Ceres Tactical Commodity 10-Q 12 Aug 15 2015 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2015	Jul. 31, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q2
Trading Symbol	ck0001325676
Entity Registrant Name	MANAGED FUTURES PREMIER AVENTIS II L.P.
Entity Central Index Key	1,325,676
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		126,795.9347

Statements of Financial Conditi

Statements of Financial Condition - USD ($)		Jun. 30, 2015	Dec. 31, 2014
Assets:
Investment in MB Master(1), at fair value	[1]	$ 190,657,774	$ 209,288,768
Cash		233,068	172,531
Total assets		190,890,842	209,461,299
Accrued expenses:
Ongoing selling agent fees		318,151	349,102
Management fees		198,276	217,637
General Partner fees		158,620	174,110
Other		228,198	180,684
Redemptions payable to Limited Partners		6,692,100	5,664,407
Total liabilities		7,595,345	6,585,940
Partners' Capital:
General Partner, 1,423.7415 and 1,648.4455 Redeemable Units outstanding at June 30, 2015 and December 31, 2014, respectively		1,987,064	2,304,961
Limited Partners, 129,908.3927 and 143,442.4917 Redeemable Units outstanding at June 30, 2015 and December 31, 2014, respectively		181,308,433	200,570,398
Total partners' capital		183,295,497	202,875,359
Total liabilities and partners' capital		$ 190,890,842	$ 209,461,299
Net asset value per unit		$ 1,395.66	$ 1,398.26
[1]	Defined in Note 1.

Statements of Financial Condit3

Statements of Financial Condition (Parenthetical) - shares	Jun. 30, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
General Partner, Redeemable Units outstanding	1,423.7415	1,648.4455
Limited Partners, Redeemable Units outstanding	129,908.3927	143,442.4917

Statements of Income and Expens

Statements of Income and Expenses and Changes in Partners' Capital - USD ($)		Total
Trading Results:
Net asset value per unit (131,332.1342 and 158,005.5832 Redeemable Units outstanding at June 30, 2015 and 2014, respectively)		$ 1,448.01
Interest income allocated from Master		$ 22,979
Expenses allocated from Master		2,338,774
Ongoing selling agent fees		3,802,798
Management fees		1,609,111
General Partner fees		601,104
Other		182,211
Total expenses		8,533,998
Net investment income (loss)		(8,511,019)
Net realized gains (losses) on closed contracts allocated from Master		3,945,727
Net change in unrealized gains (losses) on open contracts allocated from Master		(3,641,931)
Total trading results allocated from Master		303,796
Net income (loss)		(8,207,223)
Subscriptions - Limited Partners		6,957,094
Redemptions - Limited Partners		(36,755,057)
Net increase (decrease) in Partners' Capital		(38,005,186)
Partners' Capital, beginning of period at Dec. 31, 2013		259,723,302
Partners' Capital, end of period at Jun. 30, 2014		$ 221,718,116
Trading Results:
Net income (loss) per unit	[1]	$ (44.78)
Weighted average units outstanding		171,339.6612
Net asset value per unit (131,332.1342 and 158,005.5832 Redeemable Units outstanding at June 30, 2015 and 2014, respectively)		$ 1,393.86
Interest income allocated from Master		$ 7,443
Expenses allocated from Master		1,064,155
Ongoing selling agent fees		1,437,015
Management fees		716,883
General Partner fees		286,753
Other		99,091
Total expenses		3,603,897
Net investment income (loss)		(3,596,454)
Net realized gains (losses) on closed contracts allocated from Master		2,116,665
Net change in unrealized gains (losses) on open contracts allocated from Master		2,867,504
Total trading results allocated from Master		4,984,169
Net income (loss)		1,387,715
Subscriptions - Limited Partners		3,061,426
Redemptions - Limited Partners		(17,417,756)
Net increase (decrease) in Partners' Capital		(12,968,615)
Partners' Capital, beginning of period at Mar. 31, 2014		234,686,731
Partners' Capital, end of period at Jun. 30, 2014		$ 221,718,116
Trading Results:
Net income (loss) per unit	[1]	$ 9.37
Weighted average units outstanding		165,319.8155
Net asset value per unit (131,332.1342 and 158,005.5832 Redeemable Units outstanding at June 30, 2015 and 2014, respectively)		$ 1,403.23
Net asset value per unit (131,332.1342 and 158,005.5832 Redeemable Units outstanding at June 30, 2015 and 2014, respectively)		$ 1,398.26
Interest income allocated from Master		$ 6,729
Expenses allocated from Master		1,502,802
Ongoing selling agent fees		2,055,535
Management fees		1,281,210
General Partner fees		1,024,967
Other		185,416
Total expenses		6,049,930
Net investment income (loss)		(6,043,201)
Net realized gains (losses) on closed contracts allocated from Master		13,046,152
Net change in unrealized gains (losses) on open contracts allocated from Master		(6,924,286)
Total trading results allocated from Master		6,121,866
Net income (loss)		78,665
Subscriptions - General Partner		124,831
Subscriptions - Limited Partners		11,246,905
Redemptions - General Partner		(446,636)
Redemptions - Limited Partners		(30,583,627)
Net increase (decrease) in Partners' Capital		(19,579,862)
Partners' Capital, beginning of period at Dec. 31, 2014		202,875,359
Partners' Capital, end of period at Jun. 30, 2015		$ 183,295,497
Trading Results:
Net income (loss) per unit	[1]	$ (2.60)
Weighted average units outstanding		144,117.3647
Net asset value per unit (131,332.1342 and 158,005.5832 Redeemable Units outstanding at June 30, 2015 and 2014, respectively)		$ 1,419.72
Interest income allocated from Master		$ 2,955
Expenses allocated from Master		806,470
Ongoing selling agent fees		991,504
Management fees		617,951
General Partner fees		494,360
Other		86,196
Total expenses		2,996,481
Net investment income (loss)		(2,993,526)
Net realized gains (losses) on closed contracts allocated from Master		2,217,598
Net change in unrealized gains (losses) on open contracts allocated from Master		(2,454,511)
Total trading results allocated from Master		(236,913)
Net income (loss)		(3,230,439)
Subscriptions - Limited Partners		519,850
Redemptions - Limited Partners		(16,264,038)
Net increase (decrease) in Partners' Capital		(18,974,627)
Partners' Capital, beginning of period at Mar. 31, 2015		202,270,124
Partners' Capital, end of period at Jun. 30, 2015		$ 183,295,497
Trading Results:
Net income (loss) per unit	[1]	$ (24.06)
Weighted average units outstanding		139,336.8315
Net asset value per unit (131,332.1342 and 158,005.5832 Redeemable Units outstanding at June 30, 2015 and 2014, respectively)		$ 1,395.66
[1]	Represents the change in net asset value per unit during the period.

Statements of Income and Expen5

Statements of Income and Expenses and Changes in Partners' Capital (Parenthetical) - shares	Jun. 30, 2015	Jun. 30, 2014
Income Statement [Abstract]
Net asset value per Redeemable units outstanding	131,332.1342	158,005.5832

Organization

Organization	6 Months Ended
	Jun. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	1. Organization: Managed Futures Premier Aventis II L.P. (formerly known as Bristol Energy Fund L.P.) (the “Partnership”) is a limited partnership organized on April 20, 2005 under the partnership laws of the State of New York to engage, directly or indirectly, in the speculative trading of commodity interests on U.S. and international futures, options on futures and forward markets. The Partnership may also engage, directly or indirectly, in swap transactions and other derivative transactions with the approval of the General Partner (defined below). Initially, the Partnership’s investment strategy focused on energy and energy-related investments. While the Partnership is expected to continue to have significant exposure to energy and energy-related markets, such trading will no longer be the Partnership’s primary focus. Therefore, the Partnership’s past trading performance will not necessarily be indicative of future results. The commodity interests that are traded by the Partnership, through its investment in MB Master Fund L.P. (“MB Master” or the “Master”), are volatile and involve a high degree of market risk. The General Partner may also determine to invest up to all of the Partnership’s assets in United States (“U.S.”) Treasury bills. During the initial offering period, the Partnership sold 11,925 redeemable units (“Redeemable Units”). The Partnership commenced trading on September 6, 2005. The Partnership privately and continuously offers Redeemable Units to qualified investors. There is no maximum number of Redeemable Units that may be sold by the Partnership. Ceres Managed Futures LLC, a Delaware limited liability company, acts as the general partner (the “General Partner”) and commodity pool operator of the Partnership. The General Partner is wholly owned by Morgan Stanley Smith Barney Holdings LLC (“MSSB Holdings”). MSSB Holdings is ultimately owned by Morgan Stanley. Morgan Stanley is a publicly held company whose shares are listed on the New York Stock Exchange. Morgan Stanley is engaged in various financial services and other businesses. Prior to June 28, 2013, Morgan Stanley indirectly owned a majority equity interest in MSSB Holdings, and Citigroup Inc. indirectly owned a minority equity interest in MSSB Holdings. Prior to July 31, 2009, the date as of which MSSB Holdings became its owner, the General Partner was wholly owned by Citigroup Financial Products Inc., a wholly owned subsidiary of Citigroup Global Markets Holdings Inc., the sole owner of which is Citigroup Inc. As of June 30, 2015, all trading decisions for the Partnership are made by Aventis Asset Management, LLC (“Aventis” or the “Advisor”). As of June 30, 2015, the Partnership’s/MB Master’s commodity broker was Morgan Stanley & Co. LLC (“MS&Co.”), a registered futures commission merchant. MB Master has entered into a futures brokerage account agreement with MS&Co. The Partnership has also entered into a futures brokerage account agreement with MS&Co. The Partnership, through its investment in MB Master, pays MS&Co. trading fees for the clearing and, where applicable, execution of transactions as well as exchange, clearing, user, give-up, floor brokerage and National Futures Association fees (the “clearing fees”). The Partnership has also entered into a selling agreement with Morgan Stanley Smith Barney LLC (d/b/a Morgan Stanley Wealth Management) (“Morgan Stanley Wealth Management”). Pursuant to the selling agreement, Morgan Stanley Wealth Management receives a monthly ongoing selling agent fee equal to 2.00% per year of the Partnership’s adjusted month-end net assets. The ongoing selling agent fee received by Morgan Stanley Wealth Management is shared with the properly registered or exempted financial advisors of Morgan Stanley Wealth Management who have sold Redeemable Units in the Partnership. Effective April 1, 2014, the monthly ongoing selling agent fee was reduced from an annual rate of 3.75% to an annual rate of 2.50%. Effective October 1, 2014, the monthly ongoing selling agent fee was reduced from annual rate of 2.50% to its current annual rate of 2.00%. As of the same date, the General Partner fee was increased from an annual rate of 0.5% to an annual rate of 1.0%. The October 1, 2014 fee changes offset each other and, accordingly, there was no change to the aggregate fees incurred by the Partnership.

