the Company’s noncontrolling interest in Trailer Bridge increased to 55.3% resulting in an equity loss of $2.2 million , net of tax. The Company provided secured financing to Trailer Bridge and during the years ended December 31, 2017 and 2016 , the Company provided advances of $2.0 million and $1.7 million , respectively, on the secured financing. During the year ended December 31, 2017 , the Company received repayments of $6.0 million on the secured financing. As of December 31, 2017 , there was no outstanding balance on the secured financing. During the years ended December 31, 2018 , 2017 and 2016 , the Company received $3.5 million , $3.1 million and $3.0 million , respectively, for the time charter of a U.S.-flag harbor tug to Trailer Bridge. Prior to July 1, 2016, the Company also provided Trailer Bridge with technical and commercial management services and during the year ended December 31, 2016 , received $0.3 million for these services. RF Vessel Holdings. On July 3, 2017, as part of the ISH Acquisition (see Note 2), the Company acquired a 100% interest in Rail-Ferry Vessel Holdings LLC (“RF Vessel Holdings”), which owns two foreign-flag rail ferries. On September 1, 2017, the Company sold a 50% interest in RF Vessel Holdings to G&W Agave Holdings (MI) Inc. for $1.9 million and retained a 50% ownership interest in the newly-formed joint venture. During the year ended December 31, 2018 , the Company and its partner each contributed capital of $9.1 million to RF Vessel Holdings. Golfo de Mexico. On July 3, 2017, as part of the ISH Acquisition (see Note 2), the Company acquired a 100% interest in Golfo de Mexico Rail-Ferry Holdings LLC (“Golfo de Mexico”), which operates the two foreign-flag rail ferries owned by RF Vessel Holdings. On September 1, 2017, the Company sold a 50% interest in Golfo de Mexico to G&W Agave Holdings (MI) Inc. for $3.1 million and retained a 50% ownership interest in the newly-formed joint venture. During the year ended December 31, 2018 , the Company and its partner each contributed capital of $4.6 million to Golfo de Mexico. During the year ended December 31, 2017 , the Company received dividends of $0.3 million from Golfo de Mexico. The Company provides Golfo de Mexico with technical, commercial and administrative management services and during the years ended December 31, 2018 and 2017 , the Company received $1.1 million and $0.3 million , respectively, for these services. KSM. On April 1, 2017, the Company and Kotug Caribbean Holdings LLC formed Kotug Seabulk Maritime LLC (“KSM”) to operate four foreign-flag harbor tugs and one foreign-flag ocean liquid tank barge in Freeport, Grand Bahama. The Company has a 50% ownership interest in KSM. During the years ended December 31, 2018 and 2017 , the Company and its partner each contributed capital of $1.0 million and $0.3 million , respectively, to KSM. The Company provides KSM with technical, commercial and administrative management services and during the years ended December 31, 2018 and 2017 , received $0.4 million and $0.3 million , respectively, for these services. During the years ended December 31, 2018 and 2017 , the Company received $1.3 million and $1.1 million , respectively, for the bareboat charter of two foreign-flag harbor tugs to KSM. SeaJon. SeaJon LLC (“SeaJon”) owned an articulated tug-barge operating in the Great Lakes trade that was sold to a third party in June 2017 and, as of December 31, 2017, SeaJon had been liquidated. During the year ended December 31, 2017, the Company received capital distributions of $3.5 million and dividends of $12.5 million from SeaJon. During the year ended December 31, 2016, the Company received dividends of $0.6 million from SeaJon. SEA-Access. SEA-Access LLC (“SEA-Access”) was formed to acquire and operate the M/V Eagle Ford , a 124,000 dwt U.S.-flag petroleum and chemical carrier. In June 2016, the M/V Eagle Ford was scrapped and, as of December 31, 2016, SEA-Access had been liquidated. During the year ended December 31, 2016, the Company received capital distributions of $8.4 million and dividends of $2.0 million from SEA-Access. The Company provided SEA-Access with technical and commercial management services and during the year ended December 31, 2016, received $0.5 million for these services. SeaJon II. SeaJon II LLC (“SeaJon II”) was formed to own a U.S.-flag offshore tug on time charter to Trailer Bridge. The Company provided SeaJon II with technical and commercial management services and during the year ended December 31, 2016, received $0.1 million for these services. On December 2, 2016, the Company acquired a controlling interest in SeaJon II through the acquisition of its partner’s 50% equity interest for $3.4 million in cash (see Note 2). Upon the change in control, the Company marked its investment in SeaJon II to fair value resulting in a loss of $1.9 million , net of tax, which is included in equity in earnings (losses) of 50% or less owned companies in the accompanying consolidated statements of income (loss). SCFCo. SCFCo Holdings LLC (“SCFCo”) was established to operate inland river dry-cargo barges and inland river towboats on the Parana-Paraguay Rivers and a terminal facility at Port Ibicuy, Argentina. During the years ended December 31, 2017 and 2016, the Company contributed capital of $0.4 million and $0.8 million , respectively, to SCFCo. During the years ended December 31, 2017 and 2016, the Company provided SCFCo with working capital advances and loans of $2.5 million and $1.8 million , respectively. During the years ended December 31, 2018 and 2017, the Company received repayments on these working capital advances and loans of $2.6 million and $1.7 million , respectively. As of December 31, 2018 , $30.5 million of working capital advances and loans remained outstanding. The Company also provides SCFCo with certain information technology services and received $0.1 million , $0.1 million and $0.1 million , respectively, for these services during the years ended December 31, 2018 , 2017 and 2016 . During the year ended December 31, 2016, the Company identified indicators of impairment in its investment in SCFCo as a result of continuing losses and recognized impairment charges of $7.7 million for an other-than-temporary decline in the fair value of its investment. As of December 31, 2018 , the Company’s carrying value of its investment in SCFCo was $23.4 million lower than its proportionate share of the underlying equity in SCFCo. Summarized financial information for SCFCo as of and for the years ended December 31 was as follows (in thousands): 2018 2017 Current assets $ 8,322 $ 7,924 Property and equipment, net 121,001 137,224 Current liabilities 12,958 14,263 Noncurrent liabilities 56,078 54,179 2018 2017 2016 Operating Revenues $ 54,486 $ 44,177 $ 43,711 Costs and Expenses: Operating and administrative 45,911 40,106 38,980 Depreciation 17,901 17,803 17,560 63,812 57,909 56,540 Operating Loss (9,326 ) (13,732 ) (12,829 ) Interest expense (6,573 ) (6,120 ) (6,565 ) Other expense, net (2,229 ) (961 ) (657 ) Net Loss $ (18,128 ) $ (20,813 ) $ (20,051 ) Bunge-SCF Grain. Bunge-SCF Grain LLC (“Bunge-SCF Grain”) operates terminal grain elevators in Illinois. The Company has provided Bunge-SCF Grain with working capital advances. As of December 31, 2018 , the total outstanding balance of working capital advances was $7.0 million . Bunge-SCF Grain also operates and manages the Company’s grain storage and handling facility in McLeansboro, Illinois, and the Company received $0.9 million , $1.1 million and $1.0 million in rental income for the years ended December 31, 2018 , 2017 and 2016 , respectively. Certain dry-cargo barge pools managed by the Company provide freight transportation to Bunge-SCF Grain and those pools received $10.7 million , $7.2 million and $7.2 million for these services during the years ended December 31, 2018 , 2017 and 2016 , respectively. SCF Bunge Marine. SCF Bunge Marine LLC (“SCF Bunge Marine”) provides towing services on the U.S. Inland Waterways, primarily the Mississippi River, Illinois River, Tennessee River and Ohio River. The Company time charters seven inland river towboats to SCF Bunge Marine, of which four are bareboat chartered-in by the Company from a third-party leasing company. The Company and its partner are required to fund SCF Bunge Marine, if necessary, to support the payment of its time charter obligations to the Company. Pursuant to the time charter, the Company received charter fees of $50.8 million , $38.7 million and $35.0 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. During the year ended December 31, 2018 , the Company contributed capital of $0.5 million to SCF Bunge Marine. During the years ended December 31, 2018 , 2017 and 2016 , the Company received dividends of $4.6 million , $0.1 million and $2.5 million , respectively, from SCF Bunge Marine. Certain dry-cargo barge pools managed by the Company obtain towing services from SCF Bunge Marine and those pools paid $54.5 million , $41.4 million and $40.2 million for these services during the years ended December 31, 2018 , 2017 and 2016 , respectively. Other Inland Services. The Company’s other Inland Services 50% or less owned company operates a fabrication facility. O’Brien’s do Brazil. O’Brien’s do Brasil Consultoria em Emergencias e Meio Ambiente A/A (“O’Brien’s do Brazil”) is an emergency consulting organization providing preparedness, response and recovery services in Brazil. During the years ended December 31, 2018 , 2017 and 2016 , the Company received dividends of $0.2 million , $0.1 million and $0.1 million , respectively. Hawker Pacific. Hawker Pacific Airservices, Limited (“Hawker Pacific”) is an aviation sales and support organization and a distributor of aviation components from leading manufacturers. On April 30, 2018, the Company sold its 34.2% interest in Hawker Pacific for $78.0 million in cash and recognized a gain of $53.9 million , which is included in other, net in the accompanying consolidated statements of income (loss). During the years ended December 31, 2018 , 2017 and 2016 , the Company received management fees of $0.1 million , $0.3 million and $0.3 million , respectively, from Hawker Pacific. VA&E. VA&E Trading USA LLC and VA&E Trading LLP (collectively “VA&E”), were formed to focus on the global origination, trading and merchandising of sugar, pairing producers and buyers and arranging for the transportation and logistics of the product. Through November 2016, the Company provided VA&E an unsecured revolving credit facility of up to $6.0 million , a term loan of $1.1 million and a subordinated loan of $3.5 million . During the year ended December 31, 2016, the Company received repayments of $12.4 million and advanced $10.0 million on the revolving credit facility and received repayments of $1.1 million on its term loan. In December 2016, the Company maintained its subordinated loan of $3.5 million , provided an uncommitted credit facility of up to $3.5 million and terminated the revolving credit facility and term loan. During the year ended December 31, 2017, the Company advanced $3.5 million on the uncommitted credit facility. During the year ended December 31, 2018 , the Company received repayments of $5.4 million and advanced $5.4 million on the uncommitted credit facility. As of December 31, 2018 , the Company had outstanding advances of $7.4 million to VA&E, inclusive of accrued and unpaid interest. In addition, during the year ended December 31, 2018, the Company received dividends of $0.4 million from VA&E. Avion. Avion Pacific Limited (“Avion”) is a distributor of aircraft and aircraft related parts. During the years ended December 31, 2017 and 2016, the Company made advances of $1.0 million and $3.0 million , respectively, to Avion. During the year ended December 31, 2017, the Company received repayments on advances of $4.0 million from Avion. As of December 31, 2018 and 2017, the Company had no outstanding advances to Avion. During the year ended December 31, 2018, the Company received dividends of $0.8 million from Avion. Cleancor. CLEANCOR Energy Solutions LLC (“Cleancor”) is a full service solution provider delivering clean fuel to end users displacing legacy petroleum-based fuels. On June 1, 2018, the Company acquired a controlling interest in Cleancor through the acquisition of its partners’ equity interest (see Note 2). Other. The Company’s other 50% or less owned companies are primarily industrial aviation businesses in Asia. During the year ended December 31, 2018, the Company received repayments on working capital advances of $0.4 million and received capital distributions of $0.6 million from these 50% or less owned companies. During the year ended December 31, 2017, the Company received repayments on working capital advances of $0.4 million from these 50% or less owned companies. During the year ended December 31, 2016, the Company made advances of $0.8 million to these 50% or less owned companies. As of December 31, 2018 , total advances outstanding to these 50% or less owned companies were $2.0 million .

Construction Reserve Funds

Construction Reserve Funds	12 Months Ended
	Dec. 31, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Construction Reserve Funds	5. CONSTRUCTION RESERVE FUNDS The Company has established, pursuant to Section 511 of the Merchant Marine Act, 1936, as amended, construction reserve fund accounts subject to agreements with the Maritime Administration. In accordance with this statute, the Company is permitted to deposit proceeds from the sale of certain vessels into the construction reserve fund accounts and defer the taxable gains realized from the sale of those vessels. Qualified withdrawals from the construction reserve fund accounts are only permitted for the purpose of acquiring qualified U.S.-flag vessels as defined in the statute and approved by the Maritime Administration. To the extent that sales proceeds are reinvested in replacement vessels, the carryover depreciable tax basis of the vessels originally sold is attributed to the U.S.-flag vessels acquired using such qualified withdrawals. The construction reserve funds must be committed for expenditure within three years of the date of sale of the equipment, subject to two one-year extensions that can be granted at the discretion of the Maritime Administration, or be released for the Company’s general use as nonqualified withdrawals. For nonqualified withdrawals, the Company is obligated to pay taxes on the previously deferred gains at the prevailing statutory tax rate plus penalties and interest thereon for the period such taxes were deferred.

Leases And Notes Receivables Fr

Leases And Notes Receivables From Third Parties	12 Months Ended
	Dec. 31, 2018
Notes, Loans and Financing Receivable, Net, Noncurrent [Abstract]
Leases And Notes Receivables From Third Parties	6. LEASES AND NOTES RECEIVABLE FROM THIRD PARTIES From time to time, the Company engages in lending and leasing activities involving various types of equipment. The Company recognizes interest income as payments are due, typically monthly, and expenses all costs associated with its lending and leasing activities as incurred. These leases and notes receivable are typically collateralized by the underlying equipment and require scheduled lease payments or periodic principal and interest payments. As of December 31, 2018 and 2017 , the outstanding balance of leases and notes receivable from third parties was $2.3 million and $2.8 million , respectively, and is included in other long-term assets in the accompanying consolidated balance sheets. During the years ended December 31, 2018 , 2017 and 2016 , the Company made advances on notes receivable from third parties of $0.1 million , $10.1 million and $9.1 million , respectively, and received repayments on notes receivable from third parties of $0.6 million , $34.5 million and $6.3 million , respectively. During the year ended December 31, 2016 , the Company recognized reserves of $6.7 million for one of its notes receivable from third parties following non-performance and a decline in the underlying collateral value.

Long-Term Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2018
Long-term Debt, Unclassified [Abstract]
Long-Term Debt	7. LONG-TERM DEBT The Company’s borrowings as of December 31 were as follows (in thousands): 2018 2017 3.0% Convertible Senior Notes (1) $ 107,284 $ 230,000 2.5% Convertible Senior Notes 64,455 64,455 3.25% Convertible Senior Notes (2) 117,782 — 7.375% Senior Notes (3) — 153,090 SEA-Vista Credit Facility (4) 87,977 135,714 ISH Credit Facility (5) — 12,200 Other (6) 8,561 10,633 386,059 606,092 Portion due within one year (8,497 ) (77,842 ) Debt discount included in long-term debt (28,334 ) (23,152 ) Debt issuance costs included in long-term debt (3,100 ) (3,593 ) $ 346,128 $ 501,505 ______________________ (1) Excludes unamortized discount and unamortized issue costs of $7.2 million and $0.7 million , respectively, as of December 31, 2018 and $22.9 million and $2.3 million , respectively, as of December 31, 2017 . (2) Excludes unamortized discount and unamortized issue costs of $21.1 million and $1.9 million , respectively, as of December 31, 2018 . (3) Excludes unamortized discount and unamortized issue costs of $0.2 million and $0.3 million , respectively, as of December 31, 2017 . (4) Excludes unamortized issue costs of $0.4 million and $0.7 million as of December 31, 2018 and December 31, 2017 , respectively. (5) Excludes unamortized issue costs of $0.1 million as of December 31, 2017 . (6) Excludes unamortized issue costs of $0.1 million and $0.1 million as of December 31, 2018 and December 31, 2017 , respectively. The Company’s contractual long-term debt maturities for the years ended December 31 are as follows (in thousands): 2019 $ 8,497 2020 80,672 2021 500 2022 503 2023 368 Years subsequent to 2023 295,519 $ 386,059 3.0% Convertible Senior Notes. On November 13, 2013, SEACOR issued $230.0 million aggregate principal amount of its 3.0% Convertible Senior Notes due November 15, 2028 (the “ 3.0% Convertible Senior Notes”). Interest on the 3.0% Convertible Senior Notes is payable semi-annually on May 15 and November 15 of each year. Beginning November 15, 2020, contingent interest is payable during any subsequent semi-annual interest period if the average trading price of the 3.0% Convertible Senior Notes for a defined period is greater than or equal to $1,200 per bond ( $1,000 face value). The amount of contingent interest payable for any such period will be equal to 0.45% per annum of such average trading price of the 3.0% Convertible Senior Notes. Prior to August 15, 2028, the 3.0% Convertible Senior Notes are convertible into shares of SEACOR common stock, par value $0.01 per share (“Common Stock”), at a conversion rate (“Conversion Rate”) of 12.5892 shares per bond ( $1,000 face value) only if certain conditions are met, as more fully described in the indenture. After August 15, 2028, holders may elect to convert at any time. The Company has reserved the maximum number of shares of Common Stock needed upon conversion, or 1,350,620 shares as of December 31, 2018 . On or after November 19, 2018, the 3.0% Convertible Senior Notes may be redeemed, in whole or in part, at a price equal to 100% of the principal amount, plus accrued and unpaid interest to the date of redemption. On November 19, 2020, November 20, 2023 or if the Company undergoes a fundamental change, as more fully described in the indenture, the holders of the 3.0% Convertible Senior Notes may require SEACOR to purchase for cash all or part of the notes at a price equal to 100% of the principal amount, plus accrued and unpaid interest to the date of purchase. The Company accounts separately for the liability and equity components of the 3.0% Convertible Senior Notes and the associated underwriting fees in a manner that reflects the Company’s non-convertible borrowing rate. The resulting debt discount and offering costs associated with the liability component are amortized as additional non-cash interest expense over the seven year period for which the debt is expected to be outstanding (November 19, 2020) for an overall effective annual interest rate of 7.4% . On May 15, 2018, the Company exchanged $117.8 million aggregate principal amount of its outstanding 3.0% Convertible Senior Notes for a like principal amount of new 3.25% Convertible Senior Notes (see discussion below). In addition, during the year ended December 31, 2018 , the Company purchased $4.9 million in principal amount of its 3.0% Convertible Senior Notes for total consideration of $4.7 million . These transactions resulted in debt extinguishment losses of $5.4 million included in the accompanying consolidated statements of income (loss). 2.5% Convertible Senior Notes. On December 11, 2012, SEACOR issued $350.0 million aggregate principal amount of its 2.5% Convertible Senior Notes due December 15, 2027 (the “ 2.5% Convertible Senior Notes”). Interest on the 2.5% Convertible Senior Notes is payable semi-annually on June 15 and December 15 of each year. Beginning December 15, 2017, contingent interest is payable during any subsequent semi-annual interest period if the average trading price of the 2.5% Convertible Senior Notes for a defined period is greater than or equal to $1,200 per bond ( $1,000 face value). The amount of contingent interest payable for any such period will be equal to 0.25% per annum of such average trading price of the 2.5% Convertible Senior Notes. Prior to September 15, 2027, the 2.5% Convertible Senior Notes are convertible into shares of Common Stock at a conversion rate of 19.0381 shares per bond ( $1,000 face value) only if certain conditions are met, as more fully described in the indenture. After September 15, 2027, holders may elect to convert at any time. The Company has reserved the maximum number of shares of Common Stock needed upon conversion, or 1,227,101 shares as of December 31, 2018 . On December 12, 2017, the Company entered into a supplemental indenture, which amended the indenture to provide holders with an additional put right for their Notes on May 31, 2018. In addition, the Company surrendered and waived its right to redeem the Notes until May 31, 2018. Subsequent to May 31, 2018, the 2.5% Convertible Senior Notes may be redeemed, in whole or in part, at a price equal to 100% of the principal amount, plus accrued and unpaid interest to the date of redemption. On December 19, 2022, or if the Company undergoes a fundamental change, as more fully described in the indenture as amended by the first supplemental indenture dated as of December 12, 2017, the holders of the 2.5% Convertible Senior Notes may require SEACOR to purchase for cash all or part of the notes at a price equal to 100% of the principal amount, plus accrued and unpaid interest to the date of purchase. The Company accounts separately for the liability and equity components of the 2.5% Convertible Senior Notes and the associated underwriting fees in a manner that reflects the Company’s non-convertible borrowing rate. The resulting debt discount and offering costs associated with the liability component is amortized as additional non-cash interest expense over the five year period for which the debt was expected to be outstanding (December 19, 2017) for an overall effective annual interest rate of 6.5% . Beginning December 19, 2017, the effective annual interest rate is equal to the stated coupon rate of 2.5% . During the year ended December 31, 2017 , the Company purchased $61.7 million in principal amount of its 2.5% Convertible Senior Notes for total consideration of $61.9 million . Consideration of $60.5 million was allocated to the settlement of the long-term debt resulting in gains on debt extinguishment of $0.1 million included in the accompanying consolidated statements of income (loss). Consideration of $1.4 million was allocated to the purchase of the conversion option embedded in the 2.5% Convertible Senior Notes as included in the accompanying consolidated statements of changes in equity. Pursuant to the put option set forth in the indenture and governing the 2.5% Convertible Senior Notes, the Company completed a tender offer for the 2.5% Convertible Senior Notes in which, on December 19, 2017, the Company purchased $31.0 million in principal amount of its 2.5% Convertible Senior Notes that were validly surrendered for purchase for total consideration of $31.0 million . During the year ended December 31, 2016 , the Company purchased $127.4 million in principal amount of its 2.5% Convertible Senior Notes for total consideration of $124.7 million . Consideration of $117.3 million was allocated to the settlement of the long-term debt resulting in gains on debt extinguishment of $3.3 million included in the accompanying consolidated statements of income (loss). Consideration of $7.4 million was allocated to the purchase of the conversion option embedded in the 2.5% Convertible Senior Notes as included in the accompanying consolidated statements of changes in equity. 3.25% Convertible Senior Notes. On May 15, 2018, SEACOR issued $117.8 million aggregate principal amount of its 3.25% Convertible Senior Notes due May 15, 2030 (the “ 3.25% Convertible Senior Notes”). Interest on the 3.25% Convertible Senior Notes is payable semi-annually on May 15 and November 15 of each year. Beginning May 15, 2025, contingent interest is payable during any subsequent semi-annual interest period if the average trading price of the 3.25% Convertible Senior Notes for a defined period is greater than or equal to $1,200 per bond ( $1,000 face value). The amount of contingent interest payable for any such period will be equal to 0.45% per annum of such average trading price of the 3.25% Convertible Senior Notes. Prior to February 15, 2030, the 3.25% Convertible Senior Notes are convertible into shares of Common Stock, at a Conversion Rate of 13.1920 shares per bond ( $1,000 face value) only if certain conditions are met, as more fully described in the indenture. After February 15, 2030, holders may elect to convert at any time. The Company has reserved the maximum number of shares of Common Stock needed upon conversion, or 1,553,780 shares as of December 31, 2018 . On or after May 15, 2022, the 3.25% Convertible Senior Notes may be redeemed, in whole or in part, at a price equal to 100% of the principal amount, plus accrued and unpaid interest to the date of redemption. On May 15, 2025, or if the Company undergoes a fundamental change, as more fully described in the indenture, the holders of the 3.25% Convertible Senior Notes may require SEACOR to purchase for cash all or part of the notes at a price equal to 100% of the principal amount, plus accrued and unpaid interest to the date of purchase. The Company accounts separately for the liability and equity components of the 3.25% Convertible Senior Notes and the associated underwriting fees in a manner that reflects the Company’s non-convertible borrowing rate. Of the total issued amount of $117.8 million and offering costs of $2.5 million , the Company allocated $95.1 million and $2.0 million , respectively, to the liability component and $22.7 million and $0.5 million , respectively, to the equity component. The resulting debt discount and offering costs associated with the liability component are amortized as additional non-cash interest expense over the seven year period for which the debt is expected to be outstanding (May 15, 2025) for an overall effective annual interest rate of 7.2% . 7.375% Senior Notes. On September 24, 2009, SEACOR issued $250.0 million aggregate principal amount of its 7.375% Senior Notes due October 1, 2019 (the “ 7.375% Senior Notes”). The 7.375% Senior Notes were issued under a supplemental indenture dated as of September 24, 2009 (the “2009 Supplemental Indenture”) to the base indenture relating to SEACOR’s senior debt securities, dated as of January 10, 2001, between SEACOR and U.S. Bank National Association, as trustee. Interest on the 7.375% Senior Notes was payable semi-annually on April 1 and October 1 of each year. The 7.375% Senior Notes were redeemed at a price equal to the principal amount, plus accrued and unpaid interest to the date of redemption, plus a specified “make-whole” premium. The 2009 Supplemental Indenture contained covenants including, among others, limitations on liens and sale and leasebacks of certain Principal Properties, as defined, and certain restrictions on SEACOR consolidating with or merging into any other Person, as more fully described in the indenture. During the year ended December 31, 2018 , and prior to their redemption, the Company purchased $5.7 million in principal amount of its 7.375% Senior Notes for $5.9 million . On October 31, 2018, the Company redeemed the remaining $147.4 million in principal amount of its 7.375% Senior Notes for $153.0 million including a make-whole premium of $5.6 million calculated in accordance with the terms of the indenture. These transactions resulted in losses on debt extinguishment of $6.1 million included in the accompanying consolidated statements of income (loss). During the year ended December 31, 2017 , the Company purchased $7.6 million in principal amount of its 7.375% Senior Notes for $7.7 million resulting in losses on debt extinguishment of $0.2 million included in the accompanying consolidated statements of income (loss). During the year ended December 31, 2016 , the Company purchased $35.2 million in principal amount of its 7.375% Senior Notes for $33.1 million resulting in gains on debt extinguishment of $1.9 million included in the accompanying consolidated statements of income (loss). SEA-Vista Credit Facility. On April 15, 2015, SEA-Vista entered into a $300.0 million credit agreement with a syndicate of lenders that matures in 2020 (the “SEA-Vista Credit Facility”) and is secured by substantially all of SEA-Vista’s tangible and intangible assets, including its fleet of U.S.-flag petroleum and chemical carriers (See Note 1), with no recourse to SEACOR or its other subsidiaries. The SEA-Vista Credit Facility is comprised of three tranches: (i) a $100.0 million revolving credit facility (the “Revolving Loan”); (ii) an $80.0 million term loan (the “Term A-1 Loan”); and (iii) a $120.0 million delayed draw term loan (the “Term A-2 Loan”). The proceeds from the SEA-Vista Credit Facility were and will be used to fund SEA-Vista’s working capital, general corporate purposes, capital commitments and the redemption of its Title XI Bonds. All three loans bear interest at a variable rate determined by reference to the London Interbank Offered Rate (“LIBOR”) plus a margin of between 2.00% and 2.75% as determined in accordance with the SEA-Vista Credit Facility or, at the election of SEA-Vista, a Base Rate plus a margin of between 1.25% and 1.75% as determined in accordance with the SEA-Vista Credit Facility. A quarterly fee is payable on the unused commitments of all three tranches. SEA-Vista incurred $3.1 million of issuance costs related to the SEA-Vista Credit Facility. Each of the loans under the SEA-Vista Credit Facility will mature on April 15, 2020 (the “Maturity Date”), which may be accelerated in certain circumstances. The principal of the Term A-1 Loan is repayable commencing in June 2015 in quarterly installments of 1.25% of the aggregate principal amount of the Term A-1 Loan through June 30, 2017. Commencing on September 30, 2017, the principal of each of the Term A-1 Loan and the Term A-2 Loan is repayable in quarterly installments of 2.50% of the aggregate principal amount of such loans, with the outstanding principal balance, interest and all other amounts outstanding for all loans, including the Revolving Loan, due and payable on the Maturity Date. In addition, SEA-Vista has the right to make optional prepayments on each of the loans without penalty in minimum amounts of $1.0 million . During the year ended December 31, 2018 , SEA-Vista repaid $39.0 million on the Revolving Loan, $3.3 million on the Term A-1 Loan and $5.5 million on the Term A-2 Loan. In addition, as of December 31, 2018 , SEA-Vista had $94.0 million of borrowing capacity under the SEA-Vista Credit Facility. During the year ended December 31, 2017 , SEA-Vista drew $44.9 million and repaid $85.9 million on the Revolving Loan, $39.4 million on the Term A-1 Loan and $63.1 million on the Term A-2 Loan resulting in debt extinguishment losses of $0.7 million . During the year ended December 31, 2016 , SEA-Vista drew $87.0 million and repaid $14.0 million on the Revolving Loan, and made scheduled repayments of $3.8 million on the Term A-1 Loan. The SEA-Vista Credit Facility contains various financial maintenance and restrictive covenants including: funded debt to adjusted EBITDA; adjusted EBITDA to interest expense plus amortization; aggregate collateral vessel value to the sum of funded debt and unused and unexpired commitments; and minimum liquidity. In addition, the SEA-Vista Credit Facility restricts the payment of dividends and distributions as defined in the SEA-Vista Credit Facility. ISH Credit Facility. On July 3, 2017, ISH emerged from bankruptcy pursuant to the Plan (see Note 2). In conjunction with the emergence under the Plan, ISH assumed debt of $25.0 million under a credit facility with a maturity date of July 2020. The facility consisted of two tranches: (i) a $5.0 million revolving credit facility (the “ISH Revolving Loan”) and (ii) a $20.0 million term loan (the “ISH Term Loan”) (collectively the “ISH Credit Facility”). ISH incurred $0.1 million of issuance costs in connection with the ISH Credit Facility. The proceeds from this facility were used for general working capital purposes and payments to ISH’s creditors in accordance with the Plan. Interest on both loans were based on a variable rate of either LIBOR multiplied by the Statutory Reserve Rate or Prime Rate plus an applicable margin, as defined in the ISH Credit Facility. A quarterly fee of 0.5% was payable on the unused commitment of the ISH Revolving Loan. Beginning September 30, 2017, ISH was required to make quarterly prepayments on the ISH Term Loan of $0.7 million . Commencing with the calendar year ending December 31, 2018, ISH was required to make annual prepayments on the ISH Term Loan in an amount equal to 50% of excess cash flow as defined in the credit agreement. The ISH Credit Facility contained various financial and restrictive covenants applicable to ISH and its subsidiaries including indebtedness to EBITDA and adjusted EBITDA to interest expense maintenance, as defined in the ISH Credit Facility. The ISH Credit Facility was non-recourse to SEACOR and its subsidiaries other than ISH. The ISH Credit Facility was secured by substantially all of ISH’s assets, including its fleet of U.S.-flag bulk carriers (See Notes 1 and 2). During the year ended December 31, 2018 , ISH repaid the outstanding balance of $12.2 million on the ISH Term Loan and terminated the credit facility resulting in debt extinguishment losses of $0.1 million included in the accompanying consolidated statements of income (loss). During the year ended December 31, 2017 , ISH repaid $7.8 million on the ISH Term Loan and $5.0 million on the ISH Revolving Loan. Other. During 2017, the Company acquired $3.9 million of other debt related to the ISH acquisition (see Note 2). This debt bore interest at 7.0% and was collateralized by certain acquired assets. As of December 31, 2018, this debt had been fully repaid. In addition, the Company has various other obligations including equipment and facility mortgages. As of December 31, 2018 , these obligations have maturities ranging from 2020 through 2026, have interest rates ranging from to 3.4% to 4.3% and require periodic payments of interest and principal. During the year ended December 31, 2016 , proceeds from the issuance of other debt, net of issue costs was $7.4 million . During the years ended December 31, 2018 , 2017 and 2016 , repayments on other debt was $2.1 million (including the repayment and termination of the debt related to the ISH acquisition), $3.0 million and $0.4 million , respectively. Letters of Credit. As of December 31, 2018 , the Company had outstanding letters of credit totaling $9.5 million with various expiration dates through 2027 . Guarantees. The Company has guaranteed the payments of amounts owned under certain sale-leaseback transactions, equipment financing and multi-employer pension obligations on behalf of SEACOR Marine. As of December 31, 2018 , these guarantees on behalf of SEACOR Marine totaled $41.9 million and the amount declines as payments are made on the outstanding obligations through 2023. The Company earns a fee from SEACOR Marine of 50 basis points per annum on these guarantees. For the years ended December 31, 2018 and 2017 , the Company earned fees of $0.3 million and $0.6 million , respectively, related to these arrangements. Repurchase Authority. SEACOR’s Board of Directors previously approved a securities repurchase plan that authorizes the Company to acquire Common Stock, 7.375% Senior Notes, 3.0% Convertible Senior Notes, 3.25% Convertible Senior Notes, 2.5% Convertible Senior Notes (collectively the “Securities”), which may be acquired through open market purchases, privately negotiated transactions or otherwise, depending on market conditions. As of December 31, 2018 , SEACOR had remaining authorization for Securities repurchases of $66.7 million .

