Martin Midstream Partners (MMLP) 10-Q 25 Oct 21 2021 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2021	Oct. 25, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	000-50056
Entity Registrant Name	MARTIN MIDSTREAM PARTNERS L.P.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	05-0527861
Entity Address, Address Line One	4200 Stone Road
Entity Address, City or Town	Kilgore
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	75662
City Area Code	903
Local Phone Number	983-6200
Title of each class	Common Units representing limited partnership interests
Trading Symbol(s)	MMLP
Name of each exchange on which registered	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		38,802,750
Entity Central Index Key	0001176334
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Amendment Flag	false

CONSOLIDATED AND CONDENSED BALA

CONSOLIDATED AND CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Assets
Cash	$ 6,783	$ 4,958
Accounts and other receivables, less allowance for doubtful accounts of $272 and $261, respectively	75,676	52,748
Inventories	98,139	54,122
Due from affiliates	10,133	14,807
Other current assets	10,441	8,991
Total current assets	201,172	135,626
Property, plant and equipment, at cost	894,767	889,108
Accumulated depreciation	(543,309)	(509,237)
Property, plant and equipment, net	351,458	379,871
Goodwill	16,823	16,823
Right-of-use assets	21,267	22,260
Deferred income taxes, net	20,834	22,253
Other assets, net	2,684	2,805
Total assets	614,238	579,638
Liabilities and Partners’ Capital (Deficit)
Current installments of long-term debt and finance lease obligations	240	31,497
Trade and other accounts payable	73,273	51,900
Product exchange payables	1,387	373
Due to affiliates	5,469	435
Income taxes payable	401	556
Fair value of derivatives	5,049	207
Other accrued liabilities	21,696	34,407
Total current liabilities	107,515	119,375
Long-term debt, net	547,090	484,597
Finance lease obligations	108	289
Operating lease liabilities	14,960	15,181
Other long-term obligations	8,721	7,067
Total liabilities	678,394	626,509
Commitments and contingencies
Partners’ capital (deficit)	(58,157)	(46,871)
Accumulated other comprehensive loss	(5,999)	0
Total partners’ capital (deficit)	(64,156)	(46,871)
Total liabilities and partners' capital (deficit)	$ 614,238	$ 579,638

CONSOLIDATED AND CONDENSED BA_2

CONSOLIDATED AND CONDENSED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 272	$ 261

CONSOLIDATED AND CONDENSED STAT

CONSOLIDATED AND CONDENSED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues:
Revenues		$ 211,258	$ 152,533	$ 596,525	$ 492,054
Cost of products sold: (excluding depreciation and amortization)
Cost of products sold		129,570	77,345	350,414	249,445
Expenses:
Operating expenses	[1]	50,098	43,105	142,045	138,589
Selling, general and administrative	[1]	9,739	10,339	29,308	30,659
Depreciation and amortization		13,945	15,276	42,862	45,858
Total costs and expenses		203,352	146,065	564,629	464,551
Other operating income (loss), net		61	23	(610)	2,548
Gain on involuntary conversion of property, plant and equipment		186	4,522	186	4,522
Operating income		8,153	11,013	31,472	34,573
Other income (expense):
Interest expense, net		(14,110)	(12,943)	(40,372)	(32,245)
Gain on retirement of senior unsecured notes		0	0	0	3,484
Loss on exchange of senior unsecured notes		0	(8,516)	0	(8,516)
Other, net		0	0	(1)	7
Total other expense		(14,110)	(21,459)	(40,373)	(37,270)
Net loss before taxes		(5,957)	(10,446)	(8,901)	(2,697)
Income tax expense		(954)	(373)	(2,111)	(1,510)
Net loss		(6,911)	(10,819)	(11,012)	(4,207)
Less general partner's interest in net loss		138	216	220	84
Less loss allocable to unvested restricted units		20	53	30	8
Limited partners' interest in net loss		$ (6,753)	$ (10,550)	$ (10,762)	$ (4,115)
Net loss per unit attributable to limited partners - basic (in dollars per share)		$ (0.17)	$ (0.27)	$ (0.28)	$ (0.11)
Net loss per unit attributable to limited partners - diluted (in dollars per share)		$ (0.17)	$ (0.27)	$ (0.28)	$ (0.11)
Weighted average limited partner units - basic (in shares)		38,687,874	38,661,852	38,689,434	38,654,891
Weighted average limited partner units - diluted (in shares)		38,687,874	38,661,852	38,689,434	38,654,891
Terminalling and storage
Revenues:
Revenues	[1]	$ 18,980	$ 20,706	$ 56,060	$ 61,088
Transportation
Revenues:
Revenues	[1]	39,079	31,938	103,820	102,364
Sulfur services
Revenues:
Revenues		2,950	2,915	8,849	8,744
Product sales
Revenues:
Revenues	[1]	150,249	96,974	427,796	319,858
Natural gas liquids
Revenues:
Revenues	[1]	91,764	52,350	257,081	164,860
Cost of products sold: (excluding depreciation and amortization)
Cost of products sold	[1]	85,137	44,908	225,862	139,036
Sulfur services
Revenues:
Revenues	[1]	27,887	18,965	95,109	74,879
Cost of products sold: (excluding depreciation and amortization)
Cost of products sold	[1]	20,266	13,313	65,657	46,167
Terminalling and storage
Revenues:
Revenues	[1]	30,598	25,659	75,606	80,119
Cost of products sold: (excluding depreciation and amortization)
Cost of products sold	[1]	$ 24,167	$ 19,124	$ 58,895	$ 64,242
[1]	Related Party Transactions Included Above Three Months Ended Nine Months Ended September 30, September 30, 2021 2020 2021 2020 Revenues:* Terminalling and storage $ 15,866 $ 15,902 $ 46,741 $ 47,718 Transportation 5,564 5,514 14,463 16,801 Product Sales 68 69 253 199 Costs and expenses:* Cost of products sold: (excluding depreciation and amortization) Sulfur services 2,441 2,512 7,379 7,833 Terminalling and storage 7,259 4,303 18,863 14,329 Expenses: Operating expenses 20,088 18,915 58,046 60,126 Selling, general and administrative 7,659 8,356 23,624 24,723

CONSOLIDATED AND CONDENSED ST_2

CONSOLIDATED AND CONDENSED STATEMENTS OF OPERATIONS - Related Party Transactions (Parentheticals) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues:
Revenues		$ 211,258	$ 152,533	$ 596,525	$ 492,054
Cost of products sold: (excluding depreciation and amortization)
Cost of products sold		129,570	77,345	350,414	249,445
Expenses:
Operating expenses		20,088	18,915	58,046	60,126
Selling, general and administrative		7,659	8,356	23,624	24,723
Terminalling and storage
Revenues:
Revenues	[1]	18,980	20,706	56,060	61,088
Transportation
Revenues:
Revenues	[1]	39,079	31,938	103,820	102,364
Product Sales
Revenues:
Revenues	[1]	150,249	96,974	427,796	319,858
Sulfur services
Revenues:
Revenues	[1]	27,887	18,965	95,109	74,879
Cost of products sold: (excluding depreciation and amortization)
Cost of products sold	[1]	20,266	13,313	65,657	46,167
Terminalling and storage
Revenues:
Revenues	[1]	30,598	25,659	75,606	80,119
Cost of products sold: (excluding depreciation and amortization)
Cost of products sold	[1]	24,167	19,124	58,895	64,242
Related Party
Expenses:
Operating expenses		20,088	18,915	58,046	60,126
Related Party | Terminalling and storage
Revenues:
Revenues		15,866	15,902	46,741	47,718
Expenses:
Operating expenses		4,284	4,300	12,513	13,292
Related Party | Transportation
Revenues:
Revenues		5,564	5,514	14,463	16,801
Expenses:
Operating expenses		13,949	13,009	40,652	41,950
Related Party | Product Sales
Revenues:
Revenues		68	69	253	199
Related Party | Sulfur services
Cost of products sold: (excluding depreciation and amortization)
Cost of products sold		2,441	2,512	7,379	7,833
Expenses:
Operating expenses		1,321	1,120	3,370	3,403
Related Party | Terminalling and storage
Cost of products sold: (excluding depreciation and amortization)
Cost of products sold		$ 7,259	$ 4,303	$ 18,863	$ 14,329
[1]	Related Party Transactions Included Above Three Months Ended Nine Months Ended September 30, September 30, 2021 2020 2021 2020 Revenues:* Terminalling and storage $ 15,866 $ 15,902 $ 46,741 $ 47,718 Transportation 5,564 5,514 14,463 16,801 Product Sales 68 69 253 199 Costs and expenses:* Cost of products sold: (excluding depreciation and amortization) Sulfur services 2,441 2,512 7,379 7,833 Terminalling and storage 7,259 4,303 18,863 14,329 Expenses: Operating expenses 20,088 18,915 58,046 60,126 Selling, general and administrative 7,659 8,356 23,624 24,723

CONSOLIDATED AND CONDENSED ST_3

CONSOLIDATED AND CONDENSED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net loss	$ (6,911)	$ (10,819)	$ (11,012)	$ (4,207)
Changes in fair values of commodity cash flow hedges	(5,999)	0	(5,999)	0
Total comprehensive income	$ (12,910)	$ (10,819)	$ (17,011)	$ (4,207)

CONSOLIDATED AND CONDENSED ST_4

CONSOLIDATED AND CONDENSED STATEMENTS OF CAPITAL (DEFICIT) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Increase (Decrease) in Partners' Capital
Beginning balance			$ (46,871)	$ (36,196)
Net loss	$ (6,911)	$ (10,819)	(11,012)	(4,207)
Cash distributions			(593)	(5,121)
Unit-based compensation			336	1,070
Changes in fair values of commodity cash flow hedges	(5,999)	0	(5,999)	0
Purchase of treasury units			(17)	(9)
Ending balance	(64,156)	(44,463)	(64,156)	(44,463)
Common Limited | Common
Increase (Decrease) in Partners' Capital
Beginning balance			$ (48,776)	$ (38,342)
Beginning balance (in shares)			38,851,174	38,863,389
Net loss			$ (10,792)	$ (4,123)
Issuance of restricted units (in shares)			42,168	81,000
Forfeiture of restricted units (in shares)			(83,436)	(84,134)
Cash distributions			$ (581)	$ (5,019)
Unit-based compensation			336	1,070
Purchase of treasury units			$ (17)	$ (9)
Purchase of treasury units (in shares)			(7,156)	(7,748)
Ending balance	$ (59,830)	$ (46,423)	$ (59,830)	$ (46,423)
Ending balance (in shares)	38,802,750	38,852,507	38,802,750	38,852,507
General Partner Amount
Increase (Decrease) in Partners' Capital
Beginning balance			$ 1,905	$ 2,146
Net loss			(220)	(84)
Cash distributions			(12)	(102)
Ending balance	$ 1,673	$ 1,960	1,673	1,960
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Partners' Capital
Beginning balance			0	0
Changes in fair values of commodity cash flow hedges			(5,999)
Ending balance	$ (5,999)	$ 0	$ (5,999)	$ 0

CONSOLIDATED AND CONDENSED ST_5

CONSOLIDATED AND CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net loss	$ (11,012)	$ (4,207)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	42,862	45,858
Amortization of deferred debt issuance costs	2,585	2,674
Amortization of premium on notes payable	0	(191)
Deferred income tax expense	1,419	1,202
Loss on sale of property, plant and equipment, net	610	153
Gain on involuntary conversion of property, plant and equipment	(186)	(4,522)
Non-cash impact related to exchange of senior unsecured notes	0	(749)
Gain on retirement of senior unsecured notes	0	(3,484)
Derivative (income) loss	1,825	(815)
Net cash received (paid) for commodity derivatives	(2,982)	539
Non cash unit-based compensation	336	1,070
Change in current assets and liabilities, excluding effects of acquisitions and dispositions:
Accounts and other receivables	(22,924)	30,012
Product exchange receivables	0	(212)
Inventories	(44,353)	(15,184)
Due from affiliates	4,674	(1,103)
Other current assets	(1,912)	(6,130)
Trade and other accounts payable	21,092	(17,117)
Product exchange payables	1,014	(1,278)
Due to affiliates	5,034	(1,003)
Income taxes payable	(155)	(137)
Other accrued liabilities	(10,536)	(5,534)
Change in other non-current assets and liabilities	203	(692)
Net cash provided by (used in) operating activities	(12,406)	19,150
Cash flows from investing activities:
Payments for property, plant and equipment	(11,449)	(23,705)
Payments for plant turnaround costs	(2,679)	(637)
Proceeds from involuntary conversion of property, plant and equipment	274	7,203
Proceeds from sale of property, plant and equipment	225	4,392
Net cash used in investing activities	(13,629)	(12,747)
Cash flows from financing activities:
Payments of long-term debt	(211,790)	(253,637)
Payments under finance lease obligations	(2,648)	(4,021)
Proceeds from long-term debt	243,500	259,019
Purchase of treasury units	(17)	(9)
Payment of debt issuance costs	(592)	(3,628)
Cash distributions paid	(593)	(5,121)
Net cash provided by (used in) financing activities	27,860	(7,397)
Net increase (decrease) in cash	1,825	(994)
Cash at beginning of period	4,958	2,856
Cash at end of period	6,783	1,862
Non-cash additions to property, plant and equipment	$ 749	$ 1,432

Nature of Operations and Basis

Nature of Operations and Basis of Presentation	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Nature of Operations and Basis of Presentation	NATURE OF OPERATIONS AND BASIS OF PRESENTATION Martin Midstream Partners L.P. (the "Partnership") is a publicly traded limited partnership with a diverse set of operations focused primarily in the United States ("U.S.") Gulf Coast region. Its four primary business lines include: (1) terminalling, processing, storage and packaging services for petroleum products and by-products including the refining of naphthenic crude oil; (2) land and marine transportation services for petroleum products and by-products, chemicals, and specialty products; (3) sulfur and sulfur-based products processing, manufacturing, marketing and distribution; and (4) natural gas liquids marketing, distribution, and transportation services. The Partnership’s unaudited consolidated and condensed financial statements have been prepared in accordance with the requirements of Form 10-Q and U.S. Generally Accepted Accounting Principles ("U.S. GAAP") for interim financial reporting. Accordingly, these financial statements have been condensed and do not include all of the information and footnotes required by U.S. GAAP for annual audited financial statements of the type contained in the Partnership’s annual reports on Form 10-K. 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 financial position, results of operations, and cash flows for the periods shown have been made. All such adjustments are of a normal recurring nature. Results for such interim periods are not necessarily indicative of the results of operations for the full year. These financial statements should be read in conjunction with the Partnership’s audited consolidated financial statements and notes thereto included in the Partnership’s annual report on Form 10-K for the year ended December 31, 2020, filed with the SEC on March 3, 2021. 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 and condensed financial statements in conformity with U.S. GAAP. Actual results could differ from those estimates.

New Accounting Pronouncements

New Accounting Pronouncements	9 Months Ended
	Sep. 30, 2021
Accounting Changes and Error Corrections [Abstract]
New Accounting Pronouncements	NEW ACCOUNTING PRONOUNCEMENTS On January 1, 2021, the Partnership adopted Financial Accounting Standards Board ("FASB") Accounting Standards Update ("ASU") 2019-12, Income Taxes (Accounting Standards Codification ("ASC") Topic 740): Simplifying the Accounting for Income Taxes , which removes certain exceptions to general principles in ASC 740 and clarifies and amends existing guidance within U.S. GAAP. Adoption of the new standard did not have a material impact on the Partnership’s consolidated financial statements.