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2015
Accounting Policies [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	2. Basis of Presentation and Summary of Significant Accounting Policies: The accompanying financial statements and accompanying notes are unaudited but, in the opinion of the General Partner, include all adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation of the Partnership’s financial condition at June 30, 2015, and the results of its operations and changes in partners’ capital for the three and six months ended June 30, 2015 and 2014. These financial statements present the results of interim periods and do not include all disclosures normally provided in annual financial statements. These financial statements should be read together with the financial statements and notes included in the Partnership’s Annual Report on Form 10-K The preparation of financial statements and accompanying notes in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires the General Partner to make estimates and assumptions that affect the reported amounts of assets and liabilities, income and expenses, and related disclosures of contingent assets and liabilities in the financial statements and accompanying notes. As a result, actual results could differ from these estimates. Certain prior period amounts have been reclassified to conform to current period presentation. In the financial highlights for the Partnership, ongoing selling agent fees and clearing fees allocated from Master, which were previously included in net realized and unrealized gains (losses) per unit and excluded from expenses per unit, are now excluded from net realized and unrealized gains (losses) per unit and included in expenses per unit. This information was previously included as a footnote to the financial highlights table. Amounts previously referred to as Administrative fees are now referred to as General Partner fees in these financial statements. At June 30, 2015, the Partnership owned approximately 88.0% of MB Master. At December 31, 2014, the Partnership owned approximately 91.7% of MB Master. It is the Partnership’s intention to continue to invest substantially all of its assets in the Master. The performance of the Partnership is directly affected by the performance of the Master. The Master’s Statements of Financial Condition, Condensed Schedules of Investments and Statements of Income and Expenses and Changes in Partners’ Capital are included herein. The General Partner and each limited partner share in the profits and losses of the Partnership, in proportion to the amount of Partnership interest owned by each, except that no limited partner is liable for obligations of the Partnership in excess of its capital contribution and profits, if any, net of distributions and losses, if any. Due to the nature of commodity trading, the results of operations for the interim periods presented should not be considered indicative of the results that may be expected for the entire year. Partnership’s Investment: Master’s Investments: All commodity interests held by the Partnership and the Master, including derivative financial instruments and derivative commodity instruments, are held for trading purposes. The commodity interests are recorded on trade date and open contracts are recorded at fair value (as described below) at the measurement date. Investments in commodity interests denominated in foreign currencies are translated into U.S. dollars at the exchange rates prevailing at the measurement date. Gains or losses are realized when contracts are liquidated. Unrealized gains or losses on open contracts are included as a component of equity in trading account on the Statements of Financial Condition. Net realized gains or losses and any net change in unrealized gain or loss from the preceding period are reported in the Statements of Income and Expenses and Changes in Partners’ Capital. Investment Company Status: Financial Services — Investment Companies (Topic 946): Amendments to the Scope, Measurement and Disclosure Requirements Income Taxes: Net Income (loss) per unit: Recent Accounting Pronouncement: Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent) , There have been no material changes with respect to the Partnership’s critical accounting policies as reported in the Partnership’s Annual Report on Form 10-K for the year ended December 31, 2014.

Financial Highlights

Financial Highlights	6 Months Ended
	Jun. 30, 2015
Text Block [Abstract]
Financial Highlights	3. Financial Highlights: Financial highlights for the limited partner class as a whole for the three and six months ended June 30, 2015 and 2014 were as follows: Three Months Ended June 30, Six Months Ended June 30 2015 2014 2015 2014 Net realized and unrealized gains (losses) $ (2.56 ) $ 31.12 $ 39.36 $ 4.68 Net investment loss (21.50 ) (21.75 ) (41.96 ) (49.46 ) Increase (decrease) for the period (24.06 ) 9.37 (2.60 ) (44.78 ) Net asset value per unit, beginning of period 1,419.72 1,393.86 1,398.26 1,448.01 Net asset value per unit, end of period $ 1,395.66 $ 1,403.23 $ 1,395.66 $ 1,403.23 Three Months Ended June 30, Six Months Ended 2015 2014 2015 2014 Ratios to average net assets:* Net investment income (loss)** (6.2 )% (6.4 )% (6.1 )% (7.2 )% Operating expenses 6.2 % 6.4 % 6.1 % 7.2 % Incentive fees — % — % — % — % Total expenses and incentive fees 6.2 % 6.4 % 6.1 % 7.2 % Total return: Total return before incentive fees (1.7 )% 0.7 % (0.2 )% (3.1 )% Incentive fees — % — % — % — % Total return after incentive fees (1.7 )% 0.7 % (0.2 )% (3.1 )% * Annualized (except for incentive fees, if applicable). ** Interest income allocated from Master less total expenses. The above ratios and total return may vary for individual investors based on the timing of capital transactions during the period. Additionally, these ratios are calculated for the limited partner class using the limited partners’ share of income, expenses and average net assets of the Partnership and includes the income and expenses allocated from the Master.

Trading Activities

Trading Activities	6 Months Ended
	Jun. 30, 2015
Brokers and Dealers [Abstract]
Trading Activities	4. Trading Activities: The Partnership was formed for the purpose of trading contracts in a variety of commodity interests, including derivative financial instruments and derivative commodity instruments. The Partnership invests substantially all of its assets through a “master/feeder” structure. The Partnership’s pro-rata The customer agreement among the Partnership, MS&Co. and the Master gives the Partnership and the Master, respectively, the legal right to net unrealized gains and losses on open futures, forward and option contracts. The Master nets, for financial reporting purposes, the unrealized gains and losses on open futures, forward and option contracts on the Statements of Financial Condition as the criteria under Accounting Standards Codification 210-20, “Balance Sheet,” Trading and transaction fees are based on the number of trades executed by the Advisor for the Master and the Partnership’s percentage ownership of the Master. All clearing fees paid to MS&Co. are borne by the Master and allocated to the Partnership. All of the commodity interests owned by the Master are held for trading purposes. The monthly average number of futures contracts traded during the three months ended June 30, 2015 and 2014 were 7,879 and 17,446, respectively. The monthly average number of futures contracts traded during the six months ended June 30, 2015 and 2014 were 8,919 and 14,376, respectively. The monthly average number of option contracts traded during the three months ended June 30, 2015 and 2014 were 30,201 and 79,223, respectively. The monthly average number of option contracts traded during the six months ended June 30, 2015 and 2014 were 29,302 and 76,859, respectively. The monthly average number of metals forward contracts traded during the three months ended June 30, 2015 and 2014 were 855 and 0, respectively. The monthly average number of metals forward contracts traded during the six months ended June 30, 2015 and 2014 were 447 and 0, respectively. There were no direct investments at June 30, 2015 and December 31, 2014.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	5. Fair Value Measurements: Master’s Fair Value Measurements. The Master considers prices for exchange-traded commodity futures, forward, option and swap contracts to be based on unadjusted quoted prices in active markets for identical assets and liabilities (Level 1). The values of U.S. Treasury bills, non-exchange-traded forward, swap and certain option contracts for which market quotations are not readily available are priced by broker-dealers that derive fair values for those assets and liabilities from observable inputs (Level 2). As of and for the periods ended June 30, 2015 and December 31, 2014, the Master did not hold any derivative instruments that were priced at fair value using unobservable inputs through the application of the General Partner’s assumptions and internal valuation pricing models (Level 3). Transfers between levels are recognized at the end of the reporting period. During the six months ended June 30, 2015 and for the year ended December 31, 2014, there were no transfers of assets or liabilities between Level 1 and Level 2.

