Significant Accounting Policies and Practices	12 Months Ended
Dec. 31, 2019
Accounting Policies [Abstract]
Significant Accounting Policies and Practices	SIGNIFICANT ACCOUNTING POLICIES AND PRACTICES (a) Principles of Presentation and Consolidation The consolidated financial statements include the financial statements of the Partnership and its wholly-owned subsidiaries and equity method investees. In the opinion of the management of the Partnership’s general partner, all adjustments and elimination of significant intercompany balances necessary for a fair presentation of the Partnership’s results of operations, financial position and cash flows for the periods shown have been made. All such adjustments are of a normal recurring nature. In addition, the Partnership evaluates its relationships with other entities to identify whether they are variable interest entities under certain provisions of the Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC"), 810-10 and to assess whether it is the primary beneficiary of such entities. If the determination is made that the Partnership is the primary beneficiary, then that entity is included in the consolidated financial statements in accordance with ASC 810-10. No such variable interest entities exist as of December 31, 2019 or 2018. Divestiture of Natural Gas Storage Assets. On June 28, 2019, the Partnership completed the sale of its membership interests in Arcadia Gas Storage, LLC, Cadeville Gas Storage LLC, Monroe Gas Storage Company, LLC and Perryville Gas Storage LLC (the "Natural Gas Storage Assets") to Hartree Cardinal Gas, LLC ("Hartree"), a subsidiary of Hartree Bulk Storage, LLC. The Natural Gas Storage Assets consist of approximately 50 billion cubic feet of working capacity located in northern Louisiana and Mississippi. In consideration of the sale of the Natural Gas Storage Assets, the Partnership received cash proceeds of $210,067 after transaction fees and expenses. The net proceeds were used to reduce outstanding borrowings under the Partnership's revolving credit facility. The Partnership has concluded the disposition represents a strategic shift and will have a major effect on its financial results going forward. As a result, the Partnership has presented the results of operations and cash flows relating to the Natural Gas Storage Assets as discontinued operations for the years ended December 31, 2019, 2018, and 2017. See Note 5 for more information. Acquisition of Martin Transport, Inc. On January 2, 2019, the Partnership acquired all of the issued and outstanding equity interests of Martin Transport, Inc. ("MTI") from Martin Resource Management Corporation. MTI operates a fleet of tank trucks providing transportation of petroleum products, liquid petroleum gas, chemicals, sulfur and other products, as well as owns 23 terminals located throughout the U.S. Gulf Coast and Southeastern United States. The acquisition of MTI was considered a transfer of net assets between entities under common control. As a result, the acquisition of MTI was recorded at amounts based on the historical carrying value of these assets at January 1, 2019, and the Partnership is required to update its historical financial statements to include the activities of MTI as of the date of common control. See Note 4 for more information. The Partnership’s accompanying historical financial statements have been retrospectively updated to reflect the effects on financial position, cash flows and results of operations attributable to the activities of MTI as if the Partnership owned these assets for the periods presented. See Note 4 for separate results of MTI for the years ended December 31, 2018 and 2017. Net income attributable to MTI for periods prior to the Partnership’s acquisition of the assets is not allocated to the limited partners for purposes of calculating net income per limited partner unit. See Note 17. Divestiture of WTLPG Partnership Interest. On July 31, 2018, the Partnership completed the sale of its 20 percent non-operating interest in West Texas LPG Pipeline L.P. ("WTLPG") to ONEOK, Inc. ("ONEOK"). WTLPG owns an approximate 2,300 mile common-carrier pipeline system that primarily transports NGLs from New Mexico and Texas to Mont Belvieu, Texas for fractionation. A wholly-owned subsidiary of ONEOK, Inc. is the operator of the assets. The Partnership has concluded the disposition represents a strategic shift and will have a major effect on its financial results going forward. As a result, the Partnership has presented the results of operations and cash flows relating to its equity method investment in WTLPG as discontinued operations for the years ended December 31, 2018 and 2017. See Note 5 for more information. (b) Product Exchanges The Partnership enters into product exchange agreements with third parties, whereby the Partnership agrees to exchange NGLs and sulfur with third parties. The Partnership records the balance of exchange products due to other companies under these agreements at quoted market product prices and the balance of exchange products due from other companies at the lower of cost or market. Cost is determined using the first-in, first-out ("FIFO") method. Product exchanges with the same counterparty are entered into in contemplation of one another and are combined. The net amount related to location differentials is reported in "Product sales" or "Cost of products sold" in the Consolidated Statements of Operations. (c) Inventories Inventories are stated at the lower of cost or market. Cost is generally determined by using the FIFO method for all inventories except lubricants and lubricants packaging inventories. Lubricants and lubricants packaging inventories cost is determined using standard cost, which approximates actual cost, computed on a FIFO basis. (d) Revenue Recognition Terminalling and Storage – Revenue is recognized for storage contracts based on the contracted monthly tank fixed fee. For throughput contracts, revenue is recognized based on the volume moved through the Partnership’s terminals at the contracted rate. For the Partnership’s tolling agreement, revenue is recognized based on the contracted monthly reservation fee and throughput volumes moved through the facility. When lubricants and drilling fluids are sold by truck or rail, revenue is recognized when title is transfered, which is either upon delivering product to the customer or when the