Revenue

Revenue	9 Months Ended
	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Revenue	REVENUE The following table disaggregates our revenue by major source: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Terminalling and storage segment Lubricant product sales $ 30,598 $ 25,659 $ 75,606 $ 80,119 Throughput and storage 18,980 20,706 56,060 61,088 $ 49,578 $ 46,365 $ 131,666 $ 141,207 Natural gas liquids segment Natural gas liquids product sales $ 91,764 $ 52,350 $ 257,081 $ 164,860 $ 91,764 $ 52,350 $ 257,081 $ 164,860 Sulfur services segment Sulfur product sales $ 7,768 $ 6,161 $ 22,222 $ 19,010 Fertilizer product sales 20,119 12,804 72,887 55,869 Sulfur services 2,950 2,915 8,849 8,744 $ 30,837 $ 21,880 $ 103,958 $ 83,623 Transportation segment Land transportation $ 30,273 $ 21,879 $ 80,715 $ 65,986 Inland transportation 7,465 9,294 20,822 33,611 Offshore transportation 1,341 765 2,283 2,767 $ 39,079 $ 31,938 $ 103,820 $ 102,364 Revenue is measured based on a consideration specified in a contract with a customer and excludes amounts collected on behalf of third parties where the Partnership is acting as an agent. The Partnership recognizes revenue when the Partnership satisfies a performance obligation, which typically occurs when the Partnership transfers control over a product to a customer or as the Partnership delivers a service. The following is a description of the principal activities - separated by reportable segments - from which the Partnership generates revenue. Terminalling and Storage Segment 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 transferred, 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. Throughput and storage revenue in the table above includes non-cancelable revenue arrangements that are under the scope of ASC 842, whereby the Partnership has committed certain Terminalling and Storage assets in exchange for a minimum fee. Natural Gas Liquids Segment Natural Gas Liquids ("NGL") 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. Sulfur Services Segment 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. Transportation Segment 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. The table below includes estimated minimum revenue expected to be recognized in the future related to performance obligations that are unsatisfied at the end of the reporting period. The Partnership applies the practical expedient in ASC 606-10-50-14(a) and does not disclose information about remaining performance obligations that have original expected durations of one year or less. 2021 2022 2023 2024 2025 Thereafter Total Terminalling and storage Throughput and storage $ 9,843 $ 40,394 $ 41,605 $ 42,910 $ 44,197 $ 294,205 $ 473,154 Natural Gas Services Natural Gas Liquids 1,644 6,048 5,391 5,405 5,391 3,131 27,010 Sulfur services Sulfur product sales 4,291 17,165 16,415 2,156 2,156 1,477 43,660 Total $ 15,778 $ 63,607 $ 63,411 $ 50,471 $ 51,744 $ 298,813 $ 543,824

Inventories

Inventories	9 Months Ended
	Sep. 30, 2021
Inventory Disclosure [Abstract]
Inventories	INVENTORIES Components of inventories at September 30, 2021 and December 31, 2020 were as follows: September 30, December 31, Natural gas liquids $ 65,136 $ 27,878 Sulfur 49 24 Fertilizer 8,799 10,854 Lubricants 19,670 11,002 Other 4,485 4,364 $ 98,139 $ 54,122

Debt

Debt	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Debt	DEBT At September 30, 2021 and December 31, 2020, long-term debt consisted of the following: September 30, December 31, $275,000 Revolving credit facility at variable interest rate (5.00% 1 weighted average at September 30, 2021), due August 2023 secured by substantially all of the Partnership’s assets, including, without limitation, inventory, accounts receivable, vessels, equipment, fixed assets and the interests in the Partnership’s operating subsidiaries, net of unamortized debt issuance costs of $3,004 and $3,826, respectively 2 $ 205,496 $ 144,174 $400,000 Senior notes, 7.25% interest, net of unamortized debt issuance costs of $— and $—, respectively, including unamortized premium of $— and $—, respectively, issued $250,000 February 2013 and $150,000 April 2014, $26,200 repurchased during 2015, $9,344 repurchased during 2020, $335,666 refinanced as part of the August 2020 Exchange offer, $28,790 repaid at maturity in February 2021, unsecured 2,3,4 — 28,790 $53,750 Senior notes due February 2024, 10.0% interest, net of unamortized debt issuance costs of $2,719 and $3,577, respectively, secured 2,3 51,031 50,173 $291,970 Senior notes due February 2025, 11.5% interest, net of unamortized debt issuance costs of $1,407 and $1,720, respectively, secured 2,3 290,563 290,250 Total 547,090 513,387 Less: current portion — (28,790) Total long-term debt, net of current portion $ 547,090 $ 484,597 Current installments of finance lease obligations $ 240 $ 2,707 Finance lease obligations 108 289 Total finance lease obligations $ 348 $ 2,996 1 Interest rate fluctuates based on LIBOR (set on the date of each advance) or the base prime rate plus an applicable margin. The margin is set every three months. All amounts outstanding at December 31, 2020 and September 30, 2021 were at LIBOR plus an applicable margin with LIBOR having a floor of 1.00% per annum. The applicable margin for revolving loans that are LIBOR loans currently ranges from 2.75% to 4.00%, and the applicable margin for revolving loans that are base prime rate loans currently ranges from 1.75% to 3.00%. The applicable margin for LIBOR borrowings at September 30, 2021 is 4.00%. The credit facility contains various covenants that limit the Partnership’s ability to make distributions; make certain investments and acquisitions; enter into certain agreements; incur indebtedness; sell assets; and make certain amendments to the Partnership's omnibus agreement with Martin Resource Management Corporation (the "Omnibus Agreement"). The credit facility was amended on July 16, 2021 to, among other things, reduce the commitments thereunder from $300,000 to $275,000. 2 The Partnership was in compliance with all debt covenants as of September 30, 2021 and December 31, 2020, respectively. 3 The indentures for each of the outstanding series of senior notes restrict the Partnership’s ability to sell assets; pay distributions or repurchase units or redeem or repurchase subordinated debt; make investments; incur or guarantee additional indebtedness or issue preferred units; and consolidate, merge or transfer all or substantially all of its assets. 4 On February 15, 2021, the 2021 Notes matured and the Partnership retired the outstanding balance of $28,790 using funds borrowed under its revolving credit facility.

Leases

Leases	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Leases	LEASES The Partnership has numerous operating leases primarily for terminal facilities and transportation and other equipment. The leases generally provide that all expenses related to the equipment are to be paid by the lessee. Operating lease Right-of-Use assets and operating lease liabilities are recognized based on the present value of lease payments over the lease term at commencement date. Because most of the Partnership's leases do not provide an implicit rate of return, the Partnership uses its imputed collateralized rate based on the information available at commencement date in determining the present value of lease payments. The estimated rate is based on a risk-free rate plus a risk-adjusted margin. Our leases have remaining lease terms of 1 year to 15 years, some of which include options to extend the leases for up to 5 years, and some of which include options to terminate the leases within 1 year. The Partnership includes extension periods and excludes termination periods from its lease term if, at commencement, it is reasonably likely that the Partnership will exercise the option. The components of lease expense for the three and nine months ended September 30, 2021 and 2020 were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Operating lease cost $ 2,485 $ 2,572 $ 6,987 $ 8,182 Finance lease cost: Amortization of right-of-use assets $ 25 390 $ 140 1,505 Interest on lease liabilities $ 5 62 $ 21 258 Short-term lease cost $ 2,324 3,138 $ 7,905 10,054 Variable lease cost $ 28 $ 33 $ 87 $ 83 Total lease cost $ 4,867 $ 6,195 $ 15,140 $ 20,082 Supplemental balance sheet information related to leases at September 30, 2021 and December 31, 2020 was as follows: September 30, December 31, 2020 Operating Leases Operating lease right-of-use assets $ 21,267 $ 22,260 Current portion of operating lease liabilities included in "Other accrued liabilities" $ 6,746 $ 7,529 Operating lease liabilities $ 14,960 15,181 Total operating lease liabilities $ 21,706 $ 22,710 Finance Leases Property, plant and equipment, at cost $ 1,071 $ 10,352 Accumulated depreciation $ (339) (3,703) Property, plant and equipment, net $ 732 $ 6,649 Current installments of finance lease obligations $ 240 $ 2,707 Finance lease obligations $ 108 289 Total finance lease obligations $ 348 $ 2,996 The Partnership’s future minimum lease obligations as of September 30, 2021 consist of the following: Operating Leases Finance Leases Year 1 $ 7,801 $ 252 Year 2 5,102 109 Year 3 2,923 — Year 4 2,220 — Year 5 1,494 — Thereafter 7,120 — Total $ 26,660 $ 361 Less amounts representing interest costs (4,954) (13) Total lease liability $ 21,706 $ 348 The Partnership has non-cancelable revenue arrangements that are under the scope of ASC 842 whereby we have committed certain terminalling and storage assets in exchange for a minimum fee. Future minimum revenues the Partnership expects to receive under these non-cancelable arrangements as of September 30, 2021 are as follows: 2021 - $6,139; 2022 - $14,924; 2023 - $14,364; 2024 - $14,364; 2025 - $13,798; subsequent years - $38,539.
Leases	LEASES The Partnership has numerous operating leases primarily for terminal facilities and transportation and other equipment. The leases generally provide that all expenses related to the equipment are to be paid by the lessee. Operating lease Right-of-Use assets and operating lease liabilities are recognized based on the present value of lease payments over the lease term at commencement date. Because most of the Partnership's leases do not provide an implicit rate of return, the Partnership uses its imputed collateralized rate based on the information available at commencement date in determining the present value of lease payments. The estimated rate is based on a risk-free rate plus a risk-adjusted margin. Our leases have remaining lease terms of 1 year to 15 years, some of which include options to extend the leases for up to 5 years, and some of which include options to terminate the leases within 1 year. The Partnership includes extension periods and excludes termination periods from its lease term if, at commencement, it is reasonably likely that the Partnership will exercise the option. The components of lease expense for the three and nine months ended September 30, 2021 and 2020 were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Operating lease cost $ 2,485 $ 2,572 $ 6,987 $ 8,182 Finance lease cost: Amortization of right-of-use assets $ 25 390 $ 140 1,505 Interest on lease liabilities $ 5 62 $ 21 258 Short-term lease cost $ 2,324 3,138 $ 7,905 10,054 Variable lease cost $ 28 $ 33 $ 87 $ 83 Total lease cost $ 4,867 $ 6,195 $ 15,140 $ 20,082 Supplemental balance sheet information related to leases at September 30, 2021 and December 31, 2020 was as follows: September 30, December 31, 2020 Operating Leases Operating lease right-of-use assets $ 21,267 $ 22,260 Current portion of operating lease liabilities included in "Other accrued liabilities" $ 6,746 $ 7,529 Operating lease liabilities $ 14,960 15,181 Total operating lease liabilities $ 21,706 $ 22,710 Finance Leases Property, plant and equipment, at cost $ 1,071 $ 10,352 Accumulated depreciation $ (339) (3,703) Property, plant and equipment, net $ 732 $ 6,649 Current installments of finance lease obligations $ 240 $ 2,707 Finance lease obligations $ 108 289 Total finance lease obligations $ 348 $ 2,996 The Partnership’s future minimum lease obligations as of September 30, 2021 consist of the following: Operating Leases Finance Leases Year 1 $ 7,801 $ 252 Year 2 5,102 109 Year 3 2,923 — Year 4 2,220 — Year 5 1,494 — Thereafter 7,120 — Total $ 26,660 $ 361 Less amounts representing interest costs (4,954) (13) Total lease liability $ 21,706 $ 348 The Partnership has non-cancelable revenue arrangements that are under the scope of ASC 842 whereby we have committed certain terminalling and storage assets in exchange for a minimum fee. Future minimum revenues the Partnership expects to receive under these non-cancelable arrangements as of September 30, 2021 are as follows: 2021 - $6,139; 2022 - $14,924; 2023 - $14,364; 2024 - $14,364; 2025 - $13,798; subsequent years - $38,539.

Supplemental Balance Sheet Info

Supplemental Balance Sheet Information	9 Months Ended
	Sep. 30, 2021
Balance Sheet Related Disclosures [Abstract]
Supplemental Balance Sheet Information	SUPPLEMENTAL BALANCE SHEET INFORMATION Components of "Other accrued liabilities" were as follows: September 30, December 31, 2020 Accrued interest $ 5,261 $ 16,104 Asset retirement obligations 300 1,692 Property and other taxes payable 4,546 4,869 Accrued payroll 4,425 3,244 Operating lease liabilities 6,746 7,529 Other 418 969 $ 21,696 $ 34,407 The schedule below summarizes the changes in our asset retirement obligations: September 30, 2021 Beginning asset retirement obligations $ 8,759 Additions to asset retirement obligations — Accretion expense 284 Liabilities settled (22) Ending asset retirement obligations 9,021 Current portion of asset retirement obligations 1 (300) Long-term portion of asset retirement obligations 2 $ 8,721 1 The current portion of asset retirement obligations is included in "Other accrued liabilities" on the Partnership's Consolidated and Condensed Balance Sheets. 2 The non-current portion of asset retirement obligations is included in "Other long-term obligations" on the Partnership's Consolidated and Condensed Balance Sheets.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	9 Months Ended
	Sep. 30, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities	DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES The Partnership’s results of operations could be materially impacted by changes in commodity prices and interest rates. In an effort to manage its exposure to these risks, the Partnership periodically enters into various derivative instruments, including commodity and interest rate hedges. At the time derivative contracts are entered into, the Partnership assesses whether the nature of the instrument qualifies for hedge accounting treatment according to the requirements of ASC 815 – Derivatives and Hedging . For those transactions designated as hedging instruments for accounting purposes, the Partnership documents all relationships between hedging instruments and hedged items, as well as our risk-management objective and strategy for undertaking the various hedge transactions. The Partnership also assesses, both at the hedge’s inception and on an ongoing basis, whether the derivatives used in hedging transactions are highly effective in offsetting changes in cash flows or fair value of hedged items. All derivatives and hedging instruments are included on the balance sheet as an asset or a liability measured at fair value. Changes in fair value for hedging instruments are recognized on the balance sheet through Accumulated Other Comprehensive Income ("AOCI"). Settlements related to effective hedging relationships will be reclassified from AOCI to earnings during the term at which the hedged transactions are reflected on the income statement. From time to time, derivatives designated for hedge accounting may be closed prior to contract expiration. The accounting treatment of closed positions depends on whether the closure occurred due to the hedged transaction occurring early or if the hedged transaction is still expected to occur as originally forecasted. For hedged transactions that occur early, the closure results in the realized gain or loss from closure being recognized in the same period the accelerated hedged transaction affects earnings. For hedged transactions that are still expected to occur as originally forecasted, the closure results in the realized gain or loss being deferred until the hedged transaction affects earnings. If it is determined that hedged transactions associated with cash flow hedges are no longer probable of occurring, the gain or loss associated with the instrument is recognized immediately into earnings. From time to time, we may have derivative financial instruments for which we do not elect hedge accounting. Changes in fair value for derivatives not designated as hedges are recognized as gains and losses in the earnings of the periods in which they occur. (a) Commodity Derivative Instruments The Partnership from time to time has used derivatives to manage the risk of commodity price fluctuation. Commodity risk is the adverse effect on the value of a liability or future purchase that results from a change in commodity price. The Partnership has established a hedging policy and monitors and manages the commodity market risk associated with potential commodity risk exposure. In addition, the Partnership has focused on utilizing counterparties for these transactions whose financial condition is appropriate for the credit risk involved in each specific transaction. The Partnership has entered into hedging transactions as of September 30, 2021, to protect a portion of its commodity price risk exposure. These hedging arrangements are in the form of swaps for NGLs. At September 30, 2021, the Partnership had instruments totaling a gross notional quantity of 400,000 barrels settling during the period from October 31, 2021 through December 31, 2021. At December 31, 2020, the Partnership had instruments totaling a gross notional quantity of 137,000 barrels settling during the period from January 31, 2021 through February 28, 2021. These instruments settle against the applicable pricing source for each grade and location. For information regarding gains and losses on commodity derivative instruments, see "Tabular Presentation of Gains and Losses on Derivative Instruments" below. (b) Tabular Presentation of Gains and Losses on Derivative Instruments The following table summarizes the fair value and classification of the Partnership’s derivative instruments in its Consolidated and Condensed Balance Sheets: Derivative Assets Derivative Liabilities Fair Values Fair Values Balance Sheet Location September 30, 2021 December 31, 2020 Balance Sheet Location September 30, 2021 December 31, 2020 Derivatives designated as hedging instruments: Current: Commodity contracts Fair value of derivatives $ — $ — Fair value of derivatives $ 5,049 $ — Derivatives not designated as hedging instruments: Current: Commodity contracts Fair value of derivatives $ — $ — Fair value of derivatives $ — $ 207 The following table summarizes the loss recognized in AOCI at September 30, 2021 and the gain (loss) reclassified from accumulated other comprehensive loss into earnings during the three months ended September 30, 2021 for derivative financial instruments designated as cash flow hedges: Amount of Gain (Loss) Recognized in AOCI Location of Gain (Loss) Amount of Gain (Loss) Reclassified from AOCI into Income 2021 2020 2021 2020 Commodity contracts $ (5,999) $ — Cost of products sold $ — $ — Total $ (5,999) $ — $ — $ — The following table summarizes the loss recognized in AOCI at September 30, 2021 and the gain (loss) reclassified from accumulated other comprehensive loss into earnings during the nine months ended September 30, 2021 for derivative financial instruments designated as cash flow hedges: Amount of Gain (Loss) Recognized in AOCI Location of Gain (Loss) Amount of Gain (Loss) Reclassified from AOCI into Income 2021 2020 2021 2020 Commodity contracts $ (5,999) $ — Cost of products sold $ — $ — Total $ (5,999) $ — $ — $ — The following tables summarize the loss recognized in earnings for derivative instruments not designated as hedging instruments during the three months ended September 30, 2021: Location of Gain (Loss) Amount of Gain (Loss) Recognized in 2021 2020 Derivatives not designated as hedging instruments: Commodity contracts Cost of products sold $ (941) $ (134) Total effect of derivatives not designated as hedging instruments $ (941) $ (134) The following tables summarize the loss recognized in earnings for derivative instruments not designated as hedging instruments during the nine months ended September 30, 2021: Location of Gain (Loss) Amount of Gain (Loss) Recognized in 2021 2020 Derivatives not designated as hedging instruments: Commodity contracts Cost of products sold $ (1,825) $ (263) Total effect of derivatives not designated as hedging instruments $ (1,825) $ (263)