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	8. INCOME TAXES Income (loss) before income tax expense (benefit) and equity in earnings (losses) of 50% or less owned companies derived from U.S. and foreign companies for the years ended December 31 were as follows (in thousands): 2018 2017 2016 United States $ 33,563 $ 28,546 $ (93,145 ) Foreign 56,558 4,748 (1,105 ) Eliminations and other 1,568 1,911 2,014 $ 91,689 $ 35,205 $ (92,236 ) The Company files a consolidated U.S. federal tax return. The components of income tax expense (benefit) for the years ended December 31 were as follows (in thousands): 2018 2017 2016 Current: State $ 253 $ 1,136 $ 4,830 Federal 20,776 (17,181 ) 6,998 Foreign 2,899 333 379 23,928 (15,712 ) 12,207 Deferred: State (3,001 ) 12 (2,280 ) Federal (12,512 ) (51,489 ) (46,652 ) (15,513 ) (51,477 ) (48,932 ) $ 8,415 $ (67,189 ) $ (36,725 ) The following table reconciles the difference between the statutory federal income tax rate for the Company and the effective income tax rate for the years ended December 31 : 2018 2017 2016 Statutory rate 21.0 % 35.0 % 35.0 % Income subject to tonnage tax (1.3 )% (5.9 )% — % Dorian distribution — % 22.8 % — % Reversal of uncertain tax position — % (28.7 )% — % U.S. federal income tax statutory changes — % (190.2 )% — % Non-deductible expenses 0.2 % 0.8 % 1.0 % Noncontrolling interests (5.7 )% (22.4 )% 6.3 % Foreign earnings not subject to U.S. income tax (16.2 )% — % — % Foreign taxes not creditable against U.S. income tax 3.2 % — % — % Losses of foreign subsidiaries not benefited — % (6.6 )% (1.4 )% Subpart F income 12.1 % — % — % State taxes (3.1 )% 1.2 % (0.9 )% Share award plans (0.3 )% 2.0 % — % Other (0.7 )% 1.1 % (0.2 )% 9.2 % (190.9 )% 39.8 % On December 22, 2017, the U.S. enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (the “Tax Act”). The Tax Act makes broad and complex changes to the U.S. tax code, including, but not limited to, reducing the U.S. federal corporate tax rate from 35% to 21% , eliminating or capping certain deductions, imposing a mandatory one-time tax on accumulated earnings in foreign subsidiaries, introducing new tax regimes and changing how foreign earnings are subject to U.S. taxation. The statutory corporate tax rate reduction is effective for tax years beginning on or after January 1, 2018. During the year ended December 31, 2017, the Company recorded a net income tax benefit of $66.9 million as a consequence of reducing its net deferred tax liabilities to reflect the change in the statutory tax rate. The Company records an additional income tax benefit or expense based on the difference between the fair market value of share awards at the time of grant and the fair market value at the time of vesting or exercise. For the year ended December 31, 2016 , an additional net income tax expense was recorded in stockholders’ equity of $2.3 million . During the year ended December 31, 2013, the Company provided for income taxes of $10.1 million relating to potential tax exposures surrounding the spin-off of Era Group Inc. (“Era Group”) by means of a dividend to SEACOR’s shareholders of all the issued and outstanding common stock of Era Group. During the year ended December 31, 2017, the Company reversed this provision as the statute of limitations expired. In addition, the Company reversed accumulated accrued interest of $2.0 million related to this provision, included as a reduction in interest expense in the accompanying consolidated statements of income (loss). The components of the net deferred income tax liabilities for the years ended December 31 were as follows (in thousands): 2018 2017 Deferred tax liabilities: Property and equipment $ 93,049 $ 92,127 Long-term debt 18,355 22,519 Investments in 50% or less owned companies 1,934 811 Intangible assets 614 1,006 Deductible goodwill 344 — Other 31 96 Total deferred tax liabilities 114,327 116,559 Deferred tax assets: Share award plans 3,711 3,476 Losses on marketable securities 8,596 5,986 Deductible goodwill — 312 Debt and equity issuance costs 379 406 Other 11,178 11,652 Total deferred tax assets 23,864 21,832 Valuation allowance (3,957 ) (6,695 ) Net deferred tax assets 19,907 15,137 Net deferred tax liabilities $ 94,420 $ 101,422 During the year ended December 31, 2018 , the Company decreased its valuation allowance for state net operating loss carryforwards from $6.7 million to $4.0 million .

Derivative Instruments And Hedg

Derivative Instruments And Hedging Strategies	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments And Hedging Strategies	9. DERIVATIVE INSTRUMENTS AND HEDGING STRATEGIES Cash Flow Hedges. One of the Company’s 50% or less owned companies, had an interest rate swap agreement designated as a cash flow hedge that matured in April 2017 . This interest rate swap called for this company to pay a fixed interest rate of 2.79% on the amortized notional value and receive a variable interest rate based on LIBOR on the amortized notional value. By entering into this interest rate swap agreement, this company converted the variable LIBOR component of certain of its outstanding borrowings to a fixed interest rate. Other Derivative Instruments. The Company recognized gains (losses) on derivative instruments not designated as hedging instruments for the years ended December 31 as follows (in thousands): Derivative gains (losses), net 2018 2017 2016 Exchange option liability on subsidiary convertible senior notes $ — $ 19,436 $ (13,826 ) Forward currency exchange, option and future contracts — 291 (296 ) Exchange traded commodity swap, option and future contracts — — (9 ) $ — $ 19,727 $ (14,131 ) The exchange option liability on subsidiary convertible senior notes terminated on June 1, 2017 as a consequence of the Spin-Off. The Company enters and settles forward currency exchange, option and future contracts with respect to various foreign currencies. These contracts enable the Company to buy currencies in the future at fixed exchange rates, which could offset possible consequences of changes in currency exchange rates with respect to the Company’s business conducted outside of the United States. As of December 31, 2018 , there were no outstanding forward currency exchange contracts. Certain of the Company’s 50% or less owned companies have entered and settled positions in various exchange traded commodity swap, option and future contracts. As of December 31, 2018 , there were no outstanding contracts.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	10. FAIR VALUE MEASUREMENTS 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 1 inputs are quoted prices in active markets for identical assets or liabilities. Level 2 inputs are observable inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly, including quoted prices for similar assets or liabilities in active markets, quoted prices in markets that are not active, inputs other than quoted prices that are observable for the asset or liability, or inputs derived from observable market data. Level 3 inputs are unobservable inputs that are supported by little or no market activity and are significant to the fair value of the assets or liabilities. The Company’s financial assets and liabilities as of December 31 that are measured at fair value on a recurring basis were as follows (in thousands): Level 1 Level 2 Level 3 2018 ASSETS Cash, cash equivalents, restricted cash and restricted cash equivalents $ 147,212 $ — $ — Marketable securities (1) 30,316 — — Construction reserve funds 3,908 — — 2017 ASSETS Cash, cash equivalents, restricted cash and restricted cash equivalents $ 242,228 $ — $ — Marketable securities (1) 42,761 — — Construction reserve funds 51,339 — — ______________________ (1) Marketable security losses, net include losses of $12.4 million , gains of $0.1 million and losses of $18.5 million for the years ended December 31, 2018 , 2017 and 2016 , respectively, related to marketable security positions held by the Company as of December 31, 2018 . Marketable security losses, net include gains of $0.1 million and losses of $18.5 million for the years ended December 31, 2017 and 2016 , respectively, related to marketable security positions held by the Company as of December 31, 2017 . The estimated fair value of the Company’s other financial assets and liabilities as of December 31 were as follows (in thousands): Carrying Amount Level 1 Level 2 Level 3 2018 ASSETS Notes receivable from third parties (included in other receivables and other assets) $ 2,182 $ — $ 2,159 $ — Investments, at cost, in 50% or less owned companies (included in other assets) 4,300 see below LIABILITIES Long-term debt, including current portion (1) 354,625 — 353,929 — 2017 ASSETS Notes receivable from third parties (included in other receivables and other assets) $ 2,647 $ 943 $ 1,642 $ — Investments, at cost, in 50% or less owned companies (included in other assets) 4,300 see below LIABILITIES Long-term debt, including current portion (1) 579,347 — 596,246 — ______________________ (1) The estimated fair value includes the embedded conversion options on the Company’s 3.0% and 3.25% Convertible Senior Notes. The fair value of the Company’s long-term debt and notes receivable from third parties was estimated based upon quoted market prices or by using discounted cash flow analyses 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 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 non-financial assets that were measured at fair value during the years ended December 31 were as follows (in thousands): Level 1 Level 2 Level 3 2018 ASSETS Investments, at equity, and advances in 50% or less owned companies $ — 3,219 $ — 2017 ASSETS Investments, at equity, and advances in 50% or less owned companies $ — $ 6,000 $ — Investments, at equity, and advances in 50% or less owned companies. During the year ended December 31, 2018 , the Company marked its investment in Cleancor to fair value as a consequence of the Company acquiring its partners’ 50% interest, resulting in a gain of $0.1 million , net of tax, based on the fair value of the acquired interest (see Note 2). In addition, During the year ended December 31, 2018 , the company identified indicators of impairment in one of the Company’s other 50% or less owned companies and, as a consequence, recognized an impairment charge of $0.1 million for an other-than-temporary decline in fair value. The investment was determined to have an immaterial value. During the year ended December 31, 2017 , the Company identified indicators of impairment for its investment in VA&E based on their recent financial results. The Company evaluated the fair value of VA&E and determined that its assets and liabilities were carried at fair value except for property and equipment and certain deferred tax assets. Based on this evaluation, the Company concluded its carrying value was in excess of fair value and the impairment was other than temporary resulting in an impairment charge of $0.9 million , net of tax, of its equity investment.

Stock Repurchases and Dividends

Stock Repurchases and Dividends	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Stock Repurchases and Dividends	11. STOCK REPURCHASES AND DIVIDENDS SEACOR’s Board of Directors previously approved a securities repurchase plan that authorizes the Company to acquire its Securities, which may be acquired through open market purchases, privately negotiated transactions or otherwise, depending on market conditions. During the years ended December 31, 2018 , 2017 and 2016 , the Company acquired no shares of Common Stock for treasury under the Securities repurchase plan. As of December 31, 2018 , SEACOR had remaining authorization for Securities repurchases of $66.7 million . During the years ended December 31, 2017 and 2016 , the Company acquired for treasury 212,659 and 47,455 shares of Common Stock, respectively, for aggregate purchase prices of $12.3 million and $2.4 million , respectively, from its employees to cover their tax withholding obligations related to share award transactions. These shares were purchased in accordance with the terms of the Company’s Share Incentive Plans and not pursuant to the repurchase authorizations granted by SEACOR’s Board of Directors. On June 1, 2017, the Company completed the Spin-off of SEACOR Marine by means of a dividend of all of the issued and outstanding common stock of SEACOR Marine to SEACOR’s shareholders. In the Spin-off, holders of SEACOR Common Stock received approximately 1.005 shares of SEACOR Marine common stock for each share of SEACOR Common Stock held as of the record date for the Spin-off. On December 20, 2017, the Company distributed 3,977,135 shares of Dorian common stock with a value of $31.4 million (based on the closing share price on that date) to its stockholders with each holder of Common Stock receiving approximately 0.2215 shares of Dorian common stock for each share of SEACOR Common Stock held as of the record date for such distribution. The Compensation Committee of the Board of Directors elected, at its discretion, to distribute shares of Dorian on the Company’s restricted shares outstanding on the record date rather than depositing the shares in escrow pending the lapsing of restrictions.

Noncontrolling Interests in Sub

Noncontrolling Interests in Subsidiaries	12 Months Ended
	Dec. 31, 2018
Noncontrolling Interest [Abstract]
Noncontrolling Interests in Subsidiaries	12. NONCONTROLLING INTERESTS IN SUBSIDIARIES Noncontrolling interests in the Company’s consolidated subsidiaries as of December 31 were as follows (in thousands): Noncontrolling Interests 2018 2017 Ocean Services: SEA-Vista 49% 148,665 128,550 Inland Services: Other 3.0 % – 51.8% 862 977 Other 5.0% 161 151 $ 149,688 $ 129,678 SEA-Vista. SEA-Vista owns and operates the Company’s fleet of U.S.-flag petroleum and chemical carriers used in the U.S. coastwise trade of crude oil, petroleum and specialty chemical products. As of December 31, 2018 and 2017 , the net assets of SEA-Vista were $303.4 million and $262.3 million , respectively. During the year ended December 31, 2018 , the net income of SEA-Vista was $51.2 million , of which $25.1 million was attributable to noncontrolling interests. During the year ended December 31, 2017 , the net income of SEA-Vista was $45.9 million , of which $22.5 million was attributable to noncontrolling interests. During the year ended December 31, 2016 , the net income of SEA-Vista was $36.3 million , of which $17.8 million was attributable to noncontrolling interests.

Savings, Multi-Employer And Def

Savings, Multi-Employer And Defined Benefit Pension Plans	12 Months Ended
	Dec. 31, 2018
Deferred Compensation Arrangements [Abstract]
Savings, Multi-Employer And Defined Benefit Pension Plans	13. SAVINGS, MULTI-EMPLOYER AND DEFINED BENEFIT PENSION PLANS SEACOR Savings Plan. The Company provides a defined contribution plan (the “Savings Plan”) for its eligible U.S.-based employees. The Company’s contribution to the Savings Plan is limited to 3.5% of an employee’s wages depending upon the employee’s level of voluntary wage deferral into the Savings Plan and is subject to annual review by the Board of Directors. The Company’s Savings Plan costs were $2.0 million , $1.8 million and $1.8 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. SEACOR Deferred Compensation Plan. In 2005, the Company established a non-qualified deferred compensation plan, as amended (the “Deferred Compensation Plan”) to provide certain highly compensated executives and non-employee directors the ability to defer receipt of up to 75% of their cash base salary and up to 100% of their cash bonus. Each participant’s compensation deferrals are credited to a bookkeeping account and, subject to certain restrictions, each participant may elect to have their cash deferrals in such account indexed against one or more investment options, solely for purposes of determining amounts payable under the Deferred Compensation Plan (the Company is not obligated to actually invest any deferred amounts in the selected investment options). Participants may receive a distribution of deferred amounts, plus any earnings thereon (or less any losses), on a date specified by the participant or, if earlier, upon a separation from service or upon a change of control (as defined). All distributions to participants following a separation from service shall be in the form of a lump sum, except if such separation qualifies as “retirement” under the terms of the plan, in which case it may be paid in installments if previously elected by the participant. Distributions to “Key Employees” upon a separation from service (other than due to death) will not commence until at least six months after the separation from service. Participants are always 100% vested in the amounts they contribute to their Deferred Compensation Plan accounts. The Company, at its option, may contribute amounts to participants’ accounts, which may be subject to vesting requirements. The obligations of the Company to pay deferred compensation under the Deferred Compensation Plan are general unsecured obligations of the Company and rank equally with other unsecured indebtedness of the Company that is outstanding from time to time. As of December 31, 2018 and 2017 , the Company had obligations of $0.6 million and $0.5 million , respectively, related to the Deferred Compensation Plan that are included in the accompanying consolidated balance sheets as deferred gains and other liabilities. The total amount of the Company’s obligation under the Deferred Compensation Plan will vary depending upon the level of participation by participants and the amount of compensation that participants elect to defer under the plan. The duration of the Deferred Compensation Plan is indefinite (subject to the Board of Directors’ discretion to amend or terminate the plan). AMOPP and SPP. Certain subsidiaries of the Company are participating employers in two industry-wide, multi-employer defined benefit pension plans, the American Maritime Officers Pension Plan (the “AMOPP” - EIN: 13-1936709) and the Seafarers Pension Plan (the “SPP” - EIN: 13-6100329). The Company’s participation in these plans relates to certain employees of the Company’s Ocean Services business segment. During the years ended December 31, 2018 , 2017 and 2016 , the Company made contributions of $2.5 million , $2.4 million and $1.8 million , respectively in the aggregate to the AMOPP and SPP. Under federal pension law, the AMOPP was deemed in critical status for the 2009 and 2010 plan years. The AMOPP was frozen in January 2010 and a ten year rehabilitation plan was adopted by the AMOPP trustees in February 2010 whereby benefit changes and increased contributions by participating employers were expected to improve the funded status of the AMOPP. On December 28, 2012, the AMOPP was elevated to endangered status primarily as a result of favorable investment performance and the rehabilitation plan adopted by the AMOPP trustees. Based on an actuarial valuation performed as of September 30, 2017, the latest period for which an actuarial valuation is available, if the Company chose to fully withdraw from the AMOPP at that time, its withdrawal liability would have been $34.4 million . That liability may change in future years based on various factors, primarily employee census. As of December 31, 2018 , the Company had no intention to withdraw from the AMOPP and no deficit amounts have been invoiced. Depending upon the results of the future actuarial valuations and the ten year rehabilitation plan, it is possible that the AMOPP will experience further funding deficits, requiring the Company to recognize additional payroll related operating expenses in the periods invoices are received or contribution levels are increased. The SPP was neither in endangered or critical status for the 2016 plan year, the latest period for which a report is available, as the SPP was fully funded. Multi-Employer Defined Contribution Plans. In accordance with collective bargaining agreements between the Company and the American Maritime Officers Union, the latest of which expires on August 31, 2019, the Seafarers International Union, the latest of which expires on July 31, 2022, the Masters Mates and Pilots Union, which expires July 2, 2022 and the Marine Engineer Benefit Association, which expires July 2, 2022, the Company makes periodic contributions to various defined contribution and 401(k) plans for the benefit of the participants. The contributions to these plans are expensed as incurred and are included in operating expenses in the accompanying consolidated statements of income (loss). During the years ended December 31, 2018 , 2017 and 2016 , the Company made contributions of $1.0 million , $1.0 million and $0.3 million , respectively, in the aggregate to these plans. During the years ended December 31, 2018 , 2017 and 2016 , none of the Company’s contributions to any of these plans exceeded 5% of total contributions to each plan and the Company did not pay any material surcharges. As of December 31, 2018 , there is no required minimum future contributions to these plans. The Company’s obligations for future contributions are based upon the number of employees subject to the collective bargaining agreements, their rates of pay and the number of days worked. Future negotiations of collective bargaining agreements between the Company and the participating unions, including the contribution levels for these plans or any additional plans that may come into existence, may result in increases to the Company’s wage and benefit costs and those increases may be material. ISH Retirement Plan. ISH sponsored a defined benefit pension plan (the “ISH Retirement Plan”) covering non-union employees prior to its acquisition by the Company on July 3, 2017 (see Note 2). The ISH Retirement Plan generally provided participants with benefits based on years of service and compensation levels for participants hired prior to September 1, 2006. From that date forward, the benefit was calculated prospectively under a cash balance formula with pay credits based on age plus service years and interest credits based on an as defined U.S. treasury rate. Effective July 3, 2017, in conjunction with the Plan, an amendment was made to the ISH Retirement Plan that fully vested all active participants as of January 1, 2017 and froze the retirement benefits effective August 31, 2017. As of August 31, 2017, all retirement benefits earned were fully preserved and will be paid in accordance with the ISH Retirement Plan and legal requirements. The funded status of the ISH Retirement Plan and the related pension income (expense) as of and for the years ended December 31, were as follows (in thousands): 2018 2017 Fair Value of Assets $ 34,923 $ 38,492 Projected Benefit Obligation (34,299 ) (36,940 ) Funded Status (1) $ 624 $ 1,552 Pension income (expense) (2) $ (928 ) $ 1,315 _____________________ (1) Included in other assets in the accompanying consolidated balance sheets. (2) For 2017, pension income for the period July 3, 2017 through December 31, 2017. The significant assumptions used in determining the projected benefit obligation as of December 31, and pension income (expense) for the years ended December 31, were as follows: 2018 2017 Discount rate 4.05 % 3.50 % Rate of increase in compensations levels (1) N/A 4.50 % CPI 2.25 % 2.00 % Cash balance interest credits (compounded annually) 4.00 % 4.10 % Expected long-term rate of return on plan assets 6.75 % 6.75 % _____________________ (1) For the period July 3, 2017 through August 31, 2017, the date retirement benefits were frozen. The future benefit payments expected to be paid in each of the next five fiscal years are as follows (in thousands): 2019 2,130 2020 2,090 2021 2,080 2022 2,170 2023 2,150

Share Based Compensation

Share Based Compensation	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share Based Compensation	14. SHARE BASED COMPENSATION Share Incentive Plans. SEACOR’s stockholders approved the 2014 Share Incentive Plan to provide for the grant of options to purchase shares of Common Stock, stock appreciation rights, restricted stock, stock awards, performance awards and restricted stock units to non-employee directors, key officers and employees of the Company. The 2014 Share Incentive Plan superseded the 2007 Share Incentive Plan (collectively including all predecessor plans, the “Share Incentive Plans”). The Compensation Committee of the Board of Directors administers the Share Incentive Plans. A total of 6,650,000 shares of Common Stock have been authorized for grant under the Share Incentive Plans. All shares issued pursuant to such grants are newly issued shares of Common Stock. The exercise price per share of options granted cannot be less than 100% of the fair market value of Common Stock at the date of grant under the Share Incentive Plans. Grants to date have been limited to stock awards, restricted stock, restricted stock units and options to purchase shares of Common Stock. Restricted stock typically vests from one to five years after date of grant and options to purchase shares of Common Stock typically vest and become exercisable from one to five years after date of grant. Options to purchase shares of Common Stock granted under the Share Incentive Plans expire no later than the tenth anniversary of the date of grant. In the event of a participant’s death, retirement, termination by the Company without cause or a change in control of the Company, as defined in the Share Incentive Plans, restricted stock vests immediately and options to purchase shares of Common Stock vest and become immediately exercisable. Employee Stock Purchase Plans. During the year ended December 31, 2018, SEACOR’s stockholders approved an amendment to the 2009 Employee Stock Purchase Plan (collectively including all predecessor plans, the “Employee Stock Purchase Plans”) increasing the shares of Common Stock available for issuance under the plan by 300,000 and extending the term to ten years from the date of the Company’s 2018 annual meeting of stockholders. The Employee Stock Purchase Plans permit the Company to offer Common Stock for purchase by eligible employees at a price equal to 85% of the lesser of (i) the fair market value of Common Stock on the first day of the offering period or (ii) the fair market value of Common Stock on the last day of the offering period. Common Stock is made available for purchase under the Employee Stock Purchase Plans for six -month offering periods. The Employee Stock Purchase Plans are intended to comply with Section 423 of the Internal Revenue Code of 1986, as amended (the “Code”), but is not intended to be subject to Section 401(a) of the Code or the Employee Retirement Income Security Act of 1974. The Board of Directors of SEACOR may amend or terminate the Employee Stock Purchase Plans at any time; however, no increase in the number of shares of Common Stock reserved for issuance under the Employee Stock Purchase Plans may be made without stockholder approval. A total of 900,000 shares of Common Stock have been approved for purchase under the Employee Stock Purchase Plans with all shares issued from those held in treasury. Share Award Transactions. The following transactions have occurred in connection with the Company’s share based compensation plans during the years ended December 31: 2018 2017 2016 Restricted stock awards granted 121,850 153,100 137,258 Restricted stock awards forfeited — (2,444 ) (2,867 ) Director stock awards granted 2,875 1,750 3,125 Stock Option Activities: Outstanding as of the beginning of year 1,546,014 1,639,865 1,690,899 Granted (1) 142,550 1,013,893 197,550 Exercised (220,694 ) (562,587 ) (113,820 ) Forfeited — (3,374 ) (18,760 ) Expired (479 ) (541,783 ) (116,004 ) Outstanding as of the end of year 1,467,391 1,546,014 1,639,865 Employee Stock Purchase Plans shares issued 45,251 36,552 41,924 Shares available for issuance under Share Incentive and Employee Stock Purchase Plans as of the end of year (2) 884,218 896,265 522,341 ______________________ (1) On June 2, 2017, the Company granted 846,353 stock options to existing option holders under make-whole provisions upon the Spin-off. (2) Shares available for future grants and ESPP purchases were adjusted on June 2, 2017 to reflect the Spin-off in accordance with make-whole provisions of the plans. During the years ended December 31, 2018 , 2017 and 2016 , the Company recognized $4.0 million , $32.5 million and $14.1 million , respectively, of compensation expense related to stock awards, stock options, employee stock purchase plans purchases and restricted stock (collectively referred to as “share awards”). During 2017, compensation expense related to stock awards included $16.6 million associated with the Spin-off and the accelerated vesting of incentive share awards in advance of changes in the U.S. federal income tax code. As of December 31, 2018 , the Company had approximately $9.0 million in total unrecognized compensation costs of which $3.2 million and $2.6 million are expected to be recognized in 2019 and 2020 , respectively, with the remaining balance recognized through 2023 . The weighted average values of grants under the Company’s Share Incentive Plans were $29.72 , $37.20 and $31.31 for the years ended December 31, 2018 , 2017 and 2016 , respectively. The fair value of each option granted during the years ended December 31, 2018 , 2017 and 2016 , is estimated on the date of grant using the Black-Scholes option-pricing model with the following assumptions: (a) no dividend yield, (b) weighted average expected volatility of 26.6% , 25.5% and 26.5% , respectively, (c) weighted average discount rates of 2.78% , 1.92% and 1.59% , respectively, and (d) expected lives of 5.58 years, 5.59 years and 6.25 years, respectively. During the year ended December 31, 2018 , the number of shares and the weighted average grant price of restricted stock transactions were as follows: Restricted Stock Number of Shares Weighted Average Grant Price Nonvested as of December 31, 2017 — $ — Granted 121,850 $ 46.66 Vested — $ — Forfeited — $ — Nonvested as of December 31, 2018 121,850 $ 46.66 During the year ended December 31, 2018, no restricted stock vested. During the years ended December 31, 2017 and 2016 , the total grant date fair value of restricted stock that vested was $26.1 million and $10.8 million , respectively. During the year ended December 31, 2018 , the number of shares and the weighted average exercise price on stock option transactions were as follows: Total Options Number of Shares Weighted Average Exercise Price Outstanding, as of December 31, 2017 1,546,014 $ 39.73 Granted 142,550 $ 48.36 Exercised (220,694 ) $ 31.19 Expired (479 ) $ 53.38 Outstanding, as of December 31, 2018 1,467,391 $ 41.85 Outstanding and Exercisable, as of December 31, 2018 997,019 $ 41.72 During the years ended December 31, 2018 , 2017 and 2016 , the aggregate intrinsic value of exercised stock options was $3.9 million , $5.6 million and $1.4 million , respectively. As of December 31, 2018 , the weighted average remaining contractual term for total outstanding stock options and vested/exercisable stock options was 5.23 and 4.00 years, respectively. As of December 31, 2018 , the aggregate intrinsic value of all options outstanding and all vested/exercisable options outstanding was $2.0 million and $1.7 million , respectively.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2018
Related Party Transactions [Abstract]
Related Party Transactions	15. RELATED PARTY TRANSACTIONS The Company manages barge pools as part of its Inland Services segment. Pursuant to the pooling agreements, operating revenues and expenses of participating barges are combined and the net results are allocated on a pro-rata basis based on the number of barge days contributed by each participant. Companies controlled by Mr. Fabrikant, the Executive Chairman and Chief Executive Officer of SEACOR, and trusts established for the benefit of Mr. Fabrikant’s children, own barges that participate in the barge pools managed by the Company. Mr. Fabrikant and his affiliates were participants in the barge pools prior to the acquisition of SCF Marine Inc. by SEACOR in 2000. During the years ended December 31, 2018 , 2017 and 2016 , Mr. Fabrikant and his affiliates earned $0.8 million , $0.5 million and $0.8 million , respectively, of net barge pool results (after payment of $0.1 million , $0.1 million and $0.1 million , respectively, in management fees to the Company). As of December 31, 2018 and 2017 , the Company owed Mr. Fabrikant and his affiliates $0.5 million and $0.5 million , respectively, for undistributed net barge pool results. Mr. Fabrikant is a director of SEACOR Marine. The Company has provided certain transition services to SEACOR Marine related to the Spin-off and the total amount earned from these transition services during the years ended December 31, 2018 and 2017 was $4.6 million and $3.5 million , respectively. As of December 31, 2018 , SEACOR Marine owed the Company $0.5 million for these services and other costs and expenses and is included in other receivables in the accompanying consolidated balance sheets.