Investment in Master

Investment in Master	6 Months Ended
	Jun. 30, 2015
Schedule of Investments [Abstract]
Investment in Master	6. Investment in Master: On February 1, 2013, the Partnership allocated substantially all of its capital to MB Master, a limited partnership organized under the partnership laws of the State of Delaware. The Partnership purchased an interest in MB Master with cash equal to $262,944,186. MB Master permits accounts managed by Aventis using its Aventis Diversified Commodity Strategy, a proprietary, discretionary trading system, to invest together in one trading vehicle. The General Partner is also the general partner of the Master. Individual and pooled accounts currently managed by the Advisor, including the Partnership, are permitted to be limited partners of the Master. The General Partner and the Advisor believe that trading through this structure should promote efficiency and economy in the trading process. Expenses to investors as a result of the investment in the Master are approximately the same as if the Partnership traded directly and redemption rights are not affected. The General Partner is not aware of any material changes to Aventis Diversified Commodity Strategy during the fiscal quarter ended June 30, 2015. MB Master’s trading of futures, forwards and option contracts, if applicable, on commodities is done primarily on U.S. commodity exchanges and foreign commodity exchanges. The Master engages in such trading through a commodity brokerage account maintained with MS&Co. A limited partner may withdraw all or part of these capital contributions and undistributed profits, if any, from the Master as of the end of any day (the “Redemption Date”) after a request has been made to the General Partner at least 3 days in advance of the Redemption Date. Such withdrawals are classified as a liability when the limited partner elects to redeem and informs the Master. Management and incentive fees are charged at the Partnership level. All clearing fees are borne by the Master and allocated to its limited partners, including the Partnership. Professional fees and other expenses are borne by the Master and allocated to the Partnership, and also directly charged at the Partnership level. All other fees are charged at the Partnership level. MB Master’s Statements of Financial Condition and Condensed Schedules of Investments as of June 30, 2015 and December 31, 2014 and Statements of Income and Expenses and Changes in Partners’ Capital for the three and six months ended June 30, 2015 and 2014 are presented below. MB Master Fund L.P. Statements of Financial Condition (Unaudited) June 30, 2015 December 31, Assets: Equity in trading account: Investment in U.S. Treasury bills, at fair value (amortized cost $144,999,084 $ 144,999,084 $ — Cash 63,428,423 225,656,546 Cash margin 10,603,172 11,952,370 Net unrealized appreciation on open futures contracts — 2,122,505 Options purchased, at fair value (cost $9,285,023 and $11,720,470 at June 30, 2015 and December 31, 2014, respectively) 8,053,627 11,717,392 Total trading equity 227,084,306 251,448,813 Expense reimbursement 10,616 3,774 Total assets $ 227,094,922 $ 251,452,587 Liabilities and Partners’ Capital: Liabilities: Net unrealized depreciation on open futures contracts $ 943,254 $ — Net unrealized depreciation on open forward contracts 2,420,711 — Options written, at fair value (premium $6,683,003 and $13,275,727 at June 30, 2015 and December 31, 2014, respectively) 6,952,066 12,526,839 Accrued expenses: Clearing fees due to MS&Co. — 31,358 Professional fees 46,593 56,368 Redemptions payable — 10,689,151 Total liabilities 10,362,624 23,303,716 Partners’ Capital: General Partner — — Limited Partners 216,732,298 228,148,871 Total liabilities and partners’ capital $ 227,094,922 $ 251,452,587 MB Master Fund L.P. Condensed Schedule of Investments June 30, 2015 (Unaudited) Number of Fair Value % of Partners’ Futures Contracts Purchased Energy 3,396 $ (2,689,530 ) (1.24 )% Grains 2,179 2,455,059 1.13 Softs 1,067 3,103 0.00 * Total futures contracts purchased (231,368 ) (0.11 ) Futures Contracts Sold Energy 3,173 1,930,900 0.89 Grains 1,219 (2,586,205 ) (1.19 ) Softs 617 (56,581 ) (0.02 ) Total futures contracts sold (711,886 ) (0.32 ) Net unrealized depreciation on open futures contracts $ (943,254 ) (0.43 ) Unrealized Appreciation on Open Forward Contracts Metals 485 $ 1,610,134 0.74 Total Unrealized appreciation on open forward contracts 1,610,134 0.74 Unrealized Depreciation on Open Forward Contracts Metals 1,037 (4,030,845 ) (1.86 ) Total unrealized depreciation on open forward contracts (4,030,845 ) (1.86 ) Net unrealized depreciation on open forward contracts $ (2,420,711 ) (1.12 ) Options Purchased Calls Energy 896 $ 887,460 0.41 Grains 209 181,569 0.08 Metals 847 1,196,393 0.55 Softs 4,278 2,228,632 1.03 Puts Energy 671 476,100 0.22 Grains 4,486 207,250 0.10 Livestock 838 41,900 0.02 Metals 632 2,253,770 1.04 Softs 3,222 580,553 0.27 Total options purchased (cost $9,285,023) $ 8,053,627 3.72 Options Written Calls Energy 335 (1,041,850 ) (0.48 ) Metals 847 (448,837 ) (0.21 ) Softs 5,157 (1,584,218 ) (0.73 ) Puts Grains 3,380 (112,475 ) (0.05 ) Metals 632 (3,818,862 ) (1.76 ) Softs 738 54,176 0.02 Total options written (premium $6,683,003) $ (6,952,066 ) (3.21 ) U.S. Government Securities Face Amount Maturity Date Description Fair Value % of Partners’ $145,000,000 9/24/2015 U.S. Treasury bills, 0.0025% (amortized cost of $144,999,084) 144,999,084 66.90 Net fair value $ 142,736,680 65.86 % * Due to rounding MB Master Fund L.P. Condensed Schedule of Investments December 31, 2014 Number of Fair Value % of Partners’ Futures Contracts Purchased Energy RBOB Gasoline April 15 - June 15 1,662 $ (26,440,042 ) (11.59 )% Other 103 (781,530 ) (0.34 ) Grains 1,918 (1,106,332 ) (0.49 ) Softs 122 (143,685 ) (0.06 ) Total futures contracts purchased (28,471,589 ) (12.48 ) Futures Contracts Sold Energy NY Harbor ULSD June 15 989 24,702,136 10.83 Other 774 5,085,247 2.23 Grains 2,283 441,864 0.19 Livestock 590 348,405 0.15 Softs 259 16,442 0.01 Total futures contracts sold 30,594,094 13.41 Net unrealized appreciation on open futures contracts $ 2,122,505 0.93 Options Purchased Calls Energy 732 $ 104,920 0.05 Grains 1,987 3,975,845 1.74 Livestock 802 1,404,320 0.62 Softs 1,720 985,384 0.43 Puts Grains 2,292 2,069,042 0.91 Livestock 1,674 842,340 0.37 Softs 375 2,335,541 1.02 Total options purchased (cost $11,720,470) $ 11,717,392 5.14 Options Written Calls Grains 1,987 (5,323,670 ) (2.33 ) Livestock 802 (2,728,990 ) (1.20 ) Softs 2,468 (318,207 ) (0.14 ) Puts Energy 246 (678,960 ) (0.30 ) Grains 1,222 (259,655 ) (0.11 ) Softs 375 (3,217,357 ) (1.41 ) Total options written (premium $13,275,727) $ (12,526,839 ) (5.49 ) Net fair value $ 1,313,058 0.58 % MB Master Fund L.P. Statements of Income and Expenses and Changes in Partners’ Capital (Unaudited) Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Investment Income: Interest income $ 3,403 $ 8,812 $ 7,686 $ 27,506 Expenses: Clearing fees 881,354 1,191,312 1,622,769 2,639,403 Professional fees 24,339 24,152 48,223 55,066 Total expenses 905,693 1,215,464 1,670,992 2,694,469 Expense reimbursements (24,811 ) (13,345 ) (36,462 ) (28,222 ) Net expenses 880,882 1,202,119 1,634,530 2,666,247 Net investment income (loss) (877,479 ) (1,193,307 ) (1,626,844 ) (2,638,741 ) Trading results: Net gains (losses) on trading of commodity interests: Net realized gains (losses) on closed contracts 2,464,495 2,416,995 14,363,820 4,544,434 Net change in unrealized gains (losses) on open contracts (2,796,612 ) 3,206,620 (7,732,739 ) (4,347,548 ) Total trading results (332,117 ) 5,623,615 6,631,081 196,886 Net income (loss) (1,209,596 ) 4,430,308 5,004,237 (2,441,855 ) Subscriptions — Limited Partners 6,169,850 3,086,426 19,887,127 7,519,662 Redemptions — Limited Partners (17,600,266 ) (33,206,036 ) (36,300,251 ) (58,391,386 ) Distribution of interest income to feeder funds (3,403 ) (8,812 ) (7,686 ) (27,506 ) Net increase (decrease) in Partners’ Capital (12,643,415 ) (25,698,114 ) (11,416,573 ) (53,341,085 ) Partners’ Capital, beginning of period 229,375,713 284,187,666 228,148,871 311,830,637 Partners’ Capital, end of period $ 216,732,298 $ 258,489,552 $ 216,732,298 $ 258,489,552 The following tables summarize the gross and net amounts recognized relating to assets and liabilities of the Master’s derivatives and their offsetting subject to master netting arrangements or similar agreements as of June 30, 2015 and December 31, 2014, respectively. Gross Amounts Not Offset in the Statements of Financial Condition June 30, 2015 Gross Amounts Gross Amounts Offset Amounts Presented Financial Cash Collateral 1 Net Amount Assets Futures $ 5,831,541 $ (5,831,541 ) $ — $ — $ — $ — Forwards 1,610,134 (1,610,134 ) — — — — Options purchased 8,053,627 — 8,053,627 (6,952,066 ) — 1,101,561 Total assets 15,495,302 (7,441,675 ) 8,053,627 (6,952,066 ) — 1,101,561 Liabilities Futures $ (6,774,795 ) $ 5,831,541 $ (943,254 ) $ — $ — $ (943,254 ) Forwards (4,030,845 ) 1,610,134 (2,420,711 ) — — (2,420,711 ) Options written (6,952,066 ) — (6,952,066 ) 6,952,066 — — Total liabilities (17,757,706 ) 7,441,675 (10,316,031 ) 6,952,066 — (3,363,965 ) Net fair value $ (2,262,404 ) 1 Gross Amounts Not Offset in the Statements of Financial Condition December 31, 2014 Gross Amounts Gross Amounts Offset Amounts Presented in the Statements of Financial Cash Collateral 1 Net Amount Assets Futures $ 31,357,685 $ (29,235,180 ) $ 2,122,505 $ — $ — $ 2,122,505 Options purchased 11,717,392 — 11,717,392 (11,717,392 ) — — Total assets 43,075,077 (29,235,180 ) 13,839,897 (11,717,392 ) — 2,122,505 Liabilities Futures $ (29,235,180 ) $ 29,235,180 $ — $ — $ — $ — Options written (12,526,839 ) — (12,526,839 ) 11,717,392 — (809,447 ) Total liabilities (41,762,019 ) 29,235,180 (12,526,839 ) 11,717,392 — (809,447 ) Net fair value $ 1,313,058 1 1 In the event of default by the Master, MS&Co., the Master’s commodity futures broker and the sole counterparty to the Master’s off exchange-traded contracts, as applicable, has the right to offset the Master’s obligation with the Master’s cash held by MS&Co., thereby minimizing MS&Co.’s risk of loss. There is no collateral posted by MS&Co. and as such, in the event of default by MS&Co., the Master is exposed to the amount shown on the Statements of Financial Condition. In the case of exchange-traded contracts, the Master’s exposure to counterparty risk may be reduced since the exchange’s clearinghouse interposes its credit between buyer and seller and the clearinghouse’s guarantee fund may be available in the event of a default. June 30, 2015 Level 1 Level 2 Level 3 Assets Futures $ 5,831,541 $ 5,831,541 $ — $ — Forwards 1,610,134 1,610,134 — — Options purchased 8,053,627 8,053,627 — — U.S. Treasury bills 144,999,084 — 144,999,084 — Total assets 160,494,386 15,495,302 $ 144,999,084 $ — Liabilities Futures $ 6,774,795 $ 6,774,795 $ — $ — Forwards 4,030,845 4,030,845 — — Options written 6,952,066 6,952,066 — — Total liabilities 17,757,706 17,757,706 — — Net fair value $ 142,736,680 $ (2,262,404 ) $ 144,999,084 $ — December 31, 2014 Level 1 Level 2 Level 3 Assets Futures $ 31,357,685 $ 31,357,685 $ — $ — Options purchased 11,717,392 11,717,392 — — Total assets $ 43,075,077 $ 43,075,077 $ — $ — Liabilities Futures $ 29,235,180 $ 29,235,180 $ — $ — Options written 12,526,839 12,526,839 — — Total liabilities 41,762,019 41,762,019 — — Net fair value $ 1,313,058 $ 1,313,058 $ — $ — Financial Highlights of the Master: Financial highlights for the limited partner class as a whole for the three and six months ended June 30, 2015 and 2014 were as follows: Three Months Ended Six Months Ended 2015 2014 2015 2014 Ratios to average net assets: 1 Net investment income (loss) 2 (1.6 )% (1.8 )% (1.4 )% (1.9 )% Operating expenses 3 1.6 % 1.8 % 1.4 % 1.9 % Total return (0.6 )% 1.8 % 2.1 % (0.6 )% 1 Annualized. 2 Interest income less total expenses. 3 Percentages are annualized and after expense reimbursements (equal to 0.04%, 0.02%, 0.03% and 0.02%, respectively). The above ratios and total return may vary for individual investors based on the timing of capital transactions during the period. Additionally, these ratios are calculated for the limited partner class using the limited partners’ share of income, expenses and average net assets. The following tables indicate the Master’s gross fair values of derivative instruments of futures, forward and option contracts as separate assets and liabilities as of June 30, 2015 and December 31, 2014, respectively. June 30, 2015 Assets Futures Contracts Energy $ 3,008,990 Grains 2,455,059 Softs 367,492 Total unrealized appreciation on open futures contracts $ 5,831,541 Liabilities Futures Contracts Energy $ (3,767,620 ) Grains (2,586,205 ) Softs (420,970 ) Total unrealized depreciation on open futures contracts $ (6,774,795 ) Net unrealized depreciation on open futures contracts $ (943,254 )* Assets Forward Contracts Metals $ 1,610,134 Total unrealized appreciation on open forward contracts $ 1,610,134 Liabilities Forward Contracts Metals $ (4,030,845 ) Total unrealized depreciation on open forward contracts $ (4,030,845 ) Net unrealized depreciation on open forward contracts $ (2,420,711 )** Assets Options Purchased Energy $ 1,363,560 Grains 388,819 Livestock 41,900 Metals 3,450,163 Softs 2,809,185 Total options purchased $ 8,053,627 *** Liabilities Options Written Energy $ (1,041,850 ) Grains (112,475 ) Metals (4,267,699 ) Softs (1,530,042 ) Total options written $ (6,952,066 )**** * This amount is in “Net unrealized depreciation on open futures contracts” on the Master’s Statements of Financial Condition. ** This amount is in “Net unrealized depreciation on open forward contracts” on the Master’s Statements of Financial Condition. *** This amount is in “Options purchased, at fair value” on the Master’s Statements of Financial Condition. **** This amount is in “Options written, at fair value” on the Master’s Statements of Financial Condition. December 31, 2014 Assets Futures Contracts Energy $ 29,821,382 Grains 1,137,234 Livestock 360,642 Softs 38,427 Total unrealized appreciation on open futures contracts $ 31,357,685 Liabilities Futures Contracts Energy $ (27,255,571 ) Grains (1,801,702 ) Livestock (12,237 ) Softs (165,670 ) Total unrealized depreciation on open futures contracts $ (29,235,180 ) Net unrealized appreciation on open futures contracts $ 2,122,505 * Assets Options Purchased Energy $ 104,920 Grains 6,044,887 Livestock 2,246,660 Softs 3,320,925 Total options purchased $ 11,717,392 ** Liabilities Options Written Energy $ (678,960 ) Grains (5,583,325 ) Livestock (2,728,990 ) Softs (3,535,564 ) Total options written $ (12,526,839 )*** * This amount is included in “Net unrealized appreciation on open futures contracts” on the Master’s Statements of Financial Condition. ** This amount is included in “Options purchased, at fair value” on the Master’s Statements of Financial Condition. *** This amount is included in “Options written, at fair value” on the Master’s Statements of Financial Condition. The following table indicates the Master’s total trading gains and losses, by market sector, on derivative instruments for the three and six months ended June 30, 2015 and 2014. Three Months Ended June 30, Six Months Ended June 30, Sector 2015 2014 2015 2014 Energy $ 135,596 $ 1,016,012 $ 5,875,669 $ (3,891,145 ) Grains 1,144,202 9,655,676 3,914,099 8,438,456 Livestock (248,732 ) (282,249 ) 1,998,143 (3,141,108 ) Metals (2,641,215 ) — (2,697,902 ) (70,689 ) Softs 1,278,032 (4,765,824 ) (2,458,928 ) (1,138,628 ) Total $ (332,117 )* $ 5,623,615 * $ 6,631,081 * $ 196,886 * * This amount is in “Total trading results” on the Master’s Statements of Income and Expenses and Changes in Partners’ Capital.