Partners' Capital

Partners' Capital	9 Months Ended
	Sep. 30, 2021
Partners' Capital Notes [Abstract]
Partners' Capital	PARTNERS' CAPITAL As of September 30, 2021, Partners’ capital consisted of 38,802,750 common limited partner units, representing a 98% partnership interest, and a 2% general partner interest. Martin Resource Management Corporation, through subsidiaries, owns 6,114,532 of the Partnership's common limited partner units representing approximately 15.8% of the Partnership's outstanding common limited partner units. Martin Midstream GP LLC ("MMGP"), the Partnership's general partner, owns the 2% general partnership interest. Martin Resource Management Corporation controls the Partnership's general partner, by virtue of its 51% voting interest in MMGP Holdings, LLC ("Holdings"), the sole member of the Partnership's general partner. The partnership agreement of the Partnership (the "Partnership Agreement") contains specific provisions for the allocation of net income and losses to each of the partners for purposes of maintaining their respective partner capital accounts. Impact on Partners' Capital (Deficit) Related to Transactions Between Entities Under Common Control Under ASC 805, assets and liabilities transferred between entities under common control are accounted for at the historical cost of those entities' ultimate parent, in a manner similar to a pooling of interests. Any difference in the amount paid by the transferee versus the historical cost of the assets transferred is recorded as an adjustment to equity (contribution or distribution) by the transferee. This is in contrast with a business combination between unrelated parties, where assets and liabilities are recorded at their fair values at the acquisition date, with any excess of amounts paid over the fair value representing goodwill. From time to time, the most recent being in 2019, the Partnership has entered into common control acquisitions from Martin Resource Management Corporation. The consideration transferred totaling $550,773 exceeds the historical cost of the net assets received. This excess of the purchase price over the historical cost of the net assets received has resulted in cumulative distributions of $287,734 reflected as reductions to Partners' capital. Incentive Distribution Rights MMGP holds a 2% general partner interest and certain incentive distribution rights ("IDRs") in the Partnership. IDRs are a separate class of non-voting limited partner interest that may be transferred or sold by the general partner under the terms of the Partnership Agreement, and represent the right to receive an increasing percentage of cash distributions after the minimum quarterly distribution and any cumulative arrearages on common units once certain target distribution levels have been achieved. The Partnership is required to distribute all of its available cash from operating surplus, as defined in the Partnership Agreement. The target distribution levels entitle the general partner to receive 2% of quarterly cash distributions from the minimum of $0.50 per unit up to $0.55 per unit, 15% of quarterly cash distributions in excess of $0.55 per unit until all unitholders have received $0.625 per unit, 25% of quarterly cash distributions in excess of $0.625 per unit until all unitholders have received $0.75 per unit and 50% of quarterly cash distributions in excess of $0.75 per unit. The general partner was allocated no incentive distributions during the nine months ended September 30, 2021 and 2020. Distributions of Available Cash The Partnership distributes all of its available cash (as defined in the Partnership Agreement) within 45 days after the end of each quarter to unitholders of record and to the general partner. Available cash is generally defined as all cash and cash equivalents of the Partnership on hand at the end of each quarter less the amount of cash reserves its general partner determines in its reasonable discretion is necessary or appropriate to: (i) provide for the proper conduct of the Partnership’s business; (ii) comply with applicable law, any debt instruments or other agreements; or (iii) provide funds for distributions to unitholders and the general partner for any one or more of the next four quarters, plus all cash on the date of determination of available cash for the quarter resulting from working capital borrowings made after the end of the quarter. Net Income per Unit The Partnership follows the provisions of the FASB ASC 260-10 related to earnings per share, which addresses the application of the two-class method in determining income per unit for master limited partnerships having multiple classes of securities that may participate in partnership distributions accounted for as equity distributions. Undistributed earnings are allocated to the general partner and limited partners utilizing the contractual terms of the Partnership Agreement. Distributions to the general partner pursuant to the IDRs are limited to available cash that will be distributed as defined in the Partnership Agreement. Accordingly, the Partnership does not allocate undistributed earnings to the general partner for the IDRs because the general partner's share of available cash is the maximum amount that the general partner would be contractually entitled to receive if all earnings for the period were distributed. When current period distributions are in excess of earnings, the excess distributions for the period are to be allocated to the general partner and limited partners based on their respective sharing of income and losses specified in the Partnership Agreement. Additionally, as required under FASB ASC 260-10-45-61A, unvested share-based payments that entitle employees to receive non-forfeitable distributions are considered participating securities, as defined in FASB ASC 260-10-20, for earnings per unit calculations. For purposes of computing diluted net income per unit, the Partnership uses the more dilutive of the two-class and if-converted methods. Under the if-converted method, the weighted-average number of subordinated units outstanding for the period is added to the weighted-average number of common units outstanding for purposes of computing basic net income per unit and the resulting amount is compared to the diluted net income per unit computed using the two-class method. The following is a reconciliation of net income allocated to the general partner and limited partners for purposes of calculating net income attributable to limited partners per unit: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Net loss $ (6,911) $ (10,819) $ (11,012) $ (4,207) Less general partner’s interest in net loss: Distributions payable on behalf of general partner interest 4 4 12 57 General partner interest in undistributed loss (142) (220) (232) (141) Less loss allocable to unvested restricted units (20) (53) (30) (8) Limited partners’ interest in net loss $ (6,753) $ (10,550) $ (10,762) $ (4,115) The following are the unit amounts used to compute the basic and diluted earnings per limited partner unit for the periods presented: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Basic weighted average limited partner units outstanding 38,687,874 38,661,852 38,689,434 38,654,891 Dilutive effect of restricted units issued — — — — Total weighted average limited partner diluted units outstanding 38,687,874 38,661,852 38,689,434 38,654,891 All outstanding units were included in the computation of diluted earnings per unit and weighted based on the number of days such units were outstanding during the periods presented. All common unit equivalents were antidilutive for the three and nine months ended September 30, 2021 and 2020 because the limited partners were allocated a net loss in this period.

