MNRL Sub (MNRL) S-1 9 Dec 19 IPO registration Financial data

Cover

Cover	9 Months Ended
	Sep. 30, 2019
Cover page.
Document Type	S-1
Amendment Flag	false
Document Period End Date	Sep. 30, 2019
Entity Registrant Name	Brigham Minerals, Inc.
Entity Central Index Key	0001745797
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false

Balance Sheets

Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 25,848	$ 31,985	$ 6,886
Restricted cash		474
Accounts receivable	23,047	20,695	13,055
Prepaid expenses and other	2,505	7,103	987
Investment in equity securities			4,105
Short-term derivative assets	146	1,057
Total current assets	51,546	61,314	25,033
Oil and gas properties, at cost, using the full cost method of accounting:
Unevaluated property	276,888	228,151	168,691
Evaluated property	423,884	289,851	152,354
Less accumulated depreciation, depletion and amortization	(49,488)	(27,628)	(14,210)
Oil and gas properties-net	651,284	490,374	306,835
Other property and equipment	5,808	5,408	4,685
Less accumulated depreciation	(3,566)	(3,115)	(2,493)
Other property and equipment-net	2,242	2,293	2,192
Deferred tax asset	9,977
Other assets, net	1,155	45	417
Total assets	716,204	554,026	334,477
Current liabilities:
Accounts payable and accrued liabilities	7,291	5,662	4,791
Current portion of debt		2,188
Current derivative liabilities			121
Total current liabilities	7,291	7,850	4,912
Long-term debt	45,000	168,517	27,000
Deferred tax liability		3,684
Other non-current liabilities	449	27	391
Temporary equity (Note 9)	603,986
Shareholders' and members' equity:
Members' contributed capital		208,728	166,030
Accumulated other comprehensive income			682
Preferred stock	0	0
Additional paid-in capital	63,203	(3,057)
Accumulated (deficit) earnings	(3,945)	168,277	135,462
Total shareholders' equity attributable to Brigham Minerals, Inc. and members' equity	59,478	373,948	302,174
Total liabilities and shareholders' and members' equity	716,204	554,026	$ 334,477
Class A Common Stock
Shareholders' and members' equity:
Common stock	220	0
Class B Common Stock
Shareholders' and members' equity:
Common stock	$ 0	$ 0

Balance Sheets (Parenthetical)

Balance Sheets (Parenthetical)	Sep. 30, 2019$ / sharesshares
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.01
Preferred stock, shares authorized (in shares)	50,000,000
Preferred stock, shares issued (in shares)	0
Preferred stock, shares outstanding (in shares)	0
Class A Common Stock
Common stock, par value (in dollars per share) | $ / shares	$ 0.01
Common stock, shares authorized (in shares)	400,000,000
Common stock, shares issued (in shares)	21,997,198
Common stock, shares outstanding (in shares)	21,997,198
Class B Common Stock
Common stock, par value (in dollars per share) | $ / shares	$ 0.01
Common stock, shares authorized (in shares)	150,000,000
Common stock, shares issued (in shares)	28,777,802
Common stock, shares outstanding (in shares)	28,777,802

Statement of Operations

Statement of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
REVENUES
Mineral and royalty revenues	$ 24,135	$ 16,460	$ 64,774	$ 42,846	$ 59,758	$ 30,066
Lease bonus and other revenues	972	2,241	3,127	6,827	7,506	10,842
Total revenues	25,107	18,701	67,901	49,673	67,264	40,908
Other operating income:
Gain on sale of oil and gas properties, net						94,551
OPERATING EXPENSES
Gathering, transportation and marketing	1,113	887	3,750	2,894	3,944	1,754
Severance and ad valorem taxes	1,377	957	4,206	2,599	3,536	1,601
Depreciation, depletion and amortization	8,434	3,851	20,310	9,609	13,915	6,955
General and administrative	5,068	1,290	16,779	4,072	6,638	3,935
Total operating expenses	15,992	6,985	45,045	19,174	28,033	14,245
Income from operations	9,115	11,716	22,856	30,499	39,231	121,214
Gain (loss) on derivative instruments, net	91	(280)	(521)	(1,194)	424	(121)
Interest expense, net	(65)	(2,902)	(5,160)	(4,028)	(7,446)	(556)
Loss on extinguishment of debt			(6,933)
Gain (loss) on sale and distribution of equity securities				823	823	(4,222)
Other income, net	130	47	165	57	110	305
Income before income taxes	9,271	8,581	10,407	26,157	33,142	116,620
Income tax expense	807	428	1,114	456	327	1,008
NET (LOSS) INCOME	8,464	8,153	9,293	25,701	32,815	115,612
Less: net income attributable to temporary equity	(5,318)		(2,377)
Net income attributable to Brigham Minerals, Inc. shareholders	$ 3,146	$ 891	$ 1,824	$ 891	1,839
NET INCOME PER COMMON SHARE
Basic	$ 0.14	$ 0	$ 0.07	$ 0
Diluted	$ 0.14	$ 0	$ 0.07	$ 0
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING
Basic	21,838	0	13,299	0
Diluted	21,926	0	13,346	0
Brigham Resources, LLC
OPERATING EXPENSES
NET (LOSS) INCOME		$ 7,262	$ 5,092	$ 24,810	$ 30,976	$ 115,612

Condensed Consolidated and Comb

Condensed Consolidated and Combined Statement of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Net income	$ 8,464	$ 8,153	$ 9,293	$ 25,701	$ 32,815	$ 115,612
Other comprehensive income
Unrealized gains (losses) on available for sale equity securities, net				141	141	(3,540)
Reclassification of gains on sale and distribution of available for sale equity securities				(823)	(823)	4,222
Other comprehensive income				(682)	(682)	682
COMPREHENSIVE INCOME	8,464	8,153	9,293	25,019	32,133	116,294
Comprehensive income attributable to temporary equity	(5,318)		(2,377)
Comprehensive income attributable to shareholders	$ 3,146	891	1,824	891	1,839
Brigham Resources, LLC
Net income		7,262	5,092	24,810	30,976	115,612
Other comprehensive income
COMPREHENSIVE INCOME		$ 7,262	$ 5,092	$ 24,128	$ 30,294	$ 116,294

Statement of Changes in Shareho

Statement of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Brigham Resources, LLC	Post IPO	Class A Common Stock	Class B Common Stock	Shareholders' Contributed Capital	Common StockClass A Common Stock	Common StockClass B Common Stock	Additional Paid-in Capital	Retained Earnings	Retained EarningsBrigham Resources, LLC	Retained EarningsPost IPO	Accumulated Other Comprehensive Income
Beginning balance at Dec. 31, 2016	$ 300,498					$ 280,648				$ 19,850
Contributions	37,600					37,600
Distributions	(152,218)					(152,218)
Other comprehensive income	682												$ 682
Net income	115,612	$ 115,612								115,612
Ending balance at Dec. 31, 2017	302,174					166,030				135,462			682
Contributions	20,692					20,692
Distributions	(3,313)					(3,313)
Other comprehensive income	(682)												(682)
Net income	8,197									8,197
Ending balance at Mar. 31, 2018	327,068					183,409				143,659
Beginning balance at Dec. 31, 2017	302,174					166,030				135,462			682
Other comprehensive income	(682)
Net income	25,701	24,810
Net income	891
Ending balance at Sep. 30, 2018	366,834					208,728			$ (3,057)	161,163
Beginning balance at Dec. 31, 2017	302,174					166,030				135,462			682
Contributions	45,078					45,078
Distributions	(3,313)					(3,313)
Deferred tax liability arising from corporate reorganization	(3,057)								(3,057)
Proceeds from sale of equity securities	933					933
Other comprehensive income	(682)												$ (682)
Net income	32,815	30,976									$ 30,976
Net income	1,839									1,839
Ending balance at Dec. 31, 2018	373,948					208,728			(3,057)	168,277
Beginning balance at Mar. 31, 2018	327,068					183,409				143,659
Contributions	24,386					24,386
Net income	9,351									9,351
Ending balance at Jun. 30, 2018	360,805					207,795				153,010
Deferred tax liability arising from corporate reorganization	(3,057)								(3,057)
Proceeds from sale of equity securities	933					933
Net income	8,153	7,262									7,262
Net income	891									891
Ending balance at Sep. 30, 2018	366,834					208,728			(3,057)	161,163
Net income	7,114
Ending balance at Dec. 31, 2018	373,948					208,728			(3,057)	168,277
Net income	534	3,502								534	3,502
Ending balance at Mar. 31, 2019	377,984					208,728			(3,057)	172,313
Beginning balance at Dec. 31, 2018	373,948					208,728			(3,057)	168,277
Net income	9,293	5,092
Net income	1,824
Ending balance at Sep. 30, 2019	59,478						$ 220		63,203	(3,945)
Ending balance (in shares) at Sep. 30, 2019				21,997,198	28,777,802		21,997,000	28,778,000
Beginning balance at Mar. 31, 2019	377,984					208,728			(3,057)	172,313
Net income	314	$ 1,590								314	$ 1,590
Ending balance at Apr. 16, 2019	379,888					208,728			(3,057)	174,217
Exchange of Units of Brigham Minerals Holdings, LLC for Class A Common Stock and Class B Common Stock							$ 53		380,205
Exchange of Units of Brigham Minerals Holdings, LLC for Class A Common Stock and Class B Common Stock						(208,728)				(171,530)
Exchange of Units of Brigham Minerals Holdings, LLC for Class A Common Stock and Class B Common Stock (in shares)							5,322,000	28,778,000
Issuance of common stock in IPO, net of offering cost	274,913						$ 167		274,746
Issuance of common stock in IPO, net of offering cost (in shares)							16,675,000
Deferred tax asset arising from the IPO	13,664								13,664
Reclassification of non-controlling interests to temporary equity	(518,000)								(518,000)
Net income			$ (2,170)									$ (2,170)
Share-based compensation expense	7,505								7,505
Adjustment of temporary equity to redemption amount	(97,344)								(97,344)
Ending balance at Jun. 30, 2019	58,456						$ 220		57,719	517
Ending balance (in shares) at Jun. 30, 2019							21,997,000	28,778,000
Beginning balance at Apr. 16, 2019	379,888					$ 208,728			(3,057)	174,217
Deferred tax asset arising from the IPO	13,700
Ending balance at Sep. 30, 2019	59,478						$ 220		63,203	(3,945)
Ending balance (in shares) at Sep. 30, 2019				21,997,198	28,777,802		21,997,000	28,778,000
Beginning balance at Jun. 30, 2019	58,456						$ 220		57,719	517
Beginning balance (in shares) at Jun. 30, 2019							21,997,000	28,778,000
Issuance of common stock in IPO, net of offering cost	(1,465)								(1,465)
Net income	8,464
Share-based compensation expense	3,152								3,152
Common stock ($0.33 per share)	(7,206)									(7,206)
Dividend equivalent rights ($0.33 per share)	(402)									(402)
Net income	3,146									3,146
Adjustment of temporary equity to redemption amount	3,797								3,797
Ending balance at Sep. 30, 2019	$ 59,478						$ 220		$ 63,203	$ (3,945)
Ending balance (in shares) at Sep. 30, 2019				21,997,198	28,777,802		21,997,000	28,778,000

Statement of Changes in Share_2

Statement of Changes in Shareholders' Equity (Parenthetical)	3 Months Ended
	Sep. 30, 2019$ / shares
Statement of Stockholders' Equity [Abstract]
Common stock, dividends (in dollars per share)	$ 0.33
Dividend equivalent rights, dividends (in dollars per share)	$ 0.33

Statement of Cash Flows

Statement of Cash Flows - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities
Net income	$ 9,293	$ 25,701	$ 32,815	$ 115,612
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	20,310	9,609	13,915	6,955
Share-based compensation expense	8,232
Loss on extinguishment of debt	6,933
Amortization of debt issue costs	354	501	690	121
Deferred income taxes	2	303	237	295
(Gain)/loss on derivative instruments, net	521	1,194	(424)	121
Net cash received (paid) for derivative settlements	356	(670)	(754)
(Gain)/loss on sale of equity securities		(823)	(823)	4,222
Bad debt expense	293		382
(Gain) on sale of oil and gas properties				(94,551)
Changes in operating assets and liabilities:
(Increase)/decrease in accounts receivable	(2,612)	(9,342)	(8,022)	(6,787)
(Increase)/decrease in other current assets	970	(4,845)	(6,116)	(44)
(Decrease)/increase in accounts payable and accrued liabilities	1,827	218	(484)	3,956
Increase in other long-term liabilities	46		28
Other operating				(499)
Net cash provided by operating activities	46,525	21,846	31,444	29,401
Cash flows from investing activities
Acquisitions of oil and gas properties	(181,484)	(164,051)	(195,603)	(101,437)
Additions to other fixed assets	(400)	(571)	(723)	(1,311)
Proceeds from sale of oil and gas properties, net	2,001	125	125	111,024
Proceeds from sale of equity securities		933	933	17,896
Changes in restricted cash	33	(933)	(474)
Net cash (used in) provided by investing activities	(179,850)	(164,497)	(195,742)	26,172
Cash flows from financing activities
Payments of short-term related party loan		(7,000)	(7,000)
Borrowings of short-term related party loan		7,000	7,000
Payments of short-term debt	(4,596)
Payments of long-term debt	(195,404)	(70,000)	(70,000)	(15,000)
Borrowings of long-term debt	70,000	193,000	218,000	27,000
Payment of debt extinguishment fees	(2,091)
Proceeds from issuance of Class A common stock sold in initial public offering, net of offering costs	277,075
Capital contributions		46,011	46,011	37,000
Dividends paid	(7,206)
Capital distributions				(131,544)
Distributions to holders of temporary equity	(9,379)
Loan closing costs	(1,211)	(4,614)	(4,614)	(103)
Net cash provided by (used in) financing activities	127,188	164,397	189,397	(82,647)
(Decrease) increase in cash and cash equivalents	(6,137)	21,746	25,099	(27,074)
Cash and cash equivalents, beginning of period	31,985	6,886	6,886	33,960
Cash and cash equivalents, end of period	25,848	28,632	31,985	6,886
Supplemental disclosure of non-cash activity:
Equity securities received				45,633
Equity securities distributed		(3,313)	3,313	(20,092)
Accrued capital expenditures	286	5	1,426	73
Capitalized share-based compensation expense	2,425
Vesting of A-M units				600
Temporary equity cumulative adjustment to fair value	93,546
Supplemental cash flow information:
Cash interest payments	5,657	2,888	$ 6,123	$ 458
Cash paid for taxes	$ 1,014	$ 84