product leaves the Partnership's facility, depending on the specific terms of the contract. Delivery of product is invoiced as the transaction occurs and is generally paid within a month. Transportation – Revenue related to land transportation is recognized for line hauls based on a mileage rate. For contracted trips, revenue is recognized upon completion of the particular trip. The performance of the service is invoiced as the transaction occurs and is generally paid within a month. Revenue related to marine transportation is recognized for time charters based on a per day rate. For contracted trips, revenue is recognized upon completion of the particular trip. The performance of the service is invoiced as the transaction occurs and is generally paid within a month. Sulfur Services – Revenue from sulfur and fertilizer product sales is recognized when the customer takes title to the product. Delivery of product is invoiced as the transaction occurs and is generally paid within a month. Revenue from sulfur services is recognized as services are performed during each monthly period. The performance of the service is invoiced as the transaction occurs and is generally paid within a month. Natural Gas Liquids – NGL distribution revenue is recognized when product is delivered by truck, rail, or pipeline to the Partnership's NGL customers. Revenue is recognized on title transfer of the product to the customer. Delivery of product is invoiced as the transaction occurs and is generally paid within a month. (e) Equity Method Investments The Partnership uses the equity method of accounting for investments in unconsolidated entities where the ability to exercise significant influence over such entities exists. Investments in unconsolidated entities consist of capital contributions and advances plus the Partnership’s share of accumulated earnings as of the entities’ latest fiscal year-ends, less capital withdrawals and distributions. Equity method investments are subject to impairment under the provisions of ASC 323-10, which relates to the equity method of accounting for investments in common stock. No portion of the net income from these entities is included in the Partnership’s operating income. (f) Property, Plant, and Equipment Owned property, plant, and equipment is stated at cost, less accumulated depreciation. Owned buildings and equipment are depreciated using straight-line method over the estimated lives of the respective assets. Equipment under finance leases is stated at the present value of minimum lease payments less accumulated amortization. Equipment under finance leases is amortized on a straight line basis over the estimated useful life of the asset. Routine maintenance and repairs are charged to expense while costs of betterments and renewals are capitalized. When an asset is retired or sold, its cost and related accumulated depreciation are removed from the accounts, and the difference between net book value of the asset and proceeds from disposition is recognized as gain or loss. (g) Goodwill and Other Intangible Assets Goodwill is subject to a fair-value based impairment test on an annual basis, or more often if events or circumstances indicate there may be impairment. The Partnership is required to identify its reporting units and determine the carrying value of each reporting unit by assigning the assets and liabilities, including the existing goodwill and intangible assets. The Partnership is required to determine the fair value of each reporting unit and compare it to the carrying amount of the reporting unit. To the extent the carrying amount of a reporting unit exceeds the fair value of the reporting unit, the Partnership will record the amount of goodwill impairment as the excess of a reporting unit's carrying amount over its fair value, not to exceed the total amount of goodwill allocated to the reporting unit. When assessing the recoverability of goodwill and other intangible assets, the Partnership may first assess qualitative factors in determining whether it is more likely than not that the fair value of a reporting unit or other intangible asset is less than its carrying amount. After assessing qualitative factors, if the Partnership determines that it is not more likely than not that the fair value of a reporting unit or other intangible asset is less than its carrying amount, then performing a quantitative assessment is not required. If an initial qualitative assessment indicates that it is more likely than not the carrying amount exceeds the fair value of a reporting unit or other intangible asset, a quantitative analysis will be performed. The Partnership may also elect to bypass the qualitative assessment and proceed directly to a quantitative analysis depending on the facts and circumstances. Of the Partnership's four reporting units, the terminalling and storage, transportation, and sulfur services reporting units contain goodwill. No goodwill impairment was recorded for the years ended December 31, 2019, 2018, or 2017. In performing a quantitative analysis, recoverability of goodwill for each reporting unit is measured using a weighting of the discounted cash flow method and two market approaches (the guideline public company method and the guideline transaction method). The discounted cash flow model incorporates discount rates commensurate with the risks involved. Use of a discounted cash flow model is common practice in assessing impairment in the absence of available transactional market evidence to determine the fair value. The key assumptions used in the discounted cash flow valuation model include discount rates, growth rates, cash flow projections and terminal value rates. Discount rates, growth rates and cash flow projections are the most sensitive and susceptible to change as they require significant management judgment. Discount rates are determined by using a weighted average cost of capital ("WACC"). The WACC considers market and industry data as well as company-specific risk factors for each reporting unit in determining the appropriate discount rate to be used. The discount rate utilized for each reporting unit is indicative of the return an investor would expect to receive for investing in such a business. Management, considering industry and company specific historical and projected data, develops growth rates and cash flow projections for each reporting unit. Terminal value rate