Unit Based Awards

Unit Based Awards	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Unit Based Awards	UNIT BASED AWARDS The Partnership recognizes compensation cost related to unit-based awards to both employees and non-employees in its consolidated and condensed financial statements in accordance with certain provisions of ASC 718. Amounts recognized in operating expense and selling, general, and administrative expense in the consolidated and condensed financial statements with respect to these plans are as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Restricted unit Awards Employees $ — $ 305 $ 194 $ 907 Non-employee directors 48 56 142 163 Phantom unit Awards Employees 181 — 181 — Non-employee directors — — — — Total unit-based compensation expense $ 229 $ 361 $ 517 $ 1,070 Long-Term Incentive Plans The Partnership's general partner has long-term incentive plans for employees and directors of the general partner and its affiliates who perform services for the Partnership. Phantom Unit Plan On July 21, 2021, the board of directors of the general partner of the Partnership and the Compensation Committee approved the Martin Midstream Partners L.P. 2021 Phantom Unit Plan (the “Plan”), effective as of the same date. The Plan permits the awards of phantom units and phantom unit appreciation rights (collectively, "phantom unit awards") to any employee or non-employee director of the Partnership, including its executive officers. The awards may be time-based or performance-based and will be paid, if at all, in cash. The award of a phantom unit entitles the participant to a cash payment equal to the value of the phantom unit on the vesting date or dates, which value is the fair market value of a common unit of the Partnership (a “Unit”) on such vesting date or dates. The award of a phantom unit appreciation right entitles the recipient to a cash payment equal to the difference between the value of a phantom unit on the vesting date or dates in excess of the value assigned by the Compensation Committee to the phantom unit as of the grant date. Phantom units and phantom unit appreciation rights granted to participants do not confer upon participants any right to a Unit. On July 21, 2021, the Compensation Committee approved forms of time-based award agreements for phantom units and phantom unit appreciation rights, both of which awards vest in full on the third anniversary of the grant date. The grant date value of a phantom unit under a phantom unit appreciation right award is equal to the average of the closing price for a Unit during the 20 trading days immediately preceding the grant date of the award. Generally, vesting of an award is subject to a participant remaining continuously employed with the Partnership through the vesting date. However, if prior to the vesting date (i) a participant is terminated without cause (as defined in the award agreement) or terminates employment after the participant has attained both the age of 65 and ten years of employment (“retirement-eligible”), a prorated portion of the award will vest and be paid in cash no later than the 30 th day following such termination date (subject to a six-month delay in payment for certain retirement-eligible participants) or (ii) there is a change in control of the Partnership (as defined in the Plan), the award will vest in full and be paid in cash no later than the 30 th day following the date of the change of control; provided, that the participant has been in continuous employment through the termination or change in control date, as applicable. On July 21, 2021, 620,000 phantom units and 1,245,000 phantom unit appreciation rights were granted to employees of the general partner and its affiliates who perform services for the Partnership. Phantom unit awards are recorded in operating expense and selling, general and administrative expense based on the fair value of the vested portion of the awards on the balance sheet date. The fair value of these awards is updated at each balance sheet date and changes in the fair value of the vested portions of the awards are recorded as increases or decreases to compensation expense within operating expense and selling, general and administrative expense in the Consolidated and Condensed Statements of Operations. All of the Partnership's outstanding phantom unit awards at September 30, 2021 met the criteria to be treated under liability classification in accordance with ASC 718, given that these awards will settle in cash on the vesting date. Compensation expense for the phantom awards is based on the fair value of the units as of the balance sheet date as further discussed below, and such costs are recognized ratably over the service period of the awards. As the fair value of liability awards is required to be re-measured each period end, stock compensation expense amounts recognized in future periods for these awards will vary. The estimated future cash payments of these awards are presented as liabilities within "Other current liabilities" and "Other long-term obligations" in the Consolidated and Condensed Balance Sheets.As of September 30, 2021, there was a total of $2,021 of unrecognized compensation costs related to non-vested phantom unit awards. These costs are expected to be recognized over a remaining life of 2.81 years. The fair value of the phantom unit awards was estimated using a Monte Carlo valuation model as of the balance sheet date. The Monte Carlo valuation model is based on random projections of stock price paths and must be repeated numerous times to achieve a probabilistic assessment. Expected volatility was calculated based on the historical volatility of the Partnership’s common units as well as set of peer companies. Restricted Unit Plan On May 26, 2017, the unitholders of the Partnership approved the Martin Midstream Partners L.P. 2017 Restricted Unit Plan (the "2017 LTIP"). The 2017 LTIP currently permits the grant of awards covering an aggregate of 3,000,000 common units, all of which can be awarded in the form of restricted units. The 2017 LTIP is administered by the compensation committee of the general partner’s board of directors (the "Compensation Committee"). A restricted unit is a unit that is granted to grantees with certain vesting restrictions, which may be time-based and/or performance-based. Once these restrictions lapse, the grantee is entitled to full ownership of the unit without restrictions. The Compensation Committee may determine to make grants under the plan containing such terms as the Compensation Committee shall determine under the plan. With respect to time-based restricted units ("TBRUs"), the Compensation Committee will determine the time period over which restricted units granted to employees and directors will vest. The Compensation Committee may also award a percentage of restricted units with vesting requirements based upon the achievement of specified pre-established performance targets ("Performance Based Restricted Units" or "PBRUs"). The performance targets may include, but are not limited to, the following: revenue and income measures, cash flow measures, net income before interest expense and income tax expense ("EBIT"), net income before interest expense, income tax expense, and depreciation and amortization ("EBITDA"), distribution coverage metrics, expense measures, liquidity measures, market measures, corporate sustainability metrics, and other measures related to acquisitions, dispositions, operational objectives and succession planning objectives. PBRUs are earned only upon our achievement of an objective performance measure for the performance period. PBRUs which vest are payable in common units. Unvested units granted under the 2017 LTIP may or may not participate in cash distributions depending on the terms of each individual award agreement. The performance conditions related to the PBRUs awarded on March 1, 2018 were not achieved and the Partnership treated these units as forfeited at expiration on March 31, 2021. As such, the Partnership did not recognize compensation expense related to these units. The restricted units issued to directors generally vest in equal annual installments over a four-year period. Restricted units issued to employees generally vest in equal annual installments over three years of service. All of the Partnership's outstanding restricted unit awards at September 30, 2021 met the criteria to be treated under equity classification. In February 2021, the Partnership issued 14,056 TBRUs to each of the Partnership's three independent directors under the 2017 LTIP. These restricted common units vest in equal installments of 3,514 units on January 24, 2022, 2023, 2024, and 2025. The restricted units are valued at their fair value at the date of grant, which is equal to the market value of common units on such date. A summary of the restricted unit activity for the nine months ended September 30, 2021 is provided below: Number of Units Weighted Average Grant-Date Fair Value Per Unit Non-vested, beginning of period 273,424 $ 10.52 Granted (TBRU) 42,168 $ 2.49 Vested (117,280) $ 11.96 Forfeited (83,436) $ 13.90 Non-Vested, end of period 114,876 $ 3.65 Aggregate intrinsic value, end of period $ 368 A summary of the restricted units’ aggregate intrinsic value (market value at vesting date) and fair value of units vested (market value at date of grant) during the three and nine months ended September 30, 2021 and 2020 is provided below: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Aggregate intrinsic value of units vested $ — $ — $ 257 $ 151 Fair value of units vested — — 1,418 1,427 As of September 30, 2021, there was $296 of unrecognized compensation cost related to non-vested restricted units. That cost is expected to be recognized over a weighted-average period of 2.69 years.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2021
Related Party Transactions [Abstract]
Related Party Transactions	RELATED PARTY TRANSACTIONS As of September 30, 2021, Martin Resource Management Corporation owns 6,114,532 of the Partnership’s common units representing approximately 15.8% of the Partnership’s outstanding limited partner units. Martin Resource Management Corporation controls the Partnership's general partner by virtue of its 51% voting interest in Holdings, the sole member of the Partnership's general partner. The Partnership’s general partner, MMGP, owns a 2% general partner interest in the Partnership and the Partnership’s IDRs. The Partnership’s general partner’s ability, as general partner, to manage and operate the Partnership, and Martin Resource Management Corporation’s ownership as of September 30, 2021, effectively gives Martin Resource Management Corporation the ability to veto some of the Partnership’s actions and to control the Partnership’s management. The following is a description of the Partnership’s material related party agreements and transactions: Omnibus Agreement Omnibus Agreement . The Partnership and its general partner are parties to the Omnibus Agreement dated November 1, 2002, with Martin Resource Management Corporation that governs, among other things, potential competition and indemnification obligations among the parties to the agreement, related party transactions, the provision of general administration and support services by Martin Resource Management Corporation and the Partnership’s use of certain Martin Resource Management Corporation trade names and trademarks. The Omnibus Agreement was amended on November 25, 2009, to include processing crude oil into finished products including naphthenic lubricants, distillates, asphalt and other intermediate cuts. The Omnibus Agreement was amended further on October 1, 2012, to permit the Partnership to provide certain lubricant packaging products and services to Martin Resource Management Corporation. Non-Competition Provisions . Martin Resource Management Corporation has agreed for so long as it controls the general partner of the Partnership, not to engage in the business of: • providing terminalling and storage services for petroleum products and by-products including the refining, blending and packaging of finished lubricants; • providing land and marine transportation of petroleum products, by-products, and chemicals; • distributing NGLs; and • manufacturing and selling sulfur-based fertilizer products and other sulfur-related products. This restriction does not apply to: • the ownership and/or operation on the Partnership’s behalf of any asset or group of assets owned by it or its affiliates; • any business operated by Martin Resource Management Corporation, including the following: ◦ distributing asphalt, marine fuel and other liquids; ◦ providing shore-based marine services in Texas, Louisiana, Mississippi, and Alabama; ◦ operating a crude oil gathering business in Stephens, Arkansas; ◦ providing crude oil gathering and marketing services of base oils, asphalt, and distillate products in Smackover, Arkansas; ◦ providing crude oil marketing and transportation from the well head to the end market; ◦ operating an environmental consulting company; ◦ supplying employees and services for the operation of the Partnership's business; and ◦ operating, solely for the Partnership's account, the asphalt facilities in Omaha, Nebraska, Port Neches, Texas, and South Houston, Texas. • any business that Martin Resource Management Corporation acquires or constructs that has a fair market value of less than $5,000; • any business that Martin Resource Management Corporation acquires or constructs that has a fair market value of $5,000 or more if the Partnership has been offered the opportunity to purchase the business for fair market value and the Partnership declines to do so with the concurrence of the conflicts committee of the board of directors of the general partner of the Partnership (the "Conflicts Committee"); and • any business that Martin Resource Management Corporation acquires or constructs where a portion of such business includes a restricted business and the fair market value of the restricted business is $5,000 or more and represents less than 20% of the aggregate value of the entire business to be acquired or constructed; provided that, following completion of the acquisition or construction, the Partnership will be provided the opportunity to purchase the restricted business. Services. Under the Omnibus Agreement, Martin Resource Management Corporation provides the Partnership with corporate staff, support services, and administrative services necessary to operate the Partnership’s business. The Omnibus Agreement requires the Partnership to reimburse Martin Resource Management Corporation for all direct expenses it incurs or payments it makes on the Partnership’s behalf or in connection with the operation of the Partnership’s business. There is no monetary limitation on the amount the Partnership is required to reimburse Martin Resource Management Corporation for direct expenses. In addition to the direct expenses, under the Omnibus Agreement, the Partnership is required to reimburse Martin Resource Management Corporation for indirect general and administrative and corporate overhead expenses. Effective January 1, 2021, through December 31, 2021, the Conflicts Committee approved an annual reimbursement amount for indirect expenses of $14,386. The Partnership reimbursed Martin Resource Management Corporation for $3,597 and $4,103 of indirect expenses for the three months ended September 30, 2021 and 2020, respectively. The Partnership reimbursed Martin Resource Management Corporation for $10,790 and $12,364 of indirect expenses for the nine months ended September 30, 2021 and 2020, respectively. The Conflicts Committee will review and approve future adjustments in the reimbursement amount for indirect expenses, if any, annually. These indirect expenses are intended to cover the centralized corporate functions Martin Resource Management Corporation provides to the Partnership, such as accounting, treasury, clerical, engineering, legal, billing, information technology, administration of insurance, general office expenses and employee benefit plans and other general corporate overhead functions the Partnership shares with Martin Resource Management Corporation retained businesses. The provisions of the Omnibus Agreement regarding Martin Resource Management Corporation’s services will terminate if Martin Resource Management Corporation ceases to control the general partner of the Partnership. Related Party Transactions . The Omnibus Agreement prohibits the Partnership from entering into any material agreement with Martin Resource Management Corporation without the prior approval of the Conflicts Committee. For purposes of the Omnibus Agreement, the term "material agreements" means any agreement between the Partnership and Martin Resource Management Corporation that requires aggregate annual payments in excess of the then-applicable agreed upon reimbursable amount of indirect general and administrative expenses. Please read "Services" above. License Provisions. Under the Omnibus Agreement, Martin Resource Management Corporation has granted the Partnership a nontransferable, nonexclusive, royalty-free right and license to use certain of its trade names and marks, as well as the trade names and marks used by some of its affiliates. Amendment and Termination. The Omnibus Agreement may be amended by written agreement of the parties; provided, however, that it may not be amended without the approval of the Conflicts Committee if such amendment would adversely affect the unitholders. The Omnibus Agreement was first amended on November 25, 2009, to permit the Partnership to provide refining services to Martin Resource Management Corporation. The Omnibus Agreement was amended further on October 1, 2012, to permit the Partnership to provide certain lubricant packaging products and services to Martin Resource Management Corporation. Such amendments were approved by the Conflicts Committee. The Omnibus Agreement, other than the indemnification provisions and the provisions limiting the amount for which the Partnership will reimburse Martin Resource Management Corporation for general and administrative services performed on its behalf, will terminate if the Partnership is no longer an affiliate of Martin Resource Management Corporation. Master Transportation Services Agreement Master Transportation Agreement. Martin Transport, Inc. ("MTI"), a wholly owned subsidiary of the Partnership, is a party to a master transportation services agreement effective January 1, 2019, with certain wholly owned subsidiaries of Martin Resource Management Corporation. Under the agreement, MTI agreed to transport Martin Resource Management Corporation's petroleum products and by-products. Term and Pricing. The agreement will continue unless either party terminates the agreement by giving at least 30 days' written notice to the other party. The rates under the agreement are subject to any adjustments which are mutually agreed upon or in accordance with a price index. Additionally, shipping charges are also subject to fuel surcharges determined on a weekly basis in accordance with the U.S. Department of Energy’s national diesel price list. Indemnification. MTI has agreed to indemnify Martin Resource Management Corporation against all claims arising out of the negligence or willful misconduct of MTI and its officers, employees, agents, representatives and subcontractors. Martin Resource Management Corporation has agreed to indemnify MTI against all claims arising out of the negligence or willful misconduct of Martin Resource Management Corporation and its officers, employees, agents, representatives and subcontractors. In the event a claim is the result of the joint negligence or misconduct of MTI and Martin Resource Management Corporation, indemnification obligations will be shared in proportion to each party’s allocable share of such joint negligence or misconduct. Marine Agreements Marine Transportation Agreement. The Partnership is a party to a marine transportation agreement effective January 1, 2006, as amended, under which the Partnership provides marine transportation services to Martin Resource Management Corporation on a spot-contract basis at applicable market rates. Effective each January 1, this agreement automatically renews for consecutive one year periods unless either party terminates the agreement by giving written notice to the other party at least 60 days prior to the expiration of the then applicable term. The fees the Partnership charges Martin Resource Management Corporation are based on applicable market rates. Marine Fuel. The Partnership is a party to an agreement with Martin Resource Management Corporation dated November 1, 2002, under which Martin Resource Management Corporation provides the Partnership with marine fuel from its locations in the Gulf of Mexico at a fixed rate in excess of the Platt’s U.S. Gulf Coast Index for #2 Fuel Oil. Under this agreement, the Partnership agreed to purchase all of its marine fuel requirements that occur in the areas serviced by Martin Resource Management Corporation. Terminal Services Agreements Diesel Fuel Terminal Services Agreement. Effective January 1, 2016, the Partnership entered into a second amended and restated terminalling services agreement under which the Partnership provides terminal services to Martin Resource Management Corporation for marine fuel distribution. At such time, the per-gallon throughput fee the Partnership charged under this agreement was increased when compared to the previous agreement and may be adjusted annually based on a price index. This agreement was further amended on January 1, 2017, October 1, 2017, April 1, 2019, and January 1, 2020 to modify its minimum throughput requirements and throughput fees. The term of this agreement is currently evergreen and it will continue on a month to month basis until terminated by either party by giving 60 days’ written notice. Miscellaneous Terminal Services Agreements. The Partnership is currently party to several terminal services agreements and from time to time the Partnership may enter into other terminal service agreements for the purpose of providing terminal services to related parties. Individually, each of these agreements is immaterial but when considered in the aggregate they could be deemed material. These agreements are throughput based with a minimum volume commitment. Generally, the fees due under these agreements are adjusted annually based on a price index. Other Agreements Cross Tolling Agreement. The Partnership is a party to an amended and restated tolling agreement with Cross Oil Refining and Marketing, Inc. ("Cross") dated October 28, 2014, under which the Partnership processes crude oil into finished products, including naphthenic lubricants, distillates, asphalt and other intermediate cuts for Cross. The tolling agreement expires November 25, 2031. Under this tolling agreement, Cross agreed to process a minimum of 6,500 barrels per day of crude oil at the facility at a fixed price per barrel. Any additional barrels are processed at a modified price per barrel. In addition, Cross agreed to pay a monthly reservation fee and a periodic fuel surcharge fee based on certain parameters specified in the tolling agreement. Further, certain capital improvements, to the extent requested by Cross, are reimbursed through a capital recovery fee. As of December 31, 2019, the annual capital recovery fee reimbursement of $2,088 expired. An additional $2,586 of capital recovery fee reimbursement expired on December 31, 2020. All of these fees (other than the fuel surcharge and capital recovery fee) are subject to escalation annually based upon the greater of 3% or the increase in the Consumer Price Index for a specified annual perio d . A lso, the Partnership renegotiated a crude transportation contract set to expire in the first half of 2022, resulting in a reduction in revenue of $2,145 annually beginning January 1, 2020. East Texas Mack Leases. MTI leases equipment, including tractors and trailers, from East Texas Mack Sales ("East Texas Mack"). Certain of our directors or officers are owners of East Texas Mack, including entities affiliated with Ruben Martin, who owns approximately 46% of the issued and outstanding stock of East Texas Mack. Amounts paid to East Texas Mack for tractor and trailer lease payments and lease residuals for the three months ended September 30, 2021 and 2020 were $283 and $173, respectively. Amounts paid to East Texas Mack for tractor and trailer lease payments and lease residuals for the nine months ended September 30, 2021 and 2020 were $801 and $432, respectively. Other Miscellaneous Agreements. From time to time the Partnership enters into other miscellaneous agreements with Martin Resource Management Corporation for the provision of other services or the purchase of other goods. The tables below summarize the related party transactions that are included in the related financial statement captions on the face of the Partnership’s Consolidated and Condensed Statements of Operations. The revenues, costs and expenses reflected in these tables are tabulations of the related party transactions that are recorded in the corresponding captions of the consolidated and condensed financial statements and do not reflect a statement of profits and losses for related party transactions. The impact of related party revenues from sales of products and services is reflected in the consolidated and condensed financial statements as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Revenues: Terminalling and storage $ 15,866 $ 15,902 $ 46,741 $ 47,718 Transportation 5,564 5,514 14,463 16,801 Product sales: Sulfur services 28 5 87 33 Terminalling and storage 40 64 166 166 68 69 253 199 $ 21,498 $ 21,485 $ 61,457 $ 64,718 The impact of related party cost of products sold is reflected in the consolidated and condensed financial statements as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Cost of products sold: Sulfur services $ 2,441 $ 2,512 $ 7,379 $ 7,833 Terminalling and storage 7,259 4,303 18,863 14,329 $ 9,700 $ 6,815 $ 26,242 $ 22,162 The impact of related party operating expenses is reflected in the consolidated and condensed financial statements as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Operating expenses: Transportation $ 13,949 $ 13,009 $ 40,652 $ 41,950 Natural gas liquids 534 486 1,511 1,481 Sulfur services 1,321 1,120 3,370 3,403 Terminalling and storage 4,284 4,300 12,513 13,292 $ 20,088 $ 18,915 $ 58,046 $ 60,126 The impact of related party selling, general and administrative expenses is reflected in the consolidated and condensed financial statements as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Selling, general and administrative: Transportation $ 1,732 $ 1,803 $ 5,103 $ 5,459 Natural gas liquids 576 772 2,660 2,009 Sulfur services 813 765 2,320 2,254 Terminalling and storage 878 863 2,530 2,536 Indirect, including overhead allocation 3,660 4,153 11,011 12,465 $ 7,659 $ 8,356 $ 23,624 $ 24,723