Commitments And Contingencies

Commitments And Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	16. COMMITMENTS AND CONTINGENCIES The Company's capital commitments as of December 31, 2018 by year of expected payment were as follows (in thousands): 2019 2020 Total Ocean Services $ 3,479 $ 6,161 $ 9,640 Inland Services 19,599 920 20,519 $ 23,078 $ 7,081 $ 30,159 Ocean Services' capital commitments included an interest in two foreign- flag rail ferries and other equipment and vessel improvements. Inland Services’ capital commitments included two inland river towboats and other equipment and vessel and terminal improvements. Subsequent to December 31, 2018, the Company committed to purchase additional property and equipment for $3.9 million . During 2012, the Company sold National Response Corporation (“NRC”), NRC Environmental Services Inc., SEACOR Response Ltd., and certain other subsidiaries to J.F. Lehman & Company, a private equity firm (the “SES Business Transaction”). On December 15, 2010, O’Brien’s Response Management L.L.C. (“ORM”) and NRC were named as defendants in one of the several “master complaints” filed in the overall multi-district litigation relating to the Deepwater Horizon oil spill response and clean-up in the Gulf of Mexico, which is currently pending in the U.S. District Court for the Eastern District of Louisiana (the “MDL”). The “B3” master complaint naming ORM and NRC asserted various claims on behalf of a putative class against multiple defendants concerning the clean-up activities generally and the use of dispersants specifically. Both prior to and following the filing of the aforementioned “B3” master complaint, individual civil actions naming the Company, ORM, and/or NRC alleging B3 exposure-based injuries and/or damages were consolidated with the MDL and stayed pursuant to court order. On February 16, 2016, all but eleven “B3” claims against ORM and NRC were dismissed with prejudice (the “B3 Dismissal Order”). On August 2, 2016, the Court granted an omnibus motion for summary judgment as it concerns ORM and NRC in its entirety, dismissing the remaining eleven plaintiffs’ claims against ORM and NRC with prejudice (the “Remaining Eleven Plaintiffs’ Dismissal Order”). The deadline to appeal both of these orders has expired. At present, there is only one remaining claim. On April 8, 2013, the Company, ORM, and NRC were named as defendants in William and Dianna Fitzgerald v. BP Exploration et al. , No. 2:13-CV-00650 (E.D. La.) (the “ Fitzgerald Action”), which is a suit by a husband and wife whose son allegedly participated in the clean-up effort and became ill as a result of his exposure to oil and dispersants. While the decedent in the Fitzgerald Action’s claims against ORM and NRC were dismissed by virtue of the Remaining Eleven Plaintiffs’ Dismissal Order, the claim as against the Company remains stayed. Following a status conference with the Court on February 17, 2017, the Court issued several new pretrial orders in connection with the remaining claims in the MDL. Various submissions followed, and on July 18, 2017, the Court issued an order dismissing all remaining “B3” claims in the MDL with prejudice, with the exception of certain claims specifically listed on an exhibit annexed to the order (the “Master MDL B3 Dismissal Order”). Nathan Fitzgerald, the decedent in the Fitzgerald Action, was listed on the exhibit annexed to the Master MDL B3 Dismissal Order. The Court has since issued a list of those plaintiffs compliant with its previous orders and thus whose “B3” claims remain pending; the last version of this compliance list was issued on April 6, 2018 and the claim for the decedent in the Fitzgerald Action remains listed as a pending claim. On April 9, 2018, the Court issued an order requiring remaining “B3” plaintiffs to submit particularized statements of claim, and such a statement was submitted on behalf of the decedent in the Fitzgerald Action on July 9, 2018. On September 20, 2018, the Court issued an order indicating which statements of claim were sufficient and which were not, requiring the latter plaintiffs to show cause; the statement submitted on behalf of the decedent in the Fitzgerald Action was deemed sufficient, requiring nothing further at the time of the order. The Company is unable to estimate the potential exposure, if any, resulting from this matter, to the extent it remains viable, but believes it is without merit and does not expect that it will have a material effect on its consolidated financial position, results of operations or cash flows. On February 18, 2011, Triton Asset Leasing GmbH, Transocean Holdings LLC, Transocean Offshore Deepwater Drilling Inc., and Transocean Deepwater Inc. (collectively “Transocean”) named ORM and NRC as third-party defendants in a Rule 14(c) Third-Party Complaint in Transocean’s own Limitation of Liability Act action, which is part of the overall MDL, tendering to ORM and NRC the claims in the “B3” master complaint that have already been asserted against ORM and NRC. Various contribution and indemnity cross-claims and counterclaims involving ORM and NRC were subsequently filed. The Company believes that the potential exposure, if any, resulting therefrom has been reduced as a result of the various developments in the MDL, including the B3 Dismissal Order and Remaining Eleven Plaintiffs’ Dismissal Order, and does not expect that these matters will have a material effect on its consolidated financial position, results of operations or cash flows. Separately, on March 2, 2012, the Court announced that BP Exploration and BP America Production Company (“BP America”) and (collectively “BP”) and the Plaintiffs had reached an agreement on the terms of two proposed class action settlements that will resolve, among other things, Plaintiffs’ economic loss and property damage claims and clean-up related claims against BP. The Company, ORM, and NRC had no involvement in negotiating or agreeing to the terms of either settlement, nor are they parties or signatories thereto. The BP settlement pertaining to personal injury claims (the “Medical Settlement”) purported to resolve the “B3” claims asserted against BP and also established a right for class members to pursue individual claims against BP (but not ORM or NRC) for later-manifested physical conditions. The back-end litigation-option (“BELO”) provision of the Medical Settlement has specifically-delineated procedures and limitations, should any “B3” class member seek to invoke their BELO right. For example, there are limitations on the claims and defenses that can be asserted, as well as on the issues, elements, and proofs that may be litigated at any trial and the potential recovery for any Plaintiff. Notwithstanding that the Company, ORM, and NRC are listed on the Medical Settlement’s release as to claims asserted by Plaintiffs, the Medical Settlement still permits BP to seek indemnity from any party, to the extent BP has a valid indemnity right. The Medical Settlement was approved by the Court on January 11, 2013 and made effective on February 12, 2014. As of early February 2019, BP has tendered approximately 700 claims invoking BELO rights for indemnity pursuant to service contracts to ORM and approximately 70 such claims to NRC. ORM and NRC have rejected BP’s contention that BP is entitled to defense and indemnity coverage from ORM and/or NRC for any of the “B3” claims referenced in BP’s indemnity demands. Moreover, the Company believes that (1) ORM has contractual indemnity coverage for the above-referenced BELO claims through its separate agreements with sub-contractors that worked for ORM during the Deepwater Horizon oil spill response and (2) NRC’s services contract with BP does not provide for broad contractual indemnity as BP contends. The Company, ORM, and NRC are of the belief that BP’s indemnity demands with respect to any “B3” claims, including those involving Medical Settlement class members invoking BELO rights, are untimely and improper and vigorously defend its interest. Overall, however, the Company believes that both settlements have reduced the potential exposure in connection with the various cases relating to the Deepwater Horizon oil spill response and clean-up. The Company is unable to estimate the potential exposure, if any, resulting from these claims, but does not expect that they will have a material effect on its consolidated financial position, results of operations or cash flows. In the ordinary course of the Company’s business, it may agree to indemnify its counterparty to an agreement. If the indemnified party makes a successful claim for indemnification, the Company would be required to reimburse that party in accordance with the terms of the indemnification agreement. Indemnification agreements generally, but not always, are subject to threshold amounts, specified claim periods and other restrictions and limitations. In connection with the SES Business Transaction, the Company remains contingently liable for work performed in connection with the Deepwater Horizon oil spill response. Pursuant to the agreement governing the sale, the Company’s potential liability to the purchaser may not exceed the consideration received by the Company for the SES Business Transaction. The Company is currently indemnified under contractual agreements with BP for the potential “B3” liabilities relating to cleanup work performed in connection with the Deepwater Horizon oil spill response; this indemnification is unrelated to, and thus not impacted by, the indemnification BP has demanded for the BELO cases referenced above. In the ordinary course of its business, the Company becomes involved in various other litigation matters including, among other things, 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. As of December 31, 2018 , the Company leases in three U.S.-flag petroleum and chemical carriers, five U.S.-flag harbor tugs, four U.S.-flag PCTCs, 48 inland river dry-cargo barges, four inland river towboats, six inland river harbor boats and certain facilities and other equipment. These leasing agreements have been classified as operating leases for financial reporting purposes and related rental fees are charged to expense over the lease terms. The leases generally contain purchase and lease renewal options or rights of first refusal with respect to the sale or lease of the equipment. As of December 31, 2018 , the remaining lease terms of the U.S.-flag petroleum and chemical carriers, which are subject to subleases, have remaining durations from 1 to 92 months. The lease terms of the other equipment range in duration from 1 to 207 months. Certain of the equipment leases are the result of sale-leaseback transactions with finance companies (see Note 3) and certain of the gains arising from such sale-leaseback transactions have been deferred in the accompanying consolidated balance sheets and are being amortized as reductions in rental expense over the lease terms (see Note 1). Total rental expense for the Company’s operating leases during the years ended December 31, 2018 , 2017 and 2016 was $52.8 million , $42.8 million and $35.2 million , respectively. For operating leases with a remaining term in excess of one year as of December 31, 2018 , the future minimum payments in the years ended December 31 were as follows (in thousands): Total Minimum Lease Payments Non-cancelable Subleases (1) Net Minimum Lease Payments 2019 $ 43,451 $ (23,197 ) $ 20,254 2020 41,818 (23,251 ) 18,567 2021 36,518 (23,196 ) 13,322 2022 26,615 (19,923 ) 6,692 2023 14,671 (11,315 ) 3,356 Years subsequent to 2023 39,665 (29,884 ) 9,781 ____________________ (1) The total minimum offsetting payments to be received under existing non-cancelable subleases subject to these future minimum lease payments. As of December 31, 2018 , arrangements with remaining terms in excess of one year under which the Company earns lease revenues included the bareboat charter of three U.S.-flag petroleum and chemical carriers, the time charter of four U.S.-flag petroleum and chemical carriers, four U.S.-flag PCTCs, three inland river towboats and one U.S.-flag offshore tug, and the lease of various other property and equipment. As of December 31, 2018 , future minimum lease revenues from these arrangements in the years ended December 31 were as follows (in thousands): Total Minimum Lease Revenues Leased-in Obligations (1) Net Minimum Lease Income 2019 $ 144,464 $ (28,464 ) $ 116,000 2020 132,250 (28,313 ) 103,937 2021 99,901 (26,381 ) 73,520 2022 50,308 (20,405 ) 29,903 2023 33,015 (11,315 ) 21,700 Years subsequent to 2023 81,983 (29,884 ) 52,099 ____________________ (1) The total payments to be made under existing non-cancelable leases for the property and equipment subject to these future minimum lease revenues.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Segment Information	17. SEGMENT INFORMATION The following tables summarize the operating results, capital expenditures and assets of the Company’s reportable segments. Ocean Services $’000 Inland Services $’000 Witt O’Brien’s $’000 Other $’000 Corporate and Eliminations $’000 Total $’000 For the year ended December 31, 2018 Operating Revenues: External customers 414,844 285,688 131,629 3,589 — 835,750 Intersegment — — 80 — (80 ) — 414,844 285,688 131,709 3,589 (80 ) 835,750 Costs and Expenses: Operating 269,294 237,010 83,203 2,455 (114 ) 591,848 Administrative and general 40,179 13,139 24,772 1,841 22,976 102,907 Depreciation and amortization 46,270 24,164 1,944 501 1,700 74,579 355,743 274,313 109,919 4,797 24,562 769,334 Gains on Asset Dispositions 12,887 6,659 — 37 — 19,583 Operating Income (Loss) 71,988 18,034 21,790 (1,171 ) (24,642 ) 85,999 Other Income (Expense): Foreign currency losses, net (168 ) (2,002 ) (28 ) (3 ) (63 ) (2,264 ) Other, net 570 51 — 54,249 94 54,964 Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax 3,632 (5,686 ) 203 1,779 — (72 ) Segment Profit 76,022 10,397 21,965 54,854 Other Income (Expense) not included in Segment Profit (47,010 ) Plus Equity in Losses included in Segment Profit 72 Income Before Taxes and Equity in Losses 91,689 Capital Expenditures 39,207 8,298 — 2,639 128 50,272 As of December 31, 2018 Property and Equipment: Historical cost 930,230 438,848 1,227 6,892 30,132 1,407,329 Accumulated depreciation (341,999 ) (195,094 ) (1,031 ) (490 ) (22,205 ) (560,819 ) Net property and equipment 588,231 243,754 196 6,402 7,927 846,510 Investments, at Equity, and Advances to 50% or Less Owned Companies 73,939 57,899 471 24,577 — 156,886 Inventories 2,196 1,997 179 158 — 4,530 Goodwill 1,852 2,350 28,506 — — 32,708 Intangible Assets 8,965 8,991 6,595 — — 24,551 Other current and long-term assets, excluding cash and near cash assets (1) 48,770 78,903 81,410 2,142 13,178 224,403 Segment Assets 723,953 393,894 117,357 33,279 Cash and near cash assets (1) 181,436 Total Assets 1,471,024 ______________________ (1) Cash and near cash assets includes cash, cash equivalents, restricted cash, restricted cash equivalents, marketable securities and construction reserve funds. Ocean Services $’000 Inland Services $’000 Witt O’Brien’s $’000 Other $’000 Corporate and Eliminations $’000 Total $’000 For the year ended December 31, 2018 Revenues from Contracts with Customers: Voyage charters 73,979 — — — — 73,979 Contracts of affreightment 11,872 219,375 — — — 231,247 Tariff 74,157 — — — — 74,157 Unit freight 58,326 — — — — 58,326 Terminal operations — 21,501 — — — 21,501 Fleeting operations — 17,888 — — — 17,888 Logistics services — 14,309 — — — 14,309 Time and material contracts — — 119,196 — — 119,196 Retainer contracts — — 10,124 — — 10,124 Product sales (1) — — — 2,686 — 2,686 Other 3,268 5,223 2,389 425 (80 ) 11,225 Lease Revenues: Time charter, bareboat charter and rental income 193,242 7,392 — 478 — 201,112 414,844 285,688 131,709 3,589 (80 ) 835,750 ______________________ (1) Costs of goods sold related to product sales was $2.1 million . Ocean Inland Services $’000 Witt O’Brien’s $’000 Other $’000 Corporate and Eliminations $’000 Total $’000 As Adjusted As Adjusted For the year ended December 31, 2017 Operating Revenues: External customers 352,876 248,452 49,055 464 — 650,847 Intersegment — — 101 — (101 ) — 352,876 248,452 49,156 464 (101 ) 650,847 Costs and Expenses: Operating 195,285 206,836 32,017 — (301 ) 433,837 Administrative and general 36,548 16,558 13,438 831 35,731 103,106 Depreciation and amortization 46,073 25,852 819 — 2,314 75,058 277,906 249,246 46,274 831 37,744 612,001 Gains (Losses) on Asset Dispositions and Impairments, Net (323 ) 11,960 — — — 11,637 Operating Income (Loss) 74,647 11,166 2,882 (367 ) (37,845 ) 50,483 Other Income (Expense): Derivative gains, net — — — — 19,727 19,727 Foreign currency gains (losses), net (130 ) 272 50 6 125 323 Other, net 327 — — (301 ) 230 256 Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax 7,664 (5,191 ) 174 305 — 2,952 Segment Profit (Loss) 82,508 6,247 3,106 (357 ) Other Income (Expense) not included in Segment Profit (Loss) (35,584 ) Less Equity in Earnings included in Segment Profit (Loss) (2,952 ) Income Before Taxes and Equity in Earnings 35,205 Capital Expenditures 80,006 34,322 60 — 207 114,595 As of December 31, 2017 Property and Equipment: Historical cost 901,076 448,035 1,227 — 30,131 1,380,469 Accumulated depreciation (299,528 ) (181,573 ) (938 ) — (20,505 ) (502,544 ) Net property and equipment 601,548 266,462 289 — 9,626 877,925 Investments, at Equity, and Advances to 50% or Less Owned Companies 52,003 66,479 777 54,182 — 173,441 Inventories 2,352 1,934 91 — — 4,377 Goodwill 1,852 2,403 28,506 — — 32,761 Intangible Assets 10,293 10,486 7,327 — — 28,106 Other current and long-term assets, excluding cash and near cash assets (1) 49,498 71,500 28,398 1,391 9,611 160,398 Segment Assets 717,546 419,264 65,388 55,573 Cash and near cash assets (1) 336,328 Total Assets 1,613,336 ______________________ (1) Cash and near cash assets includes cash, cash equivalents, restricted cash, restricted cash equivalents, marketable securities and construction reserve funds. Ocean Services $’000 Inland Services $’000 Witt O’Brien’s $’000 Other $’000 Corporate and Eliminations $’000 Total $’000 As Adjusted As Adjusted For the year ended December 31, 2017 Revenues from Contracts with Customers: Voyage charters 33,623 — — — — 33,623 Contracts of affreightment 15,181 189,080 — — — 204,261 Tariff 68,266 — — — — 68,266 Unit freight 50,693 — — — — 50,693 Terminal operations — 21,488 — — — 21,488 Fleeting operations — 15,561 — — — 15,561 Logistics services — 8,868 — — — 8,868 Time and material contracts — — 33,352 — — 33,352 Retainer contracts — — 10,192 — — 10,192 Other 1,879 5,163 5,612 464 (101 ) 13,017 Lease Revenues: Time charter, bareboat charter and rental income 183,234 8,292 — — — 191,526 352,876 248,452 49,156 464 (101 ) 650,847 Ocean Inland Services $’000 Witt O’Brien’s $’000 Other $’000 Corporate and Eliminations $’000 Total $’000 As Adjusted As Adjusted For the year ended December 31, 2016 Operating Revenues: External customers 229,643 251,241 42,797 482 — 524,163 Intersegment — — 119 — (119 ) — 229,643 251,241 42,916 482 (119 ) 524,163 Costs and Expenses: Operating 122,631 208,158 28,561 — (397 ) 358,953 Administrative and general 27,825 14,616 16,214 1,001 26,706 86,362 Depreciation and amortization 31,162 26,327 1,539 — 3,537 62,565 181,618 249,101 46,314 1,001 29,846 507,880 Gains (Losses) on Asset Dispositions and Impairments, Net 411 3,193 (29,587 ) — — (25,983 ) Operating Income (Loss) 48,436 5,333 (32,985 ) (519 ) (29,965 ) (9,700 ) Other Income (Expense): Derivative losses, net — — — — (14,131 ) (14,131 ) Foreign currency gains (losses), net (18 ) 1,722 (181 ) (1 ) (78 ) 1,444 Other, net (6,224 ) (4 ) — (12,608 ) 120 (18,716 ) Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax (4,697 ) (15,944 ) 305 (704 ) — (21,040 ) Segment Profit (Loss) 37,497 (8,893 ) (32,861 ) (13,832 ) Other Income (Expense) not included in Segment Profit (Loss) (51,133 ) Plus Equity in Losses included in Segment Profit (Loss) 21,040 Loss Before Taxes and Equity in Losses (92,236 ) Capital Expenditures 215,837 36,803 2 — 164 252,806 As of December 31, 2016 Property and Equipment: Historical cost 960,816 432,717 1,559 — 29,474 1,424,566 Accumulated depreciation (258,004 ) (167,127 ) (1,244 ) — (18,184 ) (444,559 ) Net property and equipment 702,812 265,590 315 — 11,290 980,007 Investments, at Equity, and Advances to 50% or Less Owned Companies 51,620 69,181 566 54,094 — 175,461 Inventories 843 1,602 137 — — 2,582 Goodwill 1,852 2,400 28,506 — — 32,758 Intangible Assets — 12,018 8,060 — — 20,078 Other current and long-term assets, excluding cash and near cash assets (1) 29,801 88,165 14,284 11,193 21,576 165,019 Segment Assets 786,928 438,956 51,868 65,287 Cash and near cash assets (1) 410,777 Discontinued operations 1,075,639 Total Assets 2,862,321 ______________________ (1) Cash and near cash assets includes cash, cash equivalents, restricted cash, restricted cash equivalents, marketable securities and construction reserve funds. Ocean Services $’000 Inland Services $’000 Witt O’Brien’s $’000 Other $’000 Corporate and Eliminations $’000 Total $’000 As Adjusted As Adjusted For the year ended December 31, 2016 Revenues from Contracts with Customers: Contracts of affreightment — 192,633 — — — 192,633 Tariff 62,249 — — — 62,249 Unit freight 43,599 — — — 43,599 Terminal operations — 20,552 — — — 20,552 Fleeting operations — 12,443 — — — 12,443 Logistics services — 4,469 — — — 4,469 Time and material contracts — 25,898 — — 25,898 Retainer contracts — 11,654 — — 11,654 Other 1,451 13,912 5,364 482 (119 ) 21,090 Lease Revenues: Time charter, bareboat charter and rental income 122,344 7,232 — — — 129,576 229,643 251,241 42,916 482 (119 ) 524,163

Discontinued Operations

Discontinued Operations	12 Months Ended
	Dec. 31, 2018
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	18. DISCONTINUED OPERATIONS The Company’s discontinued operations consist of SEACOR Marine and ICP, as following the Spin-off and sale, respectively, the Company has no continuing involvement in either of these businesses (see Note 1). Summarized selected operating results of the Company’s discontinued operations for the years ended December 31 were as follows (in thousands): 2017 2016 SEACOR Marine Operating Revenues $ 62,291 $ 215,636 Costs and Expenses: Operating 65,888 166,925 Administrative and general 29,682 49,308 Depreciation and amortization 22,181 58,069 117,751 274,302 Gains (Losses) on Asset Dispositions and Impairments, Net 4,219 (116,222 ) Operating Loss (51,241 ) (174,888 ) Other Income (Expense), Net 1,780 (15,417 ) Income Tax Benefit (12,931 ) (63,468 ) Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax 1,663 (6,314 ) Net Loss $ (34,867 ) $ (133,151 ) Net Loss Attributable to Noncontrolling Interests $ (1,892 ) $ (1,103 ) ICP Operating Revenues $ 78,061 $ 177,401 Costs and Expenses: Operating 76,306 158,495 Administrative and general 2,140 3,011 Depreciation and amortization 2,354 4,299 80,800 165,805 Operating Income (Loss) (2,739 ) 11,596 Other Income, Net (including gain on sale of business) 20,557 4,520 Income Tax Expense 7,818 4,901 Net Income $ 10,000 $ 11,215 Net Income (Loss) Attributable to Noncontrolling Interests $ (539 ) $ 3,688 Eliminations Operating Revenues $ (1,176 ) $ (2,517 ) Costs and Expenses: Operating (1,289 ) (2,862 ) Administrative and general (42 ) (100 ) (1,331 ) (2,962 ) Operating Income 155 445 Other Income, Net 1,738 3,732 Income Tax Expense 663 1,462 Net Income $ 1,230 $ 2,715 Loss from Discontinued Operations, Net of Tax $ (23,637 ) $ (119,221 )

Supplemental Information For St

Supplemental Information For Statements Of Cash Flows	12 Months Ended
	Dec. 31, 2018
Supplemental Cash Flow Information [Abstract]
Supplemental Information For Statements Of Cash Flows	19. SUPPLEMENTAL INFORMATION FOR STATEMENTS OF CASH FLOWS Supplemental information for the years ended December 31 was as follows (in thousands): 2018 2017 2016 Income taxes paid $ 27,465 $ 6,152 $ 11,933 Income taxes refunded 299 14,347 3,933 Interest paid, excluding capitalized interest 26,880 32,341 26,662 Schedule of Non-Cash Investing and Financing Activities: Net issuance of conversion option on exchange of convertible debt 16,120 — — Company financed sale of equipment and real property — — 7,950 Distribution of Dorian shares to shareholders — 31,379 — Reclassification of deferred gains to property and equipment 3,052 5,954 — Equipment received to settle notes receivable — — 2,500 Non-cash proceeds on the sale of property and equipment — — 2,000

Quarterly Financial Information

Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Data [Abstract]
Quarterly Financial Information (Unaudited)	20. QUARTERLY FINANCIAL INFORMATION (UNAUDITED) Selected financial information for interim quarterly periods is presented below (in thousands, except share data). Earnings per common share of SEACOR Holdings Inc. are computed independently for each of the quarters presented and the sum of the quarterly earnings per share may not necessarily equal the total for the year. Three Months Ended Dec. 31, Sept. 30, June 30, March 31, 2018 Operating Revenues $ 213,838 $ 220,257 $ 216,831 $ 184,824 Operating Income 25,250 34,047 12,014 14,688 Net Income 4,434 27,203 46,007 5,558 Net Income (Loss) attributable to SEACOR Holdings Inc. (4,686 ) 17,067 45,126 641 Basic Earnings (Loss) Per Common Share of SEACOR Holdings Inc. $ (0.26 ) $ 0.94 $ 2.50 $ 0.04 Diluted Earnings (Loss) Per Common Share of SEACOR Holdings Inc. $ (0.26 ) $ 0.88 $ 2.14 $ 0.04 2017 As Adjusted As Adjusted As Adjusted As Adjusted Operating Revenues $ 209,352 $ 176,605 $ 128,571 $ 136,319 Operating Income 22,983 15,090 8,993 3,417 Income (Loss) from Continuing Operations 79,521 10,177 (456 ) 16,104 Income (Loss) from Discontinued Operations, Net of Tax (487 ) 10,927 (28,629 ) (5,448 ) Net Income (Loss) 79,034 21,104 (29,085 ) 10,656 Net Income (Loss) attributable to SEACOR Holdings Inc.: Continuing Operations $ 73,294 $ 6,634 $ (6,782 ) $ 9,703 Discontinued Operations (487 ) 10,927 (26,026 ) (5,620 ) $ 72,807 $ 17,561 $ (32,808 ) $ 4,083 Basic Earnings (Loss) Per Common Share of SEACOR Holdings Inc.: Continuing Operations $ 4.15 $ 0.38 $ (0.39 ) $ 0.57 Discontinued Operations (0.03 ) 0.62 (1.52 ) (0.33 ) $ 4.12 $ 1.00 $ (1.91 ) $ 0.24 Diluted Earnings (Loss) Per Common Share of SEACOR Holdings Inc.: Continuing Operations $ 3.37 $ 0.38 $ (0.39 ) $ 0.56 Discontinued Operations (0.02 ) 0.62 (1.52 ) (0.32 ) $ 3.35 $ 1.00 $ (1.91 ) $ 0.24

Valuation And Qualifying Accoun

Valuation And Qualifying Accounts	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Valuation And Qualifying Accounts	SEACOR HOLDINGS INC. SCHEDULE II – VALUATION AND QUALIFYING ACCOUNTS For the Years Ended December 31, 2018 , 2017 and 2016 (in thousands) Description Balance Beginning of Year Charges (Credits) to Cost and Expenses Deductions (1) Balance End of Year Year Ended December 31, 2018 Allowance for doubtful accounts (deducted from trade and notes receivable) $ 2,390 $ 2,067 $ (976 ) $ 3,481 Year Ended December 31, 2017 Allowance for doubtful accounts (deducted from trade and notes receivable) $ 2,989 $ (175 ) $ (424 ) $ 2,390 Year Ended December 31, 2016 Allowance for doubtful accounts (deducted from trade and notes receivable) $ 1,307 $ 2,774 $ (1,092 ) $ 2,989 ______________________ (1) Trade receivable amounts deemed uncollectible that were removed from accounts receivable and allowance for doubtful accounts.