Organization and Basis of Prese

Organization and Basis of Presentation	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	1. Business and Basis of Presentation Description of the Business Brigham Minerals, Inc. (together with its wholly owned subsidiaries, “Brigham Minerals” or the “Company”) is a Delaware corporation formed in June 2018 to become a holding company. Brigham Minerals acquired an indirect interest in Brigham Resources, LLC (“Brigham Resources”), our predecessor, on July 16, 2018 in a series of restructuring transactions pursuant to which certain entities affiliated with Warburg Pincus LLC (“Warburg Pincus”) contributed all of their respective interests in the entities through which they held interests in Brigham Resources to Brigham Minerals in exchange for all of the outstanding shares of common stock of Brigham Minerals (the “July 2018 restructuring”). As a result of such restructuring transactions, Brigham Minerals became wholly owned by an entity affiliated with Warburg Pincus, and Brigham Minerals indirectly owned a 16.5% membership interest in Brigham Resources. The remaining outstanding membership interests of Brigham Resources remained with certain other entities affiliated with Warburg Pincus, Yorktown Partners LLC and Pine Brook Road Advisors, LP, Brigham Minerals’ management and its other investors (collectively, the “Original Owners”). On November 20, 2018, Brigham Resources underwent a second series of restructuring transactions (the “November 2018 restructuring”). In the November 2018 restructuring, Brigham Resources became a wholly owned subsidiary of Brigham Minerals Holdings, LLC (“Brigham LLC”), which was a wholly owned subsidiary of Brigham Equity Holdings, LLC (“Brigham Equity Holdings”), and Brigham Equity Holdings became wholly owned by the owners of Brigham Resources immediately prior to such restructuring, directly or indirectly, through Brigham Minerals. As a result of the foregoing transactions, there was no change in the control or economic interests of the Original Owners and Brigham Minerals in Brigham Resources, although their ownership became indirect through Brigham Equity Holdings and its wholly owned subsidiary, Brigham LLC. The July 2018 restructuring and the November 2018 restructuring are collectively referred to herein as, the “2018 corporate reorganizations.” Brigham Resources wholly owns Brigham Minerals, LLC and Rearden Minerals, LLC (collectively, the “Minerals Subsidiaries”), which acquire and actively manage a portfolio of mineral and royalty interests. The Minerals Subsidiaries are Brigham Resources’ sole material assets. Brigham Resources also previously owned Brigham Resources Operating, LLC (“Brigham Operating”), an upstream oil and gas exploration and production business in the southern Delaware Basin of West Texas. In February 2017, Brigham Operating completed the sale of substantially all of its oil and natural gas properties to an unrelated third-party purchaser, following which Brigham Operating’s only material assets consisted of an ownership interest in Oryx Southern Delaware Holdings, LLC, an entity that operates a crude oil gathering system located in the southern Delaware Basin. Immediately prior to Brigham Minerals’ initial public offering of shares of its Class A common stock, which was completed in April 2019 (the “IPO”), Brigham Resources distributed to its members or their affiliates 100% of the equity interests in Brigham Operating. Subsequent to the distribution, Brigham Resources no longer had any direct or indirect ownership interest in Brigham Operating. Unless otherwise indicated, the historical financial information relating to periods prior to our IPO reflects the historical financial results of our predecessor, excluding the historical results and operations of Brigham Operating. Initial Public Offering In April 2019, Brigham Minerals completed the IPO of 16,675,000 shares of Class A common stock at a price to the public of $18.00 per share. This resulted in net proceeds of approximately $273.3 million, after deducting underwriting commissions and discounts and offering expenses. As a result of the IPO and the corporate restructuring described below, Brigham Minerals became a holding company whose sole material asset consists of a 43.3% interest in Brigham LLC, which wholly owns Brigham Resources. Brigham Resources continues to wholly own the Minerals Subsidiaries, which own all of Brigham Resources’ operating assets. In connection with the IPO, Brigham Minerals became the sole managing member of Brigham LLC and is responsible for all operational, management and administrative decisions relating to Brigham LLC’s business and consolidates the financial results of Brigham LLC and its wholly-owned subsidiary, Brigham Resources. All of the interests in Brigham Operating were distributed, directly or indirectly, to the Original Owners prior to the consummation of the IPO. As a result, neither Brigham Minerals nor Brigham LLC owned any direct or indirect interest in Brigham Operating at the time of the IPO. In connection with the IPO, • all of the outstanding membership interests in Brigham LLC were converted into a single class of common units in Brigham LLC (the “Brigham LLC Units”); • Brigham Minerals issued shares of Class A common stock to certain of our Original Owners in exchange for incentive units in Brigham Equity Holdings; • Brigham Equity Holdings distributed all of its equity interests in Brigham LLC, other than its interests in Brigham LLC attributable to certain unvested incentive units in Brigham Equity Holdings, to the Original Owners and Brigham Minerals (which resulted in the ownership in Brigham LLC of our Original Owners with respect to unvested incentive units remaining consolidated in Brigham Equity Holdings); • Brigham Minerals issued 16,675,000 shares of Class A common stock, including the Underwriters’ overallotment, to purchasers in the IPO in exchange for the cash proceeds of the IPO; • Each holder of Brigham LLC Units following the restructuring (a “Brigham Unit Holder”), other than Brigham Minerals and its subsidiaries, received a number of shares of Class B common stock equal to the number of Brigham LLC Units held by such Brigham Unit Holder following the IPO; and • Brigham Minerals contributed, directly or indirectly, the net proceeds of the IPO to Brigham LLC in exchange for an additional number of Brigham LLC Units such that Brigham Minerals holds, directly or indirectly, a total number of Brigham LLC Units equal to the number of shares of Class A common stock outstanding following the IPO. After the transactions discussed above and after the IPO, • the Original Owners own all of Brigham Minerals’ Class B common stock, representing 56.7% of Brigham Minerals’ capital stock; • the Original Owners own 5,322,198 shares, or 24.2%, of Brigham Minerals’ Class A common stock, representing 10.5% of Brigham Minerals’ capital stock; • investors in the IPO own 16,675,000 shares, or 75.8%, of Brigham Minerals’ Class A common stock, representing 32.8% of Brigham Minerals’ capital stock; • Brigham Minerals owns an approximate 43.3% interest in Brigham LLC; and • the Original Owners own directly an approximate 56.7% interest in Brigham LLC (in addition to the 10.5% interest in Brigham LLC the Original Owners own indirectly through their ownership of shares of Brigham Minerals’ Class A common stock). Following the IPO, and prior to September 30, 2019, Brigham Resources: • fully repaid the $200.0 million outstanding balance under the Owl Rock credit facility (as defined below) on May 7, 2019; • wrote-off • applied capitalized issuance cost of $8.7 million as a reduction of additional paid-in-capital • recognized a charge for share-based compensation cost of approximately $8.2 million related to the estimated fair value of the Incentive Units (as defined below), restricted stock awards (“RSAs”), restricted stock units subject to time-based vesting (“RSUs”) and restricted stock units subject to performance-based vesting (“PSUs”), net of $2.4 million of capitalized share-based compensation expense, all of which was non-cash. non-cash • entered into a credit agreement on May 16, 2019 with a banking syndicate, including Wells Fargo Bank, N.A., as administrative agent for a new revolving credit facility (as defined below) with a borrowing base of $135.0 million and outstanding balance of $45.0 million as of September 30, 2019; and • received a full refund of the cash collateral related to the existing WTI fixed price swap contracts, which was $1.6 million as of May 2019, upon entering into the new revolving credit facility. On November 7, 2019, the borrowing base on our new revolving credit facility was increased to $150.0 million. See “Note 7—Long-Term Debt” and “Note 14—Subsequent Events” to the condensed consolidated and combined financial statements of Brigham Minerals as of September 30, 2019 included elsewhere in this prospectus for further discussion. Basis of Presentation Subsequent to the July 2018 restructuring and prior to the IPO, Brigham Minerals used the equity method of accounting for its investment in Brigham Resources, its predecessor, because its 16.5% ownership in Brigham Resources provided Brigham Minerals with significant influence, but not with a controlling financial interest or the ability to direct the most significant activities of Brigham Resources. Upon the completion of the IPO, Brigham Minerals indirectly owned an approximate 43.3% interest of Brigham Resources and 100% of the voting rights and consolidates the results of operations of Brigham Resources. Accordingly, the accompanying unaudited condensed consolidated and combined financial statements and related notes of Brigham Minerals for periods prior to the IPO, including the 2018 amounts presented, have been retrospectively recast to include the historical results and operations of Brigham Resources at historical carrying values. All intercompany transactions between Brigham Minerals and Brigham Resources have been eliminated. The accompanying unaudited consolidated condensed and combined interim financial statements of Brigham Minerals have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”), except that, in accordance with the instructions to Form 10-Q, S-1, Brigham Minerals operates in one segment: oil and natural gas exploration and production.	1. Organization and Basis of Presentation Brigham Minerals, Inc. (“Brigham Minerals”) is a Delaware corporation formed in June 2018 for the purpose of completing an initial public offering (the “IPO”) and related transactions. In April 2019, Brigham Minerals completed the IPO of 16,675,000 shares of Class A common stock. As a result of the IPO and certain reorganization transactions, Brigham Minerals became a holding company whose sole material asset consists of an ownership interest in Brigham Minerals Holdings, LLC (“Brigham LLC”), which wholly owns Brigham Resources, LLC (“Brigham Resources” or the “Predecessor”). Brigham Resources wholly owns Brigham Minerals, LLC and Rearden Minerals, LLC (collectively, the “Minerals Subsidiaries”), which own all of Brigham Resources’ operating assets. The Minerals Subsidiaries acquire and actively manage a portfolio of mineral and royalty interests located in seven states in the continental U.S., including all of the major onshore producing basins. In connection with the IPO, Brigham Minerals became the sole managing member of Brigham LLC and is responsible for all operational, management and administrative decisions relating to Brigham LLC’s business. References to “we,” “us” and “our” mean Brigham Minerals. The accompanying consolidated and combined financial statements of Brigham Minerals have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). The consolidated and combined financial statements reflect all normal recurring adjustments that, in the opinion of management, are necessary for a fair presentation. All significant intercompany transactions and balances have been eliminated upon consolidation and combination. Brigham Resources operates in one segment: oil and natural gas exploration and production. Brigham Resources has historically owned and operated two distinct lines of business through its subsidiaries: • the Minerals Business through the Minerals Subsidiaries; and • an upstream oil and gas exploration and production business (the “Upstream Business”) in the Southern Delaware Basin of West Texas (including interests in certain related gathering systems) through Brigham Resources Operating, LLC (“Brigham Operating”). In February 2017, Brigham Operating completed the sale of substantially all of its oil and natural gas properties to an unrelated third-party purchaser, following which Brigham Operating’s only material assets have consisted of an ownership interest in Oryx Southern Delaware Holdings, LLC (“Oryx”), an entity that operates a crude oil gathering system located in the Southern Delaware Basin. Brigham Resources plans to distribute to its members or their affiliates 100% of the equity interests in Brigham Operating. Subsequent to such distribution Brigham Resources will no longer have any direct or indirect ownership interest in Brigham Operating. Accordingly, the accompanying consolidated financial statements of Brigham Resources exclude the assets, liabilities and results of operations of Brigham Operating. Upon the completion of the IPO and associated reorganization, Brigham Minerals indirectly owned an approximate 43.3% interest of Brigham Resources and 100% of the voting rights, and as such, consolidated the results of operations of Brigham Resources. The IPO and associated reorganization was a transaction that lacked substance, and as such, Brigham Resources was consolidated at historical carrying values. In order to furnish comparative financial information, the historical financial statements and related notes of Brigham Minerals for periods prior to the IPO have been retrospectively revised to include the combined historical financial information of both Brigham Resources (at historical carrying values) and Brigham Minerals, taking into account state and federal income taxes and liabilities associated with Brigham Minerals. All intercompany transactions between Brigham Minerals and Brigham Resources have been eliminated. Because Brigham Minerals acquired an interest in Brigham Resources as part of certain reorganization transactions in 2018, net income is attributable to stockholders of Brigham Minerals in addition to our Predecessor beginning in 2018. Subsequent to the issuance of our December 31, 2017 consolidated financial statements, we corrected the amount of equity securities distributed, included in the supplemental disclosure of non-cash