Business Segments

Business Segments	9 Months Ended
	Sep. 30, 2021
Segment Reporting [Abstract]
Business Segments	BUSINESS SEGMENTS The Partnership has four reportable segments: (1) terminalling and storage, (2) transportation, (3) sulfur services and (4) natural gas liquids. The Partnership’s reportable segments are strategic business units that offer different products and services. The operating income of these segments is reviewed by the chief operating decision maker to assess performance and make business decisions. The accounting policies of the operating segments are the same as those described in Note 2 in the Partnership’s Annual Report on Form 10-K for the year ended December 31, 2020, filed with the SEC on March 3, 2021. The Partnership evaluates the performance of its reportable segments based on operating income. There is no allocation of interest expense. Three Months Ended September 30, 2021 Operating Revenues Intersegment Revenues Eliminations Operating Revenues after Eliminations Depreciation and Amortization Operating Income (Loss) after Eliminations Capital Expenditures and Plant Turnaround Costs Terminalling and storage 51,226 (1,648) 49,578 7,049 3,269 2,087 Transportation 42,568 (3,489) 39,079 3,710 430 1,086 Sulfur services 30,837 — 30,837 2,594 4,534 1,104 Natural gas liquids 91,764 — 91,764 592 3,994 20 Indirect selling, general and administrative — — — — (4,074) — Total $ 216,395 $ (5,137) $ 211,258 $ 13,945 $ 8,153 $ 4,297 Three Months Ended September 30, 2020 Operating Revenues Intersegment Revenues Eliminations Operating Revenues after Eliminations Depreciation and Amortization Operating Income (Loss) after Eliminations Capital Expenditures and Plant Turnaround Costs Terminalling and storage 48,188 (1,823) 46,365 7,294 6,426 1,863 Transportation 35,712 (3,774) 31,938 4,412 (2,673) 1,785 Sulfur services 21,880 — 21,880 2,953 7,115 1,393 Natural gas liquids 52,350 — 52,350 617 4,668 173 Indirect selling, general and administrative — — — — (4,523) — Total $ 158,130 $ (5,597) $ 152,533 $ 15,276 $ 11,013 $ 5,214 Nine Months Ended September 30, 2021 Operating Revenues Intersegment Revenues Eliminations Operating Revenues after Eliminations Depreciation and Amortization Operating Income (Loss) after Eliminations Capital Expenditures and Plant Turnaround Costs Terminalling and storage $ 136,584 $ (4,918) $ 131,666 $ 21,150 $ 8,153 $ 6,258 Transportation 114,886 (11,066) 103,820 12,039 (7,782) 2,702 Sulfur services 103,958 — 103,958 7,882 21,136 4,968 Natural gas liquids 257,081 — 257,081 1,791 21,738 481 Indirect selling, general and administrative — — — — (11,773) — Total $ 612,509 $ (15,984) $ 596,525 $ 42,862 $ 31,472 $ 14,409 Nine Months Ended September 30, 2020 Operating Revenues Intersegment Revenues Eliminations Operating Revenues after Eliminations Depreciation and Amortization Operating Income (Loss) after Eliminations Capital Expenditures and Plant Turnaround Costs Terminalling and storage $ 146,298 $ (5,091) $ 141,207 $ 22,022 $ 10,153 $ 8,885 Transportation 116,145 (13,781) 102,364 13,020 (9,772) 6,483 Sulfur services 83,636 (13) 83,623 8,978 29,787 6,267 Natural gas liquids 164,865 (5) 164,860 1,838 17,661 348 Indirect selling, general and administrative — — — — (13,256) — Total $ 510,944 $ (18,890) $ 492,054 $ 45,858 $ 34,573 $ 21,983 The Partnership's assets by reportable segment as of September 30, 2021 and December 31, 2020, are as follows: September 30, 2021 December 31, 2020 Total assets: Terminalling and storage $ 249,723 $ 252,794 Transportation 142,767 151,953 Sulfur services 97,986 94,154 Natural gas liquids 123,762 80,737 Total assets $ 614,238 $ 579,638

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Contingencies From time to time, the Partnership is subject to various claims and legal actions arising in the ordinary course of business. In the opinion of management, the ultimate disposition of these matters will not have a material adverse effect on the Partnership. On December 31, 2015, the Partnership received a demand from a customer in its lubricants packaging business for defense and indemnity in connection with lawsuits filed against it in various United States District Courts, which generally allege that the customer engaged in unlawful and deceptive business practices in connection with its marketing and advertising of its private label motor oil. The Partnership disputes that it has any obligation to defend or indemnify the customer for its conduct. Accordingly, on January 7, 2016, the Partnership filed a Complaint for Declaratory Judgment in the Chancery Court of Davidson County, Tennessee requesting a judicial determination that the Partnership does not owe the customer the demanded defense and indemnity obligations. The lawsuits against the customer have been transferred to the United States

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS The Partnership uses a valuation framework based upon inputs that market participants use in pricing certain assets and liabilities. These inputs are classified into two categories: observable inputs and unobservable inputs. Observable inputs represent market data obtained from independent sources. Unobservable inputs represent the Partnership's own market assumptions. Unobservable inputs are used only if observable inputs are unavailable or not reasonably available without undue cost and effort. The two types of inputs are further prioritized into the following hierarchy: Level 1: Quoted market prices in active markets for identical assets or liabilities. Level 2: Observable market-based inputs or unobservable inputs that are corroborated by market data. Level 3: Unobservable inputs that reflect the entity's own assumptions and are not corroborated by market data. Assets and liabilities measured at fair value on a recurring basis are summarized below: Level 2 September 30, 2021 December 31, 2020 Commodity derivative contracts, net $ (5,049) $ (207) The Partnership is required to disclose estimated fair values for its financial instruments. Fair value estimates are set forth below for these financial instruments. The following methods and assumptions were used to estimate the fair value of each class of financial instrument: • Accounts and other receivables, trade and other accounts payable, accrued interest payable, other accrued liabilities, income taxes payable and due from/to affiliates: The carrying amounts approximate fair value due to the short maturity and highly liquid nature of these instruments, and as such these have been excluded from the table below. There is negligible credit risk associated with these instruments. • Current and non-current portion of long-term debt: The carrying amount of the revolving credit facility approximates fair value due to the debt having a variable interest rate and is in Level 2. The estimated fair value of the 2021 Notes, 2024 Notes, and 2025 Notes (collectively, the "Senior Notes") is considered Level 1, as the fair value is based on quoted market prices in active markets. September 30, 2021 December 31, 2020 Carrying Fair Carrying Fair 2021 Notes $ — $ — $ 28,790 $ 28,581 2024 Notes $ 51,031 $ 55,126 $ 50,173 $ 55,214 2025 Notes $ 290,563 $ 302,797 $ 290,250 $ 288,692 Total $ 341,594 $ 357,923 $ 369,213 $ 372,487

Condensed Consolidated Financia

Condensed Consolidated Financial Information	9 Months Ended
	Sep. 30, 2021
Consolidating Financial Statements [Abstract]
Condensed Consolidated Financial Information	CONDENSED CONSOLIDATED FINANCIAL INFORMATION    The Partnership's operations are conducted by its operating subsidiaries as it has no independent assets or operations. Martin Operating Partnership L.P. (the "Operating Partnership"), the Partnership’s wholly-owned subsidiary, and the Partnership's other operating subsidiaries have issued in the past, and may issue in the future, unconditional guarantees of senior or subordinated debt securities of the Partnership. The guarantees that have been issued are full, irrevocable and unconditional and joint and several. In addition, the Operating Partnership may also issue senior or subordinated debt securities which, if issued, will be fully, irrevocably and unconditionally guaranteed by the Partnership. Substantially all of the Partnership's operating subsidiaries are subsidiary guarantors of its Senior Notes and any subsidiaries other than the subsidiary guarantors are minor.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Provision for income taxes $ 954 $ 373 $ 2,111 $ 1,510 The operations of a partnership are generally not subject to income taxes, except for Texas margin tax, because its income is taxed directly to its partners. MTI, a wholly owned subsidiary of the Partnership, is subject to income taxes due to its corporate structure (the "Taxable Subsidiary"). Total income tax expense of $895 and $225, related to the operation of the Taxable Subsidiary, for the three months ended September 30, 2021 and 2020, resulted in an effective income tax rate ("ETR") of 23.42% and 45.72%, respectively. Total income tax expense of $1,871 and $1,162, related to the operation of the Taxable Subsidiary, for the nine months ended September 30, 2021 and 2020, resulted in an ETR of 29.51% and 80.42%, respectively. The decrease in the ETR for the income taxes during the three and nine months ended September 30, 2021, was primarily due to significantly larger pretax income recorded for both the three and nine months ended September 30, 2021 compared to the similar periods in 2020. The increase in the provision for income taxes for the three and nine months ended September 30, 2021, compared to similar periods in 2020, was primarily due to an increase in income before income taxes in the current period. A current federal income tax expense (benefit) of $153 and $0, related to the operation of the Taxable Subsidiary, was recorded for the three months ended September 30, 2021 and 2020, respectively. A current federal income tax expense (benefit) of $276 and $(174), related to the operation of the Taxable Subsidiary, was recorded for the nine months ended September 30, 2021 and 2020, respectively. A current state income tax expense of $81 and $41, related to the operation of the Taxable Subsidiary, was recorded for the three months ended September 30, 2021 and 2020, respectively. A current state income tax expense of $177 and $134, related to the operation of the Taxable Subsidiary, was recorded for the nine months ended September 30, 2021 and 2020, respectively. With respect to MTI, income taxes are accounted for under the asset and liability method pursuant to the provisions of ASC 740 related to income taxes. 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. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which 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. A deferred tax expense related to the MTI temporary differences of $661 and $183 was recorded for the three months ended September 30, 2021 and 2020, respectively. A deferred tax expense related to the MTI temporary differences of $1,419 and $1,202 was recorded for the nine months ended September 30, 2021 and 2020, respectively. A net deferred tax asset of $20,834 and $22,253, related to the cumulative book and tax temporary differences, existed at September 30, 2021 and December 31, 2020, respectively. All income tax positions taken for all open years are more likely than not to be sustained based upon their technical merit under applicable tax laws.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2021
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTSQuarterly Distribution. On October 20, 2021, the Partnership declared a quarterly cash distribution of $0.005 per common unit for the third quarter of 2021, or $0.020 per common unit on an annualized basis, which will be paid on November 12, 2021 to unitholders of record as of November 5, 2021.

New Accounting Pronouncements (

New Accounting Pronouncements (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Changes and Error Corrections [Abstract]
New Accounting Pronouncements	NEW ACCOUNTING PRONOUNCEMENTS On January 1, 2021, the Partnership adopted Financial Accounting Standards Board ("FASB") Accounting Standards Update ("ASU") 2019-12, Income Taxes (Accounting Standards Codification ("ASC") Topic 740): Simplifying the Accounting for Income Taxes , which removes certain exceptions to general principles in ASC 740 and clarifies and amends existing guidance within U.S. GAAP. Adoption of the new standard did not have a material impact on the Partnership’s consolidated financial statements.
Fair Value Measurements	The Partnership uses a valuation framework based upon inputs that market participants use in pricing certain assets and liabilities. These inputs are classified into two categories: observable inputs and unobservable inputs. Observable inputs represent market data obtained from independent sources. Unobservable inputs represent the Partnership's own market assumptions. Unobservable inputs are used only if observable inputs are unavailable or not reasonably available without undue cost and effort. The two types of inputs are further prioritized into the following hierarchy: Level 1: Quoted market prices in active markets for identical assets or liabilities. Level 2: Observable market-based inputs or unobservable inputs that are corroborated by market data. Level 3: Unobservable inputs that reflect the entity's own assumptions and are not corroborated by market data.
Fair Value of Financial Instruments	The Partnership is required to disclose estimated fair values for its financial instruments. Fair value estimates are set forth below for these financial instruments. The following methods and assumptions were used to estimate the fair value of each class of financial instrument: • Accounts and other receivables, trade and other accounts payable, accrued interest payable, other accrued liabilities, income taxes payable and due from/to affiliates: The carrying amounts approximate fair value due to the short maturity and highly liquid nature of these instruments, and as such these have been excluded from the table below. There is negligible credit risk associated with these instruments.

Revenue (Tables)

Revenue (Tables)	9 Months Ended
	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table disaggregates our revenue by major source: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Terminalling and storage segment Lubricant product sales $ 30,598 $ 25,659 $ 75,606 $ 80,119 Throughput and storage 18,980 20,706 56,060 61,088 $ 49,578 $ 46,365 $ 131,666 $ 141,207 Natural gas liquids segment Natural gas liquids product sales $ 91,764 $ 52,350 $ 257,081 $ 164,860 $ 91,764 $ 52,350 $ 257,081 $ 164,860 Sulfur services segment Sulfur product sales $ 7,768 $ 6,161 $ 22,222 $ 19,010 Fertilizer product sales 20,119 12,804 72,887 55,869 Sulfur services 2,950 2,915 8,849 8,744 $ 30,837 $ 21,880 $ 103,958 $ 83,623 Transportation segment Land transportation $ 30,273 $ 21,879 $ 80,715 $ 65,986 Inland transportation 7,465 9,294 20,822 33,611 Offshore transportation 1,341 765 2,283 2,767 $ 39,079 $ 31,938 $ 103,820 $ 102,364
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction	The table below includes estimated minimum revenue expected to be recognized in the future related to performance obligations that are unsatisfied at the end of the reporting period. The Partnership applies the practical expedient in ASC 606-10-50-14(a) and does not disclose information about remaining performance obligations that have original expected durations of one year or less. 2021 2022 2023 2024 2025 Thereafter Total Terminalling and storage Throughput and storage $ 9,843 $ 40,394 $ 41,605 $ 42,910 $ 44,197 $ 294,205 $ 473,154 Natural Gas Services Natural Gas Liquids 1,644 6,048 5,391 5,405 5,391 3,131 27,010 Sulfur services Sulfur product sales 4,291 17,165 16,415 2,156 2,156 1,477 43,660 Total $ 15,778 $ 63,607 $ 63,411 $ 50,471 $ 51,744 $ 298,813 $ 543,824

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2021
Inventory Disclosure [Abstract]
Components of Inventories	Components of inventories at September 30, 2021 and December 31, 2020 were as follows: September 30, December 31, Natural gas liquids $ 65,136 $ 27,878 Sulfur 49 24 Fertilizer 8,799 10,854 Lubricants 19,670 11,002 Other 4,485 4,364 $ 98,139 $ 54,122

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Schedule of Long-Term Debt	At September 30, 2021 and December 31, 2020, long-term debt consisted of the following: September 30, December 31, $275,000 Revolving credit facility at variable interest rate (5.00% 1 weighted average at September 30, 2021), due August 2023 secured by substantially all of the Partnership’s assets, including, without limitation, inventory, accounts receivable, vessels, equipment, fixed assets and the interests in the Partnership’s operating subsidiaries, net of unamortized debt issuance costs of $3,004 and $3,826, respectively 2 $ 205,496 $ 144,174 $400,000 Senior notes, 7.25% interest, net of unamortized debt issuance costs of $— and $—, respectively, including unamortized premium of $— and $—, respectively, issued $250,000 February 2013 and $150,000 April 2014, $26,200 repurchased during 2015, $9,344 repurchased during 2020, $335,666 refinanced as part of the August 2020 Exchange offer, $28,790 repaid at maturity in February 2021, unsecured 2,3,4 — 28,790 $53,750 Senior notes due February 2024, 10.0% interest, net of unamortized debt issuance costs of $2,719 and $3,577, respectively, secured 2,3 51,031 50,173 $291,970 Senior notes due February 2025, 11.5% interest, net of unamortized debt issuance costs of $1,407 and $1,720, respectively, secured 2,3 290,563 290,250 Total 547,090 513,387 Less: current portion — (28,790) Total long-term debt, net of current portion $ 547,090 $ 484,597 Current installments of finance lease obligations $ 240 $ 2,707 Finance lease obligations 108 289 Total finance lease obligations $ 348 $ 2,996 1 Interest rate fluctuates based on LIBOR (set on the date of each advance) or the base prime rate plus an applicable margin. The margin is set every three months. All amounts outstanding at December 31, 2020 and September 30, 2021 were at LIBOR plus an applicable margin with LIBOR having a floor of 1.00% per annum. The applicable margin for revolving loans that are LIBOR loans currently ranges from 2.75% to 4.00%, and the applicable margin for revolving loans that are base prime rate loans currently ranges from 1.75% to 3.00%. The applicable margin for LIBOR borrowings at September 30, 2021 is 4.00%. The credit facility contains various covenants that limit the Partnership’s ability to make distributions; make certain investments and acquisitions; enter into certain agreements; incur indebtedness; sell assets; and make certain amendments to the Partnership's omnibus agreement with Martin Resource Management Corporation (the "Omnibus Agreement"). The credit facility was amended on July 16, 2021 to, among other things, reduce the commitments thereunder from $300,000 to $275,000. 2 The Partnership was in compliance with all debt covenants as of September 30, 2021 and December 31, 2020, respectively. 3 The indentures for each of the outstanding series of senior notes restrict the Partnership’s ability to sell assets; pay distributions or repurchase units or redeem or repurchase subordinated debt; make investments; incur or guarantee additional indebtedness or issue preferred units; and consolidate, merge or transfer all or substantially all of its assets.