Nature Of Operations And Acco_2

Nature Of Operations And Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Nature Of Operations and Segmentation	Nature of Operations and Segmentation. SEACOR Holdings Inc. (“SEACOR”) and its subsidiaries (collectively referred to as the “Company”) are a diversified holding company with interests in domestic and international transportation and logistics, risk management consultancy and other businesses. Accounting standards require public business enterprises to report information about each of their operating business segments that exceed certain quantitative thresholds or meet certain other reporting requirements. Operating business segments have been defined as a component of an enterprise about which separate financial information is available and is evaluated regularly by the chief operating decision maker in deciding how to allocate resources and in assessing performance. The Company has identified the following reporting segments: Ocean Transportation & Logistics Services (“Ocean Services”). Ocean Services owns and operates a diversified fleet of bulk transportation, port and infrastructure, and logistics assets, including U.S. coastwise eligible vessels and vessels trading internationally. Ocean Services has a 51% controlling interest in certain subsidiaries (collectively “SEA-Vista”) that operate U.S.-flag petroleum and chemical carriers servicing the U.S. coastwise crude oil, petroleum products and chemical trades. Ocean Services’ dry bulk vessels also operate in the U.S. coastwise trade. Ocean Services’ port and infrastructure services include a wholly owned harbor and offshore towing subsidiary assisting deep-sea vessels docking in U.S. Gulf and East Coast ports, providing ocean towing services between U.S. ports and providing oil terminal support and bunkering operations in St. Eustatius and the Bahamas. Ocean Services’ logistics services include U.S.-flag Pure Car/Truck Carriers (“PCTCs”) operating globally under the U.S. Maritime Security Program (“MSP”) and liner, short-sea, rail car and project cargo transportation and logistics solutions to and from ports in the Southeastern United States, the Caribbean (including Puerto Rico), the Bahamas and Mexico. Ocean Services also provides technical ship management services for third-party vessel owners. Ocean Services contributed 50% , 54% and 44% of consolidated operating revenues during the years ended December 31, 2018 , 2017 and 2016 , respectively. Inland Transportation & Logistics Services (“Inland Services”). Inland Services markets and operates domestic river transportation equipment, and owns fleeting and high-speed multi-modal terminal locations adjacent to and along the U.S. Inland Waterways, primarily in the St. Louis, Memphis and Baton Rouge areas. Inland Services’ barges are primarily used for moving agricultural and industrial commodities and containers on the U.S. Inland Waterways, the Mississippi River, Illinois River, Tennessee River, Ohio River and their tributaries and the Gulf Intracoastal Waterways. Internationally, Inland Services also owns inland river liquid tank barges that operate on the Magdalena River in Colombia. These barges primarily transport petroleum products. Inland Services also has a 50% interest in dry-cargo barge operations on the Parana-Paraguay River Waterways in Brazil, Bolivia, Paraguay, Argentina and Uruguay primarily transporting agricultural and industrial commodities, a 57% interest in towboat operations on the U.S. Inland Waterways and a 50% interest in grain terminals/elevators along the U.S. Inland waterways. Inland Services contributed 34% , 38% and 48% of consolidated operating revenues during the years ended December 31, 2018 , 2017 and 2016 , respectively. Witt O’Brien’s. Witt O’Brien’s provides crisis and emergency management services for both the public and private sectors. These services strengthen clients’ resilience and assist their response to natural and man-made disasters by enhancing their ability to prepare for, respond to and recover from such disasters, while mitigating the impact of future disruptions on operations and helping communities build back stronger. Witt O’Brien’s contributed 16% , 8% and 8% of consolidated operating revenues during the years ended December 31, 2018 , 2017 and 2016 , respectively. During the year ended December 31, 2018 , one Witt O’Brien’s customer (Virgin Islands Public Finance Authority) accounted for $91.3 million , or 11% , of consolidated operating revenues. Other. The Company’s Other business segment includes CLEANCOR Energy Solutions LLC (“Cleancor”), a full service provider that delivers clean fuel to end users, displacing legacy petroleum-based fuels (see Note 2). Cleancor primarily earns revenues from the sale of liquefied natural gas (“LNG”) (see Note 17). Other also has activities, which primarily include lending and leasing activities and noncontrolling investments in various other businesses, primarily sales, storage, and maintenance support for general aviation in Asia and an agricultural commodity trading and logistics business that is primarily focused on the global origination, and trading and merchandising of sugar.
Discontinued Operations	Discontinued Operations. The Company reports the historical financial position, results of operations and cash flows of disposed businesses as discontinued operations when it has no continuing interest in the business. On June 1, 2017, the Company completed the spin-off of SEACOR Marine Holdings Inc. (“SEACOR Marine”), the company that operated SEACOR’s Offshore Marine Services business segment, by means of a dividend of all the issued and outstanding common stock of SEACOR Marine to SEACOR’s shareholders (the “Spin-off”). SEACOR Marine is now an independent company whose common stock is listed on the New York Stock Exchange under the symbol “SMHI.” For all periods presented herein, the Company has reported the historical results of operations and cash flows of SEACOR Marine as discontinued operations (see Note 18). On July 3, 2017, the Company completed the sale of its 70% interest in Illinois Corn Processing LLC (“ICP”), the company that operated SEACOR’s Illinois Corn Processing business segment. The Company received $21.0 million in cash and a note from the buyer for $32.8 million , after working capital adjustments, resulting in a gain of $10.9 million , net of tax. On September 15, 2017, the Company received payment of the outstanding balance of the note, including accrued and unpaid interest. For all periods presented herein, the Company has reported the historical results of operations and cash flows of ICP as discontinued operations (see Note 18).
Basis Of Consolidation	Basis of Consolidation. The consolidated financial statements include the accounts of SEACOR 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 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 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 or losses from investments in 50% or less owned companies in the accompanying consolidated statements of 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.
Use Of Estimates	Use of Estimates. The preparation of financial statements in conformity with accounting principles generally accepted in the United States 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 allowance for doubtful accounts, useful lives of property and equipment, impairments, income tax provisions and certain accrued liabilities. Actual results could differ from those estimates and those differences may be material.
Adoption of New Accounting Standards	Adoption of New Accounting Standards. On January 1, 2018, the Company adopted Financial Accounting Standard Board (“FASB”) Topic 606, Revenue from Contracts with Customers (“Topic 606”). As a consequence of adopting Topic 606, the Company now recognizes all of the operating revenues and expenses associated with the dry-cargo barge pools it manages along with additional operating expenses reflective of barge pool earnings attributable to third-party barge owners and not the Company in its capacity as manager. Under Topic 606, the Company determined it was a principal with respect to the third-party barge owners. Previously, the Company recognized operating revenues and expenses only for its proportionate share of the barge pools in which it participated, as it acted as an agent. All prior periods have been adjusted to reflect the retrospective adoption of Topic 606, which resulted in additional revenues and operating expenses of $73.0 million and $83.7 million for the years ended December 31, 2017 and 2016 , respectively. The adoption of Topic 606 had no impact on previously reported balance sheets, operating income (loss), net income (loss) or earnings (loss) per share. On January 1, 2018, the Company adopted ASU 2016-16, Intra-Entity Transfers of Assets Other Than Inventory , which eliminates the deferral of the tax effects of intercompany asset sales other than inventory until the transferred assets are sold to a third party or recovered through use. As a result of the adoption of the standard, the deferred tax charges previously recognized from those sales resulted in a decrease in deferred tax assets and a cumulative adjustment to retained earnings of $2.5 million in the consolidated balance sheets and statements of changes in equity as of January 1, 2018.
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 control of the promised goods or services to its customers. Costs to obtain or fulfill a contract are expensed as incurred. Revenue from Contracts with Customers. Ocean Services primarily earns revenues from voyage charters, contracts of affreightment, tariff based port and infrastructure services, unit freight logistics services, and technical ship management agreements with vessel owners (see Note 17). Ocean Services transfers control of the service to the customer and satisfies its performance obligation over the term of the contract, and therefore recognizes revenue over the term of the contract while related costs are expensed as incurred. Voyage charters are contracts to carry cargoes on a single voyage basis for a predetermined price, regardless of time to complete. Contracts of affreightment are contracts for cargoes that are committed on a multi-voyage basis for various periods of time, with minimum and maximum cargo tonnages specified over the period at a fixed or escalating rate per ton. Tariff based port and infrastructure services typically include operating harbor tugs alongside oceangoing vessels to escort them to their berth, assisting with the docking and undocking of these oceangoing vessels and escorting them back out to sea. They are contracted using prevailing port tariff terms on a per-use basis. In the unit freight logistics trade, transportation services typically include transporting shipping containers, rail cars, project cargoes, automobiles and U.S. military vehicles and are generally contracted on a per unit basis for the specified cargo and destination, typically in accordance with a publicly available tariff rate or based on a negotiated rate when moving larger volumes over an extended period. Managed services include technical ship management agreements whereby Ocean Services provides technical ship management services to third-party customers for a predetermined price over a specified period of time, typically a year or more. Inland Services primarily earns revenues from contracts of affreightment, terminal operations, fleeting operations and repair and maintenance services (see Note 17). Inland Services transfers control of the service to the customer and satisfies its performance obligation over the term of the contract, and therefore recognizes revenue over the term of the contract while related costs are expensed as incurred. Contracts of affreightment are contracts whereby customers are charged an established rate per ton to transport cargo from point-to-point. Terminal operations includes tank farms and dry bulk and container handling facilities that are marketed under contractual rates and terms driven by throughput volume. Fleeting operations includes fleeting services whereby barges are held in fleeting areas for an agreed-upon day rate and shifting services whereby harbor boats are used to pick up and drop off barges to assist in assembling tows and to move barges to and from the dock for loading and unloading at predetermined per-shift fees. Other operations primarily include a machine shop specializing in towboat and barge cleaning, repair and maintenance services that are charged on an hourly or a fixed fee basis depending on the scope and nature of the work. Witt O’Brien’s primarily earns revenues from time and material and retainer contracts (see Note 17). Witt O’Brien’s transfers control of the service to the customer and satisfies its performance obligation over the term of the contract, and therefore recognizes revenue over the term of the contract while related costs are expensed as incurred. Time and material contracts primarily relate to emergency response, debris management or consulting services that Witt O’Brien’s performs for a predetermined fee. Retainer contracts, which are nearly all with vessel services operators and oil companies, are contracted based on agreed-upon rates. The Company’s Other business segment includes Cleancor, which primarily earns revenues from the sale of liquefied natural gas (see Note 17). Under these arrangements, control of the goods are transfered to the customer and performance obligations are satisfied at a point in time, and therefore revenue is recognized upon delivery while any related costs are expensed as incurred. Contract liabilities from contracts with customers arise when the Company has received consideration prior to performance and are included in other current liabilities in the accompanying consolidated balance sheets. The Company’s contract liability activity for the year ended December 31 was a follows (in thousands): 2018 Balance at beginning of period $ 983 Contract liabilities arising during the period 968 Revenue recognized upon completion of prior period performance obligations (983 ) Balance at end of period $ 968
Lease Revenues	Lease Revenues. The Company’s lease revenues are primarily from time charters, bareboat charters and non-vessel rental agreements that are recognized ratably over the lease term as services are provided, typically on a per day basis. Under a time charter, the Company provides a vessel to a customer for a set term and is responsible for all operating expenses, typically excluding fuel. Under a bareboat charter, the Company provides a vessel to a customer for a set term and the customer assumes responsibility for all operating expenses and risks of operation. Under a non-vessel rental agreement, the Company provides non-vessel property or equipment to a customer for a set term and the customer assumes responsibility for all operating expenses and risks of operation.
Cash Equivalents	Cash Equivalents. The Company considers all highly liquid investments with an original maturity of three months or less when purchased to be cash equivalents. Cash equivalents consist of U.S. treasury securities, money market instruments, time deposits and overnight investments.
Restricted Cash and Restricted Cash Equivalents	Restricted Cash and Restricted Cash Equivalents. Restricted cash and restricted cash equivalents primarily relates to cash collateral for letters of credit and banking facility requirements.
Marketable Securities	Marketable Securities. Marketable equity securities with readily determinable fair values and debt securities are reported in the accompanying consolidated balance sheets as marketable securities. These investments are stated at fair value, as determined by their market observable prices, with both realized and unrealized gains and losses reported in the accompanying consolidated statements of income (loss) as marketable security losses, net. Short sales of marketable securities are stated at fair value in the accompanying consolidated balance sheets with both realized and unrealized gains and losses reported in the accompanying consolidated statements of income (loss) as marketable security losses, net. Long and short marketable security positions are primarily in energy, marine, transportation and other related businesses. Marketable securities are classified as trading securities for financial reporting purposes with gains and losses reported as operating activities in the accompanying consolidated statements of cash flows. The Company’s most significant marketable security position is its investment in 5,200,000 shares of Dorian LPG Ltd. (“Dorian”), a publicly traded company listed on the New York Stock Exchange under the symbol “LPG” (see Note 11). Dorian’s closing share price was $5.83 and $8.22 as of December 31, 2018 and 2017 , respectively. The Company’s cost basis in Dorian is $13.66 per share.
Trade Receivables, Other Receivables	Trade Receivables. Customers of Ocean Services are primarily multinational oil companies, refining companies, oil trading companies, major gasoline retailers, large industrial consumers of crude, petroleum and chemicals, trading houses, pools, major automobile manufacturers and shippers, the U.S. Government and regional power utilities. Customers of Inland Services are primarily major agricultural companies, fertilizer companies, trading companies and industrial companies. Customers of Witt O’Brien’s are primarily governments, energy companies, ship managers and owners, healthcare providers, universities and school systems. Customers of the Company’s other business activities primarily include agricultural and feed companies, asphalt producers and municipalities and government agencies. All customers are granted credit on a short-term basis and related credit risks are considered minimal. The Company routinely reviews its trade receivables and makes provisions for probable doubtful accounts; however, those provisions are estimates and actual results could differ from those estimates and those differences may be material. Trade receivables are deemed uncollectible and removed from accounts receivable and the allowance for doubtful accounts when collection efforts have been exhausted. Other Receivables. Other receivables primarily consists of income tax and insurance claim receivables. Other receivables also includes amounts due from certain of the Company’s 50% or less owned companies for working capital in excess of working capital advances, which are typically settled monthly in arrears.
Derivative Instruments	Derivative Instruments. The Company accounts for derivatives through the use of a fair value concept whereby all of the Company’s derivative positions are stated at fair value in the accompanying consolidated balance sheets. Realized and unrealized gains and losses on derivatives not designated as hedges are reported in the accompanying consolidated statements of income (loss) as derivative gains (losses), net. Realized and unrealized gains and losses on derivatives designated as fair value hedges are recognized as corresponding increases or decreases in the fair value of the underlying hedged item to the extent they are effective, with any ineffective portion reported in the accompanying consolidated statements of income (loss) as derivative gains (losses), net. Realized and unrealized gains and losses on derivatives designated as cash flow hedges are reported as a component of other comprehensive income (loss) in the accompanying consolidated statements of comprehensive income (loss) to the extent they are effective and reclassified into earnings on the same line item associated with the hedged transaction and in the same period the hedged transaction affects earnings. Any ineffective portions of cash flow hedges are reported in the accompanying consolidated statements of income (loss) as derivative gains (losses), net. Realized and unrealized gains and losses on derivatives designated as cash flow hedges that are entered into by the Company’s 50% or less owned companies are also reported as a component of the Company’s other comprehensive income (loss) in proportion to the Company’s ownership percentage, with reclassifications and ineffective portions being included in equity in earnings (losses) of 50% or less owned companies, net of tax, in the accompanying consolidated statements of income (loss).
Concentrations Of Credit Risk	Concentrations of Credit Risk. The Company is exposed to concentrations of credit risk associated with its cash, cash equivalents, restricted cash and restricted cash equivalents, construction reserve funds and derivative instruments. The Company minimizes its credit risk relating to these positions by monitoring the financial condition of the financial institutions and counterparties involved and by primarily conducting business with large, well-established financial institutions and diversifying its counterparties. The Company does not currently anticipate nonperformance of its significant counterparties. The Company is also exposed to concentrations of credit risk relating to its receivables due from customers in the industries described above. The Company does not generally require collateral or other security to support its outstanding receivables. The Company minimizes its credit risk relating to receivables by performing ongoing credit evaluations and, to date, credit losses have not been material.
Inventories	Inventories. Inventories are stated at the lower of cost (using the first-in, first-out method) or market. Inventories consist primarily of fuel and fuel oil consumed by the Company’s vessels in its Ocean Services and Inland Services business segments. The Company records write-downs, as needed, to adjust the carrying amount of inventories to the lower of cost or market. During the years ended December 31, 2018 , 2017 and 2016 , the Company had no market write-downs of inventory.
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 typically based upon a newly built asset being placed into service and represents the point at 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 their useful life as set forth in 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 December 31, 2018 , the estimated useful life (in years) of each of the Company’s major classes of new equipment was as follows: Petroleum and chemical carriers - U.S.-flag 25 Harbor and offshore tugs 25 Ocean liquid tank barges 25 Short-sea container/RORO (1) vessels 20 Bulk carriers - U.S.-flag 25 Inland river dry-cargo and specialty barges 20 Inland river liquid tank barges 25 Inland river towboats and harbor boats 25 Terminal and fleeting facilities 20 ______________________ (1) Roll On/Roll Off. The Company’s major classes of property and equipment as of December 31 were as follows (in thousands): Historical Cost (1) Accumulated Depreciation Net Book Value 2018 Ocean Services: Petroleum and chemical carriers - U.S.-flag $ 649,795 $ (241,604 ) $ 408,191 Harbor and offshore tugs - U.S.-flag 132,697 (41,764 ) 90,933 Harbor tugs - Foreign-flag 45,379 (13,822 ) 31,557 Ocean liquid tank barges - U.S.-flag 39,238 (14,649 ) 24,589 Short-sea container/RORO - Foreign-flag 29,846 (10,644 ) 19,202 Bulk carriers - U.S.-flag 13,000 (9,800 ) 3,200 Other (2) 20,073 (9,716 ) 10,357 Construction in Progress 202 — 202 930,230 (341,999 ) 588,231 Inland Services: Dry-cargo barges 222,539 (106,157 ) 116,382 Specialty barges 3,828 (1,904 ) 1,924 Liquid tank barges 20,011 (3,054 ) 16,957 Towboats 43,998 (3,294 ) 40,704 Harbor boats 18,695 (8,047 ) 10,648 Terminal and fleeting facilities 99,696 (62,274 ) 37,422 Other (2) 22,213 (10,364 ) 11,849 Construction in Progress 7,868 — 7,868 438,848 (195,094 ) 243,754 Witt O’Brien’s: Other (2) 1,227 (1,031 ) 196 Other: Other (3) 6,892 (490 ) 6,402 Corporate and Eliminations: Other (2) 30,132 (22,205 ) 7,927 $ 1,407,329 $ (560,819 ) $ 846,510 ______________________ (1) Includes property and equipment acquired in business acquisitions at acquisition date fair value. (2) Includes land and buildings, leasehold improvements, fixed-wing aircraft, vehicles and other property and equipment. (3) Includes LNG Equipment and other property and equipment. Historical Cost (1) Accumulated Depreciation Net Book Value 2017 Ocean Services: Petroleum and chemical carriers - U.S.-flag $ 652,985 $ (215,057 ) $ 437,928 Harbor and offshore tugs - U.S.-flag 84,155 (38,984 ) 45,171 Harbor tugs - Foreign-flag 45,338 (11,575 ) 33,763 Ocean liquid tank barges - U.S.-flag 39,238 (13,126 ) 26,112 Short-sea container/RORO - Foreign-flag 20,954 (8,178 ) 12,776 Bulk carriers - U.S.-flag 13,000 (4,733 ) 8,267 Other (2) 19,420 (7,875 ) 11,545 Construction in Progress 25,986 — 25,986 901,076 (299,528 ) 601,548 Inland Services: Dry-cargo barges 233,734 (101,087 ) 132,647 Specialty barges 4,180 (1,781 ) 2,399 Liquid tank barges 21,802 (2,684 ) 19,118 Towboats 44,555 (1,765 ) 42,790 Harbor boats 18,158 (6,956 ) 11,202 Terminal and fleeting facilities 95,926 (55,899 ) 40,027 Other (2) 26,938 (11,401 ) 15,537 Construction in Progress 2,742 — 2,742 448,035 (181,573 ) 266,462 Witt O’Brien’s: Other (2) 1,227 (938 ) 289 Corporate and Eliminations: Other (2) 30,131 (20,505 ) 9,626 $ 1,380,469 $ (502,544 ) $ 877,925 ______________________ (1) Includes property and equipment acquired in business acquisitions at acquisition date fair value. (2) Includes land and buildings, leasehold improvements, fixed-wing aircraft, vehicles and other property and equipment. During the years ended December 31, 2018 , 2017 and 2016 , depreciation expense totaled $69.9 million , $72.1 million , and $60.2 million , respectively. Equipment maintenance and repair costs and the costs of routine overhauls, dry-dockings 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 years ended December 31, 2018 , 2017 and 2016 capitalized interest totaled $0.2 million , $2.7 million and $11.5 million , respectively. As of December 31, 2018, the Company’s construction in progress totaling $8.1 million primarily consisted of the construction of and upgrades to inland river towboats and the construction of other Inland Services equipment, and is included in historical cost in the accompanying consolidated balance sheets.
Intangible Assets	Intangible Assets. The Company’s intangible assets primarily arose from business acquisitions (see Note 2) and consist of trademarks and tradenames, customer relationships and acquired contractual rights. These intangible assets are amortized over their estimated useful lives generally ranging from one to 15 years. During the years ended December 31, 2018 , 2017 and 2016 , the Company recognized amortization expense of $4.7 million , $2.9 million and $2.4 million , respectively. The Company’s intangible assets by type were as follows (in thousands): Trademark/ Tradenames Customer Relationships Acquired Contractual Rights Total Gross Carrying Value Year Ended December 31, 2016 $ 3,324 $ 15,365 $ 8,416 $ 27,105 Acquired intangible assets — — 10,957 10,957 Foreign currency translation — — 2 2 Fully amortized intangible assets — — (1,017 ) (1,017 ) Year Ended December 31, 2017 3,324 15,365 18,358 37,047 Acquired intangible assets — 1,120 — 1,120 Fully amortized intangible assets — (1,120 ) — (1,120 ) Year Ended December 31, 2018 $ 3,324 $ 15,365 $ 18,358 $ 37,047 Accumulated Amortization Year Ended December 31, 2016 $ (1,648 ) $ (3,867 ) $ (1,512 ) $ (7,027 ) Amortization expense (332 ) (1,279 ) (1,320 ) (2,931 ) Fully amortized intangible assets — — 1,017 1,017 Year Ended December 31, 2017 (1,980 ) (5,146 ) (1,815 ) (8,941 ) Amortization expense (332 ) (2,402 ) (1,941 ) (4,675 ) Fully amortized intangible assets — 1,120 — 1,120 Year Ended December 31, 2018 $ (2,312 ) $ (6,428 ) $ (3,756 ) $ (12,496 ) Weighted average remaining contractual life, in years 3.0 8.0 8.0 7.8 Future amortization expense of intangible assets for each of the years ended December 31 is as follows (in thousands): 2019 $ 3,555 2020 3,555 2021 3,571 2022 2,866 2023 2,852 Years subsequent to 2023 8,152 $ 24,551
Impairment Of Long-Lived Assets	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 the estimated 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. The Company performs its testing on an asset or asset group basis. Generally, fair value is determined using valuation techniques, such as expected discounted cash flows or appraisals, as appropriate. During the year ended December 31, 2018 , the Company did not recognize any impairment charges related to its property and equipment held for use. During the years ended December 31, 2017 and 2016 , the Company recognized impairment charges of $0.4 million and $1.1 million , respectively, related to property and equipment held for use, which are included in gains (losses) on asset dispositions and impairments, net in the accompanying consolidated statements of income (loss). In October 2016, Witt O’Brien’s announced the launch of a strategic growth program to focus on core services by eliminating non-core and lower margin businesses. Witt O’Brien’s core services include providing resilience solutions for key areas of critical infrastructure, including, but not limited to, government, energy, transportation, healthcare and education, in the United States and abroad. Witt O’Brien’s protects and enhances its customers’ enterprise value by strengthening their ability to prepare for, respond to and recover from natural and man-made disasters, including hurricanes, infectious disease, terrorism, cyber breaches, oil spills, shipping incidents and other disruptions. The operations scheduled for elimination include a governmental relations unit, the Company’s European (primarily United Kingdom) operations, software products and an insurance unit. As a consequence of the restructuring, during the year ended December 31, 2016 , Witt O’Brien’s recorded an impairment charge of $10.0 million to write off the carrying value of customer related intangible assets associated with the non-core service lines that were eliminated. This impairment charge is included in gains (losses) on asset dispositions and impairments, net in the accompanying consolidated statements of income (loss).
Impairment of 50% or Less Owned Companies	Impairment of 50% or Less Owned Companies. 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 years ended December 31, 2018 , 2017 and 2016 , the Company recognized impairment charges of $0.1 million , $0.9 million and $7.7 million , respectively, related to its 50% or less owned companies, which are included in equity in earnings (losses) of 50% or less owned companies, net of tax in the accompanying consolidated statements of income (loss) (see Note 4).
Goodwill	Goodwill. Goodwill is recorded when the purchase price paid for an acquisition exceeds the fair value of net identified tangible and intangible assets acquired. As of December 31, 2018 , substantially all of the Company’s goodwill is related to Witt O’Brien’s. The Company performs an annual impairment test of goodwill on October 1 of each year and further periodic tests to the extent indicators of impairment develop between annual impairment tests. The Company’s impairment review process compares the fair value of the reporting unit to its carrying value, including the goodwill, related to the reporting unit. To determine the fair value of the reporting unit, the Company may use various approaches including an asset or cost approach, market approach or income approach or any combination thereof. These approaches may require the Company to make certain estimates and assumptions including projections of future cash flows, revenues and expenses. These estimates and assumptions are reviewed each time the Company tests goodwill for impairment and are typically developed as part of the Company’s routine business planning and forecasting process. Although the Company believes its assumptions and estimates are reasonable, the Company’s actual performance against its estimates could produce different results and lead to impairment charges in future periods. During the years ended December 31, 2018 and 2017 , the Company did not recognize any impairment charges related to its goodwill. Based on an evaluation of the implied fair value of goodwill compared to its carrying value, during the year ended December 31, 2016 , the Company recognized an impairment charge of $19.6 million to reduce the goodwill carrying value to fair value, which is included in gains (losses) on asset dispositions and impairments, net in the accompanying consolidated statements of income (loss). The estimated fair value of the reporting unit was based on values established by independent valuation specialists.
Business Combinations	Business Combinations. The Company recognizes 100% of the fair value of assets acquired, liabilities assumed, and noncontrolling interests when the acquisition constitutes a change in control of the acquired entity. Shares issued in consideration for a business combination, contingent consideration arrangements and pre-acquisition loss and gain contingencies are all measured and recorded at their acquisition-date fair value. Subsequent changes to fair value of contingent consideration arrangements are generally reflected in earnings. Any in-process research and development assets acquired are capitalized as are certain acquisition-related restructuring costs if the criteria related to exit or disposal cost obligations are met as of the acquisition date. Acquisition-related transaction costs are expensed as incurred and any changes in income tax valuation allowances and tax uncertainty accruals are recorded as an adjustment to income tax expense (benefit). The operating results of entities acquired are included in the accompanying consolidated statements of income (loss) from the date of acquisition (see Note 2).
Debt Discount and Issuance Costs	Debt Discount and Issuance Costs. Debt discounts and costs incurred in connection with the issuance of debt are amortized over the life of the related debt using the effective interest rate method for term loans and straight line method for revolving credit facilities and is included in interest expense in the accompanying consolidated statements of income (loss).
Self-insurance Liabilities	Self-insurance Liabilities. The Company maintains hull, liability and war risk, general liability, workers compensation and other insurance customary in the industries in which it operates. Certain excess and property insurance policies are obtained through SEACOR sponsored programs, with premiums charged to participating businesses based on management’s risk assessment or insured asset values. The marine hull and liability policies have significant annual aggregate deductibles that are accrued based on actual claims incurred. The Company also maintains self-insured health benefit plans for its participating employees. Exposure to the health benefit plans are limited by maintaining stop-loss and aggregate liability coverage. To the extent that estimated self-insurance losses, including the accrual of annual aggregate deductibles, differ from actual losses realized, the Company’s insurance reserves could differ significantly and may result in either higher or lower insurance expense in future periods.
Income Taxes	Income Taxes. Deferred income tax assets and liabilities have been provided in recognition of the income tax effect attributable to the book and tax basis differences of assets and liabilities reported in the accompanying consolidated financial statements. Deferred tax assets or liabilities are provided using the enacted tax rates expected to apply to taxable income in the periods in which they are expected to be settled or realized. Interest and penalties relating to uncertain tax positions are recognized in interest expense and administrative and general, respectively, in the accompanying consolidated statements of income (loss). The Company records a valuation allowance to reduce its deferred tax assets if it is more likely than not that some portion or all of the deferred tax assets will not be realized. The Company records any liability associated with global intangible low-taxed income (GILTI) in the period it is incurred. In the normal course of business, the Company may be subject to challenges from tax authorities regarding the amount of taxes due. These challenges may alter the timing or amount of taxable income or deductions. As part of the calculation of income tax expense (benefit), the Company determines whether the benefits of its tax positions are at least more likely than not of being sustained based on the technical merits of the tax position. For tax positions that are more likely than not of being sustained, the Company accrues the largest amount of the tax benefit that is more likely than not of being sustained. Such accruals require management to make estimates and judgments with respect to the ultimate outcome of its tax benefits and actual results could vary materially from these estimates.
Deferred Gains	Deferred Gains – Equipment Sale-Leaseback Transactions and Financed Equipment Sales. From time to time, the Company enters into equipment sale-leaseback transactions with finance companies or provides seller financing on sales of its equipment to third parties or 50% or less owned companies. A portion of the gains realized from these transactions is not immediately recognized in income and has been recorded in the accompanying consolidated balance sheets in deferred gains and other liabilities. In sale-leaseback transactions (see Note 3), gains are deferred to the extent of the present value of future minimum lease payments and are amortized as reductions to rental expense over the applicable lease terms. In financed equipment sales (see Note 3), gains are deferred to the extent that the repayment of purchase notes is dependent on the future operations of the sold equipment and are amortized based on cash received from the buyers. Deferred gain activity related to these transactions for the years ended December 31 was as follows (in thousands): 2018 2017 2016 Balance at beginning of year $ 66,519 $ 74,774 $ 83,142 Deferred gains arising from equipment sales — 13,336 9,003 Amortization of deferred gains included in operating expenses as reduction to rental expense (12,774 ) (15,035 ) (15,072 ) Amortization of deferred gains included in gains (losses) on asset dispositions and impairments, net (11,591 ) (602 ) (602 ) Other (3,052 ) (5,954 ) (1,697 ) Balance at end of year (1) $ 39,102 $ 66,519 $ 74,774 ______________________ (1) On January 1, 2019 the Company will adopt FASB Topic 842, Leases (“Topic 842”). In accordance with Topic 842, the Company will reduce these gains by $26.9 million through a beginning period retained earnings adjustment. Deferred Gains – Equipment Sales to the Company’s 50% or Less Owned Companies. A portion of the gains realized from non-financed sales of the Company’s vessels and barges to its 50% or less owned companies is not immediately recognized in income and has been recorded in the accompanying consolidated balance sheets in deferred gains and other liabilities. Effective January 1, 2009, the Company adopted new accounting rules related to the sale of its vessels and barges to its 50% or less owned companies. In most instances, these sale transactions are now considered a sale of a business in which the Company relinquishes control to its 50% or less owned companies. Subsequent to the adoption of the new accounting rules, gains are deferred only to the extent of the Company’s uncalled capital commitments and are amortized as those commitments lapse or funded amounts are returned. For transactions occurring prior to the adoption of the new accounting rules, gains were deferred and are being amortized based on the Company’s ownership interest, cash received and the applicable equipment’s useful lives. Deferred gain activity related to these transactions for the years ended December 31 was as follows (in thousands): 2018 2017 2016 Balance at beginning of year $ 5,934 $ 7,649 $ 9,468 Amortization of deferred gains included in gains (losses) on asset dispositions and impairments, net (1,372 ) (1,715 ) (1,819 ) Balance at end of year (1) $ 4,562 $ 5,934 $ 7,649 ______________________ (1) On January 1, 2019, the Company will adopt Topic 842. In accordance with Topic 842, the Company will reduce these gains by $2.3 million through a beginning period retained earnings adjustment.
Stock Based Compensation	Stock Based Compensation. Stock based compensation is amortized to compensation expense on a straight line basis over the requisite service period of the grants using the Black-Scholes valuation model. The Company does not estimate forfeitures in its expense calculations as forfeiture history has been minor. The Company presents the excess tax benefits from the exercise of stock options as a financing cash flow in the accompanying consolidated statements of cash flows.
Foreign Currency Translation and Transactions	Foreign Currency Transactions. Certain SEACOR subsidiaries enter into transactions denominated in currencies other than their functional currency. Gains and losses resulting from changes in currency exchange rates between the functional currency and the currency in which a transaction is denominated are included in foreign currency gains (losses), net in the accompanying consolidated statements of income (loss) in the period in which the currency exchange rates change. Foreign Currency Translation. The assets, liabilities and results of operations of certain SEACOR subsidiaries are measured using their functional currency, which is the currency of the primary foreign economic environment in which they operate. Upon consolidating these subsidiaries with SEACOR, their assets and liabilities are translated to U.S. dollars at currency exchange rates as of the balance sheet dates and their revenues and expenses are translated at the weighted average currency exchange rates during the applicable reporting periods. Translation adjustments resulting from the process of translating these subsidiaries’ financial statements are reported in other comprehensive income (loss) in the accompanying consolidated statements of comprehensive income (loss).
Earnings (Loss) Per Share	Earnings (Loss) Per Share. Basic earnings (loss) per common share of SEACOR are computed based on the weighted average number of common shares issued and outstanding during the relevant periods. Diluted earnings (loss) per common share of SEACOR are computed based on the weighted average number of common shares issued and outstanding plus the effect of potentially dilutive securities through the application of the treasury stock and if-converted methods. Dilutive securities for this purpose assumes restricted stock grants have vested, common shares have been issued pursuant to the exercise of outstanding stock options and common shares have been issued pursuant to the conversion of all outstanding convertible notes. Computations of basic and diluted earnings (loss) per common share of SEACOR for the years ended December 31 were as follows (in thousands, except share data): Net Income (Loss) Average o/s Shares Per Share 2018 Basic Weighted Average Common Shares Outstanding $ 58,148 18,080,778 $ 3.22 Effect of Dilutive Securities: Options and Restricted Stock (1) — 267,810 Convertible Securities (2)(3) 1,273 1,227,101 Diluted Weighted Average Common Shares Outstanding $ 59,421 19,575,689 $ 3.04 2017 Basic Weighted Average Common Shares Outstanding $ 61,643 17,368,081 $ 3.55 Effect of Dilutive Securities: Options and Restricted Stock (1) — 308,012 Convertible Securities 14,346 5,258,065 Diluted Weighted Average Common Shares Outstanding $ 75,989 22,934,158 $ 3.31 2016 Basic Weighted Average Common Shares Outstanding $ (215,897 ) 16,914,928 $ (12.76 ) Effect of Dilutive Securities: Options and Restricted Stock (1) — — Convertible Securities (2)(4) — — Diluted Weighted Average Common Shares Outstanding $ (215,897 ) 16,914,928 $ (12.76 ) ______________________ (1) For the years ended December 31, 2018 , 2017 and 2016 , diluted earnings per common share of SEACOR excluded 333,510 , 1,924,217 and 2,020,677 , respectively, of certain share awards as the effect of their inclusion in the computation would be anti-dilutive. (2) For the years ended December 31, 2018 and 2016 diluted earnings per common share of SEACOR excluded 1,946,917 and 1,825,326 shares, respectively, issuable pursuant to the Company’s 3.0% Convertible Senior Notes (see Note 7) as the effect of their inclusion in the computation would be anti-dilutive. (3) For the year ended December 31, 2018 diluted earnings per share of SEACOR excluded 983,351 shares issuable pursuant to the Company’s 3.25% Convertible Senior Notes (see Note 7) as the effect of their inclusion in the computation would be anti-dilutive. (4) For the year ended December 31, 2016 , diluted earnings per common share of SEACOR excluded 2,664,208 shares issuable pursuant to the Company’s 2.5% Convertible Senior Notes (see Note 7) as the effect of their inclusion in the computation would be anti-dilutive.
New Accounting Pronouncements	New Accounting Pronouncements. On February 25, 2016, the FASB issued a comprehensive new leasing standard that is meant to improve transparency and comparability among companies by requiring lessees to recognize a lease liability and a corresponding lease asset for virtually all lease contracts and also requires additional disclosures about leasing arrangements. The new standard is effective for interim and annual periods beginning after December 15, 2018. The Company will adopt this standard using a modified prospective approach with recognition of a cumulative-effect adjustment to the opening balance of retained earnings at the adoption date. The Company has determined the adoption will have a material impact on its financial statements. Specifically, the Company will be recording material right-of-use assets and lease liabilities of $174.6 million for certain of its equipment, office and land leases. The Company’s computation of its right-of-use assets and lease liabilities required it to make certain assumptions, including lease discount rates. On June 16, 2016, the FASB issued an amendment to the accounting standards, which replaces the current incurred loss impairment methodology for financial assets measured at amortized cost with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information, including forecasted information, to develop credit loss estimates. The new standard is effective for interim and annual periods beginning after December 15, 2019. Early adoption is permitted for annual periods beginning after December 15, 2018. The Company has not yet determined what impact, if any, the adoption of the new standard will have on its consolidated financial position, results of operations or cash flows. On January 26, 2017, the FASB issued an amendment to the accounting standards, which simplified wording and removed step two of the goodwill impairment test. A goodwill impairment will now be the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. The FASB also eliminated the requirements for any reporting unit with a zero or negative carrying amount to perform a qualitative assessment and, if it fails that qualitative test, to perform step two of the goodwill test. The new standard is effective for annual or interim goodwill impairment tests in fiscal years beginning after December 15, 2020, with early adoption permitted for interim or annual goodwill impairment tests on testing dates after January 1, 2017. The Company has not yet determined what impact, if any, the adoption of the new standard will have on its consolidated financial position, results of operations or cash flows.

Nature Of Operations And Acco_3

Nature Of Operations And Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Contract with Customer, Asset and Liability	The Company’s contract liability activity for the year ended December 31 was a follows (in thousands): 2018 Balance at beginning of period $ 983 Contract liabilities arising during the period 968 Revenue recognized upon completion of prior period performance obligations (983 ) Balance at end of period $ 968
Schedule of Property, Plant and Equipment	As of December 31, 2018 , the estimated useful life (in years) of each of the Company’s major classes of new equipment was as follows: Petroleum and chemical carriers - U.S.-flag 25 Harbor and offshore tugs 25 Ocean liquid tank barges 25 Short-sea container/RORO (1) vessels 20 Bulk carriers - U.S.-flag 25 Inland river dry-cargo and specialty barges 20 Inland river liquid tank barges 25 Inland river towboats and harbor boats 25 Terminal and fleeting facilities 20 ______________________ (1) Roll On/Roll Off. The Company’s major classes of property and equipment as of December 31 were as follows (in thousands): Historical Cost (1) Accumulated Depreciation Net Book Value 2018 Ocean Services: Petroleum and chemical carriers - U.S.-flag $ 649,795 $ (241,604 ) $ 408,191 Harbor and offshore tugs - U.S.-flag 132,697 (41,764 ) 90,933 Harbor tugs - Foreign-flag 45,379 (13,822 ) 31,557 Ocean liquid tank barges - U.S.-flag 39,238 (14,649 ) 24,589 Short-sea container/RORO - Foreign-flag 29,846 (10,644 ) 19,202 Bulk carriers - U.S.-flag 13,000 (9,800 ) 3,200 Other (2) 20,073 (9,716 ) 10,357 Construction in Progress 202 — 202 930,230 (341,999 ) 588,231 Inland Services: Dry-cargo barges 222,539 (106,157 ) 116,382 Specialty barges 3,828 (1,904 ) 1,924 Liquid tank barges 20,011 (3,054 ) 16,957 Towboats 43,998 (3,294 ) 40,704 Harbor boats 18,695 (8,047 ) 10,648 Terminal and fleeting facilities 99,696 (62,274 ) 37,422 Other (2) 22,213 (10,364 ) 11,849 Construction in Progress 7,868 — 7,868 438,848 (195,094 ) 243,754 Witt O’Brien’s: Other (2) 1,227 (1,031 ) 196 Other: Other (3) 6,892 (490 ) 6,402 Corporate and Eliminations: Other (2) 30,132 (22,205 ) 7,927 $ 1,407,329 $ (560,819 ) $ 846,510 ______________________ (1) Includes property and equipment acquired in business acquisitions at acquisition date fair value. (2) Includes land and buildings, leasehold improvements, fixed-wing aircraft, vehicles and other property and equipment. (3) Includes LNG Equipment and other property and equipment. Historical Cost (1) Accumulated Depreciation Net Book Value 2017 Ocean Services: Petroleum and chemical carriers - U.S.-flag $ 652,985 $ (215,057 ) $ 437,928 Harbor and offshore tugs - U.S.-flag 84,155 (38,984 ) 45,171 Harbor tugs - Foreign-flag 45,338 (11,575 ) 33,763 Ocean liquid tank barges - U.S.-flag 39,238 (13,126 ) 26,112 Short-sea container/RORO - Foreign-flag 20,954 (8,178 ) 12,776 Bulk carriers - U.S.-flag 13,000 (4,733 ) 8,267 Other (2) 19,420 (7,875 ) 11,545 Construction in Progress 25,986 — 25,986 901,076 (299,528 ) 601,548 Inland Services: Dry-cargo barges 233,734 (101,087 ) 132,647 Specialty barges 4,180 (1,781 ) 2,399 Liquid tank barges 21,802 (2,684 ) 19,118 Towboats 44,555 (1,765 ) 42,790 Harbor boats 18,158 (6,956 ) 11,202 Terminal and fleeting facilities 95,926 (55,899 ) 40,027 Other (2) 26,938 (11,401 ) 15,537 Construction in Progress 2,742 — 2,742 448,035 (181,573 ) 266,462 Witt O’Brien’s: Other (2) 1,227 (938 ) 289 Corporate and Eliminations: Other (2) 30,131 (20,505 ) 9,626 $ 1,380,469 $ (502,544 ) $ 877,925 ______________________ (1) Includes property and equipment acquired in business acquisitions at acquisition date fair value. (2) Includes land and buildings, leasehold improvements, fixed-wing aircraft, vehicles and other property and equipment.
Schedule Of Intangible Assets	The Company’s intangible assets by type were as follows (in thousands): Trademark/ Tradenames Customer Relationships Acquired Contractual Rights Total Gross Carrying Value Year Ended December 31, 2016 $ 3,324 $ 15,365 $ 8,416 $ 27,105 Acquired intangible assets — — 10,957 10,957 Foreign currency translation — — 2 2 Fully amortized intangible assets — — (1,017 ) (1,017 ) Year Ended December 31, 2017 3,324 15,365 18,358 37,047 Acquired intangible assets — 1,120 — 1,120 Fully amortized intangible assets — (1,120 ) — (1,120 ) Year Ended December 31, 2018 $ 3,324 $ 15,365 $ 18,358 $ 37,047 Accumulated Amortization Year Ended December 31, 2016 $ (1,648 ) $ (3,867 ) $ (1,512 ) $ (7,027 ) Amortization expense (332 ) (1,279 ) (1,320 ) (2,931 ) Fully amortized intangible assets — — 1,017 1,017 Year Ended December 31, 2017 (1,980 ) (5,146 ) (1,815 ) (8,941 ) Amortization expense (332 ) (2,402 ) (1,941 ) (4,675 ) Fully amortized intangible assets — 1,120 — 1,120 Year Ended December 31, 2018 $ (2,312 ) $ (6,428 ) $ (3,756 ) $ (12,496 ) Weighted average remaining contractual life, in years 3.0 8.0 8.0 7.8
Schedule Of Future Amortization Expense Of Intangible Assets	Future amortization expense of intangible assets for each of the years ended December 31 is as follows (in thousands): 2019 $ 3,555 2020 3,555 2021 3,571 2022 2,866 2023 2,852 Years subsequent to 2023 8,152 $ 24,551
Schedule of Deferred Gains	Deferred gain activity related to these transactions for the years ended December 31 was as follows (in thousands): 2018 2017 2016 Balance at beginning of year $ 5,934 $ 7,649 $ 9,468 Amortization of deferred gains included in gains (losses) on asset dispositions and impairments, net (1,372 ) (1,715 ) (1,819 ) Balance at end of year (1) $ 4,562 $ 5,934 $ 7,649 ______________________ (1) On January 1, 2019, the Company will adopt Topic 842. In accordance with Topic 842, the Company will reduce these gains by $2.3 million through a beginning period retained earnings adjustment. Deferred gain activity related to these transactions for the years ended December 31 was as follows (in thousands): 2018 2017 2016 Balance at beginning of year $ 66,519 $ 74,774 $ 83,142 Deferred gains arising from equipment sales — 13,336 9,003 Amortization of deferred gains included in operating expenses as reduction to rental expense (12,774 ) (15,035 ) (15,072 ) Amortization of deferred gains included in gains (losses) on asset dispositions and impairments, net (11,591 ) (602 ) (602 ) Other (3,052 ) (5,954 ) (1,697 ) Balance at end of year (1) $ 39,102 $ 66,519 $ 74,774 ______________________ (1) On January 1, 2019 the Company will adopt FASB Topic 842, Leases (“Topic 842”). In accordance with Topic 842, the Company will reduce these gains by $26.9 million through a beginning period retained earnings adjustment.
Schedule of Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Loss. The components of accumulated other comprehensive loss were as follows (in thousands): SEACOR Holdings Inc. Stockholders’ Equity Noncontrolling Interests Foreign Currency Translation Adjustments Derivative Losses on Cash Flow Hedges, net Other Total Foreign Currency Translation Adjustments Derivative Losses on Cash Flow Hedges, net Other Other Comprehensive Income (Loss) Year ended December 31, 2015 $ (5,528 ) $ (116 ) $ 24 $ (5,620 ) $ (528 ) $ — $ 16 Other comprehensive income (loss) (9,331 ) 294 (31 ) (9,068 ) (1,085 ) (17 ) (13 ) $ (10,183 ) Income tax (expense) benefit 3,266 (103 ) 11 3,174 — — — 3,174 Year ended December 31, 2016 (11,593 ) 75 4 (11,514 ) (1,613 ) (17 ) 3 $ (7,009 ) Discontinued Operations 10,031 94 — 10,125 1,460 4 2 Other comprehensive income (loss) 1,812 (260 ) (6 ) 1,546 153 13 (5 ) $ 1,707 Income tax (expense) benefit (795 ) 91 2 (702 ) — — — (702 ) Year ended December 31, 2017 (545 ) — — (545 ) — — — $ 1,005 Other comprehensive loss (391 ) — — (391 ) — — — $ (391 ) Income tax benefit 22 — — 22 — — — 22 Year ended December 31, 2018 $ (914 ) $ — $ — $ (914 ) $ — $ — $ — $ (369 )
Schedule Of Earnings Per Share	Computations of basic and diluted earnings (loss) per common share of SEACOR for the years ended December 31 were as follows (in thousands, except share data): Net Income (Loss) Average o/s Shares Per Share 2018 Basic Weighted Average Common Shares Outstanding $ 58,148 18,080,778 $ 3.22 Effect of Dilutive Securities: Options and Restricted Stock (1) — 267,810 Convertible Securities (2)(3) 1,273 1,227,101 Diluted Weighted Average Common Shares Outstanding $ 59,421 19,575,689 $ 3.04 2017 Basic Weighted Average Common Shares Outstanding $ 61,643 17,368,081 $ 3.55 Effect of Dilutive Securities: Options and Restricted Stock (1) — 308,012 Convertible Securities 14,346 5,258,065 Diluted Weighted Average Common Shares Outstanding $ 75,989 22,934,158 $ 3.31 2016 Basic Weighted Average Common Shares Outstanding $ (215,897 ) 16,914,928 $ (12.76 ) Effect of Dilutive Securities: Options and Restricted Stock (1) — — Convertible Securities (2)(4) — — Diluted Weighted Average Common Shares Outstanding $ (215,897 ) 16,914,928 $ (12.76 ) ______________________ (1) For the years ended December 31, 2018 , 2017 and 2016 , diluted earnings per common share of SEACOR excluded 333,510 , 1,924,217 and 2,020,677 , respectively, of certain share awards as the effect of their inclusion in the computation would be anti-dilutive. (2) For the years ended December 31, 2018 and 2016 diluted earnings per common share of SEACOR excluded 1,946,917 and 1,825,326 shares, respectively, issuable pursuant to the Company’s 3.0% Convertible Senior Notes (see Note 7) as the effect of their inclusion in the computation would be anti-dilutive. (3) For the year ended December 31, 2018 diluted earnings per share of SEACOR excluded 983,351 shares issuable pursuant to the Company’s 3.25% Convertible Senior Notes (see Note 7) as the effect of their inclusion in the computation would be anti-dilutive. (4) For the year ended December 31, 2016 , diluted earnings per common share of SEACOR excluded 2,664,208 shares issuable pursuant to the Company’s 2.5% Convertible Senior Notes (see Note 7) as the effect of their inclusion in the computation would be anti-dilutive.