determination follows common methodology of capturing the present value of perpetual cash flow estimates beyond the last projected period assuming a constant WACC and low long-term growth rates. If the calculated fair value is less than the current carrying amount, the Partnership will record the amount of goodwill impairment as the excess of a reporting unit's carrying amount over its fair value, not to exceed the total amount of goodwill allocated to the reporting unit. Significant changes in these estimates and assumptions could materially affect the determination of fair value for each reporting unit which could give rise to future impairment. Changes to these estimates and assumptions can include, but may not be limited to, varying commodity prices, volume changes and operating costs due to market conditions and/or alternative providers of services. Other intangible assets that have finite lives are tested for impairment when events or circumstances indicate that the carrying value may not be recoverable. An impairment is indicated if the carrying amount of a long-lived intangible asset exceeds the sum of the undiscounted future cash flows expected to result from the use and eventual disposition of the asset. If impairment is indicated, the Partnership would record an impairment loss equal to the difference between the carrying value and the fair value of the asset. There were no intangible asset impairments in 2019, 2018 or 2017. (h) Debt Issuance Costs Debt issuance costs relating to the Partnership’s revolving credit facility and senior unsecured notes are deferred and amortized over the terms of the debt arrangements and are shown, net of accumulated amortization, as a reduction of the related long-term debt. In connection with the issuance, amendment, expansion and restatement of debt arrangements, the Partnership incurred debt issuance costs of $4,406, $1,312 and $66 in the years ended December 31, 2019, 2018 and 2017, respectively. In connection with the Partnership's July 18, 2019 revolving credit facility amendment, the Partnership expensed $608 of unamortized debt issuance costs determined not to have continuing benefit. Remaining unamortized deferred issuance costs are amortized over the term of each respective revised debt arrangement. Amortization and write-off of debt issuance costs, which is included in interest expense, totaled $4,041, $3,445 and $2,897 for the years ended December 31, 2019, 2018 and 2017, respectively. Accumulated amortization amounted to $24,644 and $20,607 at December 31, 2019 and 2018, respectively. (i) Impairment of Long-Lived Assets In accordance with ASC 360-10, long-lived assets, such as property, plant and equipment, and intangible assets with definite lives are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of an asset exceeds its estimated future cash flows, an impairment charge is recognized by the amount by which the carrying amount of the asset exceeds the fair value of the asset. Assets to be disposed of would be separately presented in the balance sheet and reported at the lower of the carrying amount or fair value less costs to sell and would no longer be depreciated. The assets and liabilities of a disposed group classified as held for sale would be presented separately in the appropriate asset and liability sections of the balance sheet. In the fourth quarter of 2017, the Partnership identified a triggering event related to the planned disposition of certain assets that were no longer deemed core assets in the Partnership's Marine Transportation division of the Transportation segment. The triggering event was the assets' inability to generate cash flows in recent quarters and going forward. As a result, an impairment charge of $1,625 was recorded in the Transportation segment results of operations in the fourth quarter of 2017. Additionally, the Partnership recorded an adjustment to the fair value less cost to sell of a certain asset classified as held for sale in the Martin Lubricants division of the Terminalling and Storage segment. As a result, an impairment charge of $600 was recorded in the Terminalling and Storage segment results of operations in the fourth quarter of 2017. On August 25, 2017, Hurricane Harvey made landfall as a Category 4 hurricane. The storm lingered over Texas and Louisiana for days producing over 50 inches of rain in some areas, resulting in widespread flooding and damage. The Partnership experienced an impact from Hurricane Harvey in our Terminalling and Storage and Sulfur Services segments, where damages were suffered to the Partnership's property, plant, and equipment at its Neches, Stanolind, Galveston, and Harbor Island terminals located along the Texas gulf coast. The damage incurred did not exceed the insurance deductible at these locations and therefore the Partnership did not receive any insurance proceeds resulting from the damage from Hurricane Harvey. In the third quarter of 2017, the Partnership recorded a write-off in the amount of $186 related to assets damaged. (j) Asset Retirement Obligations Under ASC 410-20, which relates to accounting requirements for costs associated with legal obligations to retire tangible, long-lived assets, the Partnership records an asset retirement obligation ("ARO") at fair value in the period in which it is incurred by increasing the carrying amount of the related long-lived asset. In each subsequent period, the liability is accreted over time towards the ultimate obligation amount and the capitalized costs are depreciated over the useful life of the related asset. (k) Derivative Instruments and Hedging Activities In accordance with certain provisions of ASC 815-10 related to accounting for derivative instruments and hedging activities, all derivatives and hedging instruments are included in the Consolidated Balance Sheets as an asset or liability measured at fair value and changes in fair value are recognized currently in earnings unless specific hedge accounting criteria are met. If a derivative qualifies for hedge accounting, changes in the fair value can be offset against the change in the fair value of the hedged item through earnings or recognized in other comprehensive income until such time as the hedged item is recognized in earnings. Derivative instruments not designated as hedges are marked to market with all market value adjustments being recorded in the Consolidated Statements of