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Significant Accounting Policies	2. Summary of Significant Accounting Policies Use of Estimates These condensed consolidated and combined financial statements and related notes are presented in accordance with GAAP. Preparation in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in the consolidated financial statements and accompanying notes. Although management believes these estimates are reasonable, actual results could differ from these estimates. Changes in estimates are recorded prospectively. The accompanying condensed consolidated and combined financial statements are based on a number of significant estimates including quantities of oil, natural gas and NGL reserves that are the basis for the calculations of depreciation, depletion, amortization (“DD&A”) and impairment of oil and natural gas properties. Reservoir engineering is a subjective process of estimating underground accumulations of oil and natural gas and there are numerous uncertainties inherent in estimating quantities of proved oil and natural gas reserves. The accuracy of any reserve estimate is a function of the quality of available data and of engineering and geological interpretation and judgment. As a result, reserve estimates may differ from the quantities of oil and natural gas that are ultimately recovered. Brigham Minerals’ year-end in-house Significant Accounting Policies Significant accounting policies are disclosed in Brigham Resources’ audited consolidated financial statements and notes for the year ended December 31, 2018, presented in the IPO registration statement. There have been no changes in such policies or the application of such policies during the three and nine months ended September 30, 2019, except as described below: Share-Based Compensation Brigham Minerals accounts for its share-based compensation including grants of the Incentive Units, restricted stock awards, time-based restricted stock units and performance-based stock units in the condensed consolidated and combined statements of operations based on their estimated fair values at grant date. Brigham Minerals recognizes expense on a straight-line basis over the vesting period of the respective grant, which is generally the requisite service period. Share-based compensation is included in general and administrative expenses in Brigham Minerals’ condensed consolidated and combined statements of operations included within this prospectus. There was approximately $21.3 million of unamortized compensation expense relating to outstanding awards at September 30, 2019, a portion of which will be capitalized. The unrecognized share-based compensation expense will be recognized on a straight-line basis over the remaining vesting periods of the awards. Brigham Minerals accounts for forfeitures as they occur. Earnings Per Share Brigham Minerals uses the “if-converted” Income Taxes Brigham Minerals accounts for income taxes using the asset and liability method. 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 bases. Deferred tax assets and liabilities are calculated by applying existing tax laws and the rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. On the date of our IPO, Brigham Minerals recognized a tax benefit of approximately $13.7 million, associated with the differences between the tax and book basis of the investment in Brigham Resources, LLC, as discussed in “Note 11—Income Taxes”. Temporary Equity Brigham Minerals accounts for the Original Owners’ 56.7% interest in Brigham LLC as temporary equity as a result of certain redemption rights held by the Original Owners as discussed in “Note 9—Temporary Equity.” As such, the Company adjusts temporary equity to its maximum redemption amount at the balance sheet date, if higher than the carrying amount. The redemption amount is based on the 10-day paid-in Recently Issued Accounting Standards Brigham Minerals’ status as an emerging growth company under Section 107 of the JOBS Act permits it to delay the adoption of certain accounting standards until those standards would otherwise apply to private companies. Brigham Minerals is choosing to take advantage of this extended transition period and, as a result, Brigham Minerals will comply with new or revised accounting standards on the relevant dates on which adoption of such standards is required for private companies. In January 2017, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2017-01, 2017-01 In November 2016, the FASB issued ASU 2016-18, 2016-18 In February 2016, the FASB issued ASU 2016-02, 2016-02 2018-01, 2018-11 In May 2014, the FASB issued ASU 2014-09, 932-605, Activities-Oil Gas-Revenue We completed our review of revenue contracts covering our material revenue streams, designed to evaluate any potential changes in revenue recognition upon adoption of the new standard, and concluded that the implementation of the new standard will not have a material impact on our condensed consolidated and combined financial statements. We also evaluated the information technology and internal control changes that may be required to implement the new standard based on the results of our contract review process.	2. Significant Accounting Policies Emerging Growth Company Status As a company with less than $1.07 billion in revenues during its last fiscal year, Brigham Minerals qualifies as an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”). An emerging growth company may take advantage of specified reduced reporting and other regulatory requirements. Brigham Minerals will remain an “emerging growth company” until as late as the last day of Brigham Minerals’ 2023 fiscal year, or until the earliest of (i) the last day of the fiscal year in which Brigham Minerals has $1.07 billion or more in annual revenues; (ii) the date on which Brigham Minerals becomes a “large accelerated filer” (the fiscal year-end non-affiliates non-convertible As a result of Brigham Minerals’ election to avail itself of certain provisions of the JOBS Act, the information that Brigham Minerals provides may be different than the information provided by other public companies. Use of Estimates The preparation of consolidated and combined financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in the consolidated financial statements and accompanying notes. Although management believes these estimates are reasonable, actual results could differ from these estimates. Changes in estimates are recorded prospectively. The accompanying consolidated and combined financial statements are based on a number of significant estimates including quantities of oil, natural gas and NGLs reserves that are the basis for the calculations of depreciation, depletion, amortization (“DD&A”) and impairment of oil and natural gas properties. Reservoir engineering is a subjective process of estimating underground accumulations of oil and natural gas and there are numerous uncertainties inherent in estimating quantities of proved oil and natural gas reserves. The accuracy of any reserve estimate is a function of the quality of available data and of engineering and geological interpretation and judgment. As a result, reserve estimates may differ from the quantities of oil and natural gas that are ultimately recovered. Brigham Minerals’ reserve estimates are determined by Cawley, Gillespie & Associates, Inc. (“CG&A”), an independent petroleum engineering firm. Other items subject to significant estimates and assumptions include the carrying amount of oil and natural gas properties, valuation of derivative instruments and revenue accruals. Cash and Cash Equivalents Brigham Minerals considers all highly liquid investments with an original maturity of three months or less to be cash equivalents. Restricted Cash Restricted cash consists of funds that are contractually restricted as to usage or withdrawal and have been presented separately from cash and cash equivalents on our consolidated and combined balance sheets. At December 31, 2018, Brigham Minerals had $0.4 million restricted for distribution to existing owners. Receivables Receivables consist of royalty income due from operators for oil and gas sales to purchasers. Those purchasers remit payment for production to the operator of our properties and the operator, in turn, remits payment to us. Receivables from third parties for which we did not receive actual information, either due to timing delays or due to the unavailability of data at the time when revenues are recognized, are estimated. Receivables from new wells turned in line for which we did not receive payment at the time revenues are recognized are estimated and recognized only when public production information is available. Volume estimates are based upon historical actual data if available or, otherwise, on engineering estimates. Pricing estimates are based upon actual prices realized in an area by adjusting the market price for the average basis differential from market on a basin-by-basin Brigham Minerals routinely reviews outstanding balances, assesses the financial strength of its customers and records a reserve for amounts not expected to be fully recovered. We recorded an allowance for doubtful accounts of $0.4 million for the year ended December 31, 2018, which was included in general and administrative expenses. We did not record any allowance for doubtful accounts for the year ended December 31, 2017. Concentration of Credit Risk and Significant Customers Financial instruments that potentially subject Brigham Minerals to concentrations of credit risk consist of cash, accounts receivable, commodity derivative financial instruments and its prior revolving credit facility. Cash and cash equivalents are held in a few financial institutions in amounts that may, at times, exceed federally insured limits. However, no losses have been incurred and management believes that counterparty risks are minimal based on the reputation and history of the institutions selected. Accounts receivable are concentrated among operators and purchasers engaged in the energy industry within the United States. Management periodically assesses the financial condition of these entities and institutions and considers any possible credit risk to be minimal. Concentrations of oil and gas sales to significant customers (operators) are presented in the table below. For the year ended December 31, 2018 2017 Anadarko Petroleum Corp. 15 % — Continental Resources, Inc. 10 % 10 % Noble Energy, Inc. 9 % 13 % Management does not believe that the loss of any customer would have a long-term material adverse effect on our financial position or the results of operations. Investments in Equity Securities Brigham Minerals classifies its equity securities as available-for-sale, available-for-sale available-for-sale Financial Instruments Brigham Minerals’ financial instruments consist of cash and cash equivalents, receivables, payables, derivative assets and liabilities, investments in equity securities and long-term debt. The carrying amounts of cash and cash equivalents, receivables and payables approximate fair value due to the highly liquid or short-term nature of these instruments. The equity securities are publicly traded and are valued using quoted market prices. The fair values of Brigham Minerals’ derivative assets and liabilities are based on a third-party industry-standard pricing model using contract terms and prices and assumptions and inputs that are substantially observable in active markets throughout the full term of the instruments, including forward oil and gas price curves, discount rates, volatility factors and credit risk adjustments. The carrying amount of long-term debt associated with borrowings outstanding under Brigham Minerals’ term loan facility and prior revolving credit facility approximates fair value as borrowings bear interest at variable market rates. See “Note 6—Derivative Instruments,” “Note 5—Fair Value Measurements” and “Note 7—Long-Term Debt.” Derivative Instruments In the normal course of business, Brigham Minerals is exposed to certain risks, including changes in the prices of oil, natural gas and NGLs and interest rates. Brigham Minerals has occasionally entered into derivative contracts to manage its exposure to these risks. Brigham Minerals’ risk management activity is generally accomplished through over-the-counter Oil and Gas Properties Brigham Minerals uses the full cost method of accounting for its oil and natural gas properties. Under this method, all acquisition costs incurred for the purpose of acquiring mineral and royalty interests and certain related employee costs are capitalized into a full cost pool. Costs associated with general corporate activities are expensed in the period incurred. Capitalized costs are amortized using the units-of-production Costs associated with unevaluated properties are excluded from the amortizable cost base until a determination has been made as to the existence of proved reserves. Unevaluated properties are reviewed periodically to determine whether the costs incurred should be reclassified to the full cost pool and subjected to amortization. The costs associated with unevaluated properties primarily consist of acquisition costs and capitalized general and administrative costs. Unevaluated properties are assessed for impairment on an individual basis or as a group if properties are individually insignificant. The assessment includes consideration of the following factors, among others: expectation of future drilling activity; past drilling results and activity; geological and geophysical evaluations; the assignment of proved reserves; and the economic viability of development if proved reserves are assigned. During any period in which these factors indicate an impairment, the cumulative acquisition costs incurred to date for such property are transferred to the full cost pool and are then subject to amortization. There was no impairment recorded for unevaluated properties in 2018 and 2017. Sales and abandonments of oil and natural gas properties being amortized are accounted for as adjustments to the full cost pool, with no gain or loss recognized unless the adjustments would significantly alter the relationship between capitalized costs and proved reserves. A significant alteration would not ordinarily be expected to occur upon the sale of reserves involving less than 25% of the reserve quantities of a cost center. Natural gas volumes are converted to barrels of oil equivalent (Boe) at the rate of six thousand cubic feet (Mcf) of natural gas to one barrel (Bbl) of oil. This convention is not an equivalent price basis and there may be a large difference in value between an equivalent volume of oil versus an equivalent volume of natural gas. Under the full cost method of accounting, total capitalized costs of oil and natural gas properties, net of accumulated depletion, may not exceed an amount equal to the present value of future net revenues from proved reserves, discounted at 10% per annum, plus the lower of cost or fair value of unevaluated properties (the ceiling limitation). A ceiling limitation is calculated at each reporting period. If total capitalized costs, net of accumulated DD&A are greater than the ceiling limitation, a write-down or impairment of the full cost pool is required. A write-down of the carrying value of the full cost pool is a noncash charge that reduces earnings and impacts equity in the period of occurrence and typically results in lower depletion expense in future periods. Once incurred, a write-down cannot be reversed at a later date. The ceiling limitation calculation is prepared using the 12-month As of December 31, 2018 and 2017, the full cost ceiling value of our reserves was calculated based on the average posted first-day-of-the write-off Income Taxes Brigham Minerals accounts for income taxes using the asset and liability method. 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 bases. Deferred tax assets and liabilities are calculated by applying existing tax laws and the rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. Brigham Minerals was not subject to federal income taxes prior to the July 2018 restructuring. Revenue Recognition Royalty interests represent the right to receive revenues (oil and natural gas sales), less production and operating taxes and post-production costs. Revenue is recorded when title passes to the purchaser. Royalty interests have no rights or obligations to explore, develop or operate the property and do not incur any of the costs of exploration, development and operation of the property. Brigham Minerals recognizes revenue when it is realized or realizable and earned. Revenues are considered realized or realizable and earned when: (i) persuasive evidence of an arrangement exists, (ii) delivery has occurred or services have been rendered, (iii) the seller’s price to the buyer is fixed or determinable, and (iv) collectability is reasonably assured. Pricing of oil, natural gas and NGL sales from Brigham Minerals’ properties is primarily determined by supply and demand in the marketplace and can fluctuate considerably. Brigham Minerals has no involvement or operational control over the volumes and method of sale of oil, natural gas and NGLs produced and sold from its properties. To the extent actual volumes and prices of oil, natural gas and NGLs are unavailable for a given reporting period because of timing or information not received from third parties, the expected sales volume and prices for these properties are estimated and recorded within accounts receivable in the accompanying consolidated and combined balance sheet. Receivables from new wells turned in line for which we did not receive payment at the time revenues are recognized are estimated and recognized only when public production information is available. Differences between estimates of revenue and the actual amounts are adjusted and recorded in the period that the actual amounts are known. Brigham Minerals earns lease bonus revenues and lease extension revenues (collectively referred to as “lease bonus revenue”) from leasing mineral interests to exploration and production companies in exchange for a royalty interest. Lease bonus revenues are recognized when received, at which time Brigham Minerals gives up the right to develop the land itself or to lease it to another party. Debt Issuance Cost As of December 31, 2018, capitalized debt issuance costs of $4.3 million, net of accumulated amortization of $0.3 million, was included in long-term debt on the consolidated and combined balance sheets. As of December 31, 2017, capitalized debt issuance costs of $0.4 million, net of accumulated amortization of $0.3 million, was included in other assets on the consolidated and combined balance sheets. Debt issuance costs were incurred in connection with establishing and amending credit facilities for Brigham Minerals and are amortized over the term of the credit facilities using the effective interest rate method. Amortization expense for debt issue costs was $0.7 million and $0.2 million, for the years ended December 31, 2018 and 2017. On July 27, 2018, the prior revolving credit facility was terminated and replaced with a new term loan facility. See further discussion in “Note 7—Long-Term Debt” in our consolidated financial statements. Recently Issued Accounting Standards Brigham Minerals’ status as an emerging growth company under Section 107 of the JOBS Act permits it to delay the adoption of certain accounting standards until those standards would otherwise apply to private companies. Brigham Minerals is choosing to take advantage of this extended transition period and, as a result, it will comply with new or revised accounting standards on the relevant dates on which adoption of such standards is required for private companies. In January 2017, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2017-01, ASU-2017-01 In November 2016, the FASB issued ASU 2016-18, In February 2016, the FASB issued ASU 2016-02, 2018-11, Targeted In January 2016, the FASB issued ASU 2016-01, available-for-sale In May, 2014, the FASB issued ASU 2014-09, 932-605, Activities-Oil Gas-Revenue 2014-09 one-year 2015-14,

Oil and Gas Properties

Oil and Gas Properties	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Extractive Industries [Abstract]
Oil and Gas Properties	3. Oil and Gas Properties Brigham Minerals uses the full cost method of accounting for its oil and natural gas properties. Under this method, all acquisition costs incurred for the purpose of acquiring mineral and royalty interests, including certain internal costs, are capitalized into a full cost pool. Costs associated with general corporate activities are expensed in the period incurred. Oil and gas properties as of the dates shown consisted of the following: September 30, December 31, (In thousands) Oil and gas properties, at cost, using the full cost method of accounting: Unevaluated property $ 276,888 $ 228,151 Evaluated property 423,884 289,851 Total oil and gas properties, at cost 700,772 518,002 Less accumulated depreciation, depletion, and amortization (49,488 ) (27,628 ) Total oil and gas properties, net $ 651,284 $ 490,374 Capitalized costs are depleted on a unit of production basis based on proved oil and natural gas reserves. Depletion expense was $8.3 million and $3.7 million for the three months ended September 30, 2019 and 2018, respectively, and $19.9 million and $9.1 million for the nine months ended September 30, 2019 and 2018, respectively. Average depletion of proved properties was $11.49 per Boe and $10.17 per Boe for the three months ended September 30, 2019 and 2018, respectively, and $10.91 per Boe and $9.18 per Boe for the nine months ended September 30, 2019 and 2018, respectively. The costs associated with unevaluated properties primarily consist of acquisition costs and capitalized general and administrative costs. Brigham Minerals capitalizes certain overhead expenses and other internal costs attributable to the acquisition of mineral and royalty interests as part of its investment in oil and gas properties over the periods benefitted by these activities. Capitalized costs do not include any costs related to general corporate overhead or similar activities. Capitalized costs were $2.3 million and $0.6 million for the three months ended September 30, 2019 and 2018, respectively, and $5.0 million and $2.0 million for the nine months ended September 30, 2019 and 2018, respectively.	3. Oil and Gas Properties Brigham Minerals uses the full cost method of accounting for its oil and natural gas properties. Under this method, all acquisition costs incurred for the purpose of acquiring mineral and royalty interests, including certain internal costs, are capitalized into a full cost pool. Costs associated with general corporate activities are expensed in the period incurred. Oil and gas properties consisted of the following: Years Ended December 31, 2018 2017 (in thousands, except per Oil and gas properties, at cost, using the full cost method of accounting: Not subject to depletion $ 228,151 $ 168,691 Subject to depletion 289,851 152,354 Total oil and gas properties, at cost 518,002 321,045 Less accumulated depreciation, depletion, and amortization (27,628 ) (14,210 ) Total oil and gas properties, net $ 490,374 $ 306,835 Full cost pool depletion per barrel of oil equivalent $ 9.38 $ 7.25 Costs not subject to depletion at December 31, 2018 are as follows, by the year in which such costs were incurred (in thousands) : Total 2018 2017 Prior Property Acquisition costs $ 228,151 $ 76,793 $ 68,939 $ 82,419 Capitalized costs are depleted on a unit of production basis based on proved oil and natural gas reserves. Depletion expense was $13.3 million and $6.2 million for the years ended December 31, 2018 and 2017, respectively. Brigham Minerals capitalizes certain overhead expenses and other internal costs attributable to the acquisition of mineral and royalty interests as part of its investment in oil and gas properties over the periods benefitted by these activities. Capitalized costs do not include any costs related to production and general corporate overhead or similar activities. Capitalized costs were $2.7 million and $2.1 million, for the years ended December 31, 2018 and 2017, respectively.