Business Acquisitions (Tables)

Business Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2018
Business Combinations [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	Purchase Price Allocation. The allocation of the purchase price for the Company’s acquisitions for the years ended December 31 was as follows (in thousands): 2018 2017 2016 Restricted cash and restricted cash equivalents $ — $ 13 $ — Trade and other receivables 1,264 15,823 937 Other current assets 170 2,054 150 Investments, at Equity, and Advances to 50% or Less Owned Companies (5,123 ) 10,000 (3,437 ) Property and Equipment 4,382 15,190 15,765 Intangible Assets 1,120 10,957 7,098 Other Assets (1) 7 (17,863 ) — Accounts payable and other accrued liabilities (2) (1,609 ) — 39 Other current liabilities (439 ) (17,214 ) (13 ) Long-Term Debt — (28,725 ) — Deferred Income Taxes — 3,939 — Other Liabilities — (42 ) — Noncontrolling interests in subsidiaries (82 ) — — Purchase price (3) $ (310 ) $ (5,868 ) $ 20,539 ______________________ (1) Net of debtor-in-possession financing converted into equity of $18.1 million , in 2017. (2) Includes $1.5 million of consideration to be paid in two installments. (3) Purchase price is net of cash acquired totaling $3.6 million , $16.4 million and $0.9 million in 2018 , 2017 and 2016 , respectively.

Equipment Acquisitions And Di_2

Equipment Acquisitions And Dispositions (Tables)	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Additions of Property, Plant and Equipment	Major owned equipment placed in service for the years ended December 31 were as follows: 2018 2017 (1) 2016 (2) Petroleum and chemical carriers - U.S.-flag — 3 3 Short-sea container\RORO - Foreign-flag 2 — — Harbor tugs - U.S.-flag 5 1 1 Harbor tugs - Foreign-flag — 2 — Inland river dry-cargo barges — — 46 Inland river liquid tank barges — 2 — Inland river towboats — 3 2 ______________________ (1) Excludes two U.S.-flag bulk carriers acquired in the ISH acquisition (see Note 2). (2) Excludes five inland river harbor boats acquired in the CCM acquisition and one U.S.-flag offshore tug acquired in the SeaJon II acquisition (see Note 2).
Dispositions of Property, Plant and Equipment	Major equipment dispositions for the years ended December 31 were as follows: 2018 2017 2016 Petroleum and chemical carriers - U.S.-flag 1 1 1 Harbor tugs - U.S.-flag 1 — 2 Inland river dry-cargo barges 32 50 — Inland river liquid tank barges — — 19 Inland river specialty barges 2 2 — Inland river towboats — 2 14

Investments, At Equity, And A_2

Investments, At Equity, And Advances To 50% Or Less Owned Companies (Tables)	12 Months Ended
	Dec. 31, 2018
Equity Method Investment, Summarized Financial Information [Abstract]
Summarized Financial Information For The Company's Investments, At Equity	Summarized financial information for SCFCo as of and for the years ended December 31 was as follows (in thousands): 2018 2017 Current assets $ 8,322 $ 7,924 Property and equipment, net 121,001 137,224 Current liabilities 12,958 14,263 Noncurrent liabilities 56,078 54,179 2018 2017 2016 Operating Revenues $ 54,486 $ 44,177 $ 43,711 Costs and Expenses: Operating and administrative 45,911 40,106 38,980 Depreciation 17,901 17,803 17,560 63,812 57,909 56,540 Operating Loss (9,326 ) (13,732 ) (12,829 ) Interest expense (6,573 ) (6,120 ) (6,565 ) Other expense, net (2,229 ) (961 ) (657 ) Net Loss $ (18,128 ) $ (20,813 ) $ (20,051 ) Investments, at equity, and advances to 50% or less owned companies as of December 31 were as follows (in thousands): Ownership 2018 2017 Ocean Services: Trailer Bridge (1) 55.3% $ 56,364 $ 47,324 RF Vessel Holdings 50.0% 10,826 2,378 Golfo de Mexico 50.0% 5,272 2,500 KSM 50.0% 1,478 (199 ) 73,940 52,003 Inland Services: SCFCo 50.0% 37,219 42,126 Bunge-SCF Grain 50.0% 14,738 16,166 SCF Bunge Marine (1) 57.0% 3,144 5,404 Other 50.0% 2,796 2,783 57,897 66,479 Witt O’Brien’s: O’Brien’s do Brazil 50.0% 472 777 Other: Hawker Pacific 34.2% — 21,681 VA&E 41.3% 13,073 13,596 Avion 39.1% 10,290 11,400 Cleancor 50.0% — 5,134 Other 34.0% – 47.5 % 1,214 2,371 24,577 54,182 $ 156,886 $ 173,441 ______________________ (1) The Company’s ownership percentage represents its economic interest in the joint venture. Combined Condensed Financial Information. Summarized financial information for the Company’s investments, at equity, excluding SCFCo and Trailer Bridge, as of and for the years ended December 31 was as follows (in thousands): 2018 2017 Current assets $ 184,704 $ 523,343 Noncurrent assets 77,929 124,733 Current liabilities 113,784 407,812 Noncurrent liabilities 46,503 81,899 2018 2017 2016 Operating Revenues $ 786,717 $ 1,068,190 $ 1,019,658 Costs and Expenses: Operating and administrative 771,324 1,035,952 951,019 Depreciation 7,216 11,810 24,936 778,540 1,047,762 975,955 Gains (Losses) on Asset Dispositions and Impairments, Net 38 16,115 (6,339 ) Operating Income $ 8,215 $ 36,543 $ 37,364 Net Income $ 3,967 $ 23,383 $ 4,961

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2018
Long-term Debt, Unclassified [Abstract]
Schedule Of Company's Borrowings	The Company’s borrowings as of December 31 were as follows (in thousands): 2018 2017 3.0% Convertible Senior Notes (1) $ 107,284 $ 230,000 2.5% Convertible Senior Notes 64,455 64,455 3.25% Convertible Senior Notes (2) 117,782 — 7.375% Senior Notes (3) — 153,090 SEA-Vista Credit Facility (4) 87,977 135,714 ISH Credit Facility (5) — 12,200 Other (6) 8,561 10,633 386,059 606,092 Portion due within one year (8,497 ) (77,842 ) Debt discount included in long-term debt (28,334 ) (23,152 ) Debt issuance costs included in long-term debt (3,100 ) (3,593 ) $ 346,128 $ 501,505 ______________________ (1) Excludes unamortized discount and unamortized issue costs of $7.2 million and $0.7 million , respectively, as of December 31, 2018 and $22.9 million and $2.3 million , respectively, as of December 31, 2017 . (2) Excludes unamortized discount and unamortized issue costs of $21.1 million and $1.9 million , respectively, as of December 31, 2018 . (3) Excludes unamortized discount and unamortized issue costs of $0.2 million and $0.3 million , respectively, as of December 31, 2017 . (4) Excludes unamortized issue costs of $0.4 million and $0.7 million as of December 31, 2018 and December 31, 2017 , respectively. (5) Excludes unamortized issue costs of $0.1 million as of December 31, 2017 . (6) Excludes unamortized issue costs of $0.1 million and $0.1 million as of December 31, 2018 and December 31, 2017 , respectively.
Schedule Of Long-Term Debt Maturities	The Company’s contractual long-term debt maturities for the years ended December 31 are as follows (in thousands): 2019 $ 8,497 2020 80,672 2021 500 2022 503 2023 368 Years subsequent to 2023 295,519 $ 386,059

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Schedule Of Income Before Income Tax, Domestic and Foreign	Income (loss) before income tax expense (benefit) and equity in earnings (losses) of 50% or less owned companies derived from U.S. and foreign companies for the years ended December 31 were as follows (in thousands): 2018 2017 2016 United States $ 33,563 $ 28,546 $ (93,145 ) Foreign 56,558 4,748 (1,105 ) Eliminations and other 1,568 1,911 2,014 $ 91,689 $ 35,205 $ (92,236 )
Components Of Income Tax Expense (Benefit)	The Company files a consolidated U.S. federal tax return. The components of income tax expense (benefit) for the years ended December 31 were as follows (in thousands): 2018 2017 2016 Current: State $ 253 $ 1,136 $ 4,830 Federal 20,776 (17,181 ) 6,998 Foreign 2,899 333 379 23,928 (15,712 ) 12,207 Deferred: State (3,001 ) 12 (2,280 ) Federal (12,512 ) (51,489 ) (46,652 ) (15,513 ) (51,477 ) (48,932 ) $ 8,415 $ (67,189 ) $ (36,725 )
Components 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 for the years ended December 31 : 2018 2017 2016 Statutory rate 21.0 % 35.0 % 35.0 % Income subject to tonnage tax (1.3 )% (5.9 )% — % Dorian distribution — % 22.8 % — % Reversal of uncertain tax position — % (28.7 )% — % U.S. federal income tax statutory changes — % (190.2 )% — % Non-deductible expenses 0.2 % 0.8 % 1.0 % Noncontrolling interests (5.7 )% (22.4 )% 6.3 % Foreign earnings not subject to U.S. income tax (16.2 )% — % — % Foreign taxes not creditable against U.S. income tax 3.2 % — % — % Losses of foreign subsidiaries not benefited — % (6.6 )% (1.4 )% Subpart F income 12.1 % — % — % State taxes (3.1 )% 1.2 % (0.9 )% Share award plans (0.3 )% 2.0 % — % Other (0.7 )% 1.1 % (0.2 )% 9.2 % (190.9 )% 39.8 %
Components Of Net Deferred Income Tax Liabilities	The components of the net deferred income tax liabilities for the years ended December 31 were as follows (in thousands): 2018 2017 Deferred tax liabilities: Property and equipment $ 93,049 $ 92,127 Long-term debt 18,355 22,519 Investments in 50% or less owned companies 1,934 811 Intangible assets 614 1,006 Deductible goodwill 344 — Other 31 96 Total deferred tax liabilities 114,327 116,559 Deferred tax assets: Share award plans 3,711 3,476 Losses on marketable securities 8,596 5,986 Deductible goodwill — 312 Debt and equity issuance costs 379 406 Other 11,178 11,652 Total deferred tax assets 23,864 21,832 Valuation allowance (3,957 ) (6,695 ) Net deferred tax assets 19,907 15,137 Net deferred tax liabilities $ 94,420 $ 101,422

Derivative Instruments And He_2

Derivative Instruments And Hedging Strategies (Tables)	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Recognized 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 years ended December 31 as follows (in thousands): Derivative gains (losses), net 2018 2017 2016 Exchange option liability on subsidiary convertible senior notes $ — $ 19,436 $ (13,826 ) Forward currency exchange, option and future contracts — 291 (296 ) Exchange traded commodity swap, option and future contracts — — (9 ) $ — $ 19,727 $ (14,131 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Financial Assets And Liabilities Measured At Fair Value On Recurring Basis	The Company’s financial assets and liabilities as of December 31 that are measured at fair value on a recurring basis were as follows (in thousands): Level 1 Level 2 Level 3 2018 ASSETS Cash, cash equivalents, restricted cash and restricted cash equivalents $ 147,212 $ — $ — Marketable securities (1) 30,316 — — Construction reserve funds 3,908 — — 2017 ASSETS Cash, cash equivalents, restricted cash and restricted cash equivalents $ 242,228 $ — $ — Marketable securities (1) 42,761 — — Construction reserve funds 51,339 — — ______________________ (1) Marketable security losses, net include losses of $12.4 million , gains of $0.1 million and losses of $18.5 million for the years ended December 31, 2018 , 2017 and 2016 , respectively, related to marketable security positions held by the Company as of December 31, 2018 . Marketable security losses, net include gains of $0.1 million and losses of $18.5 million for the years ended December 31, 2017 and 2016 , respectively, related to marketable security positions held by the Company as of December 31, 2017 .
Estimated Fair Value Of Other Financial Assets And Liabilities	The estimated fair value of the Company’s other financial assets and liabilities as of December 31 were as follows (in thousands): Carrying Amount Level 1 Level 2 Level 3 2018 ASSETS Notes receivable from third parties (included in other receivables and other assets) $ 2,182 $ — $ 2,159 $ — Investments, at cost, in 50% or less owned companies (included in other assets) 4,300 see below LIABILITIES Long-term debt, including current portion (1) 354,625 — 353,929 — 2017 ASSETS Notes receivable from third parties (included in other receivables and other assets) $ 2,647 $ 943 $ 1,642 $ — Investments, at cost, in 50% or less owned companies (included in other assets) 4,300 see below LIABILITIES Long-term debt, including current portion (1) 579,347 — 596,246 — ______________________ (1) The estimated fair value includes the embedded conversion options on the Company’s 3.0% and 3.25% Convertible Senior Notes.
Non-Financial Assets And Liabilities Measured At Fair Value	The Company’s non-financial assets that were measured at fair value during the years ended December 31 were as follows (in thousands): Level 1 Level 2 Level 3 2018 ASSETS Investments, at equity, and advances in 50% or less owned companies $ — 3,219 $ — 2017 ASSETS Investments, at equity, and advances in 50% or less owned companies $ — $ 6,000 $ —

Noncontrolling Interests in S_2

Noncontrolling Interests in Subsidiaries (Tables)	12 Months Ended
	Dec. 31, 2018
Noncontrolling Interest [Abstract]
Noncontrolling Interest	Noncontrolling interests in the Company’s consolidated subsidiaries as of December 31 were as follows (in thousands): Noncontrolling Interests 2018 2017 Ocean Services: SEA-Vista 49% 148,665 128,550 Inland Services: Other 3.0 % – 51.8% 862 977 Other 5.0% 161 151 $ 149,688 $ 129,678

Savings, Multi-Employer And D_2

Savings, Multi-Employer And Defined Benefit Pension Plans (Tables)	12 Months Ended
	Dec. 31, 2018
Deferred Compensation Arrangements [Abstract]
Schedule of Defined Benefit Plans Disclosures	The funded status of the ISH Retirement Plan and the related pension income (expense) as of and for the years ended December 31, were as follows (in thousands): 2018 2017 Fair Value of Assets $ 34,923 $ 38,492 Projected Benefit Obligation (34,299 ) (36,940 ) Funded Status (1) $ 624 $ 1,552 Pension income (expense) (2) $ (928 ) $ 1,315 _____________________ (1) Included in other assets in the accompanying consolidated balance sheets. (2) For 2017, pension income for the period July 3, 2017 through December 31, 2017.
Schedule of Assumptions Used	The significant assumptions used in determining the projected benefit obligation as of December 31, and pension income (expense) for the years ended December 31, were as follows: 2018 2017 Discount rate 4.05 % 3.50 % Rate of increase in compensations levels (1) N/A 4.50 % CPI 2.25 % 2.00 % Cash balance interest credits (compounded annually) 4.00 % 4.10 % Expected long-term rate of return on plan assets 6.75 % 6.75 % _____________________ (1) For the period July 3, 2017 through August 31, 2017, the date retirement benefits were frozen.
Schedule of Expected Benefit Payments	The future benefit payments expected to be paid in each of the next five fiscal years are as follows (in thousands): 2019 2,130 2020 2,090 2021 2,080 2022 2,170 2023 2,150

Share Based Compensation (Table

Share Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share Based Compensation Plans	Share Award Transactions. The following transactions have occurred in connection with the Company’s share based compensation plans during the years ended December 31: 2018 2017 2016 Restricted stock awards granted 121,850 153,100 137,258 Restricted stock awards forfeited — (2,444 ) (2,867 ) Director stock awards granted 2,875 1,750 3,125 Stock Option Activities: Outstanding as of the beginning of year 1,546,014 1,639,865 1,690,899 Granted (1) 142,550 1,013,893 197,550 Exercised (220,694 ) (562,587 ) (113,820 ) Forfeited — (3,374 ) (18,760 ) Expired (479 ) (541,783 ) (116,004 ) Outstanding as of the end of year 1,467,391 1,546,014 1,639,865 Employee Stock Purchase Plans shares issued 45,251 36,552 41,924 Shares available for issuance under Share Incentive and Employee Stock Purchase Plans as of the end of year (2) 884,218 896,265 522,341 ______________________ (1) On June 2, 2017, the Company granted 846,353 stock options to existing option holders under make-whole provisions upon the Spin-off. (2) Shares available for future grants and ESPP purchases were adjusted on June 2, 2017 to reflect the Spin-off in accordance with make-whole provisions of the plans.
Nonvested Restricted Stock Shares Activity	During the year ended December 31, 2018 , the number of shares and the weighted average grant price of restricted stock transactions were as follows: Restricted Stock Number of Shares Weighted Average Grant Price Nonvested as of December 31, 2017 — $ — Granted 121,850 $ 46.66 Vested — $ — Forfeited — $ — Nonvested as of December 31, 2018 121,850 $ 46.66
Schedule Of Share-based Compensation, Stock Options, Activity	During the year ended December 31, 2018 , the number of shares and the weighted average exercise price on stock option transactions were as follows: Total Options Number of Shares Weighted Average Exercise Price Outstanding, as of December 31, 2017 1,546,014 $ 39.73 Granted 142,550 $ 48.36 Exercised (220,694 ) $ 31.19 Expired (479 ) $ 53.38 Outstanding, as of December 31, 2018 1,467,391 $ 41.85 Outstanding and Exercisable, as of December 31, 2018 997,019 $ 41.72

Commitments And Contingencies (

Commitments And Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Unrecorded Unconditional Purchase Obligations Disclosure	The Company's capital commitments as of December 31, 2018 by year of expected payment were as follows (in thousands): 2019 2020 Total Ocean Services $ 3,479 $ 6,161 $ 9,640 Inland Services 19,599 920 20,519 $ 23,078 $ 7,081 $ 30,159
Schedule of Future Minimum Rental Payments for Operating Leases	For operating leases with a remaining term in excess of one year as of December 31, 2018 , the future minimum payments in the years ended December 31 were as follows (in thousands): Total Minimum Lease Payments Non-cancelable Subleases (1) Net Minimum Lease Payments 2019 $ 43,451 $ (23,197 ) $ 20,254 2020 41,818 (23,251 ) 18,567 2021 36,518 (23,196 ) 13,322 2022 26,615 (19,923 ) 6,692 2023 14,671 (11,315 ) 3,356 Years subsequent to 2023 39,665 (29,884 ) 9,781 ____________________ (1) The total minimum offsetting payments to be received under existing non-cancelable subleases subject to these future minimum lease payments.
Schedule of Future Minimum Lease Revenues for Operating Leases	As of December 31, 2018 , future minimum lease revenues from these arrangements in the years ended December 31 were as follows (in thousands): Total Minimum Lease Revenues Leased-in Obligations (1) Net Minimum Lease Income 2019 $ 144,464 $ (28,464 ) $ 116,000 2020 132,250 (28,313 ) 103,937 2021 99,901 (26,381 ) 73,520 2022 50,308 (20,405 ) 29,903 2023 33,015 (11,315 ) 21,700 Years subsequent to 2023 81,983 (29,884 ) 52,099 ____________________ (1) The total payments to be made under existing non-cancelable leases for the property and equipment subject to these future minimum lease revenues.

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by segment	Ocean Inland Services $’000 Witt O’Brien’s $’000 Other $’000 Corporate and Eliminations $’000 Total $’000 As Adjusted As Adjusted For the year ended December 31, 2016 Operating Revenues: External customers 229,643 251,241 42,797 482 — 524,163 Intersegment — — 119 — (119 ) — 229,643 251,241 42,916 482 (119 ) 524,163 Costs and Expenses: Operating 122,631 208,158 28,561 — (397 ) 358,953 Administrative and general 27,825 14,616 16,214 1,001 26,706 86,362 Depreciation and amortization 31,162 26,327 1,539 — 3,537 62,565 181,618 249,101 46,314 1,001 29,846 507,880 Gains (Losses) on Asset Dispositions and Impairments, Net 411 3,193 (29,587 ) — — (25,983 ) Operating Income (Loss) 48,436 5,333 (32,985 ) (519 ) (29,965 ) (9,700 ) Other Income (Expense): Derivative losses, net — — — — (14,131 ) (14,131 ) Foreign currency gains (losses), net (18 ) 1,722 (181 ) (1 ) (78 ) 1,444 Other, net (6,224 ) (4 ) — (12,608 ) 120 (18,716 ) Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax (4,697 ) (15,944 ) 305 (704 ) — (21,040 ) Segment Profit (Loss) 37,497 (8,893 ) (32,861 ) (13,832 ) Other Income (Expense) not included in Segment Profit (Loss) (51,133 ) Plus Equity in Losses included in Segment Profit (Loss) 21,040 Loss Before Taxes and Equity in Losses (92,236 ) Capital Expenditures 215,837 36,803 2 — 164 252,806 As of December 31, 2016 Property and Equipment: Historical cost 960,816 432,717 1,559 — 29,474 1,424,566 Accumulated depreciation (258,004 ) (167,127 ) (1,244 ) — (18,184 ) (444,559 ) Net property and equipment 702,812 265,590 315 — 11,290 980,007 Investments, at Equity, and Advances to 50% or Less Owned Companies 51,620 69,181 566 54,094 — 175,461 Inventories 843 1,602 137 — — 2,582 Goodwill 1,852 2,400 28,506 — — 32,758 Intangible Assets — 12,018 8,060 — — 20,078 Other current and long-term assets, excluding cash and near cash assets (1) 29,801 88,165 14,284 11,193 21,576 165,019 Segment Assets 786,928 438,956 51,868 65,287 Cash and near cash assets (1) 410,777 Discontinued operations 1,075,639 Total Assets 2,862,321 ______________________ (1) Cash and near cash assets includes cash, cash equivalents, restricted cash, restricted cash equivalents, marketable securities and construction reserve funds. Ocean Inland Services $’000 Witt O’Brien’s $’000 Other $’000 Corporate and Eliminations $’000 Total $’000 As Adjusted As Adjusted For the year ended December 31, 2017 Operating Revenues: External customers 352,876 248,452 49,055 464 — 650,847 Intersegment — — 101 — (101 ) — 352,876 248,452 49,156 464 (101 ) 650,847 Costs and Expenses: Operating 195,285 206,836 32,017 — (301 ) 433,837 Administrative and general 36,548 16,558 13,438 831 35,731 103,106 Depreciation and amortization 46,073 25,852 819 — 2,314 75,058 277,906 249,246 46,274 831 37,744 612,001 Gains (Losses) on Asset Dispositions and Impairments, Net (323 ) 11,960 — — — 11,637 Operating Income (Loss) 74,647 11,166 2,882 (367 ) (37,845 ) 50,483 Other Income (Expense): Derivative gains, net — — — — 19,727 19,727 Foreign currency gains (losses), net (130 ) 272 50 6 125 323 Other, net 327 — — (301 ) 230 256 Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax 7,664 (5,191 ) 174 305 — 2,952 Segment Profit (Loss) 82,508 6,247 3,106 (357 ) Other Income (Expense) not included in Segment Profit (Loss) (35,584 ) Less Equity in Earnings included in Segment Profit (Loss) (2,952 ) Income Before Taxes and Equity in Earnings 35,205 Capital Expenditures 80,006 34,322 60 — 207 114,595 As of December 31, 2017 Property and Equipment: Historical cost 901,076 448,035 1,227 — 30,131 1,380,469 Accumulated depreciation (299,528 ) (181,573 ) (938 ) — (20,505 ) (502,544 ) Net property and equipment 601,548 266,462 289 — 9,626 877,925 Investments, at Equity, and Advances to 50% or Less Owned Companies 52,003 66,479 777 54,182 — 173,441 Inventories 2,352 1,934 91 — — 4,377 Goodwill 1,852 2,403 28,506 — — 32,761 Intangible Assets 10,293 10,486 7,327 — — 28,106 Other current and long-term assets, excluding cash and near cash assets (1) 49,498 71,500 28,398 1,391 9,611 160,398 Segment Assets 717,546 419,264 65,388 55,573 Cash and near cash assets (1) 336,328 Total Assets 1,613,336 ______________________ (1) Cash and near cash assets includes cash, cash equivalents, restricted cash, restricted cash equivalents, marketable securities and construction reserve funds The following tables summarize the operating results, capital expenditures and assets of the Company’s reportable segments. Ocean Services $’000 Inland Services $’000 Witt O’Brien’s $’000 Other $’000 Corporate and Eliminations $’000 Total $’000 For the year ended December 31, 2018 Operating Revenues: External customers 414,844 285,688 131,629 3,589 — 835,750 Intersegment — — 80 — (80 ) — 414,844 285,688 131,709 3,589 (80 ) 835,750 Costs and Expenses: Operating 269,294 237,010 83,203 2,455 (114 ) 591,848 Administrative and general 40,179 13,139 24,772 1,841 22,976 102,907 Depreciation and amortization 46,270 24,164 1,944 501 1,700 74,579 355,743 274,313 109,919 4,797 24,562 769,334 Gains on Asset Dispositions 12,887 6,659 — 37 — 19,583 Operating Income (Loss) 71,988 18,034 21,790 (1,171 ) (24,642 ) 85,999 Other Income (Expense): Foreign currency losses, net (168 ) (2,002 ) (28 ) (3 ) (63 ) (2,264 ) Other, net 570 51 — 54,249 94 54,964 Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax 3,632 (5,686 ) 203 1,779 — (72 ) Segment Profit 76,022 10,397 21,965 54,854 Other Income (Expense) not included in Segment Profit (47,010 ) Plus Equity in Losses included in Segment Profit 72 Income Before Taxes and Equity in Losses 91,689 Capital Expenditures 39,207 8,298 — 2,639 128 50,272 As of December 31, 2018 Property and Equipment: Historical cost 930,230 438,848 1,227 6,892 30,132 1,407,329 Accumulated depreciation (341,999 ) (195,094 ) (1,031 ) (490 ) (22,205 ) (560,819 ) Net property and equipment 588,231 243,754 196 6,402 7,927 846,510 Investments, at Equity, and Advances to 50% or Less Owned Companies 73,939 57,899 471 24,577 — 156,886 Inventories 2,196 1,997 179 158 — 4,530 Goodwill 1,852 2,350 28,506 — — 32,708 Intangible Assets 8,965 8,991 6,595 — — 24,551 Other current and long-term assets, excluding cash and near cash assets (1) 48,770 78,903 81,410 2,142 13,178 224,403 Segment Assets 723,953 393,894 117,357 33,279 Cash and near cash assets (1) 181,436 Total Assets 1,471,024 ______________________ (1) Cash and near cash assets includes cash, cash equivalents, restricted cash, restricted cash equivalents, marketable securities and construction reserve funds
Disaggregation of Revenue	Ocean Services $’000 Inland Services $’000 Witt O’Brien’s $’000 Other $’000 Corporate and Eliminations $’000 Total $’000 As Adjusted As Adjusted For the year ended December 31, 2016 Revenues from Contracts with Customers: Contracts of affreightment — 192,633 — — — 192,633 Tariff 62,249 — — — 62,249 Unit freight 43,599 — — — 43,599 Terminal operations — 20,552 — — — 20,552 Fleeting operations — 12,443 — — — 12,443 Logistics services — 4,469 — — — 4,469 Time and material contracts — 25,898 — — 25,898 Retainer contracts — 11,654 — — 11,654 Other 1,451 13,912 5,364 482 (119 ) 21,090 Lease Revenues: Time charter, bareboat charter and rental income 122,344 7,232 — — — 129,576 229,643 251,241 42,916 482 (119 ) 524,163 Ocean Services $’000 Inland Services $’000 Witt O’Brien’s $’000 Other $’000 Corporate and Eliminations $’000 Total $’000 As Adjusted As Adjusted For the year ended December 31, 2017 Revenues from Contracts with Customers: Voyage charters 33,623 — — — — 33,623 Contracts of affreightment 15,181 189,080 — — — 204,261 Tariff 68,266 — — — — 68,266 Unit freight 50,693 — — — — 50,693 Terminal operations — 21,488 — — — 21,488 Fleeting operations — 15,561 — — — 15,561 Logistics services — 8,868 — — — 8,868 Time and material contracts — — 33,352 — — 33,352 Retainer contracts — — 10,192 — — 10,192 Other 1,879 5,163 5,612 464 (101 ) 13,017 Lease Revenues: Time charter, bareboat charter and rental income 183,234 8,292 — — — 191,526 352,876 248,452 49,156 464 (101 ) 650,847 Ocean Services $’000 Inland Services $’000 Witt O’Brien’s $’000 Other $’000 Corporate and Eliminations $’000 Total $’000 For the year ended December 31, 2018 Revenues from Contracts with Customers: Voyage charters 73,979 — — — — 73,979 Contracts of affreightment 11,872 219,375 — — — 231,247 Tariff 74,157 — — — — 74,157 Unit freight 58,326 — — — — 58,326 Terminal operations — 21,501 — — — 21,501 Fleeting operations — 17,888 — — — 17,888 Logistics services — 14,309 — — — 14,309 Time and material contracts — — 119,196 — — 119,196 Retainer contracts — — 10,124 — — 10,124 Product sales (1) — — — 2,686 — 2,686 Other 3,268 5,223 2,389 425 (80 ) 11,225 Lease Revenues: Time charter, bareboat charter and rental income 193,242 7,392 — 478 — 201,112 414,844 285,688 131,709 3,589 (80 ) 835,750 ______________________ (1) Costs of goods sold related to product sales was $2.1 million .