Operations. (l) Use of Estimates Management has made a number of estimates and assumptions relating to the reporting of assets and liabilities and the disclosure of contingent assets and liabilities to prepare these consolidated financial statements in conformity with accounting principles generally accepted in the U.S. Actual results could differ from those estimates. (m) Indirect Selling, General and Administrative Expenses Indirect selling, general and administrative expenses are incurred by Martin Resource Management Corporation and allocated to the Partnership to cover costs of centralized corporate functions such as accounting, treasury, engineering, information technology, risk management and other corporate services. Such expenses are based on the percentage of time spent by Martin Resource Management Corporation’s personnel that provide such centralized services. Under an omnibus agreement with Martin Resource Management Corporation, the Partnership is required to reimburse Martin Resource Management Corporation for indirect general and administrative and corporate overhead expenses. For the years ended December 31, 2019, 2018 and 2017, the conflicts committee of the Partnership's general partner ("Conflicts Committee") approved reimbursement amounts of $16,657, $16,416 and $16,416, respectively, reflecting the Partnership's allocable share of such expenses. The Conflicts Committee will review and approve future adjustments in the reimbursement amount for indirect expenses, if any, annually. (n) Environmental Liabilities and Litigation The Partnership’s policy is to accrue for losses associated with environmental remediation obligations when such losses are probable and reasonably estimable. Accruals for estimated losses from environmental remediation obligations generally are recognized no later than completion of the remedial feasibility study. Such accruals are adjusted as further information develops or circumstances change. Costs of future expenditures for environmental remediation obligations are not discounted to their present value. Recoveries of environmental remediation costs from other parties are recorded as assets when their receipt is deemed probable. (o) Trade and Accrued Accounts Receivable and Allowance for Doubtful Accounts. Trade accounts receivable are recorded at the invoiced amount and do not bear interest. The allowance for doubtful accounts is the Partnership’s best estimate of the amount of probable credit losses in the Partnership’s existing accounts receivable. (p) Deferred Catalyst Costs The cost of the periodic replacement of catalysts is deferred and amortized over the catalyst’s estimated useful life, which ranges from 12 to 36 months. (q) Deferred Turnaround Costs The Partnership capitalizes the cost of major turnarounds and amortizes these costs over the estimated period to the next turnaround, which ranges from 12 to 36 months. (r) Income Taxes The Partnership is subject to the Texas margin tax, which is considered a state income tax, and is included in income tax expense on the Consolidated Statements of Operations. Since the tax base on the Texas margin tax is derived from an income-based measure, the margin tax is construed as an income tax and, therefore, the recognition of deferred taxes applies to the margin tax. The impact on deferred taxes as a result of this provision is immaterial. Prior to the acquisition of MTI on January 2, 2019, MTI was a Qualified Subchapter S subsidiary ("QSub") of Martin Resource Management Corporation, a qualifying S Corporation. A QSub is not treated as a separate corporation for federal income tax purposes as it is deemed liquidated into its S Corporation parent. S Corporations are generally not subject to income taxes because income and losses flow through to shareholders and are reported on their individual returns. Three states in which MTI was subject to taxation prior to the acquisition - Louisiana, New Jersey and Tennessee - do not recognize the federal S Corporation status and, therefore, taxed MTI on a C Corporation basis. Subsequent to the acquisition, the QSub election terminated resulting in MTI being taxed as a stand-alone C Corporation. The Partnership's financial statements recognize the current and deferred income tax consequences that result from MTI’s activities during the current period pursuant to the provisions of the FASB ASC 740 related to income taxes. As a result of the common control transaction with the Partnership, the deferred tax consequences of the changes in the tax bases of MTI’s assets and liabilities were included in equity (ASC 740-20-45-11). With respect to the Partnership’s taxable subsidiary (MTI), income taxes are accounted for under the asset and liability method, whereby deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. In the ordinary course of business, there may be many transactions and calculations where the ultimate tax outcome is uncertain. The calculation of tax liabilities involves dealing with uncertainties in the application of complex tax laws. In accordance with the provisions of ASC 740, we use a two-step approach for recognizing and measuring tax benefits taken or expected to be taken in a tax return. In the first step, "recognition", the Partnership determines whether it is more likely than not that a tax position will be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. In evaluating whether a tax position has met the more-likely-than-not recognition threshold, the Partnership presumes that the position will be examined by the appropriate taxing authority that has full knowledge of all relevant information. In the second step, "measurement", a tax position that meets the more-likely-than-not threshold is measured to determine the amount of benefit to recognize in the financial statements. The tax position is measured at the largest amount of benefit that is greater than 50 percent likely of being realized upon ultimate settlement based upon management’s intent regarding negotiation and litigation. In evaluating all income tax positions for all open years, management has determined all positions are more likely than not to be sustained at full benefit based upon their technical merit under applicable tax laws. (s) Comprehensive Income Comprehensive income includes net income and other comprehensive income. There are no items of other comprehensive income or loss in any of the years presented.