Acquisitions and Divestitures

Acquisitions and Divestitures	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Extractive Industries [Abstract]
Acquisitions and Divestitures	4. Acquisitions and Divestitures During the nine months ended September 30, 2019 and 2018, Brigham Minerals entered into a number of acquisitions of mineral and royalty interests from various sellers in Texas, Oklahoma, Colorado, New Mexico, and North Dakota, as reflected in the tables below. The change in the oil and natural gas property balance is comprised of payments for acquisitions of minerals, land brokerage costs and capitalized general and administrative expenses that were funded with borrowings under its Owl Rock credit facility, the new revolving credit facility and proceeds from the IPO. Assets Acquired Cash Evaluated Unevaluated (In thousands) Quarter Ended March 31, 2019 $ 27,929 $ 13,403 $ 41,332 Quarter Ended June 30, 2019 25,050 14,925 39,975 Quarter Ended September 30, 2019 63,787 35,251 99,038 Total Acquired $ 116,766 $ 63,579 $ 180,345 Assets Acquired Cash Evaluated Unevaluated (In thousands) Quarter Ended March 31, 2018 $ 14,132 $ 11,462 $ 25,594 Quarter Ended June 30, 2018 44,706 34,711 79,417 Quarter Ended September 30, 2018 39,099 19,873 58,972 Total Acquired $ 97,937 $ 66,046 $ 163,983	4. Acquisitions and Divestitures In June 2018, Brigham Minerals closed on the acquisition of certain mineral interests from an unrelated third-party in the Delaware Basin in Loving County, Texas and Lea County, New Mexico for $41 million, subject to customary post-closing adjustments. Brigham Minerals funded the acquisition with capital contributions and borrowings under our prior revolving credit facility. The allocation of the purchase price was $22.8 million to evaluated properties and $18.2 million to unevaluated properties. In June 2018, Brigham Minerals entered into a definitive agreement with an unrelated third-party to acquire certain mineral interests in Reeves, Loving and Ward counties in the Delaware Basin for $25.8 million and closed on $22.0 million and $3.8 million in the third and fourth quarter of 2018, respectively. The allocation of the purchase price was $18.4 million to evaluated properties and $7.4 million to unevaluated properties. During the twelve months ended December 31, 2018, Brigham Minerals entered into a number of individually insignificant acquisitions of mineral and royalty interests from various sellers in Texas, Oklahoma and North Dakota, as reflected in the table below. The change in the oil and natural gas property balance is comprised of individually insignificant payments for acquisitions of minerals, land brokerage costs and capitalized general and administrative expenses that were funded with capital contributions and borrowings under our prior revolving credit facility and our new term loan facility. Assets Acquired Consideration Paid Evaluated Unevaluated Cash (in thousands) Quarter Ended March 31, 2018 $ 14,132 $ 11,462 $ 25,594 Quarter Ended June 30, 2018 21,903 16,558 38,461 Quarter Ended Sept 30, 2018 22,982 13,946 36,928 Quarter Ended Dec 31, 2018 15,319 13,879 29,198 Total Acquired $ 74,336 $ 55,845 $ 130,181 In August 2017, Brigham Minerals acquired certain mineral and royalty interests in the Delaware Basin for $29.2 million. Brigham Minerals funded the acquisition with capital contributions. The allocation of the purchase price was $20.5 million to unevaluated properties and $8.7 million to evaluated properties. In addition, during 2017, Brigham Minerals entered into a number of individually insignificant acquisitions. The change in the oil and natural gas property balance is comprised of individually insignificant payments for acquisitions of minerals, land brokerage costs and capitalized general and administrative capital expenditures. On February 28, 2017, Brigham Operating and Brigham Resources Midstream, LLC, wholly owned subsidiaries of Brigham Resources, closed on the sale of substantially all of their Southern Delaware Basin leasehold and related assets, including certain mineral and royalty interests owned by Brigham Resources, to a third-party public entity. The proceeds for mineral and royalty interests represented $156.7 million of the net adjusted sales price and consisted of cash of $111.1 million and shares valued at $45.6 million The mineral and royalty interests sold represented approximately 12% in aggregate of Brigham Minerals’ total proved reserves as of December 31, 2016. As a result of the sale, the relationship between capitalized costs and proved reserves was altered significantly and Brigham Minerals recorded a gain of $94.6 million.

Derivative Instruments

Derivative Instruments	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	5. Derivative Instruments Brigham Minerals periodically uses commodity derivative instruments to reduce its exposure to commodity price volatility for a portion of its forecasted crude oil and natural gas sales and thereby achieve a more predictable level of cash flows. None of the derivative instruments are designated as hedges. Brigham Minerals does not enter into derivative instruments for speculative or trading purposes. Because the counterparties to Brigham Minerals derivative instruments have investment grade credit ratings, Brigham Minerals believes it does not have significant credit risk and accordingly does not currently require its counterparties to post collateral to support the net asset positions of its derivative instruments as of September 30, 2019. Although Brigham Minerals does not currently anticipate nonperformance from its counterparties, it continually monitors the credit ratings of its counterparties. Concurrent with the termination of its prior revolving credit facility in July 2018, Brigham Resources posted cash collateral of $1.4 million for its existing WTI fixed price swap contracts. The cash collateral was $1.6 million in May 2019 prior to the termination of the Owl Rock credit facility and was returned to Brigham Resources upon entering into the new revolving credit facility, as discussed in “Note 1—Business and Basis of Presentation.” As of September 30, 2019, Brigham Minerals had certain WTI fixed price swap contracts based on the NYMEX futures index. The fair values, notional quantities and weighted-average swap prices of these contracts as of September 30, 2019, are summarized in the table below. Description & Production Period Volume Weighted Average Swap Price Fair Value Asset/ (Bbl) ($/Bbl) (In thousands) Crude Oil Swaps: October 2019—December 2019 15,000 $ 63.61 $ 146 Brigham Minerals’ derivative instruments are subject to master netting arrangements and are presented on a net basis in its condensed consolidated and combined balance sheets. The following table summarizes the location and fair value of its derivative instruments as of September 30, 2019 and December 31, 2018 (in thousands): Derivative Instruments Balance Sheet Classification Gross Amount Less Group Net Amount As of September 30, 2019 Derivative assets: Commodity swaps Current derivative assets $ 146 $ — $ 146 As of December 31, 2018 Derivative assets: Commodity swaps Current derivative assets $ 1,057 $ — $ 1,057 The following table summarizes Brigham Minerals’ gain (loss) on derivative instruments, net on its condensed consolidated and combined statement of operations for the three and nine months ended September 30, 2019 and 2018 (in thousands): Three Months Ended Nine Months Ended 2019 2018 2019 2018 (In thousands) Realized gain (loss) $ 119 $ (306 ) $ 356 $ (670 ) Unrealized gain (loss) (28 ) 26 (877 ) (524 ) Combined—realized/unrealized gain (loss) $ 91 $ (280 ) $ (521 ) $ (1,194 )	6. Derivative Instruments Brigham Minerals uses commodity derivative instruments to reduce its exposure to commodity price volatility for a portion of its forecasted crude oil and natural gas sales and thereby achieve a more predictable level of cash flows. None of the derivative instruments are designated as hedges. Brigham Minerals does not enter into derivative instruments for speculative or trading purposes. Because the counterparties to the Mineral Subsidiaries’ derivative instruments have investment grade credit ratings, Brigham Minerals believes it does not have significant credit risk and accordingly does not currently require its counterparties to post collateral to support the net asset positions of its derivative instruments as of December 31, 2018. Although Brigham Minerals does not currently anticipate nonperformance from its counterparties, it continually monitors the credit ratings of its counterparties. Concurrent with the termination of the prior revolving credit facility, we posted cash collateral of $1.6 million for our existing WTI fixed price swap contracts. We anticipate entering into swap intercreditor agreements between Owl Rock Capital Corporation (“Owl Rock”) and our hedge counterparties, at which time we would retract the cash collateral. For further discussion, see “Note 7—Long-Term Debt” in the notes to the consolidated and combined financial statements. As of December 31, 2018, Brigham Minerals had certain oil swap contracts based on the New York Mercantile Exchange (“NYMEX”) futures index. The fair values, notional quantities and weighted-average swap prices of these contracts as of December 31, 2018 , are summarized in the table below. Description & Production Period Volume Weighted Fair Value (Bbl) ($/Bbl) (in thousands) Crude Oil Swaps: January 2019-March 2019(1) 20,000 $ 64.60 $ 358 April 2019-June 2019 15,000 $ 63.61 $ 246 July 2019-September 2019 15,000 $ 63.61 $ 231 October 2019-December 2019 15,000 $ 63.61 $ 222 Total 65,000 $ 63.91 $ 1,057 (1) Includes swaps for 5,000 Bbl valued as an asset of $0.1 million that matured on Dec 31, 2018 and will be settled in January, 2019. Our derivative instruments are subject to master netting arrangements and are presented on a net basis in our consolidated and combined balance sheets. The following table summarizes the location and fair value of our derivative instruments as of December 31, 2018 and December 31, 2017 (in thousands): Derivative Instruments Balance Sheet Classification Gross Amount Less Group Net Amount (In thousands) As of December 31, 2018 Derivative assets: Commodity swaps Current derivative assets $ 1,057 $ — $ 1,057 As of December 31, 2017 Derivative liabilities: Commodity swaps Current derivative liabilities $ 121 $ — $ 121 For the year ended December 31, 2018, Brigham Minerals had realized losses on its oil swap contracts of $0.8 million and unrealized gains of $1.2 million, included in gain on derivative instruments, net on its consolidated and combined statements of operations. For the year ended December 31, 2017, Brigham Minerals had unrealized losses of $0.1 million and no realized gains or losses.

Fair Value Measurements

Fair Value Measurements	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	6. Fair Value Measurements We classify financial assets and liabilities that are measured and reported at fair value on a recurring basis using a hierarchy based on the inputs used in measuring fair value. GAAP defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). We classify the inputs used to measure fair value into the following hierarchy: • Level 1: Inputs based on quoted market prices in active markets for identical assets or liabilities at the measurement date. • Level 2: Inputs based on quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets and liabilities in markets that are not active or other inputs that are observable and can be corroborated by observable market data. • Level 3: Inputs that reflect management’s best estimates and assumptions of what market participants would use in pricing the asset or liability at the measurement date. The inputs are unobservable in the market and significant to the valuation of the instruments. Changes in economic conditions or model-based valuation techniques may require the transfer of financial instruments from one fair value level to another. In such instances, the transfer would be reported at the beginning of the period in which the change occurs. Assets and Liabilities Measured at Fair Value on a Recurring Basis Our financial assets and liabilities that were accounted for at fair value on a recurring basis at September 30, 2019 and December 31, 2018 are as follows: September 30, 2019 Level 1 Level 2 Level 3 Total (In thousands) Assets—commodity derivative instruments $ — $ 146 $ — $ 146 December 31, 2018 Level 1 Level 2 Level 3 Total (In thousands) Assets—commodity derivative instruments $ — $ 1,057 $ — $ 1,057 Our derivative instruments consist of WTI fixed price swaps carried at fair value as disclosed in “Note 5—Derivative Instruments.” Commodity derivative instruments are valued using a third-party industry-standard pricing model using contract terms and prices and assumptions and inputs that are substantially observable in active markets throughout the full term of the instruments, including forward oil and gas price curves, discount rates and volatility factors. The fair values are also compared to the values provided by the counterparties for reasonableness and are adjusted for the counterparties’ credit quality for derivative assets and our credit quality for derivative liabilities. As such, these derivative contracts are classified within Level 2. Brigham Minerals had no transfers into or out of Level 1 and no transfers into or out of Level 2 for the nine months ended September 30, 2019 and 2018. Assets and Liabilities Measured at Fair Value on a Non-Recurring Certain non-financial Fair Value of Other Financial Instruments The carrying value of cash, trade and other receivables and trade payables are considered to be representative of their respective fair values due to the short-term nature of these instruments. The carrying amount of debt outstanding pursuant to our prior revolving credit facility, Owl Rock credit facility, and new revolving credit facility approximates fair value as interest rates on these instruments approximate current market rates. We categorized our long-term debt within Level 2 of the fair value hierarchy.	5. Fair Value Measurements We classify financial assets and liabilities that are measured and reported at fair value on a recurring basis using a hierarchy based on the inputs used in measuring fair value. GAAP defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). We classify the inputs used to measure fair value into the following hierarchy: • Level 1: Inputs based on quoted market prices in active markets for identical assets or liabilities at the measurement date. • Level 2: Inputs based on quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets and liabilities in markets that are not active or other inputs that are observable and can be corroborated by observable market data. • Level 3: Inputs that reflect management’s best estimates and assumptions of what market participants would use in pricing the asset or liability at the measurement date. The inputs are unobservable in the market and significant to the valuation of the instruments. Changes in economic conditions or model-based valuation techniques may require the transfer of financial instruments from one fair value level to another. In such instances, the transfer would be reported at the beginning of the period in which the change occurs. Assets and Liabilities Measured at Fair Value on a Recurring Basis Our financial assets and liabilities that were accounted for at fair value on a recurring basis at December 31, 2018 and December 31, 2017 are as follows (in thousands): December 31, 2018 Level 1 Level 2 Level 3 Total Assets-commodity derivative instruments $ — $ 1,057 $ — $ 1,057 December 31, 2017 Level 1 Level 2 Level 3 Total Assets-investment in equity securities $ 4,105 $ — $ — $ 4,105 Liabilities-commodity derivative instruments $ — $ 121 $ — $ 121 Level 1 equity securities represent publicly traded securities valued using quoted market prices. During 2017, Brigham Minerals received shares of publicly traded securities as partial proceeds from the sale of oil and gas properties discussed in Note 4 and classified them as available for sale. As of December 31, 2017, Brigham Minerals had remaining available for sale securities with aggregate cost basis of $3.4 million and unrealized gains of $0.7 million, which is included in accumulated other comprehensive income (“AOCI”). The fair value of available for sale securities held by Brigham Minerals as of December 31, 2017 was $4.1 million and is included in investment in equity securities on the accompanying consolidated and combined balance sheets. During the twelve months ended December 31, 2018, Brigham Minerals had unrealized gains on available for sale securities of $0.1 million. During the first quarter of 2018, Brigham Minerals distributed securities valued at $3.3 million and sold the remaining securities for $0.9 million, restricted for payment of tax liabilities resulting from the sale of oil and gas properties. As a result of the distribution and sale of securities, gains of $0.8 million were reclassified out of AOCI and included in gain on sale of equity investments on the accompanying consolidated and combined statement of operations. Our derivative instruments consist of oil swaps carried at fair value. Commodity derivative instruments are valued using a third-party industry-standard pricing model using contract terms and prices and assumptions and inputs that are substantially observable in active markets throughout the full term of the instruments, including forward oil and gas price curves, discount rates and volatility factors. The fair values are also compared to the values provided by the counterparties for reasonableness and are adjusted for the counterparties’ credit quality for derivative assets and our credit quality for derivative liabilities. As such, these derivative contracts are classified within Level 2. Brigham Minerals had no transfers into or out of Level 1 and no transfers into or out of Level 2 for the twelve months ended December 31, 2018 and 2017. Assets and Liabilities Measured at Fair Value on a Non-Recurring Certain nonfinancial assets and liabilities, such as assets and liabilities acquired in a business combination, are measured at fair value on a nonrecurring basis on the acquisition date and are subject to fair value adjustments under certain circumstances. The inputs used to determine such fair value are primarily based upon internally developed cash flow models and include factors such as estimates of economic reserves, future operating and development costs, future commodity prices and a risk-adjusted discount rates, and are classified within Level 3. Fair Value of Other Financial Instruments The carrying value of cash, trade and other receivables and trade payables are considered to be representative of their respective fair values due to the short-term nature of these instruments. The carrying amount of debt outstanding pursuant to our term loan and our prior revolving credit facility approximates fair value as interest rates on these instruments approximate current market rates. We categorized our long-term debt within Level 2 of the fair value hierarchy.