Discontinued Operations (Tables

Discontinued Operations (Tables)	12 Months Ended
	Dec. 31, 2018
Discontinued Operations and Disposal Groups [Abstract]
Disposal Groups, Including Discontinued Operations	Summarized selected operating results of the Company’s discontinued operations for the years ended December 31 were as follows (in thousands): 2017 2016 SEACOR Marine Operating Revenues $ 62,291 $ 215,636 Costs and Expenses: Operating 65,888 166,925 Administrative and general 29,682 49,308 Depreciation and amortization 22,181 58,069 117,751 274,302 Gains (Losses) on Asset Dispositions and Impairments, Net 4,219 (116,222 ) Operating Loss (51,241 ) (174,888 ) Other Income (Expense), Net 1,780 (15,417 ) Income Tax Benefit (12,931 ) (63,468 ) Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax 1,663 (6,314 ) Net Loss $ (34,867 ) $ (133,151 ) Net Loss Attributable to Noncontrolling Interests $ (1,892 ) $ (1,103 ) ICP Operating Revenues $ 78,061 $ 177,401 Costs and Expenses: Operating 76,306 158,495 Administrative and general 2,140 3,011 Depreciation and amortization 2,354 4,299 80,800 165,805 Operating Income (Loss) (2,739 ) 11,596 Other Income, Net (including gain on sale of business) 20,557 4,520 Income Tax Expense 7,818 4,901 Net Income $ 10,000 $ 11,215 Net Income (Loss) Attributable to Noncontrolling Interests $ (539 ) $ 3,688 Eliminations Operating Revenues $ (1,176 ) $ (2,517 ) Costs and Expenses: Operating (1,289 ) (2,862 ) Administrative and general (42 ) (100 ) (1,331 ) (2,962 ) Operating Income 155 445 Other Income, Net 1,738 3,732 Income Tax Expense 663 1,462 Net Income $ 1,230 $ 2,715 Loss from Discontinued Operations, Net of Tax $ (23,637 ) $ (119,221 )

Supplemental Information For _2

Supplemental Information For Statements Of Cash Flows (Tables)	12 Months Ended
	Dec. 31, 2018
Supplemental Cash Flow Information [Abstract]
Cash Flow Supplemental Information	Supplemental information for the years ended December 31 was as follows (in thousands): 2018 2017 2016 Income taxes paid $ 27,465 $ 6,152 $ 11,933 Income taxes refunded 299 14,347 3,933 Interest paid, excluding capitalized interest 26,880 32,341 26,662 Schedule of Non-Cash Investing and Financing Activities: Net issuance of conversion option on exchange of convertible debt 16,120 — — Company financed sale of equipment and real property — — 7,950 Distribution of Dorian shares to shareholders — 31,379 — Reclassification of deferred gains to property and equipment 3,052 5,954 — Equipment received to settle notes receivable — — 2,500 Non-cash proceeds on the sale of property and equipment — — 2,000

Quarterly Financial Informati_2

Quarterly Financial Information (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Data [Abstract]
Quarterly Financial Information	Three Months Ended Dec. 31, Sept. 30, June 30, March 31, 2018 Operating Revenues $ 213,838 $ 220,257 $ 216,831 $ 184,824 Operating Income 25,250 34,047 12,014 14,688 Net Income 4,434 27,203 46,007 5,558 Net Income (Loss) attributable to SEACOR Holdings Inc. (4,686 ) 17,067 45,126 641 Basic Earnings (Loss) Per Common Share of SEACOR Holdings Inc. $ (0.26 ) $ 0.94 $ 2.50 $ 0.04 Diluted Earnings (Loss) Per Common Share of SEACOR Holdings Inc. $ (0.26 ) $ 0.88 $ 2.14 $ 0.04 2017 As Adjusted As Adjusted As Adjusted As Adjusted Operating Revenues $ 209,352 $ 176,605 $ 128,571 $ 136,319 Operating Income 22,983 15,090 8,993 3,417 Income (Loss) from Continuing Operations 79,521 10,177 (456 ) 16,104 Income (Loss) from Discontinued Operations, Net of Tax (487 ) 10,927 (28,629 ) (5,448 ) Net Income (Loss) 79,034 21,104 (29,085 ) 10,656 Net Income (Loss) attributable to SEACOR Holdings Inc.: Continuing Operations $ 73,294 $ 6,634 $ (6,782 ) $ 9,703 Discontinued Operations (487 ) 10,927 (26,026 ) (5,620 ) $ 72,807 $ 17,561 $ (32,808 ) $ 4,083 Basic Earnings (Loss) Per Common Share of SEACOR Holdings Inc.: Continuing Operations $ 4.15 $ 0.38 $ (0.39 ) $ 0.57 Discontinued Operations (0.03 ) 0.62 (1.52 ) (0.33 ) $ 4.12 $ 1.00 $ (1.91 ) $ 0.24 Diluted Earnings (Loss) Per Common Share of SEACOR Holdings Inc.: Continuing Operations $ 3.37 $ 0.38 $ (0.39 ) $ 0.56 Discontinued Operations (0.02 ) 0.62 (1.52 ) (0.32 ) $ 3.35 $ 1.00 $ (1.91 ) $ 0.24

Nature Of Operations And Acco_4

Nature Of Operations And Accounting Policies (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	Jan. 01, 2019	Jul. 03, 2017	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
Nature of Operations and Accounting Policies [Line Items]
Operating Revenues			$ 213,838	$ 220,257	$ 216,831	$ 184,824	$ 209,352	$ 176,605	$ 128,571	$ 136,319	$ 835,750	$ 650,847	$ 524,163
(Increase) decrease in receivables											63,764	(2,195)	26,273
Depreciation											69,900	72,100	60,200
Capitalized interest											200	2,700	11,500
Construction in progress, gross			$ 8,100								8,100
Amortization expense											4,675	2,931	2,400
Impairment of long-lived assets held-for-use												400	1,100
Equity method investment, other than temporary impairment											$ 100	$ 900	7,700
Goodwill, impairment loss													19,600
Minimum
Nature of Operations and Accounting Policies [Line Items]
Finite-lived intangible asset, useful life											1 year
Maximum
Nature of Operations and Accounting Policies [Line Items]
Finite-lived intangible asset, useful life											15 years
Dorian LPG
Nature of Operations and Accounting Policies [Line Items]
Investment owned, balance (in shares)			5.2								5.2
Share price (in dollars per share)			$ 5.83				$ 8.22				$ 5.83	$ 8.22
Investment owned, at cost per share (in dollars per share)			$ 13.66								$ 13.66
Accounting Standards Update 2014-09
Nature of Operations and Accounting Policies [Line Items]
Effect of adoption of new accounting pronouncement												$ 73,000	$ 83,700
Accounting Standards Update 2016-16
Nature of Operations and Accounting Policies [Line Items]
Cumulative effect of new accounting principle														$ (2,467)
Accounting Standards Update 2016-16 | Retained Earnings
Nature of Operations and Accounting Policies [Line Items]
Cumulative effect of new accounting principle							$ (2,467)					$ (2,467)		$ (2,467)
Accounting Standards Update 2016-02 | Subsequent Event
Nature of Operations and Accounting Policies [Line Items]
Effect of adoption of new accounting pronouncement	$ 174,600
Illinois Corn Processing LLC | Discontinued Operations, Disposed of by Sale
Nature of Operations and Accounting Policies [Line Items]
Proceeds from divestiture of businesses		$ 21,000
(Increase) decrease in receivables		32,800
Gain (loss) on disposal of discontinued operation		$ 10,900
Illinois Corn Processing LLC
Nature of Operations and Accounting Policies [Line Items]
Noncontrolling interest, ownership percentage by parent		70.00%
Dry-Cargo Barge Operations [Member]
Nature of Operations and Accounting Policies [Line Items]
Noncontrolling interest, ownership percentage by parent			50.00%								50.00%
Inland River Towboat Operations [Member]
Nature of Operations and Accounting Policies [Line Items]
Noncontrolling interest, ownership percentage by parent			57.00%								57.00%
Inland Grain Terminals/Elevators [Member]
Nature of Operations and Accounting Policies [Line Items]
Noncontrolling interest, ownership percentage by parent			50.00%								50.00%
Virgin Islands Public Finance Authority
Nature of Operations and Accounting Policies [Line Items]
Operating Revenues											$ 91,300
Virgin Islands Public Finance Authority | Customer Concentration Risk
Nature of Operations and Accounting Policies [Line Items]
Percentage of operating revenues											11.00%
Ocean Services
Nature of Operations and Accounting Policies [Line Items]
Percentage of operating revenues											50.00%	54.00%	44.00%
Operating Revenues											$ 414,844	$ 352,876	$ 229,643
Ocean Services | SEA-Vista
Nature of Operations and Accounting Policies [Line Items]
Noncontrolling interest, ownership percentage by parent			51.00%								51.00%
Inland Services
Nature of Operations and Accounting Policies [Line Items]
Percentage of operating revenues											34.00%	38.00%	48.00%
Operating Revenues											$ 285,688	$ 248,452	$ 251,241
Witt O'Brien's LLC
Nature of Operations and Accounting Policies [Line Items]
Percentage of operating revenues											16.00%	8.00%	8.00%
Operating Revenues											$ 131,629	$ 49,055	$ 42,797
Impairment of intangible assets													$ 10,000

Nature of Operations And Acco_5

Nature of Operations And Accounting Policies (Summary of Contract Liabilities) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Change in Contract with Customer, Liability [Roll Forward]
Balance at beginning of period	$ 983
Contract liabilities arising during the period	968
Revenue recognized upon completion of prior period performance obligations	(983)
Balance at end of period	$ 968

Nature Of Operations And Acco_6

Nature Of Operations And Accounting Policies (Estimated Useful life Of Major Assets) (Details)	12 Months Ended
	Dec. 31, 2018
Petroleum and chemical carriers - U.S.-flag
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	25 years
Harbor and offshore tugs
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	25 years
Ocean liquid tank barges
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	25 years
Short-sea container/RORO vessels
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	20 years
Bulk carriers - U.S.-flag
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	25 years
Inland river dry-cargo and specialty barges
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	20 years
Inland river liquid tank barges
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	25 years
Inland river towboats and harbor boats
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	25 years
Terminal and fleeting facilities
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	20 years

Nature Of Operations And Acco_7

Nature Of Operations And Accounting Policies (Schedule Of Property And Equipment By Major Classes) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Historical cost	$ 1,407,329	$ 1,380,469	$ 1,424,566
Accumulated depreciation	(560,819)	(502,544)	(444,559)
Net property and equipment	846,510	877,925	980,007
Operating Segments | Ocean Services
Property, Plant and Equipment [Line Items]
Historical cost	930,230	901,076	960,816
Accumulated depreciation	(341,999)	(299,528)	(258,004)
Net property and equipment	588,231	601,548	702,812
Operating Segments | Ocean Services | Petroleum and chemical carriers - U.S.-flag
Property, Plant and Equipment [Line Items]
Historical cost	649,795	652,985
Accumulated depreciation	(241,604)	(215,057)
Net property and equipment	408,191	437,928
Operating Segments | Ocean Services | Harbor and offshore tugs - U.S.-flag
Property, Plant and Equipment [Line Items]
Historical cost	132,697	84,155
Accumulated depreciation	(41,764)	(38,984)
Net property and equipment	90,933	45,171
Operating Segments | Ocean Services | Harbor tugs - Foreign-flag
Property, Plant and Equipment [Line Items]
Historical cost	45,379	45,338
Accumulated depreciation	(13,822)	(11,575)
Net property and equipment	31,557	33,763
Operating Segments | Ocean Services | Ocean liquid tank barges - U.S.-flag
Property, Plant and Equipment [Line Items]
Historical cost	39,238	39,238
Accumulated depreciation	(14,649)	(13,126)
Net property and equipment	24,589	26,112
Operating Segments | Ocean Services | Short-sea container/RORO vessels - Foreign-flag
Property, Plant and Equipment [Line Items]
Historical cost	29,846	20,954
Accumulated depreciation	(10,644)	(8,178)
Net property and equipment	19,202	12,776
Operating Segments | Ocean Services | Bulk carriers - U.S.-flag
Property, Plant and Equipment [Line Items]
Historical cost	13,000	13,000
Accumulated depreciation	(9,800)	(4,733)
Net property and equipment	3,200	8,267
Operating Segments | Ocean Services | Other
Property, Plant and Equipment [Line Items]
Historical cost	20,073	19,420
Accumulated depreciation	(9,716)	(7,875)
Net property and equipment	10,357	11,545
Operating Segments | Ocean Services | Construction in progress
Property, Plant and Equipment [Line Items]
Historical cost	202	25,986
Operating Segments | Inland Services
Property, Plant and Equipment [Line Items]
Historical cost	438,848	448,035	432,717
Accumulated depreciation	(195,094)	(181,573)	(167,127)
Net property and equipment	243,754	266,462	265,590
Operating Segments | Inland Services | Other
Property, Plant and Equipment [Line Items]
Historical cost	22,213	26,938
Accumulated depreciation	(10,364)	(11,401)
Net property and equipment	11,849	15,537
Operating Segments | Inland Services | Construction in progress
Property, Plant and Equipment [Line Items]
Historical cost	7,868	2,742
Operating Segments | Inland Services | Inland river dry-cargo barges
Property, Plant and Equipment [Line Items]
Historical cost	222,539	233,734
Accumulated depreciation	(106,157)	(101,087)
Net property and equipment	116,382	132,647
Operating Segments | Inland Services | Specialty barges
Property, Plant and Equipment [Line Items]
Historical cost	3,828	4,180
Accumulated depreciation	(1,904)	(1,781)
Net property and equipment	1,924	2,399
Operating Segments | Inland Services | Inland river liquid tank barges
Property, Plant and Equipment [Line Items]
Historical cost	20,011	21,802
Accumulated depreciation	(3,054)	(2,684)
Net property and equipment	16,957	19,118
Operating Segments | Inland Services | Inland river towboats
Property, Plant and Equipment [Line Items]
Historical cost	43,998	44,555
Accumulated depreciation	(3,294)	(1,765)
Net property and equipment	40,704	42,790
Operating Segments | Inland Services | Inland river harbor boats
Property, Plant and Equipment [Line Items]
Historical cost	18,695	18,158
Accumulated depreciation	(8,047)	(6,956)
Net property and equipment	10,648	11,202
Operating Segments | Inland Services | Terminal and fleeting facilities
Property, Plant and Equipment [Line Items]
Historical cost	99,696	95,926
Accumulated depreciation	(62,274)	(55,899)
Net property and equipment	37,422	40,027
Operating Segments | Witt O'Brien's LLC
Property, Plant and Equipment [Line Items]
Historical cost	1,227	1,227	1,559
Accumulated depreciation	(1,031)	(938)	(1,244)
Net property and equipment	196	289	315
Operating Segments | Witt O'Brien's LLC | Other
Property, Plant and Equipment [Line Items]
Historical cost	1,227	1,227
Accumulated depreciation	(1,031)	(938)
Net property and equipment	196	289
Operating Segments | Other
Property, Plant and Equipment [Line Items]
Historical cost	6,892	0	0
Accumulated depreciation	(490)	0	0
Net property and equipment	6,402	0	0
Operating Segments | Other | Other
Property, Plant and Equipment [Line Items]
Historical cost	6,892
Accumulated depreciation	(490)
Net property and equipment	6,402
Corporate And Eliminations
Property, Plant and Equipment [Line Items]
Historical cost	30,132	30,131	29,474
Accumulated depreciation	(22,205)	(20,505)	(18,184)
Net property and equipment	7,927	9,626	$ 11,290
Corporate And Eliminations | Other
Property, Plant and Equipment [Line Items]
Historical cost	30,132	30,131
Accumulated depreciation	(22,205)	(20,505)
Net property and equipment	$ 7,927	$ 9,626

Nature Of Operations And Acco_8

Nature Of Operations And Accounting Policies (Schedule Of Intangible Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Finite-lived Intangible Assets [Roll Forward]
Intangible assets, beginning balance	$ 37,047	$ 27,105
Acquired intangible assets	1,120	10,957
Foreign currency translation		2
Fully amortized intangible assets	(1,120)	(1,017)
Intangible assets, ending balance	37,047	37,047	$ 27,105
Changes in Accumulated Amortization [Roll Forward]
Accumulated amortization, beginning balance	(8,941)	(7,027)
Amortization expense	(4,675)	(2,931)	(2,400)
Fully amortized intangible assets	1,120	1,017
Accumulated amortization, ending balance	$ (12,496)	(8,941)	(7,027)
Weighted average remaining contractual life, in years	7 years 292 days
Trademark/ Tradenames
Finite-lived Intangible Assets [Roll Forward]
Intangible assets, beginning balance	$ 3,324	3,324
Acquired intangible assets	0	0
Foreign currency translation		0
Fully amortized intangible assets	0	0
Intangible assets, ending balance	3,324	3,324	3,324
Changes in Accumulated Amortization [Roll Forward]
Accumulated amortization, beginning balance	(1,980)	(1,648)
Amortization expense	(332)	(332)
Fully amortized intangible assets	0	0
Accumulated amortization, ending balance	$ (2,312)	(1,980)	(1,648)
Weighted average remaining contractual life, in years	3 years
Customer Relationships
Finite-lived Intangible Assets [Roll Forward]
Intangible assets, beginning balance	$ 15,365	15,365
Acquired intangible assets	1,120	0
Foreign currency translation		0
Fully amortized intangible assets	(1,120)	0
Intangible assets, ending balance	15,365	15,365	15,365
Changes in Accumulated Amortization [Roll Forward]
Accumulated amortization, beginning balance	(5,146)	(3,867)
Amortization expense	(2,402)	(1,279)
Fully amortized intangible assets	1,120	0
Accumulated amortization, ending balance	$ (6,428)	(5,146)	(3,867)
Weighted average remaining contractual life, in years	8 years
Acquired Contractual Rights
Finite-lived Intangible Assets [Roll Forward]
Intangible assets, beginning balance	$ 18,358	8,416
Acquired intangible assets	0	10,957
Foreign currency translation		2
Fully amortized intangible assets	0	(1,017)
Intangible assets, ending balance	18,358	18,358	8,416
Changes in Accumulated Amortization [Roll Forward]
Accumulated amortization, beginning balance	(1,815)	(1,512)
Amortization expense	(1,941)	(1,320)
Fully amortized intangible assets	0	1,017
Accumulated amortization, ending balance	$ (3,756)	$ (1,815)	$ (1,512)
Weighted average remaining contractual life, in years	8 years

Nature Of Operations And Acco_9

Nature Of Operations And Accounting Policies (Schedule Of Future Amortization Expense Of Intangible Assets) (Details) $ in Thousands	Dec. 31, 2018USD ($)
Finite-Lived Intangible Assets, Future Amortization Expense [Abstract]
2,019	$ 3,555
2,020	3,555
2,021	3,571
2,022	2,866
2,023	2,852
Years subsequent to 2023	8,152
Total	$ 24,551

Nature Of Operations And Acc_10

Nature Of Operations And Accounting Policies (Schedule Of Deferred Gain Activity) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2019
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Amortization of deferred gains on sale leaseback transactions	$ (12,774)	$ (15,035)	$ (15,073)
Sale Leaseback and Financed Equipment Sales
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Balance at beginning of year	66,519	74,774	83,142
Deferred gains arising from equipment sales	0	13,336	9,003
Other	(3,052)	(5,954)	(1,697)
Balance at end of year	39,102	66,519	74,774
Sale Leaseback and Financed Equipment Sales | Subsequent Event | Retained Earnings | Accounting Standards Update 2016-02
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative effect of new accounting principle				$ 26,900
Fifty Percent Or Less Owned Subsidiaries
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Balance at beginning of year	5,934	7,649	9,468
Balance at end of year	4,562	5,934	7,649
Fifty Percent Or Less Owned Subsidiaries | Subsequent Event | Retained Earnings | Accounting Standards Update 2016-02
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Cumulative effect of new accounting principle				$ 2,300
Operating Expense
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Amortization of deferred gains on sale leaseback transactions	(12,774)	(15,035)	(15,072)
Gain (Loss) on Asset Dispositions and Impairments, Net
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Amortization of deferred gains on sale of property, financed equipment sales	(11,591)	(602)	(602)
Amortization of deferred gains on sale of property, equipment sales to 50% or less owned companies	$ (1,372)	$ (1,715)	$ (1,819)

Nature Of Operations And Acc_11

Nature Of Operations And Accounting Policies (Schedule of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Total equity, beginning balance	$ 753,361	$ 1,196,268	$ 1,390,939
Discontinued Operations		(527,691)
Other comprehensive income (loss)	(391)	1,707	(10,183)
Income tax (expense) benefit	22	(702)	3,174
Total equity, ending balance	853,842	753,361	1,196,268
Foreign Currency Translation Adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Total equity, beginning balance	(545)	(11,593)	(5,528)
Discontinued Operations		10,031
Other comprehensive income (loss)	(391)	1,812	(9,331)
Income tax (expense) benefit	22	(795)	3,266
Total equity, ending balance	(914)	(545)	(11,593)
Derivative Losses on Cash Flow Hedges, net
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Total equity, beginning balance	0	75	(116)
Discontinued Operations		94
Other comprehensive income (loss)	0	(260)	294
Income tax (expense) benefit	0	91	(103)
Total equity, ending balance	0	0	75
Other
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Total equity, beginning balance	0	4	24
Discontinued Operations		0
Other comprehensive income (loss)	0	(6)	(31)
Income tax (expense) benefit	0	2	11
Total equity, ending balance	0	0	4
Accumulated Other Comprehensive Loss
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Total equity, beginning balance	(545)	(11,514)	(5,620)
Discontinued Operations		10,125
Other comprehensive income (loss)	(391)	1,546	(9,068)
Income tax (expense) benefit	22	(702)	3,174
Total equity, ending balance	(914)	(545)	(11,514)
Foreign Currency Translation Adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Total equity, beginning balance	0	(1,613)	(528)
Discontinued Operations		1,460
Other comprehensive income (loss)	0	153	(1,085)
Income tax (expense) benefit	0	0	0
Total equity, ending balance	0	0	(1,613)
Derivative Losses on Cash Flow Hedges, net
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Total equity, beginning balance	0	(17)	0
Discontinued Operations		4
Other comprehensive income (loss)	0	13	(17)
Income tax (expense) benefit	0	0	0
Total equity, ending balance	0	0	(17)
Other
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Total equity, beginning balance	0	3	16
Discontinued Operations		2
Other comprehensive income (loss)	0	(5)	(13)
Income tax (expense) benefit	0	0	0
Total equity, ending balance	0	0	3
Other Comprehensive Income (Loss)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Total equity, beginning balance	1,005	(7,009)
Total equity, ending balance	$ (369)	$ 1,005	$ (7,009)

Nature Of Operations And Acc_12

Nature Of Operations And Accounting Policies (Schedule Of Earnings Per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net Income (Loss)	$ (4,686)	$ 17,067	$ 45,126	$ 641	$ 72,807	$ 17,561	$ (32,808)	$ 4,083	$ 58,148	$ 61,643	$ (215,897)
Basic Weighted Average Common Shares Outstanding
Options and Restricted Stock									0	0	0
Convertible Securities									1,273	14,346	0
Net income (Loss), diluted									$ 59,421	$ 75,989	$ (215,897)
Weighted average number of shares outstanding, basic (in shares)									18,080,778	17,368,081	16,914,928
Effect of Dilutive Securities:
Options and Restricted Stock (in shares)									267,810	308,012	0
Convertible Securities (in shares)									1,227,101	5,258,065	0
Weighted average number of shares outstanding, diluted (in shares)									19,575,689	22,934,158	16,914,928
Basic earnings (loss) per common share (in dollars per share)	$ (0.26)	$ 0.94	$ 2.50	$ 0.04	$ 4.12	$ 1	$ (1.91)	$ 0.24	$ 3.22	$ 3.55	$ (12.76)
Diluted earnings (loss) per common share (in dollars per share)	$ (0.26)	$ 0.88	$ 2.14	$ 0.04	$ 3.35	$ 1	$ (1.91)	$ 0.24	$ 3.04	$ 3.31	$ (12.76)
3.0% Convertible Senior Notes
Effect of Dilutive Securities:
Debt instrument, stated percentage	3.00%								3.00%
3.25% Convertible Senior Notes
Effect of Dilutive Securities:
Debt instrument, stated percentage	3.25%								3.25%
2.5% Convertible Senior Notes
Effect of Dilutive Securities:
Debt instrument, stated percentage	2.50%								2.50%
Stock Compensation Plan
Effect of Dilutive Securities:
Antidilutive securities excluded from computation of earnings per share (in shares)									333,510	1,924,217	2,020,677
Convertible Debt Securities | 3.0% Convertible Senior Notes
Effect of Dilutive Securities:
Antidilutive securities excluded from computation of earnings per share (in shares)									1,946,917		1,825,326
Convertible Debt Securities | 3.25% Convertible Senior Notes
Effect of Dilutive Securities:
Antidilutive securities excluded from computation of earnings per share (in shares)									983,351
Convertible Debt Securities | 2.5% Convertible Senior Notes
Effect of Dilutive Securities:
Antidilutive securities excluded from computation of earnings per share (in shares)											2,664,208

Business Acquisitions - Narrati

Business Acquisitions - Narrative (Details) $ in Thousands	Jun. 01, 2018USD ($)	Mar. 01, 2018USD ($)installment	Jul. 03, 2017USD ($)equipment	Dec. 02, 2016USD ($)equipment	Oct. 31, 2016USD ($)equipment	Dec. 31, 2017USD ($)equipment	Dec. 31, 2016USD ($)equipment	Dec. 31, 2018USD ($)
Business Acquisition [Line Items]
Business combination, long-term debt assumed						$ 28,725	$ 0	$ 0
Cleancor
Business Acquisition [Line Items]
Business acquisition, percentage of voting interests acquired	50.00%							50.00%
Payments to acquire businesses, gross	$ 3,200
Partners' capital account, contributions	$ 1,900
SCA
Business Acquisition [Line Items]
Payments to acquire businesses, gross		$ 1,500
Business combination, number of installments | installment		2
Business combination, contingent consideration		$ 900
ISH
Business Acquisition [Line Items]
Payments to acquire businesses, gross			$ 10,500
Business combination, note receivable contributed			18,100
Business combination, long-term debt assumed			$ 28,700
CCM
Business Acquisition [Line Items]
Payments to acquire businesses, gross					$ 18,100
SeaJon II
Business Acquisition [Line Items]
Business acquisition, percentage of voting interests acquired				50.00%
Payments to acquire businesses, gross				$ 3,400
PCTC's | ISH
Business Acquisition [Line Items]
Number of equipment acquired | equipment			4
Bulk carriers - U.S.-flag | ISH
Business Acquisition [Line Items]
Number of equipment acquired | equipment			2			2
Rail ferries - Foreign-flag | ISH
Business Acquisition [Line Items]
Number of equipment acquired | equipment			2
Harbor boats | CCM
Business Acquisition [Line Items]
Number of equipment acquired | equipment					5		5
Offshore Tug - U.S.-flag | SeaJon II
Business Acquisition [Line Items]
Number of equipment acquired | equipment				1

Business Acquisitions - Purchas

Business Acquisitions - Purchase Price Allocation (Details) $ in Thousands	Mar. 01, 2018USD ($)installment	Jul. 03, 2017USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Business Combinations [Abstract]
Restricted cash and restricted cash equivalents			$ 0	$ 13	$ 0
Trade and other receivables			1,264	15,823	937
Other current assets			170	2,054	150
Investments, at Equity, and Advances to 50% or Less Owned Companies			(5,123)	10,000	(3,437)
Property and Equipment			4,382	15,190	15,765
Intangible Assets			1,120	10,957	7,098
Other Assets			7	(17,863)	0
Accounts payable and other accrued liabilities			(1,609)	0	39
Other current liabilities			(439)	(17,214)	(13)
Long-Term Debt			0	(28,725)	0
Deferred Income Taxes			0	(3,939)	0
Other Liabilities			0	(42)	0
Noncontrolling interests in subsidiaries			(82)	0	0
Purchase price			(310)	(5,868)	20,539
Business Acquisition [Line Items]
Cash Acquired			$ 3,600	$ 16,400	$ 900
ISH
Business Combinations [Abstract]
Long-Term Debt		$ (28,700)
Business Acquisition [Line Items]
Business combination, note receivable contributed		18,100
Payments to acquire businesses, gross		$ 10,500
SCA
Business Acquisition [Line Items]
Payments to acquire businesses, gross	$ 1,500
Business combination, number of installments | installment	2

Equipment Acquisitions And Di_3

Equipment Acquisitions And Dispositions (Major Equipment Additions) (Details) $ in Thousands	Jul. 03, 2017equipment	Oct. 31, 2016equipment	Dec. 31, 2018USD ($)equipment	Dec. 31, 2017USD ($)equipment	Dec. 31, 2016USD ($)equipment
Business Acquisition [Line Items]
Capital expenditures | $			$ 50,272	$ 114,595	$ 252,806
Petroleum and chemical carriers - U.S.-flag
Business Acquisition [Line Items]
Number of equipment acquired			0	3	3
Short-sea container/RORO vessels - Foreign-flag
Business Acquisition [Line Items]
Number of equipment acquired			2	0	0
Harbor and offshore tugs - U.S.-flag
Business Acquisition [Line Items]
Number of equipment acquired			5	1	1
Harbor tugs - Foreign-flag
Business Acquisition [Line Items]
Number of equipment acquired			0	2	0
Inland river dry-cargo barges
Business Acquisition [Line Items]
Number of equipment acquired			0	0	46
Inland river liquid tank barges
Business Acquisition [Line Items]
Number of equipment acquired			0	2	0
Inland river towboats
Business Acquisition [Line Items]
Number of equipment acquired			0	3	2
ISH | Bulk carriers - U.S.-flag
Business Acquisition [Line Items]
Number of equipment acquired	2			2
CCM | Inland river harbor boats
Business Acquisition [Line Items]
Number of equipment acquired		5			5
SeaJon II | Harbor and offshore tugs - U.S.-flag
Business Acquisition [Line Items]
Number of equipment acquired					1

Equipment Acquisitions And Di_4

Equipment Acquisitions And Dispositions (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)equipment	Dec. 31, 2017USD ($)equipment	Dec. 31, 2016USD ($)equipment
Business Acquisition [Line Items]
Sales price of equipment	$ 16,100	$ 164,800	$ 153,000
Gain (loss) on disposition of property plant equipment	6,600	23,300	11,300
Gain (loss) on sale of property, plant and equipment, recognized		10,000	2,300
Gain (loss) on sale of property, plant and equipment, deferred		13,300	9,000
Proceeds from disposition of property and equipment	16,100	164,789	143,028
(Increase) decrease in receivables	63,764	(2,195)	26,273
Non-cash proceeds on the sale of property and equipment	$ 0	$ 0	2,000
Seller Financing Notes Receivable
Business Acquisition [Line Items]
(Increase) decrease in receivables			$ 8,000
Petroleum and chemical carriers - U.S.-flag
Business Acquisition [Line Items]
Sale leaseback transaction, number of leased assets disposed | equipment		1	1
Sale leaseback transaction, net proceeds		$ 134,900	$ 61,000
Sale leaseback transaction, lease terms		104	76
Number of equipment disposed | equipment	1	1	1
Number of equipment acquired | equipment	0	3	3
Inland river dry-cargo barges
Business Acquisition [Line Items]
Sale leaseback transaction, number of leased assets disposed | equipment		50
Sale leaseback transaction, net proceeds		$ 12,500
Sale leaseback transaction, lease terms		84
Number of equipment disposed | equipment	32	50	0
Number of equipment acquired | equipment	0	0	46
One inland river specialty barge
Business Acquisition [Line Items]
Gain (loss) on disposition of property plant equipment		$ (300)
Number of equipment disposed | equipment		1
Harbor and offshore tugs - U.S.-flag
Business Acquisition [Line Items]
Number of equipment disposed | equipment	1	0	2
Number of equipment acquired | equipment	5	1	1
Non-cash proceeds on the sale of property and equipment			$ 2,000
Sale Leaseback
Business Acquisition [Line Items]
Gain (loss) on sale of property, plant and equipment, deferred		$ 13,300	8,200
Gain (Loss) on Asset Dispositions and Impairments, Net
Business Acquisition [Line Items]
Amortization of deferred gains on sale of property	$ 13,000	$ 2,300	$ 2,400

Equipment Acquisitions And Di_5

Equipment Acquisitions And Dispositions (Major Equipment Dispositions) (Details) - equipment	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Petroleum and chemical carriers - U.S.-flag
Business Acquisition [Line Items]
Number of equipment disposed	1	1	1
Harbor and offshore tugs - U.S.-flag
Business Acquisition [Line Items]
Number of equipment disposed	1	0	2
Inland river dry-cargo barges
Business Acquisition [Line Items]
Number of equipment disposed	32	50	0
Inland river liquid tank barges
Business Acquisition [Line Items]
Number of equipment disposed	0	0	19
Inland river specialty barges
Business Acquisition [Line Items]
Number of equipment disposed	2	2	0
Inland river towboats
Business Acquisition [Line Items]
Number of equipment disposed	0	2	14

Investments, At Equity, And A_3

Investments, At Equity, And Advances To 50% Or Less Owned Companies (Summary of Investments) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Jun. 01, 2018	Apr. 30, 2018	Dec. 31, 2017	Sep. 01, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 156,886			$ 173,441
Trailer Bridge
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest						55.30%
RF Vessel Holdings
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest					50.00%
Golfo de Mexico
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest					50.00%
KSM
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
Hawker Pacific
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest			34.20%
Ocean Services
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 73,940			52,003
Ocean Services | Trailer Bridge
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	55.30%
Equity method investments	$ 56,364			47,324
Ocean Services | RF Vessel Holdings
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
Equity method investments	$ 10,826			2,378
Ocean Services | Golfo de Mexico
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
Equity method investments	$ 5,272			2,500
Ocean Services | KSM
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
Equity method investments	$ 1,478			(199)
Inland Services
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 57,897			66,479
Inland Services | SCFCo
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
Equity method investments	$ 37,219			42,126
Inland Services | Bunge-SCF Grain
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
Equity method investments	$ 14,738			16,166
Inland Services | SCF Bunge Marine
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	57.00%
Equity method investments	$ 3,144			5,404
Inland Services | Other
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
Equity method investments	$ 2,796			2,783
Witt O'Brien's LLC | O’Brien’s do Brazil
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	50.00%
Equity method investments	$ 472			777
Other
Schedule of Equity Method Investments [Line Items]
Equity method investments	24,577			54,182
Other | Other
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 1,214			2,371
Other | Other | Minimum
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	34.00%
Other | Other | Maximum
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	47.50%
Other | Hawker Pacific
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest			34.20%
Equity method investments	$ 0			21,681
Other | VA&E
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	41.30%
Equity method investments	$ 13,073			13,596
Other | Avion
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	39.10%
Equity method investments	$ 10,290			11,400
Other | Cleancor
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest		50.00%
Equity method investments	$ 0			$ 5,134