Financial Instrument Risks

Financial Instrument Risks	6 Months Ended
	Jun. 30, 2015
Investments, All Other Investments [Abstract]
Financial Instrument Risks	7. Financial Instrument Risks: In the normal course of business, the Partnership, indirectly through its investment in the Master, is party to financial instruments with off-balance over-the-counter The Master trades futures contracts. A futures contract is a firm commitment to buy or sell a specified quantity of investments, currency or a standardized amount of a deliverable grade commodity, at a specified price on a specified future date, unless the contract is closed before the delivery date or if the delivery quantity is something where physical delivery cannot occur (such as the S&P 500 Index), whereby such contract is settled in cash. Payments (“variation margin”) may be made or received by the Master each business day, depending on the daily fluctuations in the value of the underlying contracts, and are recorded as unrealized gains or losses by the Master. When the contract is closed, the Master records a realized gain or loss equal to the difference between the value of the contract at the time it was opened and the value at the time it was closed. Transactions in futures contracts require participants to make both initial margin deposits of cash or other assets and variation margin deposits, through the futures broker, directly with the exchange on which the contracts are traded. Net realized gains (losses) and net change in unrealized gains (losses) on futures contracts are included in the Master’s Statements of Income and Expenses and Changes in Partners’ Capital. Metal contracts traded on the London Metals Exchange (“LME”) represent a firm commitment to buy or sell a specified quantity of aluminum, copper, lead, nickel, tin or zinc. LME contracts traded by the Master are cash settled based on prompt dates published by the LME. Payments (“variation margin”) may be made or received by the Master on each business day, depending on the daily fluctuations in the value of the underlying contracts, and are recorded as unrealized gains or losses by the Master. A contract is considered offset when all long positions have been matched with a like number of short positions settling on the same prompt date. When the contract is closed at the prompt date, the Master records a realized gain or loss equal to the difference between the value of the contract at the time it was opened and the value at the time it was closed. Transactions in LME contracts require participants to make both initial margin deposits of cash or other assets and variation margin deposits, through the broker, directly with the LME. Net realized gains (losses) and net change in unrealized gains (losses) on metal contracts are included in the Master’s Statements of Income and Expenses and Changes in Partners’ Capital. The risk to the limited partners that have purchased Redeemable Units is limited to the amount of their share of the Partnership’s net assets and undistributed profits. This limited liability is a result of the organization of the Partnership as a limited partnership under New York law. Market risk is the potential for changes in the value of the financial instruments traded by the Partnership/Master due to market changes, including interest and foreign exchange rate movements and fluctuations in commodity or security prices. Market risk is directly impacted by the volatility and liquidity in the markets in which the related underlying assets are traded. The Partnership/Master is exposed to a market risk equal to the value of the futures and forward contracts purchased and unlimited liability on such contracts sold short. Credit risk is the possibility that a loss may occur due to the failure of a counterparty to perform according to the terms of a contract. The Partnership’s/Master’s risk of loss in the event of a counterparty default is typically limited to the amounts recognized in the Statements of Financial Condition and is not represented by the contract or notional amounts of the instruments. The Partnership’s/Master’s risk of loss is reduced through the use of legally enforceable master netting agreements with counterparties that permit the Partnership/Master to offset unrealized gains and losses and other assets and liabilities with such counterparties upon the occurrence of certain events. The Partnership/Master has credit risk and concentration risk, as MS&Co. or an MS&Co. affiliate is the sole counterparty or broker with respect to the Partnership’s/Master’s assets. Credit risk with respect to exchange-traded instruments is reduced to the extent that, through MS&Co. or an MS&Co. affiliate, the Partnership’s/Master’s counterparty is an exchange or clearing organization. As both a buyer and seller of options, the Partnership/Master pays or receives a premium at the outset and then bears the risk of unfavorable changes in the price of the contract underlying the option. Written options expose the Partnership/Master to potentially unlimited liability; for purchased options the risk of loss is limited to the premiums paid. Certain written put options permit cash settlement and do not require the option holder to own the reference asset. The Partnership/Master does not consider these contracts to be guarantees. The General Partner monitors and attempts to control the Partnership’s/Master’s risk exposure on a daily basis through financial, credit and risk management monitoring systems, and accordingly, believes that it has effective procedures for evaluating and limiting the credit and market risks to which the Partnership/Master may be subject. These monitoring systems generally allow the General Partner to statistically analyze actual trading results with risk-adjusted performance indicators and correlation statistics. In addition, online monitoring systems provide account analysis of futures, forward and option contracts by sector, margin requirements, gain and loss transactions and collateral positions. The majority of these financial instruments mature within one year of the inception date. However, due to the nature of the Partnership’s/Master’s business, these instruments may not be held to maturity.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2015
Subsequent Events [Abstract]
Subsequent Events	8. Subsequent Events: The General Partner evaluates events that occur after the balance sheet date but before financial statements are issued. The General Partner has assessed the subsequent events through the date of issuance and has determined that other than that listed below, there were no subsequent events requiring adjustment of or disclosure in the financial statements. On or about July 31, 2015, the General Partner delegated certain administrative functions to SS&C Technologies, Inc., a Delaware corporation, currently doing business as SS&C GlobeOp (the “Administrator”). Pursuant to a Master Services Agreement, the Administrator will furnish certain administrative, accounting, regulatory, reporting, tax and other services as agreed from time to time. In addition, the Administrator will maintain certain books and records of the Partnership. The costs of retaining the Administrator will be allocated among the pools operated by the General Partner, including the Partnership. The General Partner does not expect that such additional expense will have a material impact on the Partnership’s break even point.

Basis of Presentation and Sum14

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2015
Investment Company Status	Investment Company Status: Financial Services — Investment Companies (Topic 946): Amendments to the Scope, Measurement and Disclosure Requirements
Income Taxes	Income Taxes:
Net Income (loss) per unit	Net Income (loss) per unit.
Recent Accounting Pronouncement	Recent Accounting Pronouncement: Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent) , There have been no material changes with respect to the Partnership’s critical accounting policies as reported in the Partnership’s Annual Report on Form 10-K for the year ended December 31, 2014.
Master's Fair Value Measurements	Master’s Fair Value Measurements.
Partnership [Member]
Investment Company Status	Partnership’s Investment:
Master Investments [Member]
Investment Company Status	Master’s Investments: All commodity interests held by the Partnership and the Master, including derivative financial instruments and derivative commodity instruments, are held for trading purposes. The commodity interests are recorded on trade date and open contracts are recorded at fair value (as described below) at the measurement date. Investments in commodity interests denominated in foreign currencies are translated into U.S. dollars at the exchange rates prevailing at the measurement date. Gains or losses are realized when contracts are liquidated. Unrealized gains or losses on open contracts are included as a component of equity in trading account on the Statements of Financial Condition. Net realized gains or losses and any net change in unrealized gain or loss from the preceding period are reported in the Statements of Income and Expenses and Changes in Partners’ Capital.

Financial Highlights (Tables)

Financial Highlights (Tables)	6 Months Ended
	Jun. 30, 2015
Text Block [Abstract]
Schedule of Financial Highlights for Limited Partner Class	Financial highlights for the limited partner class as a whole for the three and six months ended June 30, 2015 and 2014 were as follows: Three Months Ended June 30, Six Months Ended June 30 2015 2014 2015 2014 Net realized and unrealized gains (losses) $ (2.56 ) $ 31.12 $ 39.36 $ 4.68 Net investment loss (21.50 ) (21.75 ) (41.96 ) (49.46 ) Increase (decrease) for the period (24.06 ) 9.37 (2.60 ) (44.78 ) Net asset value per unit, beginning of period 1,419.72 1,393.86 1,398.26 1,448.01 Net asset value per unit, end of period $ 1,395.66 $ 1,403.23 $ 1,395.66 $ 1,403.23 Three Months Ended June 30, Six Months Ended 2015 2014 2015 2014 Ratios to average net assets:* Net investment income (loss)** (6.2 )% (6.4 )% (6.1 )% (7.2 )% Operating expenses 6.2 % 6.4 % 6.1 % 7.2 % Incentive fees — % — % — % — % Total expenses and incentive fees 6.2 % 6.4 % 6.1 % 7.2 % Total return: Total return before incentive fees (1.7 )% 0.7 % (0.2 )% (3.1 )% Incentive fees — % — % — % — % Total return after incentive fees (1.7 )% 0.7 % (0.2 )% (3.1 )% * Annualized (except for incentive fees, if applicable). ** Interest income allocated from Master less total expenses.