Long-Term Debt

Long-Term Debt	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Long-Term Debt	7. Long-Term Debt Prior Revolving Credit Facility Prior to its termination on July 27, 2018, the Minerals Subsidiaries maintained a secured revolving credit facility with a syndicate of financial institutions (the “prior revolving credit facility”), which had been amended periodically. The prior revolving credit facility had a commitment of $150 million, and a borrowing base and outstanding borrowings of $70 million each as of July 27, 2018. Brigham Minerals terminated the prior revolving credit facility on July 27, 2018 with proceeds from the Owl Rock credit facility (as defined below). Additionally, during the third quarter of 2018, Brigham Resources wrote off approximately $0.3 million of unamortized debt issuance costs that were related to the prior revolving credit facility. Owl Rock Credit Facility On July 27, 2018, the prior revolving credit facility was terminated in conjunction with the entry into a new credit facility (the “Owl Rock credit facility”) with Owl Rock Capital Corporation as administrative agent and collateral agent. Brigham Resources used the proceeds from the Owl Rock credit facility to repay the outstanding $70 million of principal under the prior revolving credit facility and to fund mineral and royalty acquisitions. The Owl Rock credit facility was subject to customary fees, guarantees of subsidiaries, restrictions and covenants, including certain restricted payments, and was collateralized by certain oil and natural gas properties of Brigham Resources. The Owl Rock credit facility provided for a $125 million initial term loan, a $75 million delayed draw term loan (“DDTL”) and a $10 million revolving credit facility, bore interest at a rate per annum equal to, at Brigham Resources’ option, (a) the base rate plus 4.50%, or (b) the adjusted LIBOR rate for such interest period (subject to a 1.00% floor) plus 5.50%, matured on July 27, 2024 and required Brigham Resources to maintain compliance with certain financial and collateral coverage ratios. On May 7, 2019, the Owl Rock credit facility was terminated and paid off using the proceeds generated from the IPO. As a result of the debt repayment, Brigham Minerals recognized a loss on extinguishment of debt of $6.9 million, which consisted of a $4.0 million write-off New Revolving Credit Facility On May 16, 2019 (the “closing date”) Brigham Resources entered into a credit agreement with Wells Fargo Bank, N.A., as administrative agent for the various lenders from time to time party thereto, providing for a new revolving credit facility (our “new revolving credit facility”). Our new revolving credit facility is guaranteed by Brigham Resources’ domestic subsidiaries and is collateralized by a lien on substantially all of Brigham Resources and its domestic subsidiaries’ assets, including substantially all of their respective royalty and mineral properties. Availability under our new revolving credit facility is governed by a borrowing base, which is subject to redetermination on November 1, 2019, February 1, 2020, and semi-annually thereafter on May 1 and November 1 of each year, commencing with May 1, 2020. In addition, lenders holding two-thirds two-thirds Our new revolving credit facility bears interest at a rate per annum equal to, at our option, the adjusted base rate or the adjusted LIBOR rate plus an applicable margin. The applicable margin is based on utilization of our new revolving credit facility and ranges from (a) in the case of adjusted base rate loans, 0.750% to 1.750% and (b) in the case of adjusted LIBOR rate loans, 1.750% to 2.750%. Brigham Resources may elect an interest period of one, two, three, six, or if available to all lenders, twelve months. Interest is payable in arrears at the end of each interest period, but no less frequently than quarterly. A commitment fee is payable quarterly in arrears on the daily undrawn available commitments under our new revolving credit facility in an amount ranging from 0.375% to 0.500% based on utilization of our new revolving credit facility. Our new revolving credit facility is subject to other customary fee, interest and expense reimbursement provisions. Our new revolving credit facility matures on May 16, 2024. Loans drawn under our new revolving credit facility may be prepaid at any time without premium or penalty (other than customary LIBOR breakage) and must be prepaid in the event that exposure exceeds the lesser of the borrowing base and the elected availability at such time. The principal amount of loans that are prepaid are required to be accompanied by accrued and unpaid interest and fees on such amounts. Loans that are prepaid may be reborrowed. In addition, Brigham Resources may permanently reduce or terminate in full the commitments under our new revolving credit facility prior to maturity. Any excess exposure resulting from such permanent reduction or termination must be prepaid. Upon the occurrence of an event of default under our new revolving credit facility, the administrative agent acting at the direction of the lenders holding a majority of the aggregate commitments at such time may accelerate outstanding loans and terminate all commitments under our new revolving credit facility, provided that such acceleration and termination occurs automatically upon the occurrence of a bankruptcy or insolvency event of default. Our new revolving credit facility contains customary affirmative and negative covenants, including, without limitation, reporting obligations, restrictions on asset sales, restrictions on additional debt and lien incurrence and restrictions on making distributions (subject only to no default or borrowing base deficiency) and investments. In addition, our new revolving credit facility requires us to maintain (a) a current ratio of not less than 1.00 to 1.00 and (b) a ratio of total net funded debt to consolidated EBITDA of not more than 4.00 to 1.00. As of September 30, 2019, we were in compliance with all covenants in accordance with our new revolving credit facility. On November 7, 2019, the borrowing base on our new revolving credit facility was increased to $150.0 million. See “Note 14—Subsequent Events” to the condensed consolidated and combined financial statements of Brigham Minerals as of September 30, 2019 included elsewhere in this prospectus for further discussion.	7. Long-Term Debt Prior to its termination on July 27, 2018, the Minerals Subsidiaries maintained a secured revolving credit facility with a syndicate of financial institutions (the prior “revolving credit facility”), which had been amended periodically. The revolving credit facility had aggregate commitments of $150 million and a borrowing base of $70 million, subject to periodic redeterminations based on the Minerals Subsidiaries’ oil and natural gas reserves and other factors. The borrowing base was re-determined The outstanding borrowings under the prior revolving credit facility bore interest at a rate elected by the Minerals Subsidiaries that was equal to either an adjusted base rate, which was equal to the greatest of the prime rate, the Federal Funds effective rate plus 0.5% or 3-month The credit agreement governing the prior revolving credit facility contained various affirmative and negative covenants, including limiting additional indebtedness, additional liens, sales of assets, mergers and consolidations, dividends and distributions, transactions with affiliates and entering into certain swap agreements. Additionally, the credit agreement required the maintenance of quarterly financial ratios including total debt to EBITDAX not to exceed 4 to 1 and a ratio of current assets to current liabilities of no less than 1 to 1. Brigham Resources was in compliance with all financial covenants as of December 31, 2017. On July 27, 2018, the prior revolving credit facility was terminated in conjunction with a new term loan facility (our “term loan facility”) with Owl Rock as administrative agent and collateral agent. Brigham Resources used the proceeds from the term loan facility to repay the outstanding $70 million of principal under the prior revolving credit facility and to fund mineral and royalty acquisitions. Additionally, during the third quarter of 2018, Brigham Resources wrote off approximately $0.3 million of unamortized debt issuance costs that were related to the prior revolving credit facility. Our term loan facility is subject to customary fees, guarantees of subsidiaries, restrictions and covenants, including certain restricted payments, and is collateralized by certain oil and natural gas properties of Brigham Resources. Structure Interest Maturity Amortization As of December 31, 2018, we had $175.0 million of outstanding borrowings under our term loan facility. The credit agreement governing our term loan facility also requires us to maintain compliance with the following financial and collateral coverage ratios: • an asset coverage ratio, which is the ratio of (a) the sum of (i) the present value of our and the other loan parties’ proved reserves (as set forth in the most recently delivered reserve report) that are subject to a mortgage in favor of the administrative agent under our term loan facility plus (ii) the Swap Mark-to-Market • a total net leverage ratio, which is the ratio, on a pro forma basis, of (a) Consolidated Total Indebtedness (as defined in the credit agreement) as of such date less up to $25 million of cash and certain permitted investments to (b) two times our Consolidated EBITDA (as defined in the credit agreement) for the most recently completed Test Period (as defined in the credit agreement) of not more than (y) upon the consummation of an underwritten public offering, 4.00 to 1.00 as of the last day of any fiscal quarter or (z) otherwise, 5.50 to 1.00 commencing on September 30, 2018, which steps down quarterly to 4.00 to 1.00 as of December 31, 2019. • a debt to capitalization ratio, which is the ratio of (a) Consolidated Total Indebtedness to (b) Total Invested Capital (as defined in the credit agreement) of no more than 0.40 to 1.00. Brigham Resources was in compliance with all financial covenants as of December 31, 2018. During the year ended December 31, 2018, Brigham Resources borrowed and repaid $7.0 million from Brigham Operating, at an interest rate of 7.00%.

Shareholders' and Members' Equi

Shareholders' and Members' Equity	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Federal Home Loan Banks [Abstract]
Shareholders' and Members' Equity	8. Shareholders’ and Members’ Equity Class A Common Stock Brigham Minerals has approximately 22.0 million shares of its Class A common stock outstanding as of September 30, 2019. Holders of Class A common stock are entitled to one vote per share on all matters to be voted upon by the stockholders and are entitled to ratably receive dividends when and if declared by the Company’s board of directors. Upon liquidation, dissolution, distribution of assets or other winding up, the holders of Class A common stock are entitled to receive ratably the assets available for distribution to the stockholders after payment of liabilities. Class B Common Stock Brigham Minerals has approximately 28.8 million shares of its Class B common stock outstanding as of September 30, 2019. Holders of the Class B common stock are entitled to one vote per share on all matters to be voted upon by the stockholders. Holders of Class A common stock and Class B common stock generally vote together as a single class on all matters presented to Brigham Minerals’ stockholders for their vote or approval. Holders of Class B common stock generally do not have any right to receive dividends or distributions upon a liquidation or winding up of Brigham Minerals. Earnings per Share Basic earnings per share (“EPS”) measures the performance of an entity over the reporting period. Diluted earnings per share measures the performance of an entity over the reporting period while giving effect to all potentially dilutive common shares that were outstanding during the period. Brigham Minerals uses the “if-converted” two-class For the nine months ended September 30, 2019, Brigham Minerals’ EPS calculation includes only its share of net income for the period subsequent to the IPO, and omits income or loss prior to the IPO. In addition, the basic weighted average shares outstanding calculation is based on the actual days in which the shares were outstanding from the IPO through September 30, 2019. The following table reflects the allocation of net income (loss) to common stockholders and EPS computations for the period indicated based on a weighted average number of common stock outstanding for the period: Three Months Ended Nine Months Ended 2019 2018 2019 2018 (In thousands, except per share data) Basic EPS Numerator: Basic net income attributable to Brigham Minerals, Inc. shareholders $ 3,146 $ — $ 1,824 $ — Less: net income attributable to Brigham Minerals, Inc. shareholders pre-IPO — — (848 ) — Basic net income attributable to Brigham Minerals, Inc. shareholders post-IPO $ 3,146 $ — $ 976 $ — Denominator: Basic weighted average shares outstanding 21,838 — 13,299 — Basic EPS attributable to Brigham Minerals, Inc. shareholders $ 0.14 $ — $ 0.07 $ — Diluted EPS Numerator: Basic net income attributable to Brigham Minerals, Inc. shareholders post-IPO 3,146 — 976 — Effect of time-based restricted stock awards — — — — Diluted net income attributable to Brigham Minerals, Inc. shareholders $ 3,146 $ — $ 976 $ — Denominator: Basic weighted average shares outstanding 21,838 — 13,299 — Effect of dilutive securities: Time-based restricted stock awards 88 — 47 — Diluted weighted average shares outstanding 21,926 — 13,346 — Diluted EPS attributable to Brigham Minerals, Inc. shareholders $ 0.14 $ — $ 0.07 $ — As of September 30, 2019, there were 753,546 shares related to PSUs (based on target), that could vest in the future dependent on predetermined performance goals. These units were not included in the computation of EPS for the three and nine months ended September 30, 2019, because the performance goals had not been met, assuming the end of the reporting period was the end of the contingency period.	9. Members’ Equity Series A Units On April 5, 2013, Brigham Resources received subscriptions to purchase 64,840,000 Series A Units at a price of $10 per unit. The Series A Units may be purchased within a five-year period from April 5, 2013 to April 5, 2018. Brigham Resources’ management had the right, subject to the approval of its Board of Directors and certain of its investors, to send notice to the Series A Unit holders specifying the need for additional capital. All outstanding Series A Units were sold prior to December 31, 2015. Series A Unit holders are entitled to one vote per share on voting matters and have certain rights with respect to distributions declared by Brigham Resources’ Board of Directors pursuant to a distribution waterfall set forth in the Brigham Resources LLC Agreement. The Series A Units have a liquidation preference equal to total invested capital, plus a 7% cumulative return, compounded daily. Series A-M Brigham Resources has authorized 460,000 Series A-M Series A-M A-M A-M A-M Series A-M Series A-M Series A-M Series A-Z On May 8, 2015, Brigham Resources received subscriptions to purchase 41,176,471 Series A-Z Series A-Z Series A-Z A-Z A-Z Series A-Z A-Z Series A-Z Series A-Z Restricted Units Brigham Resources has authorized 120,000 restricted incentive units (“Restricted Units”) for issuance to management, independent directors, employees and consultants. The Restricted Units vest 20% upon issuance and 20% on each of the four anniversary dates following the date of issuance. The Restricted Units participate in certain distribution events following the sale, merger or other transaction involving Brigham Resources or its assets only after certain return thresholds are met by the holders of Series A Units, Series A-Z Series A-M Series M-1, Series M-2, Series M-3 Series M-4 Series Z-1, Series Z-2, Series Z-3 Series Z-4 Series M Units M-1 M-2 M-3 M-4 Total Beginning balance 7,520 7,520 7,520 7,520 30,080 2017 issuances — — — — — 2017 forfeitures — — — — — Outstanding at December 31, 2017 7,520 7,520 7,520 7,520 30,080 2018 issuances 1,030 1,030 1,030 1,030 4,120 2018 forfeitures — — — — — Outstanding at December 31, 2018 8,550 8,550 8,550 8,550 34,200 Series Z Units Z-1 Z-2 Z-3 Z-4 Total Beginning balance 4,328 4,328 4,328 4,328 17,312 2017 issuances — — — — — 2017 forfeitures (15 ) (15 ) (15 ) (15 ) (60 ) Outstanding at December 31, 2017 4,313 4,313 4,313 4,313 17,252 2018 issuances 485 485 485 485 1,940 2018 forfeitures (105 ) (105 ) (105 ) (105 ) (420 ) Outstanding at December 31, 2018 4,693 4,693 4,693 4,693 18,772 As of December 31, 2018, 7,726 of each class of Series M Units (30,904 total) and 3,808 of each class of Series Z Units (15,232 total) had vested. As of December 31, 2017, 7,520 of each class of Series M Units (30,080 total) and 2,596 of each class of Series Z Units (10,386 total) had vested. The Series M-1 Series M-2 Series M-3 Series M-4 Series Z-1 Series Z-2 Series Z-3 Series Z-4 Series A-Z Series A-M Brigham Resources used a third-party valuation specialist to assist management in its estimation of the grant-date fair value of the Incentive Units on the respective grant dates during 2013, 2015 and 2018. Brigham Resources used the Black-Scholes option pricing valuation model with the following weighted-average assumptions: Incentive Units 2018 2015 2013 Expected volatility 28 % 33 % 40 % Expected dividend yield — — — Expected term (in years) 0.7 3.7 6.2 Risk-free interest rates 2.45 % 1.07 % 0.94 % Weighted-average grant date fair value per Incentive Unit $ 10.04 $ 0.03 $ 1.51 Total grant date fair value (in thousands) $ 3,558 $ 55 $ 1,248 In addition to the time-based vesting conditions discussed above, the awards could be earned upon the completion of an initial public offering or another liquidity event, considered a performance condition, which was not deemed probable and therefore no compensation expense was recognized prior to December 31, 2018. The total grant date fair value of the awards will be recognized in the future, upon the achievement of the performance condition.