The consolidated financial statements include the financial statements of the Partnership and its wholly-owned subsidiaries and equity method investees. In the opinion of the management of the Partnership’s general partner, all adjustments and elimination of significant intercompany balances necessary for a fair presentation of the Partnership’s results of operations, financial position and cash flows for the periods shown have been made. All such adjustments are of a normal recurring nature. In addition, the Partnership evaluates its relationships with other entities to identify whether they are variable interest entities under certain provisions of the Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC"), 810-10 and to assess whether it is the primary beneficiary of such entities. If the determination is made that the Partnership is the primary beneficiary, then that entity is included in the consolidated financial statements in accordance with ASC 810-10. No such variable interest entities exist as of December 31, 2019 or 2018.

Divestiture of Natural Gas Storage Assets. On June 28, 2019, the Partnership completed the sale of its membership interests in Arcadia Gas Storage, LLC, Cadeville Gas Storage LLC, Monroe Gas Storage Company, LLC and Perryville Gas Storage LLC (the "Natural Gas Storage Assets") to Hartree Cardinal Gas, LLC ("Hartree"), a subsidiary of Hartree Bulk Storage, LLC. The Natural Gas Storage Assets consist of approximately 50 billion cubic feet of working capacity located in northern Louisiana and Mississippi. In consideration of the sale of the Natural Gas Storage Assets, the Partnership received cash proceeds of $210,067 after transaction fees and expenses. The net proceeds were used to reduce outstanding borrowings under the Partnership's revolving credit facility. The Partnership has concluded the disposition represents a strategic shift and will have a major effect on its financial results going forward. As a result, the Partnership has presented the results of operations and cash flows relating to the Natural Gas Storage Assets as discontinued operations for the years ended December 31, 2019, 2018, and 2017. See Note 5 for more information.