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Components of Lease Expense	The components of lease expense for the three and nine months ended September 30, 2021 and 2020 were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Operating lease cost $ 2,485 $ 2,572 $ 6,987 $ 8,182 Finance lease cost: Amortization of right-of-use assets $ 25 390 $ 140 1,505 Interest on lease liabilities $ 5 62 $ 21 258 Short-term lease cost $ 2,324 3,138 $ 7,905 10,054 Variable lease cost $ 28 $ 33 $ 87 $ 83 Total lease cost $ 4,867 $ 6,195 $ 15,140 $ 20,082
Schedule of Supplemental Balance Sheet Information	Supplemental balance sheet information related to leases at September 30, 2021 and December 31, 2020 was as follows: September 30, December 31, 2020 Operating Leases Operating lease right-of-use assets $ 21,267 $ 22,260 Current portion of operating lease liabilities included in "Other accrued liabilities" $ 6,746 $ 7,529 Operating lease liabilities $ 14,960 15,181 Total operating lease liabilities $ 21,706 $ 22,710 Finance Leases Property, plant and equipment, at cost $ 1,071 $ 10,352 Accumulated depreciation $ (339) (3,703) Property, plant and equipment, net $ 732 $ 6,649 Current installments of finance lease obligations $ 240 $ 2,707 Finance lease obligations $ 108 289 Total finance lease obligations $ 348 $ 2,996
Schedule of Future Minimum Lease Obligations, Finance Lease	The Partnership’s future minimum lease obligations as of September 30, 2021 consist of the following: Operating Leases Finance Leases Year 1 $ 7,801 $ 252 Year 2 5,102 109 Year 3 2,923 — Year 4 2,220 — Year 5 1,494 — Thereafter 7,120 — Total $ 26,660 $ 361 Less amounts representing interest costs (4,954) (13) Total lease liability $ 21,706 $ 348
Schedule of Future Minimum Lease Obligations, Operating Lease	The Partnership’s future minimum lease obligations as of September 30, 2021 consist of the following: Operating Leases Finance Leases Year 1 $ 7,801 $ 252 Year 2 5,102 109 Year 3 2,923 — Year 4 2,220 — Year 5 1,494 — Thereafter 7,120 — Total $ 26,660 $ 361 Less amounts representing interest costs (4,954) (13) Total lease liability $ 21,706 $ 348

Supplemental Balance Sheet In_2

Supplemental Balance Sheet Information (Tables)	9 Months Ended
	Sep. 30, 2021
Balance Sheet Related Disclosures [Abstract]
Schedule of Other Accrued Liabilities	Components of "Other accrued liabilities" were as follows: September 30, December 31, 2020 Accrued interest $ 5,261 $ 16,104 Asset retirement obligations 300 1,692 Property and other taxes payable 4,546 4,869 Accrued payroll 4,425 3,244 Operating lease liabilities 6,746 7,529 Other 418 969 $ 21,696 $ 34,407
Schedule of Asset Retirement Obligations	The schedule below summarizes the changes in our asset retirement obligations: September 30, 2021 Beginning asset retirement obligations $ 8,759 Additions to asset retirement obligations — Accretion expense 284 Liabilities settled (22) Ending asset retirement obligations 9,021 Current portion of asset retirement obligations 1 (300) Long-term portion of asset retirement obligations 2 $ 8,721 1 The current portion of asset retirement obligations is included in "Other accrued liabilities" on the Partnership's Consolidated and Condensed Balance Sheets. 2 The non-current portion of asset retirement obligations is included in "Other long-term obligations" on the Partnership's Consolidated and Condensed Balance Sheets.

Derivative Instruments and He_2

Derivative Instruments and Hedging Activities (Tables)	9 Months Ended
	Sep. 30, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Effect of Derivative Instruments on the Consolidated Balance Sheets	The following table summarizes the fair value and classification of the Partnership’s derivative instruments in its Consolidated and Condensed Balance Sheets: Derivative Assets Derivative Liabilities Fair Values Fair Values Balance Sheet Location September 30, 2021 December 31, 2020 Balance Sheet Location September 30, 2021 December 31, 2020 Derivatives designated as hedging instruments: Current: Commodity contracts Fair value of derivatives $ — $ — Fair value of derivatives $ 5,049 $ — Derivatives not designated as hedging instruments: Current: Commodity contracts Fair value of derivatives $ — $ — Fair value of derivatives $ — $ 207
Summary of Losses Recognized in AOCI and Reclassification From AOCI	The following table summarizes the loss recognized in AOCI at September 30, 2021 and the gain (loss) reclassified from accumulated other comprehensive loss into earnings during the three months ended September 30, 2021 for derivative financial instruments designated as cash flow hedges: Amount of Gain (Loss) Recognized in AOCI Location of Gain (Loss) Amount of Gain (Loss) Reclassified from AOCI into Income 2021 2020 2021 2020 Commodity contracts $ (5,999) $ — Cost of products sold $ — $ — Total $ (5,999) $ — $ — $ — The following table summarizes the loss recognized in AOCI at September 30, 2021 and the gain (loss) reclassified from accumulated other comprehensive loss into earnings during the nine months ended September 30, 2021 for derivative financial instruments designated as cash flow hedges: Amount of Gain (Loss) Recognized in AOCI Location of Gain (Loss) Amount of Gain (Loss) Reclassified from AOCI into Income 2021 2020 2021 2020 Commodity contracts $ (5,999) $ — Cost of products sold $ — $ — Total $ (5,999) $ — $ — $ —
Effect of Derivative Instruments on the Consolidated Statement of Operations	The following tables summarize the loss recognized in earnings for derivative instruments not designated as hedging instruments during the three months ended September 30, 2021: Location of Gain (Loss) Amount of Gain (Loss) Recognized in 2021 2020 Derivatives not designated as hedging instruments: Commodity contracts Cost of products sold $ (941) $ (134) Total effect of derivatives not designated as hedging instruments $ (941) $ (134) The following tables summarize the loss recognized in earnings for derivative instruments not designated as hedging instruments during the nine months ended September 30, 2021: Location of Gain (Loss) Amount of Gain (Loss) Recognized in 2021 2020 Derivatives not designated as hedging instruments: Commodity contracts Cost of products sold $ (1,825) $ (263) Total effect of derivatives not designated as hedging instruments $ (1,825) $ (263)

Partners' Capital (Tables)

Partners' Capital (Tables)	9 Months Ended
	Sep. 30, 2021
Partners' Capital Notes [Abstract]
Reconciliation of Net Income to Partners Interest in Net Income	The following is a reconciliation of net income allocated to the general partner and limited partners for purposes of calculating net income attributable to limited partners per unit: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Net loss $ (6,911) $ (10,819) $ (11,012) $ (4,207) Less general partner’s interest in net loss: Distributions payable on behalf of general partner interest 4 4 12 57 General partner interest in undistributed loss (142) (220) (232) (141) Less loss allocable to unvested restricted units (20) (53) (30) (8) Limited partners’ interest in net loss $ (6,753) $ (10,550) $ (10,762) $ (4,115) Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Basic weighted average limited partner units outstanding 38,687,874 38,661,852 38,689,434 38,654,891 Dilutive effect of restricted units issued — — — — Total weighted average limited partner diluted units outstanding 38,687,874 38,661,852 38,689,434 38,654,891

Unit Based Awards (Tables)

Unit Based Awards (Tables)	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Schedule of Compensation Costs Related to Unit Based Plan	Amounts recognized in operating expense and selling, general, and administrative expense in the consolidated and condensed financial statements with respect to these plans are as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Restricted unit Awards Employees $ — $ 305 $ 194 $ 907 Non-employee directors 48 56 142 163 Phantom unit Awards Employees 181 — 181 — Non-employee directors — — — — Total unit-based compensation expense $ 229 $ 361 $ 517 $ 1,070
Summary of Restricted Unit Activity	A summary of the restricted unit activity for the nine months ended September 30, 2021 is provided below: Number of Units Weighted Average Grant-Date Fair Value Per Unit Non-vested, beginning of period 273,424 $ 10.52 Granted (TBRU) 42,168 $ 2.49 Vested (117,280) $ 11.96 Forfeited (83,436) $ 13.90 Non-Vested, end of period 114,876 $ 3.65 Aggregate intrinsic value, end of period $ 368
Summary of Aggregate Intrinsic Value and Fair Value of Units Vested	A summary of the restricted units’ aggregate intrinsic value (market value at vesting date) and fair value of units vested (market value at date of grant) during the three and nine months ended September 30, 2021 and 2020 is provided below: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Aggregate intrinsic value of units vested $ — $ — $ 257 $ 151 Fair value of units vested — — 1,418 1,427

Related Party Transactions (Tab

Related Party Transactions (Tables)	9 Months Ended
	Sep. 30, 2021
Related Party Transactions [Abstract]
The Impact of Related Party Transactions	The impact of related party revenues from sales of products and services is reflected in the consolidated and condensed financial statements as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Revenues: Terminalling and storage $ 15,866 $ 15,902 $ 46,741 $ 47,718 Transportation 5,564 5,514 14,463 16,801 Product sales: Sulfur services 28 5 87 33 Terminalling and storage 40 64 166 166 68 69 253 199 $ 21,498 $ 21,485 $ 61,457 $ 64,718 The impact of related party cost of products sold is reflected in the consolidated and condensed financial statements as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Cost of products sold: Sulfur services $ 2,441 $ 2,512 $ 7,379 $ 7,833 Terminalling and storage 7,259 4,303 18,863 14,329 $ 9,700 $ 6,815 $ 26,242 $ 22,162 The impact of related party operating expenses is reflected in the consolidated and condensed financial statements as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Operating expenses: Transportation $ 13,949 $ 13,009 $ 40,652 $ 41,950 Natural gas liquids 534 486 1,511 1,481 Sulfur services 1,321 1,120 3,370 3,403 Terminalling and storage 4,284 4,300 12,513 13,292 $ 20,088 $ 18,915 $ 58,046 $ 60,126 The impact of related party selling, general and administrative expenses is reflected in the consolidated and condensed financial statements as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Selling, general and administrative: Transportation $ 1,732 $ 1,803 $ 5,103 $ 5,459 Natural gas liquids 576 772 2,660 2,009 Sulfur services 813 765 2,320 2,254 Terminalling and storage 878 863 2,530 2,536 Indirect, including overhead allocation 3,660 4,153 11,011 12,465 $ 7,659 $ 8,356 $ 23,624 $ 24,723

Business Segments (Tables)

Business Segments (Tables)	9 Months Ended
	Sep. 30, 2021
Segment Reporting [Abstract]
Segment Reporting by Segment	Three Months Ended September 30, 2021 Operating Revenues Intersegment Revenues Eliminations Operating Revenues after Eliminations Depreciation and Amortization Operating Income (Loss) after Eliminations Capital Expenditures and Plant Turnaround Costs Terminalling and storage 51,226 (1,648) 49,578 7,049 3,269 2,087 Transportation 42,568 (3,489) 39,079 3,710 430 1,086 Sulfur services 30,837 — 30,837 2,594 4,534 1,104 Natural gas liquids 91,764 — 91,764 592 3,994 20 Indirect selling, general and administrative — — — — (4,074) — Total $ 216,395 $ (5,137) $ 211,258 $ 13,945 $ 8,153 $ 4,297 Three Months Ended September 30, 2020 Operating Revenues Intersegment Revenues Eliminations Operating Revenues after Eliminations Depreciation and Amortization Operating Income (Loss) after Eliminations Capital Expenditures and Plant Turnaround Costs Terminalling and storage 48,188 (1,823) 46,365 7,294 6,426 1,863 Transportation 35,712 (3,774) 31,938 4,412 (2,673) 1,785 Sulfur services 21,880 — 21,880 2,953 7,115 1,393 Natural gas liquids 52,350 — 52,350 617 4,668 173 Indirect selling, general and administrative — — — — (4,523) — Total $ 158,130 $ (5,597) $ 152,533 $ 15,276 $ 11,013 $ 5,214 Nine Months Ended September 30, 2021 Operating Revenues Intersegment Revenues Eliminations Operating Revenues after Eliminations Depreciation and Amortization Operating Income (Loss) after Eliminations Capital Expenditures and Plant Turnaround Costs Terminalling and storage $ 136,584 $ (4,918) $ 131,666 $ 21,150 $ 8,153 $ 6,258 Transportation 114,886 (11,066) 103,820 12,039 (7,782) 2,702 Sulfur services 103,958 — 103,958 7,882 21,136 4,968 Natural gas liquids 257,081 — 257,081 1,791 21,738 481 Indirect selling, general and administrative — — — — (11,773) — Total $ 612,509 $ (15,984) $ 596,525 $ 42,862 $ 31,472 $ 14,409 Nine Months Ended September 30, 2020 Operating Revenues Intersegment Revenues Eliminations Operating Revenues after Eliminations Depreciation and Amortization Operating Income (Loss) after Eliminations Capital Expenditures and Plant Turnaround Costs Terminalling and storage $ 146,298 $ (5,091) $ 141,207 $ 22,022 $ 10,153 $ 8,885 Transportation 116,145 (13,781) 102,364 13,020 (9,772) 6,483 Sulfur services 83,636 (13) 83,623 8,978 29,787 6,267 Natural gas liquids 164,865 (5) 164,860 1,838 17,661 348 Indirect selling, general and administrative — — — — (13,256) — Total $ 510,944 $ (18,890) $ 492,054 $ 45,858 $ 34,573 $ 21,983
Assets by Segment	The Partnership's assets by reportable segment as of September 30, 2021 and December 31, 2020, are as follows: September 30, 2021 December 31, 2020 Total assets: Terminalling and storage $ 249,723 $ 252,794 Transportation 142,767 151,953 Sulfur services 97,986 94,154 Natural gas liquids 123,762 80,737 Total assets $ 614,238 $ 579,638

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	Assets and liabilities measured at fair value on a recurring basis are summarized below: Level 2 September 30, 2021 December 31, 2020 Commodity derivative contracts, net $ (5,049) $ (207) September 30, 2021 December 31, 2020 Carrying Fair Carrying Fair 2021 Notes $ — $ — $ 28,790 $ 28,581 2024 Notes $ 51,031 $ 55,126 $ 50,173 $ 55,214 2025 Notes $ 290,563 $ 302,797 $ 290,250 $ 288,692 Total $ 341,594 $ 357,923 $ 369,213 $ 372,487

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Schedule of Income Tax Expense	Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Provision for income taxes $ 954 $ 373 $ 2,111 $ 1,510

Nature of Operations and Basi_2

Nature of Operations and Basis of Presentation (Details)	9 Months Ended
	Sep. 30, 2021segment
Accounting Policies [Abstract]
Number of primary business lines	4