Temporary Equity

Temporary Equity	9 Months Ended
	Sep. 30, 2019
Temporary Equity Disclosure [Abstract]
Temporary Equity	9. Temporary Equity Temporary equity represents the Original Owners’ 56.7% ownership of Brigham LLC. In addition, the Original Owners own all of our Class B common stock. Each share of Class B common stock does not have any economic rights but entitles its holder to one vote on all matters to be voted on by our stockholders, generally and a redemption right into Class A shares. As discussed in “Note 1- • Each holder of Brigham LLC Units following the restructuring, other than Brigham Minerals and its subsidiaries, received a number of shares of Class B common stock equal to the number of Brigham LLC Units held by such Brigham Unit Holder following the IPO; • Brigham Minerals contributed, directly or indirectly, the net proceeds of the IPO to Brigham LLC in exchange for an additional number of Brigham LLC Units such that Brigham Minerals holds, directly or indirectly, a total number of Brigham LLC Units equal to the number of shares of Class A common stock outstanding following the IPO; and • Under the Amended and Restated Limited Liability Company Agreement of Brigham LLC (the “Brigham LLC Agreement”), each Brigham Unit Holder, subject to certain limitations, has a right (the “Redemption Right”) to cause Brigham LLC to acquire all or a portion of its Brigham LLC Units for, at Brigham LLC’s election, (i) shares of our Class A common stock at a redemption ratio of one share of Class A common stock for each Brigham LLC Unit redeemed, subject to conversion rate adjustments for stock splits, stock dividends and reclassification and other similar transactions or (ii) an equivalent amount of cash. We will determine whether to issue shares of Class A common stock or cash based on facts in existence at the time of the decision, which we expect would include the relative value of the Class A common stock (including trading prices for the Class A common stock at the time), the cash purchase price, the availability of other sources of liquidity (such as an issuance of preferred stock) to acquire the Brigham LLC Units and alternative uses for such cash. Alternatively, upon the exercise of the Redemption Right, Brigham Minerals (instead of Brigham LLC) will have a call right to, for administrative convenience, acquire each tendered Brigham LLC Unit directly from the redeeming Brigham Unit Holder for, at its election, (x) one share of Class A common stock or (y) an equivalent amount of cash (the “Call Right”). The decision to make a cash payment upon a Brigham Unit Holder’s exercise of its Redemption Right is required to be made by the Company’s directors who are independent under Section 10A-3 Class B common stock is classified as temporary equity in the condensed consolidated and combined balance sheet as, pursuant to the Brigham LLC Agreement, the Redemption Rights of each Brigham Unit Holder for either shares of Class A common stock or an equivalent amount of cash is not solely within Brigham Minerals’ control. This is due to the holders of the Class B common stock collectively owning a majority of the voting stock of the Company, which allows the holders of Class B common stock to elect the members of the board of directors of the Company, including those directors that determine whether to make a cash payment upon a Brigham Unit Holder’s exercise of its Redemption Right. Temporary equity is recorded at the greater of the book value or redemption amount. From the date of the IPO through September 30, 2019, the Company recorded adjustments to the value of temporary equity as presented in the table below: Temporary (In thousands) Balance—April 17, 2019 $ 518,000 Net loss attribution post-IPO (2,941 ) Distribution of pre-IPO (441 ) Adjustment of temporary equity to redemption amount(2) 97,344 Balance—June 30, 2019 $ 611,962 Net income attribution 3Q, 2019 $ 5,318 Distribution to non-controlling (9,497 ) Adjustment of temporary equity to redemption amount(3) (3,797 ) Balance—September 30, 2019 $ 603,986 (1) Based on 28,777,802 shares of Class B common stock outstanding and Class A share price of $18.00 at IPO date. (2) Based on 28,777,802 shares of Class B common stock outstanding and Class A share 10-day (3) Based on 28,777,802 shares of Class B common stock outstanding and Class A share 10-day

Share-Based Compensation

Share-Based Compensation	9 Months Ended
	Sep. 30, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	10. Share-Based Compensation LLC Incentive Units As part of the Second Amended and Restated Limited Liability Company Agreement of Brigham Resources, LLC dated May 8, 2015, Brigham Resources authorized 120,000 restricted incentive units for issuance to management, independent directors, employees, and consultants (such incentive units, as converted as described below, the “Incentive Units”). Brigham Resources granted Incentive Units in April 2013 and September 2015 and 2018. In connection with the 2018 corporate reorganizations and the corporate reorganization consummated in connection with Brigham Minerals’ IPO (collectively with the 2018 corporate reorganizations, the “corporate reorganization”), these Incentive Units were converted into units in Brigham Equity Holdings, LLC (“Brigham Equity Holdings”) with equivalent rights, responsibilities, and preferences. The Incentive Units are subject to vesting as follows: 20% of the Incentive Units were vested on the date of grant and 20% of the Incentive Units vest on each anniversary of the date of grant if the holder remains continuously employed by Brigham Resources or its affiliates through the applicable vesting date. In connection with our IPO, holders of Incentive Units that were vested at such time received one share of Brigham Minerals’ Class B common stock and one Brigham LLC Unit for each vested Incentive Unit. Upon vesting of the Incentive Units following the IPO, holders of the Incentive Units will receive one share of Brigham Minerals’ Class B common stock and one Brigham LLC Unit for each vested Incentive Unit. In connection with the completion of the IPO, Brigham LLC and Brigham Equity Holdings discontinued granting new Incentive Units; however Brigham Equity Holdings will continue to administer the existing awards that remain outstanding. As discussed in “Note 9—Temporary Equity,” participants may receive one share of Brigham Minerals’ Class A common stock in exchange for one share of Class B common stock and one Brigham LLC Unit, or cash at the option of Brigham Minerals. Brigham Minerals accounts for the Incentive Units as compensation cost measured at the fair value of the award on the date of grant. No compensation expense was recognized prior to the IPO because the IPO was not considered probable. A summary of the Incentive Unit activity for the nine months ended September 30, 2019 is as follows: Incentive Units Number of Grant-date (In thousands) Outstanding—January 1, 2019 3,272 $ 1.49 Vested (3,058 ) 0.88 Outstanding—September 30, 2019 215 $ 10.04 A summary of the Incentive Unit activity for the nine months ended September 30, 2018 is as follows: Incentive Units Number of Grant-date (In thousands) Outstanding—January 1, 2018 2,918 $ 0.45 Granted 354 10.04 Vested — — Outstanding—September 30, 2018 3,272 $ 1.49 Brigham LLC used a third-party valuation specialist to assist management in its estimation of the grant-date fair value of the Incentive Units on the respective grant dates during 2013, 2015 and 2018. Brigham LLC used the Black-Scholes option pricing valuation model with the following weighted-average assumptions: Incentive Units 2018 2015 2013 Expected volatility 28 % 33 % 40 % Expected dividend yield — — — Expected term (in years) 0.7 3.7 6.2 Risk-free interest rates 2.45 % 1.07 % 0.94 % Weighted-average grant date fair value per Incentive Unit $ 10.04 $ 0.03 $ 1.51 Long Term Incentive Plan In connection with the IPO, Brigham Minerals adopted the Brigham Minerals, Inc. 2019 Long Term Incentive Plan (“LTIP”) for employees, consultants and directors who perform services for Brigham Minerals. The LTIP provides for issuance of awards based on shares of Class A common stock. Brigham Minerals has issued RSAs, RSUs and PSUs under the LTIP. The shares to be delivered under the LTIP shall be made available from (i) authorized but unissued shares, (ii) shares held as treasury stock or (iii) previously issued shares reacquired by Brigham Minerals including shares purchased on the open market. A total of 5,999,600 shares of Class A common stock have been authorized for issuance under the LTIP. At September 30, 2019, 4,334,974 shares of Class A common stock remained available for future grants. Currently, all RSAs, RSUs and PSUs granted under the LTIP are entitled to receive dividends (in the case of RSAs) or have dividend equivalent rights (“DERs”), which entitle holders of RSUs and PSUs to the same dividend value per share as holders of the Company’s Class A common stock. Such dividends and DERs are subject to the same vesting and other terms and conditions as the corresponding unvested RSAs, RSUs, and PSUs. Dividends and DERs are accumulated and paid when the underlying shares vest. The fair value of the RSA awards granted with the right to receive dividends and RSU awards granted with the right to receive DERs are generally based on the trading price of the Company’s Class A common stock as of the date of grant. Brigham Minerals accounts for the awards granted under the LTIP as compensation cost measured at the fair value of the award on the date of grant. RSAs are grants of shares of Class A common stock subject to a risk of forfeiture and restrictions on transferability. The share-based compensation expense of such RSAs was determined using the closing price of Class A common stock on April 23, 2019, the date of grant, of $21.25. On April 23, 2019, 312,189 RSAs were granted and 152,742 RSAs vested immediately. The remaining unvested RSAs generally vest in one-third RSUs represent the right to receive shares of Class A common stock at the end of the vesting period in an amount equal to the number of RSUs that vest. The RSUs that have been granted generally vest in one-third PSUs represent the right to receive shares of Class A common stock on December 31, 2021. 753,546 PSUs (based on target) were granted on April 23, 2019. The terms and conditions of the PSUs allow for vesting of the awards ranging between 0% (or forfeiture) and 200% of target. The vesting level is calculated based on the actual total stockholder return achieved during the performance period including projected dividends. The fair value of such PSUs was determined using a Monte Carlo simulation and will be recognized over the applicable performance period. The Monte Carlo simulation model utilizes multiple input variables that determine the probability of satisfying the market condition stipulated in the award to calculate the fair value of the award. Expected volatilities in the model were estimated using a historical period consistent with the performance period of approximately three years. The risk-free interest rate was based on the United States Treasury rate for a term commensurate with the expected life of the grant. Using the assumptions in the table below, Brigham Minerals estimated the fair value of PSUs at the date of grant to be $20.36. Performance- Expected dividend yield 8.1 % Risk-free interest rate 2.3 % Volatility 30.0 % The number of PSUs that will be earned is estimated quarterly and as of September 30, 2019, we estimated that 379,107 PSUs will be earned. No PSUs were forfeited, converted or vested during the three and nine months ended September 30, 2019. Share-Based Compensation Expense Share-based compensation expense is included in general and administrative expense in the Company’s condensed consolidated and combined statement of operations included within this prospectus. Share-based compensation cost recorded for each type of share-based compensation award, was as follows for the periods indicated: Three Months Ended Nine Months Ended 2019 2018 2019 2018 (In thousands) Incentive Units(1)(3) $ 559 $ — $ 2,726 $ — RSAs(2)(3) 285 — 3,741 — RSUs(3) 1,686 — 2,932 — PSUs(4) 622 — 1,258 — Capitalized share-based compensation(5) (1,415 ) — (2,425 ) — Total share-based compensation expense $ 1,737 $ — $ 8,232 $ — (1) Includes a cumulative effect adjustment to share-based compensation cost of $2.0 million pertaining to the period from the grant date through the IPO date. No compensation expense was recorded prior to the IPO because the IPO was not considered probable. (2) Includes $3.2 million recorded at grant date of April 23, 2019, associated with 152,742 RSAs, which vested immediately. (3) Share-based compensation expense relating to Incentive Units, restricted stock awards and time-based restricted stock units with ratable vesting is recognized on a straight-line basis over the requisite service period for the entire award. (4) Share-based compensation expense relating to PSUs with cliff-vesting is recognized on a straight-line basis over the performance period for the entire award. (5) During the three and nine months ended September 30, 2019, Brigham Minerals capitalized $1.4 million and $2.4 million, respectively, of the share-based compensation to unevaluated property on its balance sheet. Future Share-Based Compensation Expense The following table reflects the future share-based compensation expense to be recorded for the share-based compensation awards that were outstanding at September 30, 2019, a portion of which will be capitalized: Incentive RSAs RSUs PSUs Total (In thousands) 2019 $ 178 $ 285 $ 1,686 $ 723 $ 2,872 2020 712 1,129 4,217 2,869 $ 8,927 2021 712 1,129 3,891 2,868 $ 8,600 2022 533 350 — — $ 883 Total $ 2,135 $ 2,893 $ 9,794 $ 6,460 $ 21,282

Income Taxes

Income Taxes	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes The Company accounts for income taxes using the asset and liability method. 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 bases. Deferred tax assets and liabilities are calculated by applying existing tax laws and the rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. Brigham Resources, the Company’s predecessor, is a limited liability company that is not subject to U.S. federal income tax, but is subject to the Texas Margin Tax and state income taxes in Oklahoma, North Dakota, and Colorado. As part of the July 2018 restructuring, certain entities affiliated with Warburg Pincus contributed all of their respective interests in certain wholly owned “blocker” entities through which they held interests in Brigham Resources to Brigham Minerals in exchange for all of the outstanding shares of common stock of Brigham Minerals. On the date of the July 2018 restructuring, a corresponding “first day” tax charge of approximately $3.1 million was recorded to establish a net deferred tax liability for differences between the tax and book basis of the investment in Brigham Resources. The offset of the deferred tax liability was recorded to additional paid-in-capital. Brigham Minerals is a corporation and is subject to U.S. federal income tax. In April 2019, Brigham Minerals completed the IPO of 16,675,000 shares of Class A common stock at a price to the public of $18.00 per share. The tax implications of the July 2018 restructuring, initial public IPO and the tax impact of the Company’s status as a taxable corporation subject to U.S. federal income tax have been reflected in the accompanying condensed consolidated and combined financial statements. On IPO date, a corresponding tax benefit of approximately $13.7 million was recorded associated with the differences between the tax and book basis of the investment in Brigham Resources, LLC. The offset of the deferred tax asset was recorded to additional paid-in The effective combined U.S. federal and state income tax rate for the nine months ended September 30, 2019 was 7.9%. During the three and nine months ended September 30, 2019, the Company recognized an income tax expense of $0.8 million and $1.1 million, respectively. During the three and nine months ended September 30, 2018, the income tax expense recognized was $0.4 million and $0.5 million, respectively. Total income tax expense for the three and nine months ended September 30, 2019 differed from amounts computed by applying the U.S. federal statutory tax rate of 21% due to the impact of the temporary equity, net income attributable to Predecessor, state taxes (net of the anticipated federal benefit), and percentage depletion in excess of basis.	12. Income Taxes Brigham Minerals accounts for income taxes using the asset and liability method. 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 bases. Deferred tax assets and liabilities are calculated by applying existing tax laws and the rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. Brigham Resources, Brigham Minerals’ predecessor, is a limited liability company that is not subject to U.S. federal income tax, but is subject to the Texas Margin Tax and state income taxes in Oklahoma, North Dakota, and Colorado. As part of the July 2018 restructuring, certain entities affiliated with Warburg Pincus LLC contributed all of their respective interests in certain wholly owned “blocker” entities through which they held interests in Brigham Resources to Brigham Minerals in exchange for all of the outstanding shares of common stock of Brigham Minerals. On the date of the July 2018 restructuring, a corresponding “first day” tax charge of approximately $3.1 million was recorded to establish a net deferred tax liability for differences between the tax and book basis of the investment in Brigham Resources. The offset of the deferred tax liability was recorded to additional paid-in-capital. Brigham Minerals is a corporation and is subject to U.S. federal income tax. The tax implications of the corporate reorganization and the tax impact of Brigham Minerals’ status as a taxable corporation subject to U.S. federal income tax have been reflected in the accompanying consolidated and combined financial statements. The effective combined U.S. federal and state income tax rate of the period ended December 31, 2018 was 1.0%. Total income tax expense differed from the U.S. federal statutory tax rates due to state taxes. During the year ended December 31, 2018, Brigham Minerals recorded current tax expense of $0.1 million and deferred tax expense of $0.2 million. During the year ended December 31, 2017, Brigham Minerals recorded current tax expense of $0.7 million and deferred tax expense of $0.3 million as indicated in the table below (in thousands): 2018 2017 State Income Tax Current (benefit)/expense (23 ) 713 Deferred (benefit)/expense (138 ) 295 Federal Income Tax Current expense 114 — Deferred expense 374 — Totals: 327 1,008 Total current income taxes 91 713 Total deferred income taxes 236 295 Totals: 327 1,008 The following table reconciles the income tax provision with income tax expense at the federal statutory rate for the periods indicated (in thousands): 2018 2017 Income before income taxes 33,142 116,620 Less: income before income taxes attributable to predecessor 30,805 116,620 Income before income taxes attributable to shareholders 2,337 — Income tax at the federal statutory rate 491 — State income taxes, net of federal benefit (150 ) 1,008 Percentage depletion in excess of basis (14 ) — Total income tax provision 327 1,008 Brigham Minerals had $3.7 million and $0.4 million recorded as deferred tax liability at December 31, 2018 and 2017, respectively. The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities were are follows (in thousands): 2018 2017 Noncurrent: Deferred tax assets: — — Total noncurrent deferred tax assets: — — Deferred tax liabilities: Oil and gas properties (208 ) (391 ) Investment in subsidiary (3,476 ) — Total noncurrent deferred tax liabilities (3,684 ) (391 ) Net noncurrent deferred tax liabilities (3,684 ) (391 )