Investment in Master (Tables)

Investment in Master (Tables)	6 Months Ended
	Jun. 30, 2015
Schedule of Investments [Abstract]
Statements of Financial Condition	MB Master Fund L.P. Statements of Financial Condition (Unaudited) June 30, 2015 December 31, Assets: Equity in trading account: Investment in U.S. Treasury bills, at fair value (amortized cost $144,999,084 $ 144,999,084 $ — Cash 63,428,423 225,656,546 Cash margin 10,603,172 11,952,370 Net unrealized appreciation on open futures contracts — 2,122,505 Options purchased, at fair value (cost $9,285,023 and $11,720,470 at June 30, 2015 and December 31, 2014, respectively) 8,053,627 11,717,392 Total trading equity 227,084,306 251,448,813 Expense reimbursement 10,616 3,774 Total assets $ 227,094,922 $ 251,452,587 Liabilities and Partners’ Capital: Liabilities: Net unrealized depreciation on open futures contracts $ 943,254 $ — Net unrealized depreciation on open forward contracts 2,420,711 — Options written, at fair value (premium $6,683,003 and $13,275,727 at June 30, 2015 and December 31, 2014, respectively) 6,952,066 12,526,839 Accrued expenses: Clearing fees due to MS&Co. — 31,358 Professional fees 46,593 56,368 Redemptions payable — 10,689,151 Total liabilities 10,362,624 23,303,716 Partners’ Capital: General Partner — — Limited Partners 216,732,298 228,148,871 Total liabilities and partners’ capital $ 227,094,922 $ 251,452,587
Condensed Schedule of Investments	MB Master Fund L.P. Condensed Schedule of Investments June 30, 2015 (Unaudited) Number of Fair Value % of Partners’ Futures Contracts Purchased Energy 3,396 $ (2,689,530 ) (1.24 )% Grains 2,179 2,455,059 1.13 Softs 1,067 3,103 0.00 * Total futures contracts purchased (231,368 ) (0.11 ) Futures Contracts Sold Energy 3,173 1,930,900 0.89 Grains 1,219 (2,586,205 ) (1.19 ) Softs 617 (56,581 ) (0.02 ) Total futures contracts sold (711,886 ) (0.32 ) Net unrealized depreciation on open futures contracts $ (943,254 ) (0.43 ) Unrealized Appreciation on Open Forward Contracts Metals 485 $ 1,610,134 0.74 Total Unrealized appreciation on open forward contracts 1,610,134 0.74 Unrealized Depreciation on Open Forward Contracts Metals 1,037 (4,030,845 ) (1.86 ) Total unrealized depreciation on open forward contracts (4,030,845 ) (1.86 ) Net unrealized depreciation on open forward contracts $ (2,420,711 ) (1.12 ) Options Purchased Calls Energy 896 $ 887,460 0.41 Grains 209 181,569 0.08 Metals 847 1,196,393 0.55 Softs 4,278 2,228,632 1.03 Puts Energy 671 476,100 0.22 Grains 4,486 207,250 0.10 Livestock 838 41,900 0.02 Metals 632 2,253,770 1.04 Softs 3,222 580,553 0.27 Total options purchased (cost $9,285,023) $ 8,053,627 3.72 Options Written Calls Energy 335 (1,041,850 ) (0.48 ) Metals 847 (448,837 ) (0.21 ) Softs 5,157 (1,584,218 ) (0.73 ) Puts Grains 3,380 (112,475 ) (0.05 ) Metals 632 (3,818,862 ) (1.76 ) Softs 738 54,176 0.02 Total options written (premium $6,683,003) $ (6,952,066 ) (3.21 ) U.S. Government Securities Face Amount Maturity Date Description Fair Value % of Partners’ $145,000,000 9/24/2015 U.S. Treasury bills, 0.0025% (amortized cost of $144,999,084) 144,999,084 66.90 Net fair value $ 142,736,680 65.86 % * Due to rounding MB Master Fund L.P. Condensed Schedule of Investments December 31, 2014 Number of Fair Value % of Partners’ Futures Contracts Purchased Energy RBOB Gasoline April 15 - June 15 1,662 $ (26,440,042 ) (11.59 )% Other 103 (781,530 ) (0.34 ) Grains 1,918 (1,106,332 ) (0.49 ) Softs 122 (143,685 ) (0.06 ) Total futures contracts purchased (28,471,589 ) (12.48 ) Futures Contracts Sold Energy NY Harbor ULSD June 15 989 24,702,136 10.83 Other 774 5,085,247 2.23 Grains 2,283 441,864 0.19 Livestock 590 348,405 0.15 Softs 259 16,442 0.01 Total futures contracts sold 30,594,094 13.41 Net unrealized appreciation on open futures contracts $ 2,122,505 0.93 Options Purchased Calls Energy 732 $ 104,920 0.05 Grains 1,987 3,975,845 1.74 Livestock 802 1,404,320 0.62 Softs 1,720 985,384 0.43 Puts Grains 2,292 2,069,042 0.91 Livestock 1,674 842,340 0.37 Softs 375 2,335,541 1.02 Total options purchased (cost $11,720,470) $ 11,717,392 5.14 Options Written Calls Grains 1,987 (5,323,670 ) (2.33 ) Livestock 802 (2,728,990 ) (1.20 ) Softs 2,468 (318,207 ) (0.14 ) Puts Energy 246 (678,960 ) (0.30 ) Grains 1,222 (259,655 ) (0.11 ) Softs 375 (3,217,357 ) (1.41 ) Total options written (premium $13,275,727) $ (12,526,839 ) (5.49 ) Net fair value $ 1,313,058 0.58 %
Statements of Income and Expenses and Changes in Partners' Capital	MB Master Fund L.P. Statements of Income and Expenses and Changes in Partners’ Capital (Unaudited) Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Investment Income: Interest income $ 3,403 $ 8,812 $ 7,686 $ 27,506 Expenses: Clearing fees 881,354 1,191,312 1,622,769 2,639,403 Professional fees 24,339 24,152 48,223 55,066 Total expenses 905,693 1,215,464 1,670,992 2,694,469 Expense reimbursements (24,811 ) (13,345 ) (36,462 ) (28,222 ) Net expenses 880,882 1,202,119 1,634,530 2,666,247 Net investment income (loss) (877,479 ) (1,193,307 ) (1,626,844 ) (2,638,741 ) Trading results: Net gains (losses) on trading of commodity interests: Net realized gains (losses) on closed contracts 2,464,495 2,416,995 14,363,820 4,544,434 Net change in unrealized gains (losses) on open contracts (2,796,612 ) 3,206,620 (7,732,739 ) (4,347,548 ) Total trading results (332,117 ) 5,623,615 6,631,081 196,886 Net income (loss) (1,209,596 ) 4,430,308 5,004,237 (2,441,855 ) Subscriptions — Limited Partners 6,169,850 3,086,426 19,887,127 7,519,662 Redemptions — Limited Partners (17,600,266 ) (33,206,036 ) (36,300,251 ) (58,391,386 ) Distribution of interest income to feeder funds (3,403 ) (8,812 ) (7,686 ) (27,506 ) Net increase (decrease) in Partners’ Capital (12,643,415 ) (25,698,114 ) (11,416,573 ) (53,341,085 ) Partners’ Capital, beginning of period 229,375,713 284,187,666 228,148,871 311,830,637 Partners’ Capital, end of period $ 216,732,298 $ 258,489,552 $ 216,732,298 $ 258,489,552
Summary of Gross and Net Amounts Recognized Relating to Assets and Liabilities of Master's Derivatives and their Offsetting Subject to Master Netting Arrangements or Similar Agreements	The following tables summarize the gross and net amounts recognized relating to assets and liabilities of the Master’s derivatives and their offsetting subject to master netting arrangements or similar agreements as of June 30, 2015 and December 31, 2014, respectively. Gross Amounts Not Offset in the Statements of Financial Condition June 30, 2015 Gross Amounts Gross Amounts Offset Amounts Presented Financial Cash Collateral 1 Net Amount Assets Futures $ 5,831,541 $ (5,831,541 ) $ — $ — $ — $ — Forwards 1,610,134 (1,610,134 ) — — — — Options purchased 8,053,627 — 8,053,627 (6,952,066 ) — 1,101,561 Total assets 15,495,302 (7,441,675 ) 8,053,627 (6,952,066 ) — 1,101,561 Liabilities Futures $ (6,774,795 ) $ 5,831,541 $ (943,254 ) $ — $ — $ (943,254 ) Forwards (4,030,845 ) 1,610,134 (2,420,711 ) — — (2,420,711 ) Options written (6,952,066 ) — (6,952,066 ) 6,952,066 — — Total liabilities (17,757,706 ) 7,441,675 (10,316,031 ) 6,952,066 — (3,363,965 ) Net fair value $ (2,262,404 ) 1 Gross Amounts Not Offset in the Statements of Financial Condition December 31, 2014 Gross Amounts Gross Amounts Offset Amounts Presented in the Statements of Financial Cash Collateral 1 Net Amount Assets Futures $ 31,357,685 $ (29,235,180 ) $ 2,122,505 $ — $ — $ 2,122,505 Options purchased 11,717,392 — 11,717,392 (11,717,392 ) — — Total assets 43,075,077 (29,235,180 ) 13,839,897 (11,717,392 ) — 2,122,505 Liabilities Futures $ (29,235,180 ) $ 29,235,180 $ — $ — $ — $ — Options written (12,526,839 ) — (12,526,839 ) 11,717,392 — (809,447 ) Total liabilities (41,762,019 ) 29,235,180 (12,526,839 ) 11,717,392 — (809,447 ) Net fair value $ 1,313,058 1 1 In the event of default by the Master, MS&Co., the Master’s commodity futures broker and the sole counterparty to the Master’s off exchange-traded contracts, as applicable, has the right to offset the Master’s obligation with the Master’s cash held by MS&Co., thereby minimizing MS&Co.’s risk of loss. There is no collateral posted by MS&Co. and as such, in the event of default by MS&Co., the Master is exposed to the amount shown on the Statements of Financial Condition. In the case of exchange-traded contracts, the Master’s exposure to counterparty risk may be reduced since the exchange’s clearinghouse interposes its credit between buyer and seller and the clearinghouse’s guarantee fund may be available in the event of a default.
Derivative Instruments, Fair Value Based on Hierarchy	June 30, 2015 Level 1 Level 2 Level 3 Assets Futures $ 5,831,541 $ 5,831,541 $ — $ — Forwards 1,610,134 1,610,134 — — Options purchased 8,053,627 8,053,627 — — U.S. Treasury bills 144,999,084 — 144,999,084 — Total assets 160,494,386 15,495,302 $ 144,999,084 $ — Liabilities Futures $ 6,774,795 $ 6,774,795 $ — $ — Forwards 4,030,845 4,030,845 — — Options written 6,952,066 6,952,066 — — Total liabilities 17,757,706 17,757,706 — — Net fair value $ 142,736,680 $ (2,262,404 ) $ 144,999,084 $ — December 31, 2014 Level 1 Level 2 Level 3 Assets Futures $ 31,357,685 $ 31,357,685 $ — $ — Options purchased 11,717,392 11,717,392 — — Total assets $ 43,075,077 $ 43,075,077 $ — $ — Liabilities Futures $ 29,235,180 $ 29,235,180 $ — $ — Options written 12,526,839 12,526,839 — — Total liabilities 41,762,019 41,762,019 — — Net fair value $ 1,313,058 $ 1,313,058 $ — $ —
Financial Highlights of Master	Financial Highlights of the Master: Financial highlights for the limited partner class as a whole for the three and six months ended June 30, 2015 and 2014 were as follows: Three Months Ended Six Months Ended 2015 2014 2015 2014 Ratios to average net assets: 1 Net investment income (loss) 2 (1.6 )% (1.8 )% (1.4 )% (1.9 )% Operating expenses 3 1.6 % 1.8 % 1.4 % 1.9 % Total return (0.6 )% 1.8 % 2.1 % (0.6 )% 1 Annualized. 2 Interest income less total expenses. 3 Percentages are annualized and after expense reimbursements (equal to 0.04%, 0.02%, 0.03% and 0.02%, respectively).
Gross Fair Values of Derivative Instruments of Futures, Forward and Options Contracts	The following tables indicate the Master’s gross fair values of derivative instruments of futures, forward and option contracts as separate assets and liabilities as of June 30, 2015 and December 31, 2014, respectively. June 30, 2015 Assets Futures Contracts Energy $ 3,008,990 Grains 2,455,059 Softs 367,492 Total unrealized appreciation on open futures contracts $ 5,831,541 Liabilities Futures Contracts Energy $ (3,767,620 ) Grains (2,586,205 ) Softs (420,970 ) Total unrealized depreciation on open futures contracts $ (6,774,795 ) Net unrealized depreciation on open futures contracts $ (943,254 )* Assets Forward Contracts Metals $ 1,610,134 Total unrealized appreciation on open forward contracts $ 1,610,134 Liabilities Forward Contracts Metals $ (4,030,845 ) Total unrealized depreciation on open forward contracts $ (4,030,845 ) Net unrealized depreciation on open forward contracts $ (2,420,711 )** Assets Options Purchased Energy $ 1,363,560 Grains 388,819 Livestock 41,900 Metals 3,450,163 Softs 2,809,185 Total options purchased $ 8,053,627 *** Liabilities Options Written Energy $ (1,041,850 ) Grains (112,475 ) Metals (4,267,699 ) Softs (1,530,042 ) Total options written $ (6,952,066 )**** * This amount is in “Net unrealized depreciation on open futures contracts” on the Master’s Statements of Financial Condition. ** This amount is in “Net unrealized depreciation on open forward contracts” on the Master’s Statements of Financial Condition. *** This amount is in “Options purchased, at fair value” on the Master’s Statements of Financial Condition. **** This amount is in “Options written, at fair value” on the Master’s Statements of Financial Condition. December 31, 2014 Assets Futures Contracts Energy $ 29,821,382 Grains 1,137,234 Livestock 360,642 Softs 38,427 Total unrealized appreciation on open futures contracts $ 31,357,685 Liabilities Futures Contracts Energy $ (27,255,571 ) Grains (1,801,702 ) Livestock (12,237 ) Softs (165,670 ) Total unrealized depreciation on open futures contracts $ (29,235,180 ) Net unrealized appreciation on open futures contracts $ 2,122,505 * Assets Options Purchased Energy $ 104,920 Grains 6,044,887 Livestock 2,246,660 Softs 3,320,925 Total options purchased $ 11,717,392 ** Liabilities Options Written Energy $ (678,960 ) Grains (5,583,325 ) Livestock (2,728,990 ) Softs (3,535,564 ) Total options written $ (12,526,839 )*** * This amount is included in “Net unrealized appreciation on open futures contracts” on the Master’s Statements of Financial Condition. ** This amount is included in “Options purchased, at fair value” on the Master’s Statements of Financial Condition. *** This amount is included in “Options written, at fair value” on the Master’s Statements of Financial Condition.
Trading Gains and Losses by Market Sector on Derivative Instruments	The following table indicates the Master’s total trading gains and losses, by market sector, on derivative instruments for the three and six months ended June 30, 2015 and 2014. Three Months Ended June 30, Six Months Ended June 30, Sector 2015 2014 2015 2014 Energy $ 135,596 $ 1,016,012 $ 5,875,669 $ (3,891,145 ) Grains 1,144,202 9,655,676 3,914,099 8,438,456 Livestock (248,732 ) (282,249 ) 1,998,143 (3,141,108 ) Metals (2,641,215 ) — (2,697,902 ) (70,689 ) Softs 1,278,032 (4,765,824 ) (2,458,928 ) (1,138,628 ) Total $ (332,117 )* $ 5,623,615 * $ 6,631,081 * $ 196,886 * * This amount is in “Total trading results” on the Master’s Statements of Income and Expenses and Changes in Partners’ Capital.