Revenue - Disaggregation of Rev

Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue
Revenues		$ 211,258	$ 152,533	$ 596,525	$ 492,054
Lubricant product sales
Disaggregation of Revenue
Revenues	[1]	30,598	25,659	75,606	80,119
Throughput and storage
Disaggregation of Revenue
Revenues	[1]	18,980	20,706	56,060	61,088
Natural gas liquids
Disaggregation of Revenue
Revenues	[1]	91,764	52,350	257,081	164,860
Sulfur services
Disaggregation of Revenue
Revenues		2,950	2,915	8,849	8,744
Terminalling and storage segment
Disaggregation of Revenue
Revenues		49,578	46,365	131,666	141,207
Terminalling and storage segment | Lubricant product sales
Disaggregation of Revenue
Revenues		30,598	25,659	75,606	80,119
Terminalling and storage segment | Throughput and storage
Disaggregation of Revenue
Revenues		18,980	20,706	56,060	61,088
Natural gas liquids segment
Disaggregation of Revenue
Revenues		91,764	52,350	257,081	164,860
Natural gas liquids segment | Natural gas liquids
Disaggregation of Revenue
Revenues		91,764	52,350	257,081	164,860
Sulfur services segment
Disaggregation of Revenue
Revenues		30,837	21,880	103,958	83,623
Sulfur services segment | Sulfur product sales
Disaggregation of Revenue
Revenues		7,768	6,161	22,222	19,010
Sulfur services segment | Fertilizer product sales
Disaggregation of Revenue
Revenues		20,119	12,804	72,887	55,869
Sulfur services segment | Sulfur services
Disaggregation of Revenue
Revenues		2,950	2,915	8,849	8,744
Transportation segment
Disaggregation of Revenue
Revenues		39,079	31,938	103,820	102,364
Transportation segment | Land transportation
Disaggregation of Revenue
Revenues		30,273	21,879	80,715	65,986
Transportation segment | Inland transportation
Disaggregation of Revenue
Revenues		7,465	9,294	20,822	33,611
Transportation segment | Offshore transportation
Disaggregation of Revenue
Revenues		$ 1,341	$ 765	$ 2,283	$ 2,767
[1]	Related Party Transactions Included Above Three Months Ended Nine Months Ended September 30, September 30, 2021 2020 2021 2020 Revenues:* Terminalling and storage $ 15,866 $ 15,902 $ 46,741 $ 47,718 Transportation 5,564 5,514 14,463 16,801 Product Sales 68 69 253 199 Costs and expenses:* Cost of products sold: (excluding depreciation and amortization) Sulfur services 2,441 2,512 7,379 7,833 Terminalling and storage 7,259 4,303 18,863 14,329 Expenses: Operating expenses 20,088 18,915 58,046 60,126 Selling, general and administrative 7,659 8,356 23,624 24,723

Revenue - Estimated Revenue Exp

Revenue - Estimated Revenue Expected to be Recognized in Future (Details) $ in Thousands	Sep. 30, 2021USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 543,824
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 15,778
Revenue, remaining performance obligation, expected timing of satisfaction, period	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 63,607
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 63,411
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 50,471
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 51,744
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 298,813
Revenue, remaining performance obligation, expected timing of satisfaction, period
Terminalling and storage segment | Terminalling and storage
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 473,154
Terminalling and storage segment | Terminalling and storage | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 9,843
Revenue, remaining performance obligation, expected timing of satisfaction, period	3 months
Terminalling and storage segment | Terminalling and storage | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 40,394
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Terminalling and storage segment | Terminalling and storage | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 41,605
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Terminalling and storage segment | Terminalling and storage | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 42,910
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Terminalling and storage segment | Terminalling and storage | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 44,197
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Terminalling and storage segment | Terminalling and storage | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 294,205
Revenue, remaining performance obligation, expected timing of satisfaction, period
Natural gas liquids | Natural gas liquids
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 27,010
Natural gas liquids | Natural gas liquids | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 1,644
Revenue, remaining performance obligation, expected timing of satisfaction, period	3 months
Natural gas liquids | Natural gas liquids | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 6,048
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Natural gas liquids | Natural gas liquids | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 5,391
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Natural gas liquids | Natural gas liquids | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 5,405
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Natural gas liquids | Natural gas liquids | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 5,391
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Natural gas liquids | Natural gas liquids | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 3,131
Revenue, remaining performance obligation, expected timing of satisfaction, period
Sulfur services segment | Sulfur services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 43,660
Sulfur services segment | Sulfur services | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 4,291
Revenue, remaining performance obligation, expected timing of satisfaction, period	3 months
Sulfur services segment | Sulfur services | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 17,165
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Sulfur services segment | Sulfur services | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 16,415
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Sulfur services segment | Sulfur services | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 2,156
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Sulfur services segment | Sulfur services | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 2,156
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Sulfur services segment | Sulfur services | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Revenue, remaining performance obligation	$ 1,477
Revenue, remaining performance obligation, expected timing of satisfaction, period

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Inventory Disclosure [Abstract]
Natural gas liquids	$ 65,136	$ 27,878
Sulfur	49	24
Fertilizer	8,799	10,854
Lubricants	19,670	11,002
Other	4,485	4,364
Inventories	$ 98,139	$ 54,122

Debt (Details)

Debt (Details) - USD ($)	1 Months Ended		9 Months Ended
	Feb. 28, 2021	Aug. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Jul. 16, 2021	Jul. 15, 2021	Feb. 15, 2021	Dec. 31, 2020	Dec. 31, 2015	Apr. 30, 2014	Feb. 28, 2013
Debt Instrument
Total long-term debt			$ 547,090,000					$ 513,387,000
Less: current portion			0					(28,790,000)
Total long-term debt, net of current portion			547,090,000					484,597,000
Current installments of finance lease obligations			240,000					2,707,000
Finance lease obligations			108,000					289,000
Total lease liability			348,000					2,996,000
Payment of long term debt			211,790,000	$ 253,637,000
Revolving Loan Facility
Debt Instrument
Total long-term debt			205,496,000					144,174,000
Maximum borrowing capacity			$ 275,000,000		$ 275,000,000	$ 300,000,000
Weighted average interest rate (percent)			5.00%
Unamortized debt issuance costs			$ 3,004,000					3,826,000
Revolving Loan Facility | LIBOR
Debt Instrument
Interest rate floor (percent)			1.00%
Applicable margins (percent)			4.00%
Revolving Loan Facility | LIBOR | Minimum
Debt Instrument
Applicable margins (percent)			2.75%
Revolving Loan Facility | LIBOR | Maximum
Debt Instrument
Applicable margins (percent)			4.00%
Revolving Loan Facility | Prime Rate | Minimum
Debt Instrument
Applicable margins (percent)			1.75%
Revolving Loan Facility | Prime Rate | Maximum
Debt Instrument
Applicable margins (percent)			3.00%
Senior Notes | Senior Notes 7.25%
Debt Instrument
Total long-term debt			$ 0				$ 28,790,000	28,790,000
Unamortized debt issuance costs								0
Face amount								$ 400,000,000		$ 150,000,000	$ 250,000,000
Stated interest rate (percent)								7.25%
Unamortized premium								$ 0
Repurchase amount								9,344,000	$ 26,200,000
Debt refinanced		$ 335,666,000
Payment of long term debt	$ 28,790,000
Senior Notes | Senior Notes 10.0%
Debt Instrument
Total long-term debt			51,031,000					50,173,000
Unamortized debt issuance costs			2,719,000					3,577,000
Face amount			$ 53,750,000
Stated interest rate (percent)			10.00%
Senior Notes | Senior Note 11.5%
Debt Instrument
Total long-term debt			$ 290,563,000					290,250,000
Unamortized debt issuance costs			1,407,000					$ 1,720,000
Face amount			$ 291,970,000
Stated interest rate (percent)			11.50%

Debt - Narratives (Details)

Debt - Narratives (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Debt Disclosure [Abstract]
Cash paid for interest	$ 22,635	$ 15,698	$ 48,630	$ 34,811
Capitalized interest	$ 0	$ 16	$ 0	$ 26

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021USD ($)
New Accounting Pronouncements or Change in Accounting Principle
Lease termination term	1 year
Non-cancelable revenue arrangements, future minimum revenues, 2021	$ 6,139
Non-cancelable revenue arrangements, future minimum revenues, 2022	14,924
Non-cancelable revenue arrangements, future minimum revenues, 2023	14,364
Non-cancelable revenue arrangements, future minimum revenues, 2024	14,364
Non-cancelable revenue arrangements, future minimum revenues, 2025	13,798
Non-cancelable revenue arrangements, future minimum revenues, subsequent years	$ 38,539
Minimum
New Accounting Pronouncements or Change in Accounting Principle
Remaining lease term (years)	1 year
Maximum
New Accounting Pronouncements or Change in Accounting Principle
Remaining lease term (years)	15 years
Lease renewal term (years)	5 years

Leases - Lease Costs (Details)

Leases - Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Operating lease cost	$ 2,485	$ 2,572	$ 6,987	$ 8,182
Finance lease cost:
Amortization of right-of-use assets	25	390	140	1,505
Interest on lease liabilities	5	62	21	258
Short-term lease cost	2,324	3,138	7,905	10,054
Variable lease cost	28	33	87	83
Total lease cost	$ 4,867	$ 6,195	$ 15,140	$ 20,082

Leases - Balance Sheet Informat

Leases - Balance Sheet Information (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Operating Leases
Operating lease right-of-use assets	$ 21,267	$ 22,260
Current portion of operating lease liabilities included in "Other accrued liabilities"	6,746	7,529
Operating lease liabilities	14,960	15,181
Total operating lease liabilities	$ 21,706	$ 22,710
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other accrued liabilities	Other accrued liabilities
Finance Leases
Property, plant and equipment, at cost	$ 1,071	$ 10,352
Accumulated depreciation	(339)	(3,703)
Property, plant and equipment, net	732	6,649
Current installments of finance lease obligations	240	2,707
Finance lease obligations	108	289
Total finance lease obligations	$ 348	$ 2,996

Leases - Future Minimum Lease O

Leases - Future Minimum Lease Obligations (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Operating Leases
Year 1	$ 7,801
Year 2	5,102
Year 3	2,923
Year 4	2,220
Year 5	1,494
Thereafter	7,120
Total	26,660
Less amounts representing interest costs	(4,954)
Total lease liability	21,706	$ 22,710
Finance Leases
Year 1	252
Year 2	109
Year 3	0
Year 4	0
Year 5	0
Thereafter	0
Total	361
Less amounts representing interest costs	(13)
Total lease liability	$ 348	$ 2,996

Supplemental Balance Sheet In_3

Supplemental Balance Sheet Information - Other Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Accrued interest	$ 5,261	$ 16,104
Asset retirement obligations	300	1,692
Property and other taxes payable	4,546	4,869
Accrued payroll	4,425	3,244
Operating lease liabilities	6,746	7,529
Other	418	969
Total other accrued liabilities	$ 21,696	$ 34,407

Supplemental Balance Sheet In_4

Supplemental Balance Sheet Information - Asset Retirement Obligations (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Asset Retirement Obligation, Roll Forward Analysis
Beginning asset retirement obligations	$ 8,759
Additions to asset retirement obligations	0
Accretion expense	284
Liabilities settled	(22)
Ending asset retirement obligations	9,021
Current portion of asset retirement obligations	(300)	$ (1,692)
Long-term portion of asset retirement obligations	$ 8,721

Derivative Instruments and He_3

Derivative Instruments and Hedging Activities - Narrative (Details) - bbl bbl in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Commodity contracts
Derivatives, Fair Value
Notional quantity (in bbl)	400	137

Derivative Instruments and He_4

Derivative Instruments and Hedging Activities - Balance Sheet Derivatives (Details) - Commodity contracts - Fair value of derivatives - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Designated as Hedging Instrument
Derivatives, Fair Value
Derivative Assets	$ 0	$ 0
Derivative Liabilities	5,049	0
Derivatives not designated as hedging instruments
Derivatives, Fair Value
Derivative Assets	0	0
Derivative Liabilities	$ 0	$ 207

Derivative Instruments and He_5

Derivative Instruments and Hedging Activities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax
Amount of Gain (Loss) Reclassified from AOCI into Income	$ 0	$ 0	$ 0	$ 0
Amount Recognized in AOCI After Reclassification	(5,999)	0	(5,999)	0
Commodity contracts
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax
Amount of Gain (Loss) Recognized in AOCI	(5,999)	0	(5,999)	0
Commodity contracts | Cost of products sold
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax
Amount of Gain (Loss) Reclassified from AOCI into Income	$ 0	$ 0	$ 0	$ 0

Derivative Instruments and He_6

Derivative Instruments and Hedging Activities - Statement of Operations Derivatives (Details) - Derivatives not designated as hedging instruments - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Derivative Instruments, Gain (Loss)
Amount of Gain (Loss) Recognized in Income on Derivatives	$ (941)	$ (134)	$ (1,825)	$ (263)
Commodity contracts | Cost of products sold
Derivative Instruments, Gain (Loss)
Amount of Gain (Loss) Recognized in Income on Derivatives	$ (941)	$ (134)	$ (1,825)	$ (263)

Partners' Capital - Narrative (

Partners' Capital - Narrative (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Limited Partners' Capital Account
Common limited partner units (in shares)	38,802,750
Cash distributions	$ 593	$ 5,121
Martin Resource Management Corporation | Martin Resource Management
Limited Partners' Capital Account
Voting interest percentage	51.00%
Martin Resource Management
Limited Partners' Capital Account
Common limited partner units (in shares)	6,114,532
Voting interest percentage	15.80%
Martin Resource Management Corporation
Limited Partners' Capital Account
Ownership interest (percentage)	98.00%
Martin Resource Management Corporation | Martin Resource Management Corporation
Limited Partners' Capital Account
Purchase price			$ 550,773
Cash distributions			$ 287,734
MMGP LLC
Limited Partners' Capital Account
General partner interest percentage	2.00%
MMGP LLC | Martin Resource Management
Limited Partners' Capital Account
Ownership interest (percentage)	15.80%
General partner interest percentage	2.00%

Partners' Capital - Incentive D

Partners' Capital - Incentive Distribution Rights and Distributions of Available Cash (Details) - USD ($)	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Limited Partners' Capital Account
Distribution period	45 days
MMGP
Limited Partners' Capital Account
Incentive distribution	$ 0	$ 0
MMGP | Target Level 1
Limited Partners' Capital Account
Target cash distribution, percent	2.00%
MMGP | Target Level 2
Limited Partners' Capital Account
Target cash distribution, percent	15.00%
Target cash distribution (USD per share)	$ 0.625
MMGP | Target Level 3
Limited Partners' Capital Account
Target cash distribution, percent	25.00%
Target cash distribution (USD per share)	$ 0.75
MMGP | Target Level 4
Limited Partners' Capital Account
Target cash distribution, percent	50.00%
MMGP | Minimum | Target Level 1
Limited Partners' Capital Account
Target cash distribution (USD per share)	$ 0.50
MMGP | Minimum | Target Level 2
Limited Partners' Capital Account
Target cash distribution (USD per share)	0.55
MMGP | Minimum | Target Level 3
Limited Partners' Capital Account
Target cash distribution (USD per share)	0.625
MMGP | Minimum | Target Level 4
Limited Partners' Capital Account
Target cash distribution (USD per share)	0.75
MMGP | Maximum | Target Level 1
Limited Partners' Capital Account
Target cash distribution (USD per share)	$ 0.55
MMGP LLC
Limited Partners' Capital Account
General partner interest percentage	2.00%
MMGP LLC | MMGP
Limited Partners' Capital Account
General partner interest percentage	2.00%