Acquisition of Martin Transport, Inc. On January 2, 2019, the Partnership acquired all of the issued and outstanding equity interests of Martin Transport, Inc. ("MTI") from Martin Resource Management Corporation. MTI operates a fleet of tank trucks providing transportation of petroleum products, liquid petroleum gas, chemicals, sulfur and other products, as well as owns 23 terminals located throughout the U.S. Gulf Coast and Southeastern United States.

The acquisition of MTI was considered a transfer of net assets between entities under common control. As a result, the acquisition of MTI was recorded at amounts based on the historical carrying value of these assets at January 1, 2019, and the Partnership is required to update its historical financial statements to include the activities of MTI as of the date of common

control. See Note 4 for more information. The Partnership’s accompanying historical financial statements have been retrospectively updated to reflect the effects on financial position, cash flows and results of operations attributable to the activities of MTI as if the Partnership owned these assets for the periods presented. See Note 4 for separate results of MTI for the years ended December 31, 2018 and 2017. Net income attributable to MTI for periods prior to the Partnership’s acquisition of the assets is not allocated to the limited partners for purposes of calculating net income per limited partner unit. See Note 17.

Divestiture of WTLPG Partnership Interest. On July 31, 2018, the Partnership completed the sale of its 20 percent non-operating interest in West Texas LPG Pipeline L.P. ("WTLPG") to ONEOK, Inc. ("ONEOK"). WTLPG owns an approximate 2,300 mile common-carrier pipeline system that primarily transports NGLs from New Mexico and Texas to Mont Belvieu, Texas for fractionation. A wholly-owned subsidiary of ONEOK, Inc. is the operator of the assets. The Partnership has concluded the disposition represents a strategic shift and will have a major effect on its financial results going forward. As a result, the Partnership has presented the results of operations and cash flows relating to its equity method investment in WTLPG as discontinued operations for the years ended December 31, 2018 and 2017. See Note 5 for more information.

The Partnership enters into product exchange agreements with third parties, whereby the Partnership agrees to exchange NGLs and sulfur with third parties. The Partnership records the balance of exchange products due to other companies under these agreements at quoted market product prices and the balance of exchange products due from other companies at the lower of cost or market. Cost is determined using the first-in, first-out ("FIFO") method. Product exchanges with the same counterparty are entered into in contemplation of one another and are combined. The net amount related to location differentials is reported in "Product sales" or "Cost of products sold" in the Consolidated Statements of Operations.

Inventories are stated at the lower of cost or market. Cost is generally determined by using the FIFO method for all inventories except lubricants and lubricants packaging inventories. Lubricants and lubricants packaging inventories cost is determined using standard cost, which approximates actual cost, computed on a FIFO basis.

Terminalling and Storage – Revenue is recognized for storage contracts based on the contracted monthly tank fixed fee. For throughput contracts, revenue is recognized based on the volume moved through the Partnership’s terminals at the contracted rate. For the Partnership’s tolling agreement, revenue is recognized based on the contracted monthly reservation fee and throughput volumes moved through the facility. When lubricants and drilling fluids are sold by truck or rail, revenue is recognized when title is transfered, which is either upon delivering product to the customer or when the product leaves the Partnership's facility, depending on the specific terms of the contract. Delivery of product is invoiced as the transaction occurs and is generally paid within a month.

Sulfur Services – Revenue from sulfur and fertilizer product sales is recognized when the customer takes title to the product. Delivery of product is invoiced as the transaction occurs and is generally paid within a month. Revenue from sulfur services is recognized as services are performed during each monthly period. The performance of the service is invoiced as the transaction occurs and is generally paid within a month.

Natural Gas Liquids – NGL distribution revenue is recognized when product is delivered by truck, rail, or pipeline to the Partnership's NGL customers. Revenue is recognized on title transfer of the product to the customer. Delivery of product is invoiced as the transaction occurs and is generally paid within a month.

The Partnership uses the equity method of accounting for investments in unconsolidated entities where the ability to exercise significant influence over such entities exists. Investments in unconsolidated entities consist of capital contributions and advances plus the Partnership’s share of accumulated earnings as of the entities’ latest fiscal year-ends, less capital withdrawals and distributions. Equity method investments are subject to impairment under the provisions of ASC 323-10, which relates to the equity method of accounting for investments in common stock. No portion of the net income from these entities is included in the Partnership’s operating income.

Routine maintenance and repairs are charged to expense while costs of betterments and renewals are capitalized. When an asset is retired or sold, its cost and related accumulated depreciation are removed from the accounts, and the difference between net book value of the asset and proceeds from disposition is recognized as gain or loss.

Goodwill is subject to a fair-value based impairment test on an annual basis, or more often if events or circumstances indicate there may be impairment. The Partnership is required to identify its reporting units and determine the carrying value of each reporting unit by assigning the assets and liabilities, including the existing goodwill and intangible assets. The Partnership is required to determine the fair value of each reporting unit and compare it to the carrying amount of the reporting unit. To the extent the carrying amount of a reporting unit exceeds the fair value of the reporting unit, the Partnership will record the amount of goodwill impairment as the excess of a reporting unit's carrying amount over its fair value, not to exceed the total amount of goodwill allocated to the reporting unit.