Investments, At Equity, And A_4

Investments, At Equity, And Advances To 50% Or Less Owned Companies (Summarized Financial Information For The Company's Investments, At Equity) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Balance Sheet [Abstract]
Current assets	$ 184,704	$ 523,343
Noncurrent assets	77,929	124,733
Current liabilities	113,784	407,812
Noncurrent liabilities	46,503	81,899
Income Statement [Abstract]
Operating Revenues	786,717	1,068,190	$ 1,019,658
Costs and Expenses:
Operating and administrative	771,324	1,035,952	951,019
Depreciation	7,216	11,810	24,936
Total costs and expenses	778,540	1,047,762	975,955
Gains (Losses) on Asset Dispositions and Impairments, Net	38	16,115	(6,339)
Operating Income (Loss)	8,215	36,543	37,364
Net Income (Loss)	3,967	23,383	4,961
SCFCo
Balance Sheet [Abstract]
Current assets	8,322	7,924
Property and equipment, net	121,001	137,224
Current liabilities	12,958	14,263
Noncurrent liabilities	56,078	54,179
Income Statement [Abstract]
Operating Revenues	54,486	44,177	43,711
Costs and Expenses:
Operating and administrative	45,911	40,106	38,980
Depreciation	17,901	17,803	17,560
Total costs and expenses	63,812	57,909	56,540
Operating Income (Loss)	(9,326)	(13,732)	(12,829)
Interest expense	(6,573)	(6,120)	(6,565)
Other expense, net	(2,229)	(961)	(657)
Net Income (Loss)	$ (18,128)	$ (20,813)	$ (20,051)

Investments, At Equity, And A_5

Investments, At Equity, And Advances To 50% Or Less Owned Companies (Narrative) (Details) $ in Thousands	Apr. 30, 2018USD ($)	Sep. 01, 2017USD ($)	Jul. 03, 2017equipment	Dec. 02, 2016USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2018USD ($)equipment	Dec. 31, 2017USD ($)equipment	Dec. 31, 2016USD ($)equipment	Nov. 30, 2016USD ($)
Schedule of Equity Method Investments [Line Items]
Retained earnings, undistributed earnings (losses) from equity method investees						$ 65,000	$ 40,100
Equity in earnings (losses) of 50% or less owned companies, net of tax						(72)	2,952	$ (21,040)
Proceeds on sale of a controlling interest in a subsidiary						0	5,000	0
Proceeds from equity method investment, distribution						5,907	12,891	5,162
Equity method investment, other than temporary impairment						100	900	7,700
Proceeds from sale of equity method investments						78,015	0	$ 0
Trailer Bridge
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest					55.30%			55.30%
Equity in earnings (losses) of 50% or less owned companies, net of tax					$ (2,200)
Payments for advance to affiliate							2,000	$ 1,700
Proceeds from collection of advance to affiliate							6,000
RF Vessel Holdings
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest		50.00%
Ownership percentage sold		50.00%
Proceeds on sale of a controlling interest in a subsidiary		$ 1,900
Partners' capital account, contributions						9,100
Golfo de Mexico
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest		50.00%
Ownership percentage sold		50.00%
Proceeds on sale of a controlling interest in a subsidiary		$ 3,100
Partners' capital account, contributions						$ 4,600
Proceeds from equity method investment, distribution							300
KSM
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest						50.00%
Partners' capital account, contributions						$ 1,000	300
SeaJon
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investment, distribution							12,500	600
Proceeds from equity method investment, distribution, return of capital							3,500
Sea-Access
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investment, distribution								2,000
Proceeds from equity method investment, distribution, return of capital								8,400
SeaJon II
Schedule of Equity Method Investments [Line Items]
Equity in earnings (losses) of 50% or less owned companies, net of tax				$ (1,900)
SCFCo
Schedule of Equity Method Investments [Line Items]
Partners' capital account, contributions							400	800
Payments for advances and loans to affiliate							2,500	1,800
Proceeds from collection of advances and loans to affiliate						2,600	1,700
Advances and loans to affiliate						30,500
Equity method investment, other than temporary impairment								7,700
Equity method investment, difference between carrying amount and underlying equity						23,400
Bunge-SCF Grain
Schedule of Equity Method Investments [Line Items]
Advanced to joint ventures						7,000
SCF Bunge Marine
Schedule of Equity Method Investments [Line Items]
Partners' capital account, contributions						500
Proceeds from equity method investment, distribution						4,600	100	2,500
O’Brien’s do Brazil
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investment, distribution						200	100	100
Hawker Pacific
Schedule of Equity Method Investments [Line Items]
Ownership of equity interest	34.20%
Proceeds from sale of equity method investments	$ 78,000
Realized gain (loss) on disposal of equity method investments	$ 53,900
VA&E
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investment, distribution						400
Advances and loans to affiliate						7,400
Equity method investment, other than temporary impairment							900
Revolving credit facility, receivable, funds committed to related parties									$ 6,000
Proceeds from collection of revolving credit facility, affiliate								12,400
Payments to fund revolving credit facility, affiliate								10,000
Line of credit facility, maximum borrowing capacity					3,500			3,500
Avion
Schedule of Equity Method Investments [Line Items]
Payments for advance to affiliate							1,000	3,000
Proceeds from collection of advance to affiliate							4,000
Proceeds from equity method investment, distribution						800
Other investments
Schedule of Equity Method Investments [Line Items]
Payments for advance to affiliate								800
Proceeds from collection of advance to affiliate						400	400
Proceeds from equity method investment, distribution, return of capital						600
Equity method investment, other than temporary impairment						100
Advanced to joint ventures						2,000
RF Vessel Holdings
Schedule of Equity Method Investments [Line Items]
Business acquisition, percentage of voting interests acquired			100.00%
Golfo de Mexico
Schedule of Equity Method Investments [Line Items]
Business acquisition, percentage of voting interests acquired			100.00%
SeaJon II
Schedule of Equity Method Investments [Line Items]
Business acquisition, percentage of voting interests acquired				50.00%
Payments to acquire businesses, gross				$ 3,400
Term Loan | VA&E
Schedule of Equity Method Investments [Line Items]
Loans to Affiliate									1,100
Repayments of loans to affiliate								1,100
Subordinated Debt | VA&E
Schedule of Equity Method Investments [Line Items]
Loans to Affiliate					$ 3,500			3,500	$ 3,500
Uncommitted Credit Facility | VA&E
Schedule of Equity Method Investments [Line Items]
Payments for advance to affiliate						5,400	3,500
Proceeds from collection of advance to affiliate						5,400
Time Charter | Trailer Bridge
Schedule of Equity Method Investments [Line Items]
Revenue from related parties						3,500	3,100	3,000
Time Charter | SCF Bunge Marine
Schedule of Equity Method Investments [Line Items]
Revenue from related parties						50,800	38,700	35,000
Technical and Commercial Management Services | Trailer Bridge
Schedule of Equity Method Investments [Line Items]
Revenue from related parties								300
Technical and Commercial Management Services | Sea-Access
Schedule of Equity Method Investments [Line Items]
Revenue from related parties								500
Technical and Commercial Management Services | SeaJon II
Schedule of Equity Method Investments [Line Items]
Revenue from related parties								100
Administrative Management Services | Golfo de Mexico
Schedule of Equity Method Investments [Line Items]
Revenue from related parties						1,100	300
Technical, Commercial and Administrative Management Services | KSM
Schedule of Equity Method Investments [Line Items]
Revenue from related parties						400	300
Bareboat Charter | KSM
Schedule of Equity Method Investments [Line Items]
Revenue from related parties						1,300	1,100
Information Technology Services | SCFCo
Schedule of Equity Method Investments [Line Items]
Revenue from related parties						100	100	100
Rental Income | Bunge-SCF Grain
Schedule of Equity Method Investments [Line Items]
Revenue from related parties						900	1,100	1,000
Freight Transportation | Bunge-SCF Grain
Schedule of Equity Method Investments [Line Items]
Revenue from related parties						10,700	7,200	7,200
Towing Services | SCF Bunge Marine
Schedule of Equity Method Investments [Line Items]
Related party transaction expense						54,500	41,400	40,200
Management Fees | Hawker Pacific
Schedule of Equity Method Investments [Line Items]
Revenue from related parties						$ 100	$ 300	$ 300
Rail ferries - Foreign-flag | RF Vessel Holdings
Schedule of Equity Method Investments [Line Items]
Number of equipment acquired | equipment			2
Rail ferries - Foreign-flag | Golfo de Mexico
Schedule of Equity Method Investments [Line Items]
Number of equipment acquired | equipment			2
Harbor tugs - Foreign-flag
Schedule of Equity Method Investments [Line Items]
Number of equipment acquired | equipment						0	2	0
Harbor tugs - Foreign-flag | KSM
Schedule of Equity Method Investments [Line Items]
Number of Equipment Operated | equipment						4
Number of Equipment Chartered-Out | equipment						2
Ocean liquid tank barge - Foreign-flag | KSM
Schedule of Equity Method Investments [Line Items]
Number of Equipment Operated | equipment						1
Time Chartered, Inland River Towboats | SCF Bunge Marine
Schedule of Equity Method Investments [Line Items]
Number of Equipment Chartered-Out | equipment						7
Bareboat Chartered, Inland River Towboats | SCF Bunge Marine
Schedule of Equity Method Investments [Line Items]
Number of equipment chartered-in | equipment						4

Leases And Notes Receivables _2

Leases And Notes Receivables From Third Parties (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Notes, Loans and Financing Receivable, Net, Noncurrent [Abstract]
Leases and notes receivable	$ 2.3	$ 2.8
Notes receivable third party	(0.1)	(10.1)	$ (9.1)
Proceeds from collection of notes receivable	$ 0.6	$ 34.5	6.3
Provision for loan and lease losses			$ 6.7

Long-Term Debt (Schedule Of Com

Long-Term Debt (Schedule Of Company's Borrowings) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Long-term debt, gross	$ 386,059	$ 606,092
Portion due within one year	(8,497)	(77,842)
Debt discount included in long-term debt	(28,334)	(23,152)
Debt issuance costs included in long-term debt	(3,100)	(3,593)
Long-term debt, excluding current maturities	346,128	501,505
Convertible Debt | 3.0% Convertible Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross	107,284	230,000
Debt discount included in long-term debt	(7,200)	(22,900)
Debt issuance costs included in long-term debt	(700)	(2,300)
Convertible Debt | 2.5% Convertible Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross	64,455	64,455
Convertible Debt | 3.25% Convertible Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross	117,782	0
Debt discount included in long-term debt	(21,100)
Debt issuance costs included in long-term debt	(1,900)
Senior Notes | 7.375% Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross	0	153,090
Debt discount included in long-term debt		(200)
Debt issuance costs included in long-term debt		(300)
Line of Credit | SEA-Vista Credit Facility
Debt Instrument [Line Items]
Long-term debt, gross	87,977	135,714
Debt issuance costs included in long-term debt	(400)	(700)
Line of Credit | ISH Credit Facility
Debt Instrument [Line Items]
Long-term debt, gross	0	12,200
Debt issuance costs included in long-term debt		(100)
Notes Payable, Other Payables
Debt Instrument [Line Items]
Long-term debt, gross	8,561	10,633
Debt issuance costs included in long-term debt	$ (100)	$ (100)

Long-Term Debt (Schedule Of Lon

Long-Term Debt (Schedule Of Long-Term Debt Maturities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Long-term Debt, Unclassified [Abstract]
2,019	$ 8,497
2,020	80,672
2,021	500
2,022	503
2,023	368
Years subsequent to 2023	295,519
Long-term debt, gross	$ 386,059	$ 606,092

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details)	Nov. 20, 2023	Oct. 31, 2018USD ($)	May 15, 2018USD ($)	Dec. 20, 2017	Dec. 19, 2017USD ($)	Jul. 03, 2017USD ($)	Apr. 15, 2015USD ($)	Nov. 13, 2013USD ($)	Dec. 31, 2018USD ($)$ / shares	Dec. 31, 2018USD ($)shares$ / shares	Dec. 31, 2017USD ($)$ / shares	Dec. 31, 2016USD ($)	May 15, 2025	Dec. 19, 2022	Nov. 19, 2020	Dec. 11, 2012USD ($)	Sep. 24, 2009USD ($)
Debt Instrument [Line Items]
Common stock, par value (in dollars per share) | $ / shares									$ 0.01	$ 0.01	$ 0.01
Debt extinguishment gains (losses), net										$ (11,626,000)	$ (819,000)	$ 5,184,000
Payments for conversion option in convertible debt										33,000	1,354,000	7,374,000
Long-term debt acquired in business acquisition									$ 0	0	28,725,000	0
Proceeds from debt, net of issuance costs										(2,495,000)	44,900,000	94,379,000
Letters of credit outstanding amount									9,500,000	$ 9,500,000
Guarantee fee income, interest rate earned on outstanding guarantees										50.00%
Securities repurchased plan, remaining authorized repurchase amount									66,700,000	$ 66,700,000
SEACOR Marine Holdings Inc.
Debt Instrument [Line Items]
Guarantor obligations, maximum exposure, undiscounted									$ 41,900,000	41,900,000
Guarantee fee income										$ 300,000	600,000
3.0% Convertible Senior Notes
Debt Instrument [Line Items]
Debt instrument, stated percentage									3.00%	3.00%
2.5% Convertible Senior Notes
Debt Instrument [Line Items]
Debt instrument, stated percentage									2.50%	2.50%
2.5% Convertible Senior Notes | Debt Instrument, Conversion Option
Debt Instrument [Line Items]
Payments for conversion option in convertible debt											$ 1,400,000	7,400,000
3.25% Convertible Senior Notes
Debt Instrument [Line Items]
Debt instrument, stated percentage									3.25%	3.25%
Convertible Debt
Debt Instrument [Line Items]
Common stock, par value (in dollars per share) | $ / shares									$ 0.01	$ 0.01
Convertible Debt | 3.0% Convertible Senior Notes
Debt Instrument [Line Items]
Debt instrument, stated percentage									3.00%	3.00%
Aggregate principal amount								$ 230,000,000
Bond trading price triggering contingent interest								1,200
Individual bond, face value								$ 1,000
Debt instrument, contingent interest rate								0.45%
Debt instrument, convertible, conversion ratio				0.0125892
Debt instrument, convertible, number of equity instruments (in shares) | shares										1,350,620
Debt instrument, term										7 years
Debt instrument, interest rate, effective percentage									7.40%	7.40%
Debt conversion, original debt, amount			$ 117,800,000
Debt instrument, repurchased amount									$ 4,900,000	$ 4,900,000
Repayments of long-term debt and payments for conversion option in convertible debt										$ 4,700,000
Debt extinguishment gains (losses), net									$ (5,400,000)
Convertible Debt | 3.0% Convertible Senior Notes | Debt Instrument, Put Option, Period One | Scenario, Forecast
Debt Instrument [Line Items]
Debt instrument, put option, percentage															100.00%
Convertible Debt | 3.0% Convertible Senior Notes | Debt Instrument, Put Option, Period Two | Scenario, Forecast
Debt Instrument [Line Items]
Debt instrument, redemption price, percentage	100.00%
Convertible Debt | 3.0% Convertible Senior Notes | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Debt instrument, redemption price, percentage										100.00%
Convertible Debt | 2.5% Convertible Senior Notes
Debt Instrument [Line Items]
Debt instrument, stated percentage									2.50%	2.50%
Aggregate principal amount																$ 350,000,000
Bond trading price triggering contingent interest										$ 1,200
Individual bond, face value																$ 1,000
Debt instrument, contingent interest rate																0.25%
Debt instrument, convertible, conversion ratio				0.0190381
Debt instrument, convertible, number of equity instruments (in shares) | shares										1,227,101
Debt instrument, term										5 years
Debt instrument, interest rate, effective percentage									2.50%	2.50%	6.50%
Debt instrument, repurchased amount											$ 61,700,000	127,400,000
Debt extinguishment gains (losses), net											100,000	3,300,000
Repayments of long-term debt											60,500,000	117,300,000
Convertible Debt | 2.5% Convertible Senior Notes | Debt Instrument, Conversion Option
Debt Instrument [Line Items]
Repayments of long-term debt and payments for conversion option in convertible debt											61,900,000	124,700,000
Convertible Debt | 2.5% Convertible Senior Notes | Debt Instrument, Put Option, Period One | Scenario, Forecast
Debt Instrument [Line Items]
Debt instrument, put option, percentage														100.00%
Convertible Debt | 2.5% Convertible Senior Notes | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Debt instrument, redemption price, percentage										100.00%
Convertible Debt | 2.5% Convertible Senior Notes | Put Option
Debt Instrument [Line Items]
Debt instrument, repurchased amount					$ 31,000,000
Repayments of long-term debt					$ 31,000,000
Convertible Debt | 3.25% Convertible Senior Notes
Debt Instrument [Line Items]
Debt instrument, stated percentage									3.25%	3.25%
Aggregate principal amount			117,800,000
Bond trading price triggering contingent interest			1,200
Individual bond, face value			$ 1,000
Debt instrument, contingent interest rate			0.45%
Debt instrument, convertible, conversion ratio			0.0131920
Debt instrument, convertible, number of equity instruments (in shares) | shares										1,553,780
Debt instrument, interest rate, effective percentage									7.20%	7.20%
Payments of debt issuance costs			$ 2,500,000
Long-term debt, net of discount			95,100,000
Debt issuance costs, gross, carrying amount of liability component			2,000,000
Debt instrument, convertible, carrying amount of equity component			22,700,000
Debt issuance costs, gross, carrying amount of equity component			$ 500,000
Debt instrument, convertible, discounts and issuance costs, amortization period										7 years
Convertible Debt | 3.25% Convertible Senior Notes | Debt Instrument, Put Option, Period One | Scenario, Forecast
Debt Instrument [Line Items]
Debt instrument, put option, percentage													100.00%
Convertible Debt | 3.25% Convertible Senior Notes | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Debt instrument, redemption price, percentage										100.00%
Senior Notes | 7.375% Senior Notes
Debt Instrument [Line Items]
Debt instrument, stated percentage									7.375%	7.375%
Aggregate principal amount																	$ 250,000,000
Debt instrument, repurchased amount		$ 147,400,000							$ 5,700,000	$ 5,700,000	7,600,000	35,200,000
Debt extinguishment gains (losses), net										(6,100,000)	(200,000)	1,900,000
Repayments of long-term debt		153,000,000								5,900,000	7,700,000	33,100,000
Loss on repurchase of debt instrument		$ 5,600,000
Line of Credit | SEA-Vista Credit Facility
Debt Instrument [Line Items]
Debt extinguishment gains (losses), net											(700,000)
Payments of debt issuance costs							$ 3,100,000
Line of credit facility, maximum borrowing capacity							300,000,000
Line of credit facility, current borrowing capacity									$ 94,000,000	$ 94,000,000
Line of Credit | SEA-Vista Credit Facility | Minimum
Debt Instrument [Line Items]
Debt instrument, prepayment increments							1,000,000
Line of Credit | SEA-Vista Credit Facility | London Interbank Offered Rate (LIBOR) | Minimum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate										2.00%
Line of Credit | SEA-Vista Credit Facility | London Interbank Offered Rate (LIBOR) | Maximum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate										2.75%
Line of Credit | SEA-Vista Credit Facility | Base Rate | Minimum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate										1.25%
Line of Credit | SEA-Vista Credit Facility | Base Rate | Maximum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate										1.75%
Line of Credit | SEA-Vista Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Repayments of long-term debt										$ 39,000,000	85,900,000	14,000,000
Line of credit facility, maximum borrowing capacity							100,000,000
Proceeds from issuance of long-term debt											44,900,000	87,000,000
Line of Credit | Sea-Vista Credit Facility, Term Loan A-1 | Secured Debt
Debt Instrument [Line Items]
Aggregate principal amount							$ 80,000,000
Repayments of long-term debt										3,300,000	39,400,000	3,800,000
Debt instrument, periodic payment, principal, Percent							1.25%
Line of Credit | Sea-Vista Credit Facility, Term Loan A-2 | Secured Debt
Debt Instrument [Line Items]
Aggregate principal amount							$ 120,000,000
Repayments of long-term debt										5,500,000	63,100,000
Debt instrument, periodic payment, principal, Percent							2.50%
Line of Credit | ISH Credit Facility
Debt Instrument [Line Items]
Payments of debt issuance costs						$ 100,000
Line of credit facility, maximum borrowing capacity						25,000,000
Line of Credit | ISH Credit Facility | Secured Debt
Debt Instrument [Line Items]
Aggregate principal amount						20,000,000
Debt extinguishment gains (losses), net										(100,000)
Repayments of long-term debt										12,200,000	7,800,000
Debt instrument, periodic payment, principal						700,000
Line of Credit | ISH Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Repayments of long-term debt											5,000,000
Line of credit facility, maximum borrowing capacity						$ 5,000,000
Line of credit facility, unused capacity, commitment fee percentage						0.50%
Notes Payable, Other Payables
Debt Instrument [Line Items]
Repayments of long-term debt										$ 2,100,000	$ 3,000,000	400,000
Proceeds from debt, net of issuance costs												$ 7,400,000
Notes Payable, Other Payables | ISH Acquired Debt
Debt Instrument [Line Items]
Debt instrument, stated percentage											7.00%
Long-term debt acquired in business acquisition											$ 3,900,000
Notes Payable, Other Payables | Equipment and Facility Mortgages | Minimum
Debt Instrument [Line Items]
Debt instrument, stated percentage									3.40%	3.40%
Notes Payable, Other Payables | Equipment and Facility Mortgages | Maximum
Debt Instrument [Line Items]
Debt instrument, stated percentage									4.30%	4.30%

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2013
Tax Credit Carryforward [Line Items]
Tax cuts and jobs act, change in tax rate, deferred tax liability, income tax benefit	$ 66.9
Adjustment to additional paid in capital, income tax effect from share-based compensation, net		$ 2.3
Liability for uncertainty in income taxes				$ 10.1
Increase (decrease) in unrecognized tax benefits	(2)
State and Local Jurisdiction
Tax Credit Carryforward [Line Items]
Operating loss carryforwards, valuation allowance	$ 6.7		$ 4

Income Taxes (Schedule Of Incom

Income Taxes (Schedule Of Income Before Income Tax Expense (Benefit) And Equity In Earnings Of 50% Or Less Owned Companies) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Contingency [Line Items]
Income before income tax expense (benefit) and equity in earnings of 50% or less owned companies	$ 91,689	$ 35,205	$ (92,236)
Reportable Geographical Components | United States
Income Tax Contingency [Line Items]
Income before income tax expense (benefit) and equity in earnings of 50% or less owned companies	33,563	28,546	(93,145)
Reportable Geographical Components | Foreign
Income Tax Contingency [Line Items]
Income before income tax expense (benefit) and equity in earnings of 50% or less owned companies	56,558	4,748	(1,105)
Eliminations
Income Tax Contingency [Line Items]
Income before income tax expense (benefit) and equity in earnings of 50% or less owned companies	$ 1,568	$ 1,911	$ 2,014

Income Taxes (Components Of Inc

Income Taxes (Components Of Income Tax Expense (Benefit)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
State	$ 253	$ 1,136	$ 4,830
Federal	20,776	(17,181)	6,998
Foreign	2,899	333	379
Current income tax expense	23,928	(15,712)	12,207
Deferred:
State	(3,001)	12	(2,280)
Federal	(12,512)	(51,489)	(46,652)
Deferred income tax benefit	(15,513)	(51,477)	(48,932)
Income tax expense (benefit)	$ 8,415	$ (67,189)	$ (36,725)

Income Taxes (Schedule Of Effec

Income Taxes (Schedule Of Effective Income Tax Rate) (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Statutory rate	21.00%	35.00%	35.00%
Income subject to tonnage tax	(1.30%)	(5.90%)	(0.00%)
Dorian distribution	0.00%	22.80%	0.00%
Reversal of uncertain tax position	0.00%	(28.70%)	0.00%
U.S. federal income tax statutory changes	0.00%	(190.20%)	0.00%
Non-deductible expenses	0.20%	0.80%	1.00%
Noncontrolling interests	(5.70%)	(22.40%)	6.30%
Foreign earnings not subject to U.S. income tax	(16.20%)	(0.00%)	(0.00%)
Foreign taxes not creditable against U.S. income tax	3.20%	0.00%	0.00%
Losses of foreign subsidiaries not benefited	0.00%	(6.60%)	(1.40%)
Subpart F income	12.10%	0.00%	0.00%
State taxes	(3.10%)	1.20%	(0.90%)
Effective Income Tax Rate Reconciliation, Share-based Compensation, Excess Tax Benefit, Percent	0.30%
Share award plans		2.00%	(0.00%)
Other	(0.70%)	1.10%	(0.20%)
Effective income tax rate	9.20%	(190.90%)	39.80%

Income Taxes (Components Of The

Income Taxes (Components Of The Net Deferred Income Tax Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax liabilities:
Property and equipment	$ 93,049	$ 92,127
Long-term debt	18,355	22,519
Investments in 50% or less owned companies	1,934	811
Intangible assets	614	1,006
Deductible goodwill	344	0
Other	31	96
Total deferred tax liabilities	114,327	116,559
Deferred tax assets:
Share award plans	3,711	3,476
Losses on marketable securities	8,596	5,986
Deductible goodwill	0	312
Debt and equity issuance costs	379	406
Other	11,178	11,652
Total deferred tax assets	23,864	21,832
Valuation allowance	(3,957)	(6,695)
Net deferred tax assets	19,907	15,137
Net deferred tax liabilities	$ 94,420	$ 101,422

Derivative Instruments And He_3

Derivative Instruments And Hedging Strategies (Narrative) (Details)	Apr. 30, 2017
Cash Flow Hedging | Interest Rate Swap
Derivatives, Fair Value [Line Items]
Derivative, fixed interest rate	2.79%

Derivative Instruments And He_4

Derivative Instruments And Hedging Strategies (Recognized Gains (Losses) On Derivative Instruments Not Designated As Hedging Instruments) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Derivative gains (losses), net	$ 0	$ 19,727	$ (14,131)
Exchange Option Liability
Derivative [Line Items]
Derivative gains (losses), net	0	19,436	(13,826)
Forward Currency Exchange, Option And Future Contracts
Derivative [Line Items]
Derivative gains (losses), net	0	291	(296)
Exchange traded commodity swap, option and future contracts
Derivative [Line Items]
Derivative gains (losses), net	$ 0	$ 0	$ (9)

Fair Value Measurements (Financ

Fair Value Measurements (Financial Assets And Liabilities Measured At Fair Value On Recurring Basis) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Marketable Security Positions Held By The Company As Of December 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable security gains (losses), net	$ (12,400)	$ 100	$ (18,500)
Marketable Security Positions Held By The Company As Of December 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable security gains (losses), net		100	$ (18,500)
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, cash equivalents, restricted cash and restricted cash equivalents	147,212	242,228
Marketable securities	30,316	42,761
Construction reserve funds	3,908	51,339
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, cash equivalents, restricted cash and restricted cash equivalents	0	0
Marketable securities	0	0
Construction reserve funds	0	0
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, cash equivalents, restricted cash and restricted cash equivalents	0	0
Marketable securities	0	0
Construction reserve funds	$ 0	$ 0

Fair Value Measurements (Estima

Fair Value Measurements (Estimated Fair Value Of Other Financial Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
3.0% Convertible Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, stated percentage	3.00%
3.25% Convertible Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, stated percentage	3.25%
Convertible Debt | 3.0% Convertible Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, stated percentage	3.00%
Convertible Debt | 3.25% Convertible Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, stated percentage	3.25%
Reported Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes receivable from third parties (included in other receivables and other assets)	$ 2,182	$ 2,647
Investments, at cost, in 50% or less owned companies (included in other assets)	4,300	4,300
Long-term debt, including current portion	354,625	579,347
Estimate of Fair Value Measurement | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes receivable from third parties (included in other receivables and other assets)	0	943
Long-term debt, including current portion	0	0
Estimate of Fair Value Measurement | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes receivable from third parties (included in other receivables and other assets)	2,159	1,642
Long-term debt, including current portion	353,929	596,246
Estimate of Fair Value Measurement | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes receivable from third parties (included in other receivables and other assets)	0	0
Long-term debt, including current portion	$ 0	$ 0

Fair Value Measurements (Non-Fi

Fair Value Measurements (Non-Financial Assets And Liabilities Measured At Fair Value) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jun. 01, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity method investment, other than temporary impairment	$ 100	$ 900	$ 7,700
Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity method investment, other than temporary impairment	$ 100
VA&E
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity method investment, other than temporary impairment		900
Cleancor
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business acquisition, percentage of voting interests acquired	50.00%			50.00%
Cleancor | Equity in Earnings of 50% or Less Owned Companies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business combination, step acquisition, equity interest in acquiree, remeasurement gain	$ 100
Fair Value, Measurements, Nonrecurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at equity, and advances in 50% or less owned companies	0	0
Fair Value, Measurements, Nonrecurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at equity, and advances in 50% or less owned companies	3,219	6,000
Fair Value, Measurements, Nonrecurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at equity, and advances in 50% or less owned companies	$ 0	$ 0

Stock Repurchases and Dividen_2

Stock Repurchases and Dividends (Details) $ in Thousands	Dec. 20, 2017USD ($)shares	Jun. 01, 2017	Dec. 31, 2017USD ($)shares	Dec. 31, 2016USD ($)shares	Dec. 31, 2018USD ($)
Equity, Class of Treasury Stock [Line Items]
Securities repurchased plan, remaining authorized repurchase amount					$ 66,700
Treasury stock, shares acquired (in shares) | shares			212,659	47,455
Purchase of treasury shares			$ 12,300	$ 2,396
Common stock, spin-off, conversion ratio		1.005
Dorian LPG
Equity, Class of Treasury Stock [Line Items]
Common stock dividends, shares (in shares) | shares	3,977,135
Dividends	$ 31,400
Stock split, conversion ratio	0.2215

Noncontrolling Interests in S_3

Noncontrolling Interests in Subsidiaries (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Noncontrolling Interest [Line Items]
Noncontrolling interests in subsidiaries	$ 149,688				$ 129,678				$ 149,688	$ 129,678
Net income (loss)	$ 4,434	$ 27,203	$ 46,007	$ 5,558	79,034	$ 21,104	$ (29,085)	$ 10,656	83,202	81,709	$ (195,772)
Net income (loss) attributable to noncontrolling interest									$ 25,054	20,066	20,125
SEA-Vista | Ocean Services
Noncontrolling Interest [Line Items]
Noncontrolling interest, ownership percentage by noncontrolling owners	49.00%								49.00%
Noncontrolling interests in subsidiaries	$ 148,665				128,550				$ 148,665	128,550
Other Inland River Services Noncontrolling Interests | Inland Services
Noncontrolling Interest [Line Items]
Noncontrolling interests in subsidiaries	$ 862				977				$ 862	977
Other Inland River Services Noncontrolling Interests | Minimum | Inland Services
Noncontrolling Interest [Line Items]
Noncontrolling interest, ownership percentage by noncontrolling owners	3.00%								3.00%
Other Inland River Services Noncontrolling Interests | Maximum | Inland Services
Noncontrolling Interest [Line Items]
Noncontrolling interest, ownership percentage by noncontrolling owners	51.80%								51.80%
Other Noncontrolling Interests | Other
Noncontrolling Interest [Line Items]
Noncontrolling interest, ownership percentage by noncontrolling owners	5.00%								5.00%
Noncontrolling interests in subsidiaries	$ 161				151				$ 161	151
SEA-Vista | Ocean Services
Noncontrolling Interest [Line Items]
Net assets	$ 303,400				$ 262,300				303,400	262,300
Net income (loss)									51,200	45,900	36,300
Net income (loss) attributable to noncontrolling interest									$ 25,100	$ 22,500	$ 17,800

Savings, Multi-Employer And D_3

Savings, Multi-Employer And Defined Benefit Pension Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution percent of employees' gross pay	3.50%
Defined contribution plan, cost	$ 2,000	$ 1,800	$ 1,800
Deferred compensation arrangement with individual, maximum annual salary deferral, percentage	75.00%
Deferred compensation arrangement with individual, maximum cash bonus deferral, percentage	100.00%
Deferred compensation obligation	$ 600	500
Multiemployer Plans, Pension
Defined Benefit Plan Disclosure [Line Items]
Multiemployer plan, contributions by employer	2,500	2,400	1,800
Multiemployer Plans, Postretirement Benefit
Defined Benefit Plan Disclosure [Line Items]
Multiemployer plan, contributions by employer	1,000	1,000	$ 300
American Maritime Officers Pension Plan | Withdrawal from Multiemployer Defined Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Loss contingency, estimate of possible loss				$ 34,400
ISH Retirement Plan [Member]
Defined Benefit Plan [Abstract]
Fair Value of Assets	34,923	38,492
Projected Benefit Obligation	(34,299)	(36,940)
Funded Status	624	1,552
Pension income (expense)	$ (928)	$ 1,315
Defined Benefit Plan, Assumptions Used in Calculations [Abstract]
Benefit obligation, Discount rate	4.05%	3.50%
Benefit obligation, Rate of increase in compensations levels		4.50%
Benefit obligation, CPI	2.25%	2.00%
Benefit obligation, Cash balance interest credits (compounded annually)	4.00%	4.10%
Net periodic benefit cost, Expected long-term rate of return on plan assets	6.75%	6.75%
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2,019	$ 2,130
2,020	2,090
2,021	2,080
2,022	2,170
2,023	$ 2,150