Partners' Capital - Net Income

Partners' Capital - Net Income Per Unit (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Partners' Capital Notes [Abstract]
Net loss	$ (6,911)	$ (10,819)	$ (11,012)	$ (4,207)
Less general partner’s interest in net loss:
Distributions payable on behalf of general partner interest	4	4	12	57
General partner interest in undistributed loss	(142)	(220)	(232)	(141)
Less loss allocable to unvested restricted units	(20)	(53)	(30)	(8)
Limited partners' interest in net loss	$ (6,753)	$ (10,550)	$ (10,762)	$ (4,115)
Basic weighted average limited partner units outstanding (in shares)	38,687,874	38,661,852	38,689,434	38,654,891
Dilutive effect of restricted units issued (in shares)	0	0	0	0
Total weighted average limited partner diluted units outstanding (in shares)	38,687,874	38,661,852	38,689,434	38,654,891

Unit Based Awards - Schedule of

Unit Based Awards - Schedule of Compensation Costs (Details) - Selling, General and Administrative Expenses - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award
Total unit-based compensation expense	$ 229	$ 361	$ 517	$ 1,070
Restricted unit Awards | Employees
Share-based Compensation Arrangement by Share-based Payment Award
Total unit-based compensation expense	0	305	194	907
Restricted unit Awards | Non-employee directors
Share-based Compensation Arrangement by Share-based Payment Award
Total unit-based compensation expense	48	56	142	163
Phantom unit Awards | Employees
Share-based Compensation Arrangement by Share-based Payment Award
Total unit-based compensation expense	181	0	181	0
Phantom unit Awards | Non-employee directors
Share-based Compensation Arrangement by Share-based Payment Award
Total unit-based compensation expense	$ 0	$ 0	$ 0	$ 0

Unit Based Awards - Narrative (

Unit Based Awards - Narrative (Details) $ in Thousands	Jan. 24, 2025shares	Jan. 24, 2024shares	Jan. 24, 2023shares	Jan. 24, 2022shares	Jul. 21, 2021shares	Feb. 28, 2021directorshares	Sep. 30, 2021USD ($)shares	May 26, 2017shares
Phantom unit Awards
Share-based Compensation Arrangement by Share-based Payment Award
Trading days					20 years
Unrecognized compensation cost related to non-vested restricted units | $							$ 2,021
Weighted average period for recognition (in years)							2 years 9 months 21 days
Phantom unit Awards | Employees
Share-based Compensation Arrangement by Share-based Payment Award
Granted, number of units (in shares)					620,000
Phantom unit Awards | Affiliates
Share-based Compensation Arrangement by Share-based Payment Award
Granted, number of units (in shares)					1,245,000
Restricted unit Awards
Share-based Compensation Arrangement by Share-based Payment Award
Unrecognized compensation cost related to non-vested restricted units | $							$ 296
Weighted average period for recognition (in years)							2 years 8 months 8 days
Number of shares authorized (in shares)								3,000,000
Vested, number of units (in shares)							117,280
Restricted unit Awards | Employees
Share-based Compensation Arrangement by Share-based Payment Award
Vesting period (in years)							3 years
Restricted unit Awards | Non-employee directors
Share-based Compensation Arrangement by Share-based Payment Award
Vesting period (in years)							4 years
Time Based Restricted Units
Share-based Compensation Arrangement by Share-based Payment Award
Granted, number of units (in shares)							42,168
Number of independent directors receiving grants | director						3
Time Based Restricted Units | Non-employee directors
Share-based Compensation Arrangement by Share-based Payment Award
Granted, number of units (in shares)						14,056
Time Based Restricted Units | Non-employee directors | Scenario, Forecast
Share-based Compensation Arrangement by Share-based Payment Award
Vested, number of units (in shares)	3,514	3,514	3,514	3,514

Unit Based Awards - Restricted

Unit Based Awards - Restricted Unit Activity (Details) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2021USD ($)$ / sharesshares
Restricted unit Awards
Number of Units
Non-vested, beginning of period (in shares) | shares	273,424
Vested (in shares) | shares	(117,280)
Forfeited (in shares) | shares	(83,436)
Non-vested, end of period (in shares) | shares	114,876
Weighted Average Grant-Date Fair Value Per Unit
Non-vested, beginning of period (USD per share) | $ / shares	$ 10.52
Vested (USD per share) | $ / shares	11.96
Forfeited (USD per share) | $ / shares	13.90
Non-vested, end of period (USD per share) | $ / shares	$ 3.65
Aggregate intrinsic value, end of period | $	$ 368
Time Based Restricted Units
Number of Units
Granted (in shares) | shares	42,168
Weighted Average Grant-Date Fair Value Per Unit
Granted (USD per share) | $ / shares	$ 2.49

Unit Based Awards - Intrinsic a

Unit Based Awards - Intrinsic and Fair Value (Details) - Restricted unit Awards - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award
Aggregate intrinsic value of units vested	$ 0	$ 0	$ 257	$ 151
Fair value of units vested	$ 0	$ 0	$ 1,418	$ 1,427

Related Party Transactions - Na

Related Party Transactions - Narrative (Details)	9 Months Ended
	Sep. 30, 2021shares
MMGP LLC
Related Party Transaction
General partner interest percentage	2.00%
Martin Resource Management
Related Party Transaction
Common limited partner units (in shares)	6,114,532
Voting interest percentage	15.80%
Martin Resource Management | Martin Resource Management | MMGP Holdings, LLC
Related Party Transaction
General partner interest percentage	51.00%
Martin Resource Management | MMGP LLC
Related Party Transaction
General partner interest percentage	2.00%

Related Party Transactions - Om

Related Party Transactions - Omnibus Agreement (Details) - Omnibus Agreement - Martin Resource Management - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jan. 01, 2021
Related Party Transaction
Non-compete restriction threshold	$ 5,000,000		$ 5,000,000
Non-compete restriction ownership option opportunity threshold minimum	5,000,000		5,000,000
Non-compete restriction ownership option opportunity threshold minimum with equity limitation	$ 5,000,000		$ 5,000,000
Equity limitation on ownership restriction percentage	20.00%		20.00%
Approved annual reimbursements for indirect expenses					$ 14,386,000
Indirect expenses reimbursed	$ 3,597,000	$ 4,103,000	$ 10,790,000	$ 12,364,000

Related Party Transactions - Ma

Related Party Transactions - Master Transportation Services Agreement (Details)	9 Months Ended
	Sep. 30, 2021
Master Transportation Services Agreement | Martin Resource Management
Related Party Transaction
Termination written notice, minimum (in days)	30 days

Related Party Transactions - _2

Related Party Transactions - Marine Agreements (Details) - Marine Transportation Agreement - Martin Resource Management	9 Months Ended
	Sep. 30, 2021
Related Party Transaction
Automatic consecutive term renewal period (in years)	1 year
Termination written notice, minimum (in days)	60 days

Related Party Transactions - Te

Related Party Transactions - Terminal Services Agreements (Details)	9 Months Ended
	Sep. 30, 2021
Terminal Services Agreements | Martin Resource Management
Related Party Transaction
Termination written notice, minimum (in days)	60 days

Related Party Transactions - Ot

Related Party Transactions - Other Agreements (Details) - Martin Resource Management $ in Thousands	3 Months Ended		6 Months Ended	9 Months Ended
	Sep. 30, 2021USD ($)bbl	Sep. 30, 2020USD ($)	Jun. 30, 2022USD ($)	Sep. 30, 2021USD ($)bbl	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
East Texas Mack Leases
Related Party Transaction
Ownership interest (percent)	46.00%			46.00%
Operating cash flows from operating leases	$ 283	$ 173		$ 801	$ 432
Cross Tolling Agreement
Related Party Transaction
Production minimum per day (in bbl) | bbl	6,500			6,500
Capital recovery fee reimbursement, expired						$ 2,586	$ 2,088
Annual escalation benchmark percentage	3.00%			3.00%
Cross Tolling Agreement | Scenario, Forecast
Related Party Transaction
Annual revenue decrease from contract expiration			$ 2,145

Related Party Transactions - Sc

Related Party Transactions - Schedule of the Impact of Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating expenses:
Operating expenses	$ 20,088	$ 18,915	$ 58,046	$ 60,126
Related Party
Revenues:
Revenue from related parties	21,498	21,485	61,457	64,718
Cost of products sold:
Cost of products sold	9,700	6,815	26,242	22,162
Operating expenses:
Operating expenses	20,088	18,915	58,046	60,126
Selling, general and administrative:
Selling, general and administrative	7,659	8,356	23,624	24,723
Related Party | Indirect, including overhead allocation
Selling, general and administrative:
Selling, general and administrative	3,660	4,153	11,011	12,465
Related Party | Terminalling and storage
Revenues:
Revenue from related parties	15,866	15,902	46,741	47,718
Operating expenses:
Operating expenses	4,284	4,300	12,513	13,292
Selling, general and administrative:
Selling, general and administrative	878	863	2,530	2,536
Related Party | Transportation
Revenues:
Revenue from related parties	5,564	5,514	14,463	16,801
Operating expenses:
Operating expenses	13,949	13,009	40,652	41,950
Selling, general and administrative:
Selling, general and administrative	1,732	1,803	5,103	5,459
Related Party | Natural gas liquids
Operating expenses:
Operating expenses	534	486	1,511	1,481
Selling, general and administrative:
Selling, general and administrative	576	772	2,660	2,009
Related Party | Product sales
Revenues:
Revenue from related parties	68	69	253	199
Related Party | Sulfur services
Revenues:
Revenue from related parties	28	5	87	33
Cost of products sold:
Cost of products sold	2,441	2,512	7,379	7,833
Operating expenses:
Operating expenses	1,321	1,120	3,370	3,403
Selling, general and administrative:
Selling, general and administrative	813	765	2,320	2,254
Related Party | Terminalling and storage
Revenues:
Revenue from related parties	40	64	166	166
Cost of products sold:
Cost of products sold	$ 7,259	$ 4,303	$ 18,863	$ 14,329

Business Segments - Narratives

Business Segments - Narratives (Details)	9 Months Ended
	Sep. 30, 2021segment
Segment Reporting [Abstract]
Number of reportable segments	4

Business Segments - Income Stat

Business Segments - Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information
Total revenue	$ 211,258	$ 152,533	$ 596,525	$ 492,054
Depreciation and Amortization	13,945	15,276	42,862	45,858
Operating Income (Loss) after Eliminations	8,153	11,013	31,472	34,573
Capital Expenditures and Plant Turnaround Costs	4,297	5,214	14,409	21,983
Terminalling and storage
Segment Reporting Information
Total revenue	49,578	46,365	131,666	141,207
Depreciation and Amortization	7,049	7,294	21,150	22,022
Operating Income (Loss) after Eliminations	3,269	6,426	8,153	10,153
Capital Expenditures and Plant Turnaround Costs	2,087	1,863	6,258	8,885
Transportation
Segment Reporting Information
Total revenue	39,079	31,938	103,820	102,364
Depreciation and Amortization	3,710	4,412	12,039	13,020
Operating Income (Loss) after Eliminations	430	(2,673)	(7,782)	(9,772)
Capital Expenditures and Plant Turnaround Costs	1,086	1,785	2,702	6,483
Sulfur services
Segment Reporting Information
Total revenue	30,837	21,880	103,958	83,623
Depreciation and Amortization	2,594	2,953	7,882	8,978
Operating Income (Loss) after Eliminations	4,534	7,115	21,136	29,787
Capital Expenditures and Plant Turnaround Costs	1,104	1,393	4,968	6,267
Natural gas liquids
Segment Reporting Information
Total revenue	91,764	52,350	257,081	164,860
Depreciation and Amortization	592	617	1,791	1,838
Operating Income (Loss) after Eliminations	3,994	4,668	21,738	17,661
Capital Expenditures and Plant Turnaround Costs	20	173	481	348
Operating Revenues
Segment Reporting Information
Total revenue	216,395	158,130	612,509	510,944
Operating Revenues | Terminalling and storage
Segment Reporting Information
Total revenue	51,226	48,188	136,584	146,298
Operating Revenues | Transportation
Segment Reporting Information
Total revenue	42,568	35,712	114,886	116,145
Operating Revenues | Sulfur services
Segment Reporting Information
Total revenue	30,837	21,880	103,958	83,636
Operating Revenues | Natural gas liquids
Segment Reporting Information
Total revenue	91,764	52,350	257,081	164,865
Intersegment Revenues Eliminations
Segment Reporting Information
Total revenue	(5,137)	(5,597)	(15,984)	(18,890)
Intersegment Revenues Eliminations | Terminalling and storage
Segment Reporting Information
Total revenue	(1,648)	(1,823)	(4,918)	(5,091)
Intersegment Revenues Eliminations | Transportation
Segment Reporting Information
Total revenue	(3,489)	(3,774)	(11,066)	(13,781)
Intersegment Revenues Eliminations | Sulfur services
Segment Reporting Information
Total revenue	0	0	0	(13)
Intersegment Revenues Eliminations | Natural gas liquids
Segment Reporting Information
Total revenue	0	0	0	(5)
Indirect selling, general and administrative
Segment Reporting Information
Depreciation and Amortization	0	0	0	0
Operating Income (Loss) after Eliminations	(4,074)	(4,523)	(11,773)	(13,256)
Capital Expenditures and Plant Turnaround Costs	$ 0	$ 0	$ 0	$ 0

Business Segments - Balance She

Business Segments - Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Total assets:
Total assets	$ 614,238	$ 579,638
Terminalling and storage
Total assets:
Total assets	249,723	252,794
Transportation
Total assets:
Total assets	142,767	151,953
Sulfur services
Total assets:
Total assets	97,986	94,154
Natural gas liquids
Total assets:
Total assets	$ 123,762	$ 80,737

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Recurring | Level 2 | Commodity Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Commodity derivative contracts, net	$ (5,049)	$ (207)
Nonrecurring | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Notes payable	341,594	369,213
Nonrecurring | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Notes payable	357,923	372,487
Nonrecurring | 2021 Notes | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Notes payable	0	28,790
Nonrecurring | 2021 Notes | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Notes payable	0	28,581
Nonrecurring | 2024 Notes | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Notes payable	51,031	50,173
Nonrecurring | 2024 Notes | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Notes payable	55,126	55,214
Nonrecurring | 2025 Notes | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Notes payable	290,563	290,250
Nonrecurring | 2025 Notes | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Notes payable	$ 302,797	$ 288,692

Income Taxes - Income Tax Expen

Income Taxes - Income Tax Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 954	$ 373	$ 2,111	$ 1,510

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Income Tax Contingency
Income tax expense	$ 954	$ 373	$ 2,111	$ 1,510
Deferred income tax expense			1,419	1,202
MTI
Income Tax Contingency
Income tax expense	$ 895	$ 225	$ 1,871	$ 1,162
Effective income tax rate (percentage)	23.42%	45.72%	29.51%	80.42%
Current federal income tax expense (benefit)	$ 153	$ 0	$ 276	$ (174)
State income tax expense (benefit)	81	41	177	134
Deferred income tax expense	661	$ 183	1,419	$ 1,202
Deferred tax asset	$ 20,834		$ 20,834		$ 22,253

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent Event	Oct. 20, 2021$ / shares
Subsequent Event
Dividends declared (USD per share)	$ 0.005
Estimated annualized dividends (USD per share)	$ 0.020