Organization - Additional Infor

Organization - Additional Information (Detail) - shares	Sep. 06, 2005	Jun. 30, 2015	Sep. 30, 2014	Mar. 31, 2014
Related Party Transaction [Line Items]
Limited partnership organization formation date		Apr. 20, 2005
Number of units sold during initial offering period	11,925
Maximum number of units sold by partnership		0
Effective October 1, 2014 [Member]
Related Party Transaction [Line Items]
Percentage of General Partner fee increased		0.50%
Annual rate of General Partner fee		1.00%
Morgan Stanley Wealth Management [Member] | Selling Agreement [Member]
Related Party Transaction [Line Items]
Per year brokerage fee		2.00%	2.50%	3.75%

Basis of Presentation and Sum18

Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail)	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Related Party Transactions [Abstract]
Percentage of Partnership owned	88.00%	91.70%

Financial Highlights - Schedule

Financial Highlights - Schedule of Financial Highlights for Limited Partner Class (Detail) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement of Partners' Capital [Abstract]
Net realized and unrealized gains (losses)	$ (2.56)	$ 31.12	$ 39.36	$ 4.68
Net investment loss	(21.50)	(21.75)	(41.96)	(49.46)
Increase (decrease) for the period	(24.06)	9.37	(2.60)	(44.78)
Net asset value per unit, beginning of period	1,419.72	1,393.86	1,398.26	1,448.01
Net asset value per unit, end of period	$ 1,395.66	$ 1,403.23	$ 1,395.66	$ 1,403.23
Ratios to average net assets:
Net investment income (loss)	(6.20%)	(6.40%)	(6.10%)	(7.20%)
Operating expenses	6.20%	6.40%	6.10%	7.20%
Incentive fees	0.00%	0.00%	0.00%	0.00%
Total expenses and incentive fees	6.20%	6.40%	6.10%	7.20%
Total return:
Total return before incentive fees	(1.70%)	0.70%	(0.20%)	(3.10%)
Incentive fees	0.00%	0.00%	0.00%	0.00%
Total return after incentive fees	(1.70%)	0.70%	(0.20%)	(3.10%)

Trading Activities - Additional

Trading Activities - Additional Information (Detail) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Average number of futures traded	7,879	17,446	8,919	14,376
Average number of options contracts traded	30,201	79,223	29,302	76,859
Average number of metals forward contracts traded	855	0	447	0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Transfers of assets or liabilities between Level 1 and Level 2	$ 0	$ 0

Investment in Master - Addition

Investment in Master - Additional Information (Detail)	Feb. 01, 2013USD ($)
MB Master Fund L.P. [Member]
Related Party Transaction [Line Items]
Cash value, Partnership purchased	$ 262,944,186

Investment in Master - Statemen

Investment in Master - Statements of Financial Condition (Detail) - USD ($)		Jun. 30, 2015	Dec. 31, 2014
Equity in trading account:
Investment in U.S. Treasury bills, at fair value (amortized cost $144,999,084 and $0 at June 30, 2015 and December 31, 2014, respectively)	[1]	$ 190,657,774	$ 209,288,768
Cash		233,068	172,531
Total assets		190,890,842	209,461,299
Accrued expenses:
Total liabilities		7,595,345	6,585,940
Partners' Capital:
Limited Partners		181,308,433	200,570,398
Total liabilities and partners' capital		190,890,842	209,461,299
MB Master Fund L.P. [Member]
Equity in trading account:
Investment in U.S. Treasury bills, at fair value (amortized cost $144,999,084 and $0 at June 30, 2015 and December 31, 2014, respectively)		142,736,680	1,313,058
Cash		63,428,423	225,656,546
Cash margin		10,603,172	11,952,370
Net unrealized appreciation on open futures contracts			2,122,505
Options purchased, at fair value (cost $9,285,023 and $11,720,470 at June 30, 2015 and December 31, 2014, respectively)		8,053,627	11,717,392
Total trading equity		227,084,306	251,448,813
Expense reimbursement		10,616	3,774
Total assets		227,094,922	251,452,587
Liabilities:
Options written, at fair value (premium $6,683,003 and $13,275,727 at June 30, 2015 and December 31, 2014, respectively)		6,952,066	12,526,839
Accrued expenses:
Clearing fees due to MS&Co.			31,358
Professional fees		46,593	56,368
Redemptions payable			10,689,151
Total liabilities		10,362,624	23,303,716
Partners' Capital:
General Partner		0	0
Limited Partners		216,732,298	228,148,871
Total liabilities and partners' capital		227,094,922	$ 251,452,587
MB Master Fund L.P. [Member] | Futures [Member]
Liabilities:
Net unrealized depreciation on open contracts		943,254
MB Master Fund L.P. [Member] | Forward Contracts [Member]
Liabilities:
Net unrealized depreciation on open contracts		2,420,711
MB Master Fund L.P. [Member] | U.S. Treasury Bills [Member]
Equity in trading account:
Investment in U.S. Treasury bills, at fair value (amortized cost $144,999,084 and $0 at June 30, 2015 and December 31, 2014, respectively)		$ 144,999,084
[1]	Defined in Note 1.