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	12. Commitments and Contingencies Commitments Brigham Minerals leases office space under operating leases. Rent expense for the three months ended September 30, 2019 and 2018 was $0.2 million and $0.1 million, respectively. Rent expense for the nine months ended September 30, 2019 and 2018 was $0.4 million and $0.2 million, respectively. Future minimum lease commitments under noncancelable operating leases at September 30, 2019 are presented below: Commitment (In thousands) Year 2019 $ 160 2020 970 2021 1,275 2022 1,312 2023 1,349 Thereafter 5,020 Total $ 10,086 Contingencies Brigham Minerals may, from time to time, be a party to certain lawsuits and claims arising in the ordinary course of business. The outcome of such lawsuits and claims cannot be estimated with certainty and management may not be able to estimate the range of possible losses. Brigham Minerals records reserves for contingencies when information available indicates that a loss is probable and the amount of the loss can be reasonably estimated. Brigham Minerals had no reserves for contingencies at September 30, 2019 and December 31, 2018.	8. Commitments and Contingencies Commitments Brigham Minerals leases office space under operating leases. Rent expense for the years ended December 31, 2018 and 2017 was $0.3 million and $0.2 million, respectively. Future minimum lease commitments under noncancelable operating leases at December 31, 2018 are presented below (in thousands): Year Commitment 2019 $ 538 2020 654 2021 672 2022 689 2023 474 2024 111 Total $ 3,138 Contingencies Brigham Minerals may, from time to time, be a party to certain lawsuits and claims arising in the ordinary course of business. The outcome of such lawsuits and claims cannot be estimated with certainty and management may not be able to estimate the range of possible losses. Brigham Minerals records reserves for contingencies when information available indicates that a loss is probable and the amount of the loss can be reasonably estimated. Brigham Minerals had no reserves for contingencies at December 31, 2018 and December 31, 2017.

Related-Party Transactions

Related-Party Transactions	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Related Party Transactions [Abstract]
Related-Party Transactions	13. Related-Party Transactions Brigham Land Management (“BLM”) occasionally provides us with land brokerage services. The services are provided at market prices and are periodically verified by third-party quotes. BLM is owned by Vince Brigham, an advisor to us and brother of Ben M. Brigham, our founder and Executive Chairman of our Board of Directors. For the nine months ended September 30, 2019 and 2018, the amounts paid to BLM for land brokerage services were immaterial. At September 30, 2019 and December 31, 2018, the liabilities recorded for services performed by BLM during the respective periods were immaterial. Brigham Exploration Company, partially owned by Ben M. Brigham, on occasion leases some of our acreage at market rates. In connection with such leases, we received $0.4 million for the nine months ended September 30, 2019 from Brigham Exploration. There were no payments received from Brigham Exploration Company in connection with such leases for the three months ended September 30, 2019 and for the three and nine months ended September 30, 2018.	11. Related-Party Transactions Brigham Land Management (“BLM”) provides Brigham Minerals with land brokerage services. The services are provided at market prices and are periodically verified by third-party quotes. BLM is owned by Vince Brigham, an advisor to Brigham Minerals and brother of Ben M. Brigham, founder of Brigham Resources and Executive Chairman of the Board. For the years ended December 31, 2018 and 2017, Brigham Resources paid BLM $0.1 million and $0.6 million, respectively for land brokerage services. At December 31, 2018 and 2017, the liabilities recorded for services performed by BLM during the respective periods were immaterial. Brigham Exploration Company (“BEXP”), owned by Ben M. Brigham, leases some of Brigham Resources’ acreage at market rates. For the year ended December 31, 2017, BEXP paid Brigham Resources $0.6 million. There were no payments for the year ended December 31, 2018. During the quarter ended September 30, 2018, Brigham Minerals borrowed $7.0 million from Brigham Operating at an interest rate of 7.00%, which was repaid prior to September 30, 2018.

Subsequent Events

Subsequent Events	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	14. Subsequent Events On November 7, 2019, Brigham Minerals declared a dividend of $0.33 per Class A common stock payable on November 27, 2019, to unitholders of record at the close of business on November 20, 2019. On November 7, 2019, the borrowing base on our new revolving credit facility was increased to $150.0 million.	14. Subsequent Events In April 2019, Brigham Minerals completed the initial public offering of 16,675,000 shares of Class A common stock at a price to the public of $18.00 per share (the “IPO”). This resulted in net proceeds of approximately $273.3 million, after deducting underwriting commissions and discounts and offering expenses. Brigham LLC used a portion of the net proceeds from the IPO, which were contributed to it by Brigham Minerals to repay the $200.0 million of outstanding borrowings under the Brigham Resources prior revolving credit facility and a $2.1 million prepayment premium fee related to early extinguishment of debt. As a result of the IPO, Brigham Minerals became a holding company whose sole material asset consists of an interest in Brigham LLC, which wholly owns Brigham Resources. Brigham Resources continues to wholly own the Minerals Subsidiaries, which own all of Brigham Resources’ operating assets. In connection with the IPO, Brigham Minerals became the sole managing member of Brigham LLC and is responsible for all operational, management and administrative decisions relating to Brigham LLC’s business and consolidates the financial results of Brigham LLC and its wholly owned subsidiary, Brigham Resources. All of the interests in Brigham Operating were distributed, directly or indirectly, to the existing owners prior to the consummation of the IPO. As a result, neither Brigham Minerals nor Brigham LLC owned any direct or indirect interest in Brigham Operating at the time of the IPO. Following the IPO, the existing owners controlled a majority of our outstanding voting securities and held a combined 67.2% economic interest in Brigham LLC (directly through their ownership of Brigham LLC Units and indirectly through shares of Brigham Minerals’ Class A common stock). In connection with the IPO, Brigham Minerals adopted the Brigham Minerals, Inc. 2019 Long Term Incentive Plan (the “2019 Plan”) and granted awards of restricted stock units subject to time-based or performance-based vesting and shares of restricted stock subject to time-based vesting to certain of its directors, officers and employees. On May 7, 2019, the term loan facility was terminated and paid off using the proceeds generated from the IPO. As a result of the debt repayment, Brigham Minerals recognized a loss on extinguishment of debt of $6.9 million, which consisted of a $4.0 million write-off of capitalized debt issuance costs, a $2.1 million prepayment fee and accrued legal fees of $0.8 million. On May 16, 2019, Brigham Resources entered into a credit agreement with Wells Fargo Bank, N.A., as administrative agent for the various lenders from time to time party thereto, providing for a new revolving credit facility. The revolving credit facility is subject to a borrowing base that is redetermined periodically and bears interest at a rate per annum equal to, at Brigham Resources’ option, the adjusted base rate or the adjusted LIBOR rate plus an applicable margin. The applicable margin is based on utilization of the revolving credit facility and ranges from (a) in the case of adjusted base rate loans, 0.750% to 1.750% and (b) in the case of adjusted LIBOR rate loans, 1.750% to 2.750%. Brigham Resources may elect an interest period of one, two, three, six, or if available to all lenders, twelve months. A commitment fee is payable quarterly in arrears on the daily undrawn available commitments under the revolving credit facility in an amount ranging from 0.375% to 0.500% based on utilization of the revolving credit facility. The revolving credit facility matures on May 16, 2024 and may be prepaid at any time without premium or penalty (other than customary LIBOR breakage). The revolving credit facility is subject to other customary fees, interest and expense reimbursement provisions. On November 7, 2019, the borrowing base on the revolving credit facility was increased to $150.0 million from a $120.0 million borrowing base as of the closing date of the revolving credit facility. As of December 6, 2019, Brigham Minerals had $80.0 million of outstanding borrowings under its revolving credit facility. On August 5, 2019 and November 7, 2019, Brigham Minerals declared a dividend of $0.33 per share of Class A common stock payable on August 29, 2019, and November 27, 2019, respectively, to shareholders of record at the close of business on August 22, 2019 and November 20, 2019, respectively.

Employee Benefit Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2018
Postemployment Benefits [Abstract]
Employee Benefit Plan	10. Employee Benefit Plan We sponsor a 401(k) tax-deferred

Quarterly Financial Information

Quarterly Financial Information-Unaudited	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information-Unaudited	13. Quarterly Financial Information—Unaudited Summarized quarterly financial data for the years ended December 31, 2018 and 2017 are presented in the following tables. During the periods presented below, earnings per share information is not available due to no shares being recognized for accounting purposes for periods prior to the IPO. Additionally, due to the effect of rounding, the sum of the individual quarterly earnings per share amounts may not equal the calculated year earnings per share amount. 2018 Quarters Total Fourth Third Second First Total revenues $ 67,264 $ 17,591 $ 18,701 $ 16,889 $ 14,083 Income from operations $ 39,231 $ 8,732 $ 11,716 $ 10,564 $ 8,219 Net Income $ 32,815 $ 7,114 $ 8,153 $ 9,351 $ 8,197 2017 Quarters Total Fourth Third Second First Total revenues $ 40,908 $ 12,404 $ 8,380 $ 8,201 $ 11,923 Income from operations $ 121,214 $ 7,697 $ 5,044 $ 5,127 $ 103,346 Net income $ 115,612 $ 7,234 $ 654 $ 5,024 $ 102,700

Reserve and Related Financial D

Reserve and Related Financial Data (SMOG)-Unaudited	12 Months Ended
	Dec. 31, 2018
Text Block [Abstract]
Reserve and Related Financial Data (SMOG)-Unaudited	15. Reserve and Related Financial Data (SMOG)—Unaudited Oil and Natural Gas Reserves Proved reserves represent quantities of oil, natural gas and NGLs which, by analysis of geoscience and engineering data, can be estimated with reasonable certainty to be recoverable in the future from known reservoirs under existing economic conditions, operating methods and government regulations. Proved developed reserves are proved reserves which can be expected to be recovered through existing wells with existing equipment, infrastructure and operating methods. Proved reserves were estimated in accordance with guidelines established by the SEC, which require that reserve estimates be prepared under existing economic and operating conditions based upon the 12-month first-day-of-the-month The reserves at December 31, 2018 presented below were audited by CG&A and the reserves at December 31, 2017 presented below were prepared by CG&A. Estimates of proved reserves are inherently imprecise and are continually subject to revision based on production history, results of additional exploration and development, price changes and other factors. The reserves are located in various fields in Texas, New Mexico, Oklahoma, Colorado, Wyoming, North Dakota, Montana and Pennsylvania. All of the proved reserves are located in the continental United States. Crude Oil Natural Gas NGL Total Proved reserve quantities, December 31, 2016 7,174 22,991 2,356 13,363 Sales of minerals-in-place (1,291 ) (815 ) (200 ) (1,627 ) Extentions and discoveries 1,548 6,012 709 3,259 Acquisitions 2,141 9,380 1,116 4,820 Revisions of previous estimates (394 ) 2,601 108 147 Production (454 ) (1,768 ) (109 ) (858 ) Proved reserve quantities, December 31, 2017 8,724 38,401 3,980 19,104 Sales of minerals-in-place — — — — Extentions and discoveries 1,765 5,285 562 3,208 Acquisitions 3,669 13,862 1,374 7,354 Revisions of previous estimates (390 ) (3,245 ) (577 ) (1,508 ) Production (777 ) (2,507 ) (222 ) (1,417 ) Proved reserve quantities, December 31, 2018 12,991 51,796 5,117 26,741 Proved developed reserve quantities: December 31, 2017 2,804 13,028 1,185 6,160 December 31, 2018 6,067 21,735 1,898 11,588 Proved undeveloped reserve quantities: December 31, 2017 5,920 25,373 2,795 12,944 December 31, 2018 6,924 30,061 3,219 15,153 Changes in proved reserves that occurred during 2018 were primarily due to: • the acquisition of additional mineral and royalty interests located in the Permian, DJ, Anadarko and Williston Basins in multiple transactions, which included 7,354 MBoe of additional proved reserves; • well additions, extensions and discoveries of approximately 3,208 MBoe, as 555 horizontal well locations were converted from probable, possible and contingent resources to proved, due to continuous activity and delineation of additional zones on our mineral and royalty interests; and • net negative volume revisions of approximately 1,508 MBoe. These revisions were comprised of 536 MBoe of positive revisions attributable to pricing and were offset by negative revisions of 1,100 MBoe attributable to operator development timing as well as 944 MBoe of revisions associated with unit configuration and EUR adjustments to existing proved locations. Changes in proved reserves that occurred during 2017 were primarily due to: • the acquisition of additional mineral and royalty interests located in the Permian, DJ, Anadarko and Williston Basins in multiple transactions, which included 4,820 MBoe of additional proved reserves; • well additions, extensions and discoveries of approximately 3,259 MBoe, as 854 horizontal well locations were converted from probable, possible and contingent resources to proved, due to continuous activity and delineation of additional zones on our mineral and royalty interests; • the divestiture of 1,627 MBoe through one sale of mineral and royalty interests located in the Permian Basin; and • positive volume revisions of approximately 2,581 MBoe attributable primarily to increased recovery in close proximity to our mineral and royalty interests, partially offset by negative revisions of approximately 2,434 MBoe, attributable primarily to operator development timing and revision of existing proved locations. Standardized Measure of Discounted Future Net Cash Flows Guidelines prescribed in FASB’s Accounting Standards Codification (“ASC”) Topic 932 Extractive Industries—Oil and Gas, have been followed for computing a standardized measure of future net cash flows and changes therein relating to estimated proved reserves. Future cash inflows are determined by applying prices and costs, including transportation, quality and basis differentials, to the year-end The assumptions used to compute the standardized measure are those prescribed by the FASB and the SEC. These assumptions do not necessarily reflect Brigham Resources’ expectations of actual revenues to be derived from those reserves, nor their present value. The limitations inherent in the reserve quantity estimation process, as discussed previously, are equally applicable to the standardized measure computations since these reserve quantity estimates are the basis for the valuation process. Reserve estimates are inherently imprecise and estimates of new discoveries and undeveloped locations are more imprecise than estimates of established proved producing oil and gas properties. Accordingly, these estimates are expected to change as future information becomes available. The standardized measure excludes federal income taxes as Brigham Resources is a limited liability company and not subject to federal income taxes; however, Brigham Resources is subject to state taxes. The following summary sets forth the future net cash flows relating to proved oil and gas reserves based on the standardized measure prescribed in ASC Topic 932: For the Year Ended 2018 2017 (in thousands) Future crude oil, natural gas and NGL sales $ 1,049,141 $ 595,874 Future severance tax and ad valorem taxes (70,248 ) (40,225 ) Future income tax expense (144,421 ) (1,151 ) Future net cash flows 834,472 554,498 10% annual discount (391,013 ) (238,030 ) Standardized measure of discounted future net cash flows $ 443,459 $ 316,468 The following prices were used in the determination of standardized measure: For the Year Ended 2018 2017 Oil (per Bbl) $ 61.31 $ 47.80 Natural gas (per MMBtu) 2.51 2.74 NGLs (per Bbl) 23.98 18.56 These prices were based on the 12-month first-of-month The principal sources of change in the standardized measure of discounted future net cash flows are: For the Year Ended 2018 2017 (in thousands) Standardized measure of discounted future net cash flows, beginning of the year $ 316,468 $ 185,752 Changes in the year resulting from: Sales, less production costs and taxes (52,278 ) (26,711 ) Revisions of previous quantity estimates (22,942 ) 4,894 Extensions, discoveries and other additions 71,668 56,511 Net change in prices and production costs 71,770 30,565 Accretion of discount 31,713 18,612 Purchase of reserves in place 148,580 79,190 Divestitures of reserves in place — (26,742 ) Net change in income Tax (75,369 ) (298 ) Timing differences and other (46,151 ) (5,305 ) Standardized measure of discounted future net cash flows, end of the year $ 443,459 $ 316,468 Capitalized oil and natural gas costs The aggregate amounts of costs capitalized for oil and natural gas producing activities and related aggregate amounts of accumulated depletion follow: For the Year Ended 2018 2017 (in thousands) Oil and gas properties, at cost, using full cost method of accounting: Not subject to depletion $ 228,151 $ 168,691 Subject to depletion 289,851 152,354 Total oil and gas properties, at cost 518,002 321,045 Less accumulated depreciation, depletion and amortization (27,628 ) (14,210 ) Total oil and gas properties, net $ 490,374 $ 306,835 Costs incurred in oil and natural gas activities The following costs were incurred in oil and natural gas producing activities: For the Year Ended 2018 2017 (in thousands) Acquisition of properties Unevaluated $ 59,460 $ 50,224 Evaluated 137,496 51,862 Total $ 196,956 $ 102,086