Share Based Compensation (Narra

Share Based Compensation (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional compensation expense	$ 4	$ 32.5	$ 14.1
Share-based compensation arrangement by share-based payment award, accelerated compensation cost		$ 16.6
Unrecognized compensation costs	9
Compensation costs expected to be recognized in 2019	3.2
Compensation costs expected to be recognized in 2020	$ 2.6
Weighted average values of grants (in dollars per share)	$ 29.72	$ 37.20	$ 31.31
Aggregate intrinsic value of exercised stock options	$ 3.9	$ 5.6	$ 1.4
Weighted average remaining contractual term for total outstanding stock options	5 years 84 days
Weighted average remaining contractual term for vested/exercisable stock options	4 years
Aggregate intrinsic value of options outstanding	$ 2
Aggregate intrinsic value of vested/exercisable options outstanding	$ 1.7
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total grant date fair value of restricted stock vested		$ 26.1	$ 10.8
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock authorized for grant (in shares)	900,000
Exercise price per share of options granted, percentage, minimum	85.00%
Increase in number of shares available under employee stock purchase plan (in shares)	300,000
Employee common stock purchase plan, duration	10 years
Employee common stock purchase plan, offering period	6
Employee Stock Options and Stock Options Issued for Services
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average expected volatility	26.60%	25.50%	26.50%
Weighted average discount rates	2.78%	1.92%	1.59%
Expected lives	5 years 210 days	5 years 215 days	6 years 91 days
Share Incentive Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock authorized for grant (in shares)	6,650,000
Exercise price per share of options granted, percentage, minimum	100.00%
Share Incentive Plans | Restricted Stock | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock and stock options vesting period	1 year
Share Incentive Plans | Restricted Stock | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock and stock options vesting period	5 years
Share Incentive Plans | Employee Stock Option | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock and stock options vesting period	1 year
Share Incentive Plans | Employee Stock Option | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock and stock options vesting period	5 years

Share Based Compensation (Share

Share Based Compensation (Share Based Compensation Plans) (Details) - shares	Jun. 02, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Restricted stock awards granted (in shares)		121,850	153,100	137,258
Restricted stock awards forfeited (in shares)		0	(2,444)	(2,867)
Director stock awards granted (in shares)		2,875	1,750	3,125
Stock Option Activities:
Outstanding as of the beginning of year (in shares)		1,546,014	1,639,865	1,690,899
Granted (in shares)	846,353	142,550	1,013,893	197,550
Exercised (in shares)		(220,694)	(562,587)	(113,820)
Forfeited (in shares)		0	(3,374)	(18,760)
Expired (in shares)		(479)	(541,783)	(116,004)
Outstanding as of the end of year (in shares)		1,467,391	1,546,014	1,639,865
Employee Stock Purchase Plans shares issued (in shares)		45,251	36,552	41,924
Shares available for issuance under Share Incentive and Employee Stock Purchase Plans as of the end of year (in shares)		884,218	896,265	522,341

Share Based Compensation (Sched

Share Based Compensation (Schedule Of Share-based Compensation, Restricted Stock And Restricted Stock Units Activity) (Details) - Restricted Stock	12 Months Ended
	Dec. 31, 2018$ / sharesshares
Number of Shares
Nonvested, beginning balance (in shares) | shares	0
Granted (in shares) | shares	121,850
Vested (in shares) | shares	0
Forfeited (in shares) | shares	0
Nonvested, ending balance (in shares) | shares	121,850
Weighted Average Grant Price
Nonvested, beginning balance, Weighted Average Grant Price (in dollars per share) | $ / shares	$ 0
Granted, Weighted Average Grant Price (in dollars per share) | $ / shares	46.66
Vested, Weighted Average Grant Price (in dollars per share) | $ / shares	0
Forfeited, Weighted Average Grant Price (in dollars per share) | $ / shares	0
Nonvested, ending balance, Weighted Average Grant Price (in dollars per share) | $ / shares	$ 46.66

Share Based Compensation (Sch_2

Share Based Compensation (Schedule Of Share-based Compensation, Stock Options, Activity) (Details) - $ / shares	Jun. 02, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stock Option Activities:
Outstanding as of the beginning of year (in shares)		1,546,014	1,639,865	1,690,899
Granted (in shares)	846,353	142,550	1,013,893	197,550
Exercised (in shares)		(220,694)	(562,587)	(113,820)
Expired (in shares)		(479)	(541,783)	(116,004)
Outstanding as of the end of year (in shares)		1,467,391	1,546,014	1,639,865
Outstanding and Exercisable, end of period (in shares)		997,019
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Outstanding, beginning balance, Weighted Average Exercise Price (in dollars per share)		$ 39.73
Granted, Weighted Average Exercise Price (in dollars per share)		48.36
Exercised, Weighted Average Exercise Price (in dollars per share)		31.19
Expired, Weighted Average Exercise Price (in dollars per share)		53.38
Outstanding, ending balance, Weighted Average Exercise Price (in dollars per share)		41.85	$ 39.73
Outstanding and Exercisable, end of period, Weighted Average Exercise Price (in dollars per share)		$ 41.72

Related Party Transactions (Det

Related Party Transactions (Details) - Affiliated Entity - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Dry-Cargo Barge Pools Management
Related Party Transaction [Line Items]
Related party transaction, amounts	$ 0.8	$ 0.5	$ 0.8
Revenue from related parties	0.1	0.1	$ 0.1
Payables to related parties	0.5	0.5
SEACOR Marine Holdings Inc. | Transition Services
Related Party Transaction [Line Items]
Revenue from related parties	4.6	$ 3.5
Due from related parties, current	$ 0.5

Commitments And Contingencies_2

Commitments And Contingencies (Capital Commitments and Narrative) (Details) $ in Thousands	Dec. 15, 2010claim	Dec. 31, 2018USD ($)equipmentclaim	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Feb. 26, 2019USD ($)	Aug. 02, 2016	Feb. 16, 2016
Commitments and Contingencies [Line Items]
Unrecorded unconditional purchase obligation, due in next twelve months | $		$ 23,078
Unrecorded unconditional purchase obligation, due within two years | $		7,081
Unrecorded unconditional purchase obligation | $		30,159
Total rental expense for operating leases | $		$ 52,800	$ 42,800	$ 35,200
Rail ferries - Foreign-flag
Commitments and Contingencies [Line Items]
Number of equipment committed to purchase		2
Inland river towboats
Commitments and Contingencies [Line Items]
Number of equipment committed to purchase		2
Property subject to or available for operating lease, number of units		4
Petroleum and chemical carriers - U.S.-flag
Commitments and Contingencies [Line Items]
Property subject to or available for operating lease, number of units		3
Sale leaseback transaction, lease terms			104	76
Harbor and offshore tugs - U.S.-flag
Commitments and Contingencies [Line Items]
Property subject to or available for operating lease, number of units		5
Pure Car/Truck Carriers - U.S.-flag
Commitments and Contingencies [Line Items]
Property subject to or available for operating lease, number of units		4
Inland river dry-cargo barges
Commitments and Contingencies [Line Items]
Property subject to or available for operating lease, number of units		48
Sale leaseback transaction, lease terms			84
Inland river harbor boats
Commitments and Contingencies [Line Items]
Property subject to or available for operating lease, number of units		6
Bareboat Chartered, Petroleum and Chemical Carriers - U.S.-flag
Commitments and Contingencies [Line Items]
Property subject to or available for operating lease, number of units		3
Time Chartered, Petroleum and Chemical Carriers - U.S.-flag
Commitments and Contingencies [Line Items]
Property subject to or available for operating lease, number of units		4
Time Chartered, PCTCs - U.S.-flag
Commitments and Contingencies [Line Items]
Property subject to or available for operating lease, number of units		4
Time Chartered, Inland River Towboats
Commitments and Contingencies [Line Items]
Property subject to or available for operating lease, number of units		3
Time Chartered, Offshore Tug - U.S.-flag
Commitments and Contingencies [Line Items]
Property subject to or available for operating lease, number of units		1
Minimum | Petroleum and chemical carriers - U.S.-flag
Commitments and Contingencies [Line Items]
Sale leaseback transaction, lease terms		1
Minimum | Other Equipment
Commitments and Contingencies [Line Items]
Lessee, operating lease, term of contract		1 year
Maximum | Petroleum and chemical carriers - U.S.-flag
Commitments and Contingencies [Line Items]
Sale leaseback transaction, lease terms		92
Maximum | Other Equipment
Commitments and Contingencies [Line Items]
Lessee, operating lease, term of contract		207 months
Deepwater Horizon Oil Spill Multi District Litigation
Commitments and Contingencies [Line Items]
Loss contingency, new claims filed | claim	1
Loss contingency, pending claims						11	11
BELO/ORM
Commitments and Contingencies [Line Items]
Loss contingency, new claims filed | claim		700
BELO/NRC
Commitments and Contingencies [Line Items]
Loss contingency, new claims filed | claim		70
Subsequent Event
Commitments and Contingencies [Line Items]
Unrecorded unconditional purchase obligation | $					$ 3,900
Ocean Services
Commitments and Contingencies [Line Items]
Unrecorded unconditional purchase obligation, due in next twelve months | $		$ 3,479
Unrecorded unconditional purchase obligation, due within two years | $		6,161
Unrecorded unconditional purchase obligation | $		9,640
Inland Services
Commitments and Contingencies [Line Items]
Unrecorded unconditional purchase obligation, due in next twelve months | $		19,599
Unrecorded unconditional purchase obligation, due within two years | $		920
Unrecorded unconditional purchase obligation | $		$ 20,519

Commitments And Contingencies_3

Commitments And Contingencies (Future Minimum Payments Under Operating Leases) (Details) $ in Thousands	Dec. 31, 2018USD ($)
Commitments and Contingencies Disclosure [Abstract]
Total Minimum Payments, 2019	$ 43,451
Total Minimum Payments, 2020	41,818
Total Minimum Payments, 2021	36,518
Total Minimum Payments, 2022	26,615
Total Minimum Payments, 2023	14,671
Total Minimum Payments, Years subsequent to 2023	39,665
Non-cancelable Subleases, 2019	(23,197)
Non-cancelable Subleases, 2020	(23,251)
Non-cancelable Subleases, 2021	(23,196)
Non-cancelable Subleases, 2022	(19,923)
Non-cancelable Subleases, 2023	(11,315)
Non-cancelable Subleases, Years subsequent to 2023	(29,884)
Net Minimum Lease Payments, 2019	20,254
Net Minimum Lease Payments, 2020	18,567
Net Minimum Lease Payments, 2021	13,322
Net Minimum Lease Payments, 2022	6,692
Net Minimum Lease Payments, 2023	3,356
Net Minimum Lease Payments, Years subsequent to 2023	$ 9,781

Commitments And Contingencies_4

Commitments And Contingencies (Future Minimum Lease Rentals) (Details) $ in Thousands	Dec. 31, 2018USD ($)
Commitments and Contingencies Disclosure [Abstract]
Total Minimum Lease Revenues, 2019	$ 144,464
Total Minimum Lease Revenues, 2020	132,250
Total Minimum Lease Revenues, 2021	99,901
Total Minimum Lease Revenues, 2022	50,308
Total Minimum Lease Revenues, 2023	33,015
Total Minimum Lease Revenues, Years subsequent to 2023	(81,983)
Leased-in Obligations, 2019	(28,464)
Leased-in Obligations, 2020	(28,313)
Leased-in Obligations, 2021	(26,381)
Leased-in Obligations, 2022	(20,405)
Leased-in Obligations, 2023	(11,315)
Leased-in Obligations, Years subsequent to 2023	(29,884)
Net Minimum Lease Income, 2019	116,000
Net Minimum Lease Income, 2020	103,937
Net Minimum Lease Income, 2021	73,520
Net Minimum Lease Income, 2022	29,903
Net Minimum Lease Income, 2023	21,700
Net Minimum Lease Income, Years subsequent to 2023	$ 52,099

Segment Information (Operating

Segment Information (Operating Results, Capital Expenditures And Assets By Reportable Segments) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Revenues:
Operating Revenues	$ 213,838	$ 220,257	$ 216,831	$ 184,824	$ 209,352	$ 176,605	$ 128,571	$ 136,319	$ 835,750	$ 650,847	$ 524,163
Costs and Expenses:
Operating									591,848	433,837	358,953
Administrative and general									102,907	103,106	86,362
Depreciation and amortization									74,579	75,058	62,565
Total costs and expenses									769,334	612,001	507,880
(Gains) losses on asset dispositions and impairments, net									19,583	11,637	(25,983)
Operating Income (Loss)	25,250	$ 34,047	$ 12,014	$ 14,688	22,983	$ 15,090	$ 8,993	$ 3,417	85,999	50,483	(9,700)
Other Income (Expense):
Derivative (gains) losses, net									0	19,727	(14,131)
Foreign currency (gains) losses, net									(2,264)	323	1,444
Other, net									54,964	256	(18,716)
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax									(72)	2,952	(21,040)
Income Before Taxes and Equity in Earnings (Losses)									91,689	35,205	(92,236)
Capital Expenditures									50,272	114,595	252,806
Property and Equipment:
Historical cost	1,407,329				1,380,469				1,407,329	1,380,469	1,424,566
Accumulated depreciation	(560,819)				(502,544)				(560,819)	(502,544)	(444,559)
Net property and equipment	846,510				877,925				846,510	877,925	980,007
Investments, at Equity, and Advances to 50% or Less Owned Companies	156,886				173,441				156,886	173,441	175,461
Inventories	4,530				4,377				4,530	4,377	2,582
Goodwill	32,708				32,761				32,708	32,761	32,758
Intangible Assets	24,551				28,106				24,551	28,106	20,078
Other current and long-term assets, excluding cash and near cash assets	224,403				160,398				224,403	160,398	165,019
Total Assets	1,471,024				1,613,336				1,471,024	1,613,336	2,862,321
Discontinued operations											1,075,639
Ocean Services
Operating Revenues:
Operating Revenues									414,844	352,876	229,643
Inland Services
Operating Revenues:
Operating Revenues									285,688	248,452	251,241
Witt O'Brien's LLC
Operating Revenues:
Operating Revenues									131,629	49,055	42,797
Other
Operating Revenues:
Operating Revenues									3,589	464	482
Intersegment Eliminations
Operating Revenues:
Operating Revenues									(80)	(101)	(119)
Intersegment Eliminations | Ocean Services
Operating Revenues:
Operating Revenues									0	0	0
Intersegment Eliminations | Inland Services
Operating Revenues:
Operating Revenues									0	0	0
Intersegment Eliminations | Witt O'Brien's LLC
Operating Revenues:
Operating Revenues									(80)	(101)	(119)
Intersegment Eliminations | Other
Operating Revenues:
Operating Revenues									0	0	0
Operating Segments | Ocean Services
Operating Revenues:
Operating Revenues									414,844	352,876	229,643
Costs and Expenses:
Operating									269,294	195,285	122,631
Administrative and general									40,179	36,548	27,825
Depreciation and amortization									46,270	46,073	31,162
Total costs and expenses									355,743	277,906	181,618
(Gains) losses on asset dispositions and impairments, net									12,887	(323)	411
Operating Income (Loss)									71,988	74,647	48,436
Other Income (Expense):
Derivative (gains) losses, net										0	0
Foreign currency (gains) losses, net									(168)	(130)	(18)
Other, net									570	327	(6,224)
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax									3,632	7,664	(4,697)
Segment Profit (Loss)									76,022	82,508	37,497
Capital Expenditures									39,207	80,006	215,837
Property and Equipment:
Historical cost	930,230				901,076				930,230	901,076	960,816
Accumulated depreciation	(341,999)				(299,528)				(341,999)	(299,528)	(258,004)
Net property and equipment	588,231				601,548				588,231	601,548	702,812
Investments, at Equity, and Advances to 50% or Less Owned Companies	73,939				52,003				73,939	52,003	51,620
Inventories	2,196				2,352				2,196	2,352	843
Goodwill	1,852				1,852				1,852	1,852	1,852
Intangible Assets	8,965				10,293				8,965	10,293	0
Other current and long-term assets, excluding cash and near cash assets	48,770				49,498				48,770	49,498	29,801
Total Assets	723,953				717,546				723,953	717,546	786,928
Operating Segments | Inland Services
Operating Revenues:
Operating Revenues									285,688	248,452	251,241
Costs and Expenses:
Operating									237,010	206,836	208,158
Administrative and general									13,139	16,558	14,616
Depreciation and amortization									24,164	25,852	26,327
Total costs and expenses									274,313	249,246	249,101
(Gains) losses on asset dispositions and impairments, net									6,659	11,960	3,193
Operating Income (Loss)									18,034	11,166	5,333
Other Income (Expense):
Derivative (gains) losses, net										0	0
Foreign currency (gains) losses, net									(2,002)	272	1,722
Other, net									51	0	(4)
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax									(5,686)	(5,191)	(15,944)
Segment Profit (Loss)									10,397	6,247	(8,893)
Capital Expenditures									8,298	34,322	36,803
Property and Equipment:
Historical cost	438,848				448,035				438,848	448,035	432,717
Accumulated depreciation	(195,094)				(181,573)				(195,094)	(181,573)	(167,127)
Net property and equipment	243,754				266,462				243,754	266,462	265,590
Investments, at Equity, and Advances to 50% or Less Owned Companies	57,899				66,479				57,899	66,479	69,181
Inventories	1,997				1,934				1,997	1,934	1,602
Goodwill	2,350				2,403				2,350	2,403	2,400
Intangible Assets	8,991				10,486				8,991	10,486	12,018
Other current and long-term assets, excluding cash and near cash assets	78,903				71,500				78,903	71,500	88,165
Total Assets	393,894				419,264				393,894	419,264	438,956
Operating Segments | Witt O'Brien's LLC
Operating Revenues:
Operating Revenues									131,709	49,156	42,916
Costs and Expenses:
Operating									83,203	32,017	28,561
Administrative and general									24,772	13,438	16,214
Depreciation and amortization									1,944	819	1,539
Total costs and expenses									109,919	46,274	46,314
(Gains) losses on asset dispositions and impairments, net									0	0	(29,587)
Operating Income (Loss)									21,790	2,882	(32,985)
Other Income (Expense):
Derivative (gains) losses, net										0	0
Foreign currency (gains) losses, net									(28)	50	(181)
Other, net									0	0	0
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax									203	174	305
Segment Profit (Loss)									21,965	3,106	(32,861)
Capital Expenditures									0	60	2
Property and Equipment:
Historical cost	1,227				1,227				1,227	1,227	1,559
Accumulated depreciation	(1,031)				(938)				(1,031)	(938)	(1,244)
Net property and equipment	196				289				196	289	315
Investments, at Equity, and Advances to 50% or Less Owned Companies	471				777				471	777	566
Inventories	179				91				179	91	137
Goodwill	28,506				28,506				28,506	28,506	28,506
Intangible Assets	6,595				7,327				6,595	7,327	8,060
Other current and long-term assets, excluding cash and near cash assets	81,410				28,398				81,410	28,398	14,284
Total Assets	117,357				65,388				117,357	65,388	51,868
Operating Segments | Other
Operating Revenues:
Operating Revenues									3,589	464	482
Costs and Expenses:
Operating									2,455	0	0
Administrative and general									1,841	831	1,001
Depreciation and amortization									501	0	0
Total costs and expenses									4,797	831	1,001
(Gains) losses on asset dispositions and impairments, net									37	0	0
Operating Income (Loss)									(1,171)	(367)	(519)
Other Income (Expense):
Derivative (gains) losses, net										0	0
Foreign currency (gains) losses, net									(3)	6	(1)
Other, net									54,249	(301)	(12,608)
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax									1,779	305	(704)
Segment Profit (Loss)									54,854	(357)	(13,832)
Capital Expenditures									2,639	0	0
Property and Equipment:
Historical cost	6,892				0				6,892	0	0
Accumulated depreciation	(490)				0				(490)	0	0
Net property and equipment	6,402				0				6,402	0	0
Investments, at Equity, and Advances to 50% or Less Owned Companies	24,577				54,182				24,577	54,182	54,094
Inventories	158				0				158	0	0
Goodwill	0				0				0	0	0
Intangible Assets	0				0				0	0	0
Other current and long-term assets, excluding cash and near cash assets	2,142				1,391				2,142	1,391	11,193
Total Assets	33,279				55,573				33,279	55,573	65,287
Corporate And Eliminations
Operating Revenues:
Operating Revenues									(80)	(101)	(119)
Costs and Expenses:
Operating									(114)	(301)	(397)
Administrative and general									22,976	35,731	26,706
Depreciation and amortization									1,700	2,314	3,537
Total costs and expenses									24,562	37,744	29,846
(Gains) losses on asset dispositions and impairments, net									0	0	0
Operating Income (Loss)									(24,642)	(37,845)	(29,965)
Other Income (Expense):
Derivative (gains) losses, net										19,727	(14,131)
Foreign currency (gains) losses, net									(63)	125	(78)
Other, net									94	230	120
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax									0	0	0
Capital Expenditures									128	207	164
Property and Equipment:
Historical cost	30,132				30,131				30,132	30,131	29,474
Accumulated depreciation	(22,205)				(20,505)				(22,205)	(20,505)	(18,184)
Net property and equipment	7,927				9,626				7,927	9,626	11,290
Investments, at Equity, and Advances to 50% or Less Owned Companies	0				0				0	0	0
Inventories	0				0				0	0	0
Goodwill	0				0				0	0	0
Intangible Assets	0				0				0	0	0
Other current and long-term assets, excluding cash and near cash assets	13,178				9,611				13,178	9,611	21,576
Segment Reconciling Items
Other Income (Expense):
Other, net									(47,010)	(35,584)	(51,133)
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax									72	(2,952)	21,040
Property and Equipment:
Cash and near cash assets	$ 181,436				$ 336,328				$ 181,436	$ 336,328	$ 410,777

Segment Information (Disaggrega

Segment Information (Disaggregation of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Lease revenues									$ 201,112	$ 191,526	$ 129,576
Operating Revenues	$ 213,838	$ 220,257	$ 216,831	$ 184,824	$ 209,352	$ 176,605	$ 128,571	$ 136,319	835,750	650,847	524,163
Ocean Services
Disaggregation of Revenue [Line Items]
Operating Revenues									414,844	352,876	229,643
Inland Services
Disaggregation of Revenue [Line Items]
Operating Revenues									285,688	248,452	251,241
Witt O’Brien’s
Disaggregation of Revenue [Line Items]
Operating Revenues									131,629	49,055	42,797
Other
Disaggregation of Revenue [Line Items]
Operating Revenues									3,589	464	482
Voyage charters
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									73,979	33,623
Contracts of affreightment
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									231,247	204,261	192,633
Tariff
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									74,157	68,266	62,249
Unit freight
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									58,326	50,693	43,599
Terminal operations
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									21,501	21,488	20,552
Fleeting operations
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									17,888	15,561	12,443
Logistics Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									14,309	8,868	4,469
Time and material contracts
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									119,196	33,352	25,898
Retainer contracts
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									10,124	10,192	11,654
Product sales
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									2,686
Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									11,225	13,017	21,090
Product
Disaggregation of Revenue [Line Items]
Cost of goods and services sold									2,100
Operating Segments | Ocean Services
Disaggregation of Revenue [Line Items]
Lease revenues									193,242	183,234	122,344
Operating Revenues									414,844	352,876	229,643
Operating Segments | Inland Services
Disaggregation of Revenue [Line Items]
Lease revenues									7,392	8,292	7,232
Operating Revenues									285,688	248,452	251,241
Operating Segments | Witt O’Brien’s
Disaggregation of Revenue [Line Items]
Lease revenues									0	0	0
Operating Revenues									131,709	49,156	42,916
Operating Segments | Other
Disaggregation of Revenue [Line Items]
Lease revenues									478	0	0
Operating Revenues									3,589	464	482
Operating Segments | Voyage charters | Ocean Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									73,979	33,623
Operating Segments | Voyage charters | Inland Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0
Operating Segments | Voyage charters | Witt O’Brien’s
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0
Operating Segments | Voyage charters | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0
Operating Segments | Contracts of affreightment | Ocean Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									11,872	15,181	0
Operating Segments | Contracts of affreightment | Inland Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									219,375	189,080	192,633
Operating Segments | Contracts of affreightment | Witt O’Brien’s
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Operating Segments | Contracts of affreightment | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Operating Segments | Tariff | Ocean Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									74,157	68,266	62,249
Operating Segments | Tariff | Inland Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0
Operating Segments | Tariff | Witt O’Brien’s
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Operating Segments | Tariff | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Operating Segments | Unit freight | Ocean Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									58,326	50,693	43,599
Operating Segments | Unit freight | Inland Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0
Operating Segments | Unit freight | Witt O’Brien’s
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Operating Segments | Unit freight | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Operating Segments | Terminal operations | Ocean Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Operating Segments | Terminal operations | Inland Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									21,501	21,488	20,552
Operating Segments | Terminal operations | Witt O’Brien’s
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Operating Segments | Terminal operations | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Operating Segments | Fleeting operations | Ocean Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Operating Segments | Fleeting operations | Inland Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									17,888	15,561	12,443
Operating Segments | Fleeting operations | Witt O’Brien’s
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Operating Segments | Fleeting operations | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Operating Segments | Logistics Services | Ocean Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Operating Segments | Logistics Services | Inland Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									14,309	8,868	4,469
Operating Segments | Logistics Services | Witt O’Brien’s
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Operating Segments | Logistics Services | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Operating Segments | Time and material contracts | Ocean Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Operating Segments | Time and material contracts | Inland Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0
Operating Segments | Time and material contracts | Witt O’Brien’s
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									119,196	33,352	25,898
Operating Segments | Time and material contracts | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Operating Segments | Retainer contracts | Ocean Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Operating Segments | Retainer contracts | Inland Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0
Operating Segments | Retainer contracts | Witt O’Brien’s
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									10,124	10,192	11,654
Operating Segments | Retainer contracts | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Operating Segments | Product sales | Ocean Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0
Operating Segments | Product sales | Inland Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0
Operating Segments | Product sales | Witt O’Brien’s
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0
Operating Segments | Product sales | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									2,686
Operating Segments | Other | Ocean Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									3,268	1,879	1,451
Operating Segments | Other | Inland Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									5,223	5,163	13,912
Operating Segments | Other | Witt O’Brien’s
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									2,389	5,612	5,364
Operating Segments | Other | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									425	464	482
Corporate And Eliminations
Disaggregation of Revenue [Line Items]
Lease revenues									0	0	0
Operating Revenues									(80)	(101)	(119)
Corporate And Eliminations | Voyage charters
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0
Corporate And Eliminations | Contracts of affreightment
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Corporate And Eliminations | Tariff
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Corporate And Eliminations | Unit freight
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Corporate And Eliminations | Terminal operations
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Corporate And Eliminations | Fleeting operations
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Corporate And Eliminations | Logistics Services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Corporate And Eliminations | Time and material contracts
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Corporate And Eliminations | Retainer contracts
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0	0	0
Corporate And Eliminations | Product sales
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									0
Corporate And Eliminations | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers									$ (80)	$ (101)	$ (119)

Discontinued Operations (Detail

Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Costs and Expenses [Abstract]
Net Income (Loss)	$ (487)	$ 10,927	$ (28,629)	$ (5,448)	$ 0	$ (23,637)	$ (119,221)
Discontinued Operations
Costs and Expenses [Abstract]
Net Income (Loss)						(23,637)	(119,221)
Reportable Legal Entities | Discontinued Operations, Disposed of by Means Other than Sale, Spinoff | SEACOR Marine
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating Revenues						62,291	215,636
Costs and Expenses [Abstract]
Operating						65,888	166,925
Administrative and general						29,682	49,308
Depreciation and amortization						22,181	58,069
Total costs and expenses						117,751	274,302
Gains (Losses) on Asset Dispositions and Impairments, Net						4,219	(116,222)
Operating Income (Loss)						(51,241)	(174,888)
Other Income, Net						1,780
Other Expenses, Net							(15,417)
Income Tax Expense (Benefit)						(12,931)	(63,468)
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax						1,663	(6,314)
Net Income (Loss)						(34,867)	(133,151)
Net Income (Loss) Attributable to Noncontrolling Interests						(1,892)	(1,103)
Reportable Legal Entities | Discontinued Operations, Disposed of by Sale | Illinois Corn Processing LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating Revenues						78,061	177,401
Costs and Expenses [Abstract]
Operating						76,306	158,495
Administrative and general						2,140	3,011
Depreciation and amortization						2,354	4,299
Total costs and expenses						80,800	165,805
Operating Income (Loss)						(2,739)	11,596
Other Income, Net						20,557	4,520
Income Tax Expense (Benefit)						7,818	4,901
Net Income (Loss)						10,000	11,215
Net Income (Loss) Attributable to Noncontrolling Interests						(539)	3,688
Eliminations | Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating Revenues						(1,176)	(2,517)
Costs and Expenses [Abstract]
Operating						(1,289)	(2,862)
Administrative and general						(42)	(100)
Total costs and expenses						(1,331)	(2,962)
Operating Income (Loss)						155	445
Other Income, Net						1,738	3,732
Income Tax Expense (Benefit)						663	1,462
Net Income (Loss)						$ 1,230	$ 2,715

Supplemental Information For _3

Supplemental Information For Statements Of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplemental Cash Flow Information [Abstract]
Income taxes paid	$ 27,465	$ 6,152	$ 11,933
Income taxes refunded	299	14,347	3,933
Interest paid, excluding capitalized interest	26,880	32,341	26,662
Schedule of Non-Cash Investing and Financing Activities:
Net issuance of conversion option on exchange of convertible debt	16,120	0	0
Company financed sale of equipment and real property	0	0	7,950
Distribution of Dorian shares to shareholders	0	31,379	0
Reclassification of deferred gains to property and equipment	3,052	5,954	0
Equipment received to settle notes receivable	0	0	2,500
Non-cash proceeds on the sale of property and equipment	$ 0	$ 0	$ 2,000

Quarterly Financial Informati_3

Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Data [Abstract]
Operating Revenues	$ 213,838	$ 220,257	$ 216,831	$ 184,824	$ 209,352	$ 176,605	$ 128,571	$ 136,319	$ 835,750	$ 650,847	$ 524,163
Operating Income	25,250	34,047	12,014	14,688	22,983	15,090	8,993	3,417	85,999	50,483	(9,700)
Income (Loss) from Continuing Operations					79,521	10,177	(456)	16,104	83,202	105,346	(76,551)
Income (Loss) from Discontinued Operations, Net of Tax					(487)	10,927	(28,629)	(5,448)	0	(23,637)	(119,221)
Net Income (Loss)	4,434	27,203	46,007	5,558	79,034	21,104	(29,085)	10,656	83,202	81,709	(195,772)
Net Income (Loss) attributable to SEACOR Holdings Inc.:
Continuing Operations					73,294	6,634	(6,782)	9,703	58,148	82,849	(94,091)
Discontinued Operations					(487)	10,927	(26,026)	(5,620)	0	(21,206)	(121,806)
Net Income (Loss) attributable to SEACOR Holdings Inc.	$ (4,686)	$ 17,067	$ 45,126	$ 641	$ 72,807	$ 17,561	$ (32,808)	$ 4,083	$ 58,148	$ 61,643	$ (215,897)
Basic Earnings (Loss) Per Common Share of SEACOR Holdings Inc.:
Continuing Operations (in dollars per share)					$ 4.15	$ 0.38	$ (0.39)	$ 0.57	$ 3.22	$ 4.77	$ (5.56)
Discontinued Operations (in dollars per share)					(0.03)	0.62	(1.52)	(0.33)	0	(1.22)	(7.20)
Basic Earnings (Loss) Per Common Share of SEACOR Holdings Inc. (in dollars per share)	$ (0.26)	$ 0.94	$ 2.50	$ 0.04	4.12	1	(1.91)	0.24	3.22	3.55	(12.76)
Diluted Earnings (Loss) Per Common Share of SEACOR Holdings Inc.:
Continuing Operations (in dollars per share)					3.37	0.38	(0.39)	0.56	3.04	4.24	(5.56)
Discontinued Operations (in dollars per share)					(0.02)	0.62	(1.52)	(0.32)	0	(0.93)	(7.20)
Diluted Earnings (Loss) Per Common Share of SEACOR Holdings Inc. (in dollars per share)	$ (0.26)	$ 0.88	$ 2.14	$ 0.04	$ 3.35	$ 1	$ (1.91)	$ 0.24	$ 3.04	$ 3.31	$ (12.76)

Valuation And Qualifying Acco_2

Valuation And Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance Beginning of Year	$ 2,390	$ 2,989	$ 1,307
Charges (Credits) to Cost and Expenses	2,067	(175)	2,774
Deductions	(976)	(424)	(1,092)
Balance End of Year	$ 3,481	$ 2,390	$ 2,989

Uncategorized Items - ckh-20181

Label	Element	Value
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance	us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance1	$ 750,894,000
Common Stock [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance	us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance1	387,000
Noncontrolling Interest [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance	us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance1	129,678,000
AOCI Attributable to Parent [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance	us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance1	(545,000)
Treasury Stock [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance	us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance1	(1,368,300,000)
Additional Paid-in Capital [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance	us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance1	1,573,013,000
Retained Earnings [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance	us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAdjustedBalance1	$ 416,661,000