Investment in Master - Statem24

Investment in Master - Statements of Financial Condition (Parenthetical) (Detail) - MB Master Fund L.P. [Member] - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Condensed Balance Sheet Statements, Captions [Line Items]
Cost of options purchased	$ 9,285,023	$ 11,720,470
Stock option redemption premium	6,683,003	13,275,727
U.S. Treasury Bills [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Investment in U.S. Treasury bills, amortized cost	$ 144,999,084	$ 0

Investment in Master - Condense

Investment in Master - Condensed Schedule of Investments (Detail)		6 Months Ended
		Jun. 30, 2015USD ($)Contract	Dec. 31, 2014USD ($)Contract
Schedule of Investments [Line Items]
Investment in Master, at fair value	[1]	$ 190,657,774	$ 209,288,768
MB Master Fund L.P. [Member]
Schedule of Investments [Line Items]
Unrealized Appreciation on Open Forward Contracts			2,122,505
Investment in Master, at fair value		$ 142,736,680	$ 1,313,058
% of Partners' Capital		65.86%	0.58%
Net unrealized depreciation on open futures contracts		$ (943,254)
Net unrealized depreciation on open forward contracts		(2,420,711)
MB Master Fund L.P. [Member] | Futures Contracts Purchased [Member]
Schedule of Investments [Line Items]
Investment in Master, at fair value		$ (231,368)	$ (28,471,589)
% of Partners' Capital		(0.11%)	(12.48%)
MB Master Fund L.P. [Member] | Futures Contracts Purchased [Member] | Energy [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		3,396
Investment in Master, at fair value		$ (2,689,530)
% of Partners' Capital		(1.24%)
MB Master Fund L.P. [Member] | Futures Contracts Purchased [Member] | Energy [Member] | Rbob Gasoline [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract			1,662
Investment in Master, at fair value			$ (26,440,042)
% of Partners' Capital			(11.59%)
MB Master Fund L.P. [Member] | Futures Contracts Purchased [Member] | Energy [Member] | Other Futures Contracts [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract			103
Investment in Master, at fair value			$ (781,530)
% of Partners' Capital			(0.34%)
MB Master Fund L.P. [Member] | Futures Contracts Purchased [Member] | Grains [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		2,179	1,918
Investment in Master, at fair value		$ 2,455,059	$ (1,106,332)
% of Partners' Capital		1.13%	(0.49%)
MB Master Fund L.P. [Member] | Futures Contracts Purchased [Member] | Softs [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		1,067	122
Investment in Master, at fair value		$ 3,103	$ (143,685)
% of Partners' Capital		0.00%	(0.06%)
MB Master Fund L.P. [Member] | Futures Contracts Sold [Member]
Schedule of Investments [Line Items]
Investment in Master, at fair value		$ (711,886)	$ 30,594,094
% of Partners' Capital		(0.32%)	13.41%
MB Master Fund L.P. [Member] | Futures Contracts Sold [Member] | Energy [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		3,173
Investment in Master, at fair value		$ 1,930,900
% of Partners' Capital		0.89%
MB Master Fund L.P. [Member] | Futures Contracts Sold [Member] | Energy [Member] | Other Futures Contracts [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract			774
Investment in Master, at fair value			$ 5,085,247
% of Partners' Capital			2.23%
MB Master Fund L.P. [Member] | Futures Contracts Sold [Member] | Energy [Member] | Ny Harbor Ulsd [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract			989
Investment in Master, at fair value			$ 24,702,136
% of Partners' Capital			10.83%
MB Master Fund L.P. [Member] | Futures Contracts Sold [Member] | Grains [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		1,219	2,283
Investment in Master, at fair value		$ (2,586,205)	$ 441,864
% of Partners' Capital		(1.19%)	0.19%
MB Master Fund L.P. [Member] | Futures Contracts Sold [Member] | Softs [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		617	259
Investment in Master, at fair value		$ (56,581)	$ 16,442
% of Partners' Capital		(0.02%)	0.01%
MB Master Fund L.P. [Member] | Futures Contracts Sold [Member] | Livestock [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract			590
Investment in Master, at fair value			$ 348,405
% of Partners' Capital			0.15%
MB Master Fund L.P. [Member] | Unrealized Appreciation On Open Forward Contracts [Member]
Schedule of Investments [Line Items]
Unrealized Appreciation on Open Forward Contracts		$ 1,610,134
% of Partners' Capital		0.74%
MB Master Fund L.P. [Member] | Unrealized Appreciation On Open Forward Contracts [Member] | Metals [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		485
Unrealized Appreciation on Open Forward Contracts		$ 1,610,134
% of Partners' Capital		0.74%
MB Master Fund L.P. [Member] | Unrealized Depreciation On Open Forward Contracts [Member]
Schedule of Investments [Line Items]
Unrealized Depreciation on Open Forward Contracts		$ (4,030,845)
% of Partners' Capital		(1.86%)
MB Master Fund L.P. [Member] | Unrealized Depreciation On Open Forward Contracts [Member] | Metals [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		1,037
Unrealized Depreciation on Open Forward Contracts		$ (4,030,845)
% of Partners' Capital		(1.86%)
MB Master Fund L.P. [Member] | Options Purchased [Member]
Schedule of Investments [Line Items]
Investment in Master, at fair value		$ 8,053,627	$ 11,717,392
% of Partners' Capital		3.72%	5.14%
MB Master Fund L.P. [Member] | Options Purchased [Member] | Energy [Member] | Calls [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		896	732
Investment in Master, at fair value		$ 887,460	$ 104,920
% of Partners' Capital		0.41%	0.05%
MB Master Fund L.P. [Member] | Options Purchased [Member] | Energy [Member] | Puts [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		671
Investment in Master, at fair value		$ 476,100
% of Partners' Capital		0.22%
MB Master Fund L.P. [Member] | Options Purchased [Member] | Grains [Member] | Calls [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		209	1,987
Investment in Master, at fair value		$ 181,569	$ 3,975,845
% of Partners' Capital		0.08%	1.74%
MB Master Fund L.P. [Member] | Options Purchased [Member] | Grains [Member] | Puts [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		4,486	2,292
Investment in Master, at fair value		$ 207,250	$ 2,069,042
% of Partners' Capital		0.10%	0.91%
MB Master Fund L.P. [Member] | Options Purchased [Member] | Softs [Member] | Calls [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		4,278	1,720
Investment in Master, at fair value		$ 2,228,632	$ 985,384
% of Partners' Capital		1.03%	0.43%
MB Master Fund L.P. [Member] | Options Purchased [Member] | Softs [Member] | Puts [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		3,222	375
Investment in Master, at fair value		$ 580,553	$ 2,335,541
% of Partners' Capital		0.27%	1.02%
MB Master Fund L.P. [Member] | Options Purchased [Member] | Livestock [Member] | Calls [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract			802
Investment in Master, at fair value			$ 1,404,320
% of Partners' Capital			0.62%
MB Master Fund L.P. [Member] | Options Purchased [Member] | Livestock [Member] | Puts [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		838	1,674
Investment in Master, at fair value		$ 41,900	$ 842,340
% of Partners' Capital		0.02%	0.37%
MB Master Fund L.P. [Member] | Options Purchased [Member] | Metals [Member] | Calls [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		847
Investment in Master, at fair value		$ 1,196,393
% of Partners' Capital		0.55%
MB Master Fund L.P. [Member] | Options Purchased [Member] | Metals [Member] | Puts [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		632
Investment in Master, at fair value		$ 2,253,770
% of Partners' Capital		1.04%
MB Master Fund L.P. [Member] | Options Written [Member]
Schedule of Investments [Line Items]
Investment in Master, at fair value		$ (6,952,066)	$ (12,526,839)
% of Partners' Capital		(3.21%)	(5.49%)
MB Master Fund L.P. [Member] | Options Written [Member] | Energy [Member] | Calls [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		335
Investment in Master, at fair value		$ (1,041,850)
% of Partners' Capital		(0.48%)
MB Master Fund L.P. [Member] | Options Written [Member] | Energy [Member] | Puts [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract			246
Investment in Master, at fair value			$ (678,960)
% of Partners' Capital			(0.30%)
MB Master Fund L.P. [Member] | Options Written [Member] | Grains [Member] | Calls [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract			1,987
Investment in Master, at fair value			$ (5,323,670)
% of Partners' Capital			(2.33%)
MB Master Fund L.P. [Member] | Options Written [Member] | Grains [Member] | Puts [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		3,380	1,222
Investment in Master, at fair value		$ (112,475)	$ (259,655)
% of Partners' Capital		(0.05%)	(0.11%)
MB Master Fund L.P. [Member] | Options Written [Member] | Softs [Member] | Calls [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		5,157	2,468
Investment in Master, at fair value		$ (1,584,218)	$ (318,207)
% of Partners' Capital		(0.73%)	(0.14%)
MB Master Fund L.P. [Member] | Options Written [Member] | Softs [Member] | Puts [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		738	375
Investment in Master, at fair value		$ 54,176	$ (3,217,357)
% of Partners' Capital		0.02%	(1.41%)
MB Master Fund L.P. [Member] | Options Written [Member] | Livestock [Member] | Calls [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract			802
Investment in Master, at fair value			$ (2,728,990)
% of Partners' Capital			(1.20%)
MB Master Fund L.P. [Member] | Options Written [Member] | Metals [Member] | Calls [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		847
Investment in Master, at fair value		$ (448,837)
% of Partners' Capital		(0.21%)
MB Master Fund L.P. [Member] | Options Written [Member] | Metals [Member] | Puts [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		632
Investment in Master, at fair value		$ (3,818,862)
% of Partners' Capital		(1.76%)
MB Master Fund L.P. [Member] | Net Unrealized Appreciation On Open Futures Contracts [Member]
Schedule of Investments [Line Items]
Investment in Master, at fair value			$ 2,122,505
% of Partners' Capital			0.93%
MB Master Fund L.P. [Member] | U.S. Treasury Bills [Member]
Schedule of Investments [Line Items]
Face Amount		$ 145,000,000
Maturity Date		Sep. 24, 2015
Investment in Master, at fair value		$ 144,999,084
% of Partners' Capital		66.90%
Futures [Member] | MB Master Fund L.P. [Member]
Schedule of Investments [Line Items]
Unrealized Depreciation on Open Forward Contracts		$ (943,254)
% of Partners' Capital		(0.43%)
Forward Contracts [Member] | MB Master Fund L.P. [Member]
Schedule of Investments [Line Items]
Unrealized Depreciation on Open Forward Contracts		$ (2,420,711)
% of Partners' Capital		(1.12%)
[1]	Defined in Note 1.

Investment in Master - Conden26

Investment in Master - Condensed Schedule of Investments (Parenthetical) (Detail) - MB Master Fund L.P. [Member] - USD ($)	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Schedule of Investments [Line Items]
Cost of options purchased	$ 9,285,023	$ 11,720,470
Stock option redemption premium	6,683,003	13,275,727
Options Purchased [Member]
Schedule of Investments [Line Items]
Cost of options purchased	9,285,023	11,720,470
Options Written [Member]
Schedule of Investments [Line Items]
Stock option redemption premium	6,683,003	13,275,727
U.S. Treasury Bills [Member]
Schedule of Investments [Line Items]
Investment in U.S. Treasury bills, amortized cost	$ 144,999,084	$ 0
Investment, interest rate	0.0025%