When assessing the recoverability of goodwill and other intangible assets, the Partnership may first assess qualitative factors in determining whether it is more likely than not that the fair value of a reporting unit or other intangible asset is less than its carrying amount. After assessing qualitative factors, if the Partnership determines that it is not more likely than not that the fair value of a reporting unit or other intangible asset is less than its carrying amount, then performing a quantitative assessment is not required. If an initial qualitative assessment indicates that it is more likely than not the carrying amount exceeds the fair value of a reporting unit or other intangible asset, a quantitative analysis will be performed. The Partnership may also elect to bypass the qualitative assessment and proceed directly to a quantitative analysis depending on the facts and circumstances.

In performing a quantitative analysis, recoverability of goodwill for each reporting unit is measured using a weighting of the discounted cash flow method and two market approaches (the guideline public company method and the guideline transaction method). The discounted cash flow model incorporates discount rates commensurate with the risks involved. Use of a discounted cash flow model is common practice in assessing impairment in the absence of available transactional market evidence to determine the fair value. The key assumptions used in the discounted cash flow valuation model include discount rates, growth rates, cash flow projections and terminal value rates. Discount rates, growth rates and cash flow projections are the most sensitive and susceptible to change as they require significant management judgment. Discount rates are determined by using a weighted average cost of capital ("WACC"). The WACC considers market and industry data as well as company-specific risk factors for each reporting unit in determining the appropriate discount rate to be used. The discount rate utilized for each reporting unit is indicative of the return an investor would expect to receive for investing in such a business. Management, considering industry and company specific historical and projected data, develops growth rates and cash flow projections for each reporting unit. Terminal value rate determination follows common methodology of capturing the present value of perpetual cash flow estimates beyond the last projected period assuming a constant WACC and low long-term growth

Significant changes in these estimates and assumptions could materially affect the determination of fair value for each reporting unit which could give rise to future impairment. Changes to these estimates and assumptions can include, but may not be limited to, varying commodity prices, volume changes and operating costs due to market conditions and/or alternative providers of services.

Other intangible assets that have finite lives are tested for impairment when events or circumstances indicate that the carrying value may not be recoverable. An impairment is indicated if the carrying amount of a long-lived intangible asset exceeds the sum of the undiscounted future cash flows expected to result from the use and eventual disposition of the asset. If impairment is indicated, the Partnership would record an impairment loss equal to the difference between the carrying value and the fair value of the asset. There were no intangible asset impairments in 2019, 2018 or 2017.

In accordance with ASC 360-10, long-lived assets, such as property, plant and equipment, and intangible assets with definite lives are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of an asset exceeds its estimated future cash flows, an impairment charge is recognized by the amount by which the carrying amount of the asset exceeds the fair value of the asset. Assets to be disposed of would be separately presented in the balance sheet and reported at the lower of the carrying amount or fair value less costs to sell and would no longer be depreciated. The assets and liabilities of a disposed group classified as held for sale would be presented separately in the appropriate asset and liability sections of the balance sheet.

In the fourth quarter of 2017, the Partnership identified a triggering event related to the planned disposition of certain assets that were no longer deemed core assets in the Partnership's Marine Transportation division of the Transportation segment. The triggering event was the assets' inability to generate cash flows in recent quarters and going forward. As a result, an impairment charge of $1,625 was recorded in the Transportation segment results of operations in the fourth quarter of 2017. Additionally, the Partnership recorded an adjustment to the fair value less cost to sell of a certain asset classified as held for sale in the Martin Lubricants division of the Terminalling and Storage segment. As a result, an impairment charge of $600 was recorded in the Terminalling and Storage segment results of operations in the fourth quarter of 2017.

Partnership experienced an impact from Hurricane Harvey in our Terminalling and Storage and Sulfur Services segments, where damages were suffered to the Partnership's property, plant, and equipment at its Neches, Stanolind, Galveston, and Harbor Island terminals located along the Texas gulf coast. The damage incurred did not exceed the insurance deductible at these locations and therefore the Partnership did not receive any insurance proceeds resulting from the damage from Hurricane Harvey. In the third quarter of 2017, the Partnership recorded a write-off in the amount of $186 related to assets damaged.

Under ASC 410-20, which relates to accounting requirements for costs associated with legal obligations to retire tangible, long-lived assets, the Partnership records an asset retirement obligation ("ARO") at fair value in the period in which it is incurred by increasing the carrying amount of the related long-lived asset. In each subsequent period, the liability is accreted over time towards the ultimate obligation amount and the capitalized costs are depreciated over the useful life of the related asset.

In accordance with certain provisions of ASC 815-10 related to accounting for derivative instruments and hedging activities, all derivatives and hedging instruments are included in the Consolidated Balance Sheets as an asset or liability measured at fair value and changes in fair value are recognized currently in earnings unless specific hedge accounting criteria are met. If a derivative qualifies for hedge accounting, changes in the fair value can be offset against the change in the fair value of the hedged item through earnings or recognized in other comprehensive income until such time as the hedged item is recognized in earnings.

Management has made a number of estimates and assumptions relating to the reporting of assets and liabilities and the disclosure of contingent assets and liabilities to prepare these consolidated financial statements in conformity with accounting principles generally accepted in the U.S. Actual results could differ from those estimates.

Indirect selling, general and administrative expenses are incurred by Martin Resource Management Corporation and allocated to the Partnership to cover costs of centralized corporate functions such as accounting, treasury, engineering, information technology, risk management and other corporate services. Such expenses are based on the percentage of time spent by Martin Resource Management Corporation’s personnel that provide such centralized services. Under an omnibus agreement with Martin Resource Management Corporation, the Partnership is required to reimburse Martin Resource Management Corporation for indirect general and administrative and corporate overhead expenses. For the years ended December 31, 2019, 2018 and 2017, the conflicts committee of the Partnership's general partner ("Conflicts Committee") approved reimbursement amounts of $16,657, $16,416 and $16,416, respectively, reflecting the Partnership's allocable share of such expenses. The Conflicts Committee will review and approve future adjustments in the reimbursement amount for indirect expenses, if any, annually.

The Partnership’s policy is to accrue for losses associated with environmental remediation obligations when such losses are probable and reasonably estimable. Accruals for estimated losses from environmental remediation obligations generally are recognized no later than completion of the remedial feasibility study. Such accruals are adjusted as further information develops or circumstances change. Costs of future expenditures for environmental remediation obligations are not discounted to their present value. Recoveries of environmental remediation costs from other parties are recorded as assets when their receipt is deemed probable.

The Partnership is subject to the Texas margin tax, which is considered a state income tax, and is included in income tax expense on the Consolidated Statements of Operations. Since the tax base on the Texas margin tax is derived from an income-based measure, the margin tax is construed as an income tax and, therefore, the recognition of deferred taxes applies to the margin tax. The impact on deferred taxes as a result of this provision is immaterial.

Prior to the acquisition of MTI on January 2, 2019, MTI was a Qualified Subchapter S subsidiary ("QSub") of Martin Resource Management Corporation, a qualifying S Corporation. A QSub is not treated as a separate corporation for federal income tax purposes as it is deemed liquidated into its S Corporation parent. S Corporations are generally not subject to income taxes because income and losses flow through to shareholders and are reported on their individual returns. Three states in which MTI was subject to taxation prior to the acquisition - Louisiana, New Jersey and Tennessee - do not recognize the federal S Corporation status and, therefore, taxed MTI on a C Corporation basis. Subsequent to the acquisition, the QSub election terminated resulting in MTI being taxed as a stand-alone C Corporation.

The Partnership's financial statements recognize the current and deferred income tax consequences that result from MTI’s activities during the current period pursuant to the provisions of the FASB ASC 740 related to income taxes. As a result of the common control transaction with the Partnership, the deferred tax consequences of the changes in the tax bases of MTI’s assets and liabilities were included in equity (ASC 740-20-45-11).

With respect to the Partnership’s taxable subsidiary (MTI), income taxes are accounted for under the asset and liability method, whereby deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date.

In the ordinary course of business, there may be many transactions and calculations where the ultimate tax outcome is uncertain. The calculation of tax liabilities involves dealing with uncertainties in the application of complex tax laws. In accordance with the provisions of ASC 740, we use a two-step approach for recognizing and measuring tax benefits taken or expected to be taken in a tax return. In the first step, "recognition", the Partnership determines whether it is more likely than not that a tax position will be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. In evaluating whether a tax position has met the more-likely-than-not recognition threshold, the Partnership presumes that the position will be examined by the appropriate taxing authority that has full knowledge of all relevant information. In the second step, "measurement", a tax position that meets the more-likely-than-not threshold is measured to determine the amount of benefit to recognize in the financial statements. The tax position is measured at the largest amount of benefit that is greater than 50 percent likely of being realized upon ultimate settlement based upon management’s intent regarding negotiation and litigation. In evaluating all income tax positions for all open years, management has determined all positions are more likely than not to be sustained at full benefit based upon their technical merit under applicable tax laws.