Investment in Master - Statem27

Investment in Master - Statements of Income and Expenses and Changes in Partners' Capital (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Expenses:
Total expenses	$ 2,996,481	$ 3,603,897	$ 6,049,930	$ 8,533,998
Net gains (losses) on trading of commodity interests:
Net increase (decrease) in Partners' Capital	(18,974,627)	(12,968,615)	(19,579,862)	(38,005,186)
Partners' Capital, beginning of period	202,270,124	234,686,731	202,875,359	259,723,302
Partners' Capital, end of period	183,295,497	221,718,116	183,295,497	221,718,116
MB Master Fund L.P. [Member]
Investment Income:
Interest income	3,403	8,812	7,686	27,506
Expenses:
Clearing fees	881,354	1,191,312	1,622,769	2,639,403
Professional fees	24,339	24,152	48,223	55,066
Total expenses	905,693	1,215,464	1,670,992	2,694,469
Expense reimbursements	(24,811)	(13,345)	(36,462)	(28,222)
Net expenses	880,882	1,202,119	1,634,530	2,666,247
Net investment income (loss)	(877,479)	(1,193,307)	(1,626,844)	(2,638,741)
Net gains (losses) on trading of commodity interests:
Net realized gains (losses) on closed contracts	2,464,495	2,416,995	14,363,820	4,544,434
Net change in unrealized gains (losses) on open contracts	(2,796,612)	3,206,620	(7,732,739)	(4,347,548)
Total trading results	(332,117)	5,623,615	6,631,081	196,886
Net income (loss)	(1,209,596)	4,430,308	5,004,237	(2,441,855)
Subscriptions - Limited Partners	6,169,850	3,086,426	19,887,127	7,519,662
Redemptions - Limited Partners	(17,600,266)	(33,206,036)	(36,300,251)	(58,391,386)
Distribution of interest income to feeder funds	(3,403)	(8,812)	(7,686)	(27,506)
Net increase (decrease) in Partners' Capital	(12,643,415)	(25,698,114)	(11,416,573)	(53,341,085)
Partners' Capital, beginning of period	229,375,713	284,187,666	228,148,871	311,830,637
Partners' Capital, end of period	$ 216,732,298	$ 258,489,552	$ 216,732,298	$ 258,489,552

Investment in Master - Summary

Investment in Master - Summary of Gross and Net Amounts Recognized Relating to Assets and Liabilities of Master's Derivatives and their Offsetting Subject to Master Netting Arrangements or Similar Agreements (Detail) - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Derivative [Line Items]
Gross Amounts Recognized, Assets	$ 15,495,302	$ 43,075,077
Gross Amounts Offset in the Statements of Financial Condition, Assets	(7,441,675)	(29,235,180)
Amounts Presented in the Statements of Financial Condition, Assets	8,053,627	13,839,897
Gross Amounts Not Offset in the Statements of Financial Condition, Assets, Financial Instruments	(6,952,066)	(11,717,392)
Gross Amounts Not Offset in the Statements of Financial Condition, Assets, Cash Collateral (Received)/Pledged	0	0
Gross Amounts Not Offset in the Statements of Financial Condition, Assets, Net Amount	1,101,561	2,122,505
Gross Amounts Recognized, Liabilities	(17,757,706)	(41,762,019)
Gross Amount Offset in the Statements of Financial Condition, Liabilities	7,441,675	29,235,180
Amounts Presented in the Statements of Financial Condition, Liabilities	(10,316,031)	(12,526,839)
Gross Amounts Not Offset in the Statements of Financial Condition, Liabilities, Financial Instruments	6,952,066	11,717,392
Gross Amounts Not Offset in the Statements of Financial Condition, Liabilities, Cash Collateral (Received)/Pledged	0	0
Liabilities, Net Amount	(3,363,965)	(809,447)
Net fair value	(2,262,404)	1,313,058
Options Written [Member]
Derivative [Line Items]
Gross Amounts Recognized, Liabilities	(6,952,066)	(12,526,839)
Amounts Presented in the Statements of Financial Condition, Liabilities	(6,952,066)	(12,526,839)
Gross Amounts Not Offset in the Statements of Financial Condition, Liabilities, Financial Instruments	6,952,066	11,717,392
Gross Amounts Not Offset in the Statements of Financial Condition, Liabilities, Cash Collateral (Received)/Pledged	0	0
Liabilities, Net Amount		(809,447)
Options Purchased [Member]
Derivative [Line Items]
Gross Amounts Recognized, Assets	8,053,627	11,717,392
Amounts Presented in the Statements of Financial Condition, Assets	8,053,627	11,717,392
Gross Amounts Not Offset in the Statements of Financial Condition, Assets, Financial Instruments	(6,952,066)	(11,717,392)
Gross Amounts Not Offset in the Statements of Financial Condition, Assets, Cash Collateral (Received)/Pledged	0	0
Gross Amounts Not Offset in the Statements of Financial Condition, Assets, Net Amount	1,101,561
Futures [Member]
Derivative [Line Items]
Gross Amounts Recognized, Assets	5,831,541	31,357,685
Gross Amounts Offset in the Statements of Financial Condition, Assets	(5,831,541)	(29,235,180)
Amounts Presented in the Statements of Financial Condition, Assets		2,122,505
Gross Amounts Not Offset in the Statements of Financial Condition, Assets, Cash Collateral (Received)/Pledged	0	0
Gross Amounts Not Offset in the Statements of Financial Condition, Assets, Net Amount		2,122,505
Gross Amounts Recognized, Liabilities	(6,774,795)	(29,235,180)
Gross Amount Offset in the Statements of Financial Condition, Liabilities	5,831,541	29,235,180
Amounts Presented in the Statements of Financial Condition, Liabilities	(943,254)
Gross Amounts Not Offset in the Statements of Financial Condition, Liabilities, Cash Collateral (Received)/Pledged	0	$ 0
Liabilities, Net Amount	(943,254)
Forward Contracts [Member]
Derivative [Line Items]
Gross Amounts Recognized, Assets	1,610,134
Gross Amounts Offset in the Statements of Financial Condition, Assets	(1,610,134)
Gross Amounts Not Offset in the Statements of Financial Condition, Assets, Cash Collateral (Received)/Pledged	0
Gross Amounts Recognized, Liabilities	(4,030,845)
Gross Amount Offset in the Statements of Financial Condition, Liabilities	1,610,134
Amounts Presented in the Statements of Financial Condition, Liabilities	(2,420,711)
Gross Amounts Not Offset in the Statements of Financial Condition, Liabilities, Cash Collateral (Received)/Pledged	0
Liabilities, Net Amount	$ (2,420,711)

Investment in Master - Derivati

Investment in Master - Derivative Instruments, Fair Value Based on Hierarchy (Detail) - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Derivative [Line Items]
Total assets	$ 160,494,386	$ 43,075,077
Derivative liabilities	17,757,706	41,762,019
Net fair value	142,736,680	1,313,058
U.S. Treasury Bills [Member]
Derivative [Line Items]
Total assets	144,999,084
Options Written [Member]
Derivative [Line Items]
Derivative liabilities	6,952,066	12,526,839
Futures [Member]
Derivative [Line Items]
Total assets	5,831,541	31,357,685
Derivative liabilities	6,774,795	29,235,180
Forward Contracts [Member]
Derivative [Line Items]
Total assets	1,610,134
Derivative liabilities	4,030,845
Options Purchased [Member]
Derivative [Line Items]
Total assets	8,053,627	11,717,392
Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) [Member]
Derivative [Line Items]
Total assets	15,495,302	43,075,077
Derivative liabilities	17,757,706	41,762,019
Net fair value	(2,262,404)	1,313,058
Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) [Member] | Options Written [Member]
Derivative [Line Items]
Derivative liabilities	6,952,066	12,526,839
Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) [Member] | Futures [Member]
Derivative [Line Items]
Total assets	5,831,541	31,357,685
Derivative liabilities	6,774,795	29,235,180
Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) [Member] | Forward Contracts [Member]
Derivative [Line Items]
Total assets	1,610,134
Derivative liabilities	4,030,845
Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) [Member] | Options Purchased [Member]
Derivative [Line Items]
Total assets	8,053,627	$ 11,717,392
Significant Other Observable Inputs (Level 2) [Member]
Derivative [Line Items]
Total assets	144,999,084
Net fair value	144,999,084
Significant Other Observable Inputs (Level 2) [Member] | U.S. Treasury Bills [Member]
Derivative [Line Items]
Total assets	$ 144,999,084

Investment in Master - Financia

Investment in Master - Financial Highlights of Master (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Ratios to average net assets:
Net investment income (loss)	(6.20%)	(6.40%)	(6.10%)	(7.20%)
Operating expenses	6.20%	6.40%	6.10%	7.20%
MB Master Fund L.P. [Member]
Ratios to average net assets:
Net investment income (loss)	(1.60%)	(1.80%)	(1.40%)	(1.90%)
Operating expenses	1.60%	1.80%	1.40%	1.90%
Total return	(0.60%)	1.80%	2.10%	(0.60%)

Investment in Master - Financ31

Investment in Master - Financial Highlights of Master (Parenthetical) (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
MB Master Fund L.P. [Member]
Related Party Transaction [Line Items]
Expense reimbursements percentage	0.04%	0.02%	0.03%	0.02%

Investment in Master - Gross Fa

Investment in Master - Gross Fair Values of Derivative Instruments of Futures, Forward and Options Contracts (Detail) - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Derivative assets	$ 160,494,386	$ 43,075,077
Derivative liabilities	(17,757,706)	(41,762,019)
Net unrealized appreciation (depreciation) on open contracts	(943,254)	2,122,505
Options Purchased [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	8,053,627	11,717,392
Options Purchased [Member] | Energy [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	1,363,560	104,920
Options Purchased [Member] | Grains [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	388,819	6,044,887
Options Purchased [Member] | Livestock [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	41,900	2,246,660
Options Purchased [Member] | Softs [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	2,809,185	3,320,925
Options Purchased [Member] | Metals [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	3,450,163
Options Written [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	(6,952,066)	(12,526,839)
Options Written [Member] | Energy [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	(1,041,850)	(678,960)
Options Written [Member] | Grains [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	(112,475)	(5,583,325)
Options Written [Member] | Livestock [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities		(2,728,990)
Options Written [Member] | Softs [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	(1,530,042)	(3,535,564)
Options Written [Member] | Metals [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	(4,267,699)
Futures [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	5,831,541	31,357,685
Derivative liabilities	(6,774,795)	(29,235,180)
Futures [Member] | Energy [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	3,008,990	29,821,382
Derivative liabilities	(3,767,620)	(27,255,571)
Futures [Member] | Grains [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	2,455,059	1,137,234
Derivative liabilities	(2,586,205)	(1,801,702)
Futures [Member] | Livestock [Member]
Derivatives, Fair Value [Line Items]
Derivative assets		360,642
Derivative liabilities		(12,237)
Futures [Member] | Softs [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	367,492	38,427
Derivative liabilities	(420,970)	$ (165,670)
Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	1,610,134
Derivative liabilities	(4,030,845)
Net unrealized appreciation (depreciation) on open contracts	(2,420,711)
Forward Contracts [Member] | Metals [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	1,610,134
Derivative liabilities	$ (4,030,845)

Investment in Master - Trading

Investment in Master - Trading Gains and Losses by Market Sector on Derivative Instruments (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Trading Activity, Gains and Losses, Net [Line Items]
Trading gains and losses	$ (332,117)	$ 5,623,615	$ 6,631,081	$ 196,886
Energy [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Trading gains and losses	135,596	1,016,012	5,875,669	(3,891,145)
Grains [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Trading gains and losses	1,144,202	9,655,676	3,914,099	8,438,456
Livestock [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Trading gains and losses	(248,732)	(282,249)	1,998,143	(3,141,108)
Metals [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Trading gains and losses	(2,641,215)		(2,697,902)	(70,689)
Softs [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Trading gains and losses	$ 1,278,032	$ (4,765,824)	$ (2,458,928)	$ (1,138,628)

Financial Instrument Risks - Ad

Financial Instrument Risks - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial instruments maturity period	1 year