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates These condensed consolidated and combined financial statements and related notes are presented in accordance with GAAP. Preparation in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in the consolidated financial statements and accompanying notes. Although management believes these estimates are reasonable, actual results could differ from these estimates. Changes in estimates are recorded prospectively. The accompanying condensed consolidated and combined financial statements are based on a number of significant estimates including quantities of oil, natural gas and NGL reserves that are the basis for the calculations of depreciation, depletion, amortization (“DD&A”) and impairment of oil and natural gas properties. Reservoir engineering is a subjective process of estimating underground accumulations of oil and natural gas and there are numerous uncertainties inherent in estimating quantities of proved oil and natural gas reserves. The accuracy of any reserve estimate is a function of the quality of available data and of engineering and geological interpretation and judgment. As a result, reserve estimates may differ from the quantities of oil and natural gas that are ultimately recovered. Brigham Minerals’ year-end in-house	Use of Estimates The preparation of consolidated and combined financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in the consolidated financial statements and accompanying notes. Although management believes these estimates are reasonable, actual results could differ from these estimates. Changes in estimates are recorded prospectively. The accompanying consolidated and combined financial statements are based on a number of significant estimates including quantities of oil, natural gas and NGLs reserves that are the basis for the calculations of depreciation, depletion, amortization (“DD&A”) and impairment of oil and natural gas properties. Reservoir engineering is a subjective process of estimating underground accumulations of oil and natural gas and there are numerous uncertainties inherent in estimating quantities of proved oil and natural gas reserves. The accuracy of any reserve estimate is a function of the quality of available data and of engineering and geological interpretation and judgment. As a result, reserve estimates may differ from the quantities of oil and natural gas that are ultimately recovered. Brigham Minerals’ reserve estimates are determined by Cawley, Gillespie & Associates, Inc. (“CG&A”), an independent petroleum engineering firm. Other items subject to significant estimates and assumptions include the carrying amount of oil and natural gas properties, valuation of derivative instruments and revenue accruals.
Share-Based Compensation	Share-Based Compensation Brigham Minerals accounts for its share-based compensation including grants of the Incentive Units, restricted stock awards, time-based restricted stock units and performance-based stock units in the condensed consolidated and combined statements of operations based on their estimated fair values at grant date. Brigham Minerals recognizes expense on a straight-line basis over the vesting period of the respective grant, which is generally the requisite service period. Share-based compensation is included in general and administrative expenses in Brigham Minerals’ condensed consolidated and combined statements of operations included within this prospectus. There was approximately $21.3 million of unamortized compensation expense relating to outstanding awards at September 30, 2019, a portion of which will be capitalized. The unrecognized share-based compensation expense will be recognized on a straight-line basis over the remaining vesting periods of the awards. Brigham Minerals accounts for forfeitures as they occur.
Earnings Per Share	Earnings Per Share Brigham Minerals uses the “if-converted”
Income Taxes	Income Taxes Brigham Minerals accounts for income taxes using the asset and liability method. 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 bases. Deferred tax assets and liabilities are calculated by applying existing tax laws and the rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. On the date of our IPO, Brigham Minerals recognized a tax benefit of approximately $13.7 million, associated with the differences between the tax and book basis of the investment in Brigham Resources, LLC, as discussed in “Note 11—Income Taxes”.	Income Taxes Brigham Minerals accounts for income taxes using the asset and liability method. 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 bases. Deferred tax assets and liabilities are calculated by applying existing tax laws and the rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. Brigham Minerals was not subject to federal income taxes prior to the July 2018 restructuring.
Temporary Equity	Temporary Equity Brigham Minerals accounts for the Original Owners’ 56.7% interest in Brigham LLC as temporary equity as a result of certain redemption rights held by the Original Owners as discussed in “Note 9—Temporary Equity.” As such, the Company adjusts temporary equity to its maximum redemption amount at the balance sheet date, if higher than the carrying amount. The redemption amount is based on the 10-day paid-in
Recently Issued Accounting Standards	Recently Issued Accounting Standards Brigham Minerals’ status as an emerging growth company under Section 107 of the JOBS Act permits it to delay the adoption of certain accounting standards until those standards would otherwise apply to private companies. Brigham Minerals is choosing to take advantage of this extended transition period and, as a result, Brigham Minerals will comply with new or revised accounting standards on the relevant dates on which adoption of such standards is required for private companies. In January 2017, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2017-01, 2017-01 In November 2016, the FASB issued ASU 2016-18, 2016-18 In February 2016, the FASB issued ASU 2016-02, 2016-02 2018-01, 2018-11 In May 2014, the FASB issued ASU 2014-09, 932-605, Activities-Oil Gas-Revenue We completed our review of revenue contracts covering our material revenue streams, designed to evaluate any potential changes in revenue recognition upon adoption of the new standard, and concluded that the implementation of the new standard will not have a material impact on our condensed consolidated and combined financial statements. We also evaluated the information technology and internal control changes that may be required to implement the new standard based on the results of our contract review process.	Recently Issued Accounting Standards Brigham Minerals’ status as an emerging growth company under Section 107 of the JOBS Act permits it to delay the adoption of certain accounting standards until those standards would otherwise apply to private companies. Brigham Minerals is choosing to take advantage of this extended transition period and, as a result, it will comply with new or revised accounting standards on the relevant dates on which adoption of such standards is required for private companies. In January 2017, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2017-01, ASU-2017-01 In November 2016, the FASB issued ASU 2016-18, In February 2016, the FASB issued ASU 2016-02, 2018-11, Targeted In January 2016, the FASB issued ASU 2016-01, available-for-sale In May, 2014, the FASB issued ASU 2014-09, 932-605, Activities-Oil Gas-Revenue 2014-09 one-year 2015-14,
Emerging Growth Company Status		Emerging Growth Company Status As a company with less than $1.07 billion in revenues during its last fiscal year, Brigham Minerals qualifies as an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”). An emerging growth company may take advantage of specified reduced reporting and other regulatory requirements. Brigham Minerals will remain an “emerging growth company” until as late as the last day of Brigham Minerals’ 2023 fiscal year, or until the earliest of (i) the last day of the fiscal year in which Brigham Minerals has $1.07 billion or more in annual revenues; (ii) the date on which Brigham Minerals becomes a “large accelerated filer” (the fiscal year-end non-affiliates non-convertible As a result of Brigham Minerals’ election to avail itself of certain provisions of the JOBS Act, the information that Brigham Minerals provides may be different than the information provided by other public companies.
Cash and Cash Equivalents		Cash and Cash Equivalents Brigham Minerals considers all highly liquid investments with an original maturity of three months or less to be cash equivalents. Restricted Cash Restricted cash consists of funds that are contractually restricted as to usage or withdrawal and have been presented separately from cash and cash equivalents on our consolidated and combined balance sheets. At December 31, 2018, Brigham Minerals had $0.4 million restricted for distribution to existing owners.
Receivables		Receivables Receivables consist of royalty income due from operators for oil and gas sales to purchasers. Those purchasers remit payment for production to the operator of our properties and the operator, in turn, remits payment to us. Receivables from third parties for which we did not receive actual information, either due to timing delays or due to the unavailability of data at the time when revenues are recognized, are estimated. Receivables from new wells turned in line for which we did not receive payment at the time revenues are recognized are estimated and recognized only when public production information is available. Volume estimates are based upon historical actual data if available or, otherwise, on engineering estimates. Pricing estimates are based upon actual prices realized in an area by adjusting the market price for the average basis differential from market on a basin-by-basin Brigham Minerals routinely reviews outstanding balances, assesses the financial strength of its customers and records a reserve for amounts not expected to be fully recovered. We recorded an allowance for doubtful accounts of $0.4 million for the year ended December 31, 2018, which was included in general and administrative expenses. We did not record any allowance for doubtful accounts for the year ended December 31, 2017.
Concentration of Credit Risk and Significant Customers		Concentration of Credit Risk and Significant Customers Financial instruments that potentially subject Brigham Minerals to concentrations of credit risk consist of cash, accounts receivable, commodity derivative financial instruments and its prior revolving credit facility. Cash and cash equivalents are held in a few financial institutions in amounts that may, at times, exceed federally insured limits. However, no losses have been incurred and management believes that counterparty risks are minimal based on the reputation and history of the institutions selected. Accounts receivable are concentrated among operators and purchasers engaged in the energy industry within the United States. Management periodically assesses the financial condition of these entities and institutions and considers any possible credit risk to be minimal. Concentrations of oil and gas sales to significant customers (operators) are presented in the table below. For the year ended December 31, 2018 2017 Anadarko Petroleum Corp. 15 % — Continental Resources, Inc. 10 % 10 % Noble Energy, Inc. 9 % 13 % Management does not believe that the loss of any customer would have a long-term material adverse effect on our financial position or the results of operations.
Investments in Equity Securities		Investments in Equity Securities Brigham Minerals classifies its equity securities as available-for-sale, available-for-sale available-for-sale
Financial Instruments		Financial Instruments Brigham Minerals’ financial instruments consist of cash and cash equivalents, receivables, payables, derivative assets and liabilities, investments in equity securities and long-term debt. The carrying amounts of cash and cash equivalents, receivables and payables approximate fair value due to the highly liquid or short-term nature of these instruments. The equity securities are publicly traded and are valued using quoted market prices. The fair values of Brigham Minerals’ derivative assets and liabilities are based on a third-party industry-standard pricing model using contract terms and prices and assumptions and inputs that are substantially observable in active markets throughout the full term of the instruments, including forward oil and gas price curves, discount rates, volatility factors and credit risk adjustments. The carrying amount of long-term debt associated with borrowings outstanding under Brigham Minerals’ term loan facility and prior revolving credit facility approximates fair value as borrowings bear interest at variable market rates. See “Note 6—Derivative Instruments,” “Note 5—Fair Value Measurements” and “Note 7—Long-Term Debt.”
Derivative Instruments		Derivative Instruments In the normal course of business, Brigham Minerals is exposed to certain risks, including changes in the prices of oil, natural gas and NGLs and interest rates. Brigham Minerals has occasionally entered into derivative contracts to manage its exposure to these risks. Brigham Minerals’ risk management activity is generally accomplished through over-the-counter
Oil and Gas Properties		Oil and Gas Properties Brigham Minerals uses the full cost method of accounting for its oil and natural gas properties. Under this method, all acquisition costs incurred for the purpose of acquiring mineral and royalty interests and certain related employee costs are capitalized into a full cost pool. Costs associated with general corporate activities are expensed in the period incurred. Capitalized costs are amortized using the units-of-production Costs associated with unevaluated properties are excluded from the amortizable cost base until a determination has been made as to the existence of proved reserves. Unevaluated properties are reviewed periodically to determine whether the costs incurred should be reclassified to the full cost pool and subjected to amortization. The costs associated with unevaluated properties primarily consist of acquisition costs and capitalized general and administrative costs. Unevaluated properties are assessed for impairment on an individual basis or as a group if properties are individually insignificant. The assessment includes consideration of the following factors, among others: expectation of future drilling activity; past drilling results and activity; geological and geophysical evaluations; the assignment of proved reserves; and the economic viability of development if proved reserves are assigned. During any period in which these factors indicate an impairment, the cumulative acquisition costs incurred to date for such property are transferred to the full cost pool and are then subject to amortization. There was no impairment recorded for unevaluated properties in 2018 and 2017. Sales and abandonments of oil and natural gas properties being amortized are accounted for as adjustments to the full cost pool, with no gain or loss recognized unless the adjustments would significantly alter the relationship between capitalized costs and proved reserves. A significant alteration would not ordinarily be expected to occur upon the sale of reserves involving less than 25% of the reserve quantities of a cost center. Natural gas volumes are converted to barrels of oil equivalent (Boe) at the rate of six thousand cubic feet (Mcf) of natural gas to one barrel (Bbl) of oil. This convention is not an equivalent price basis and there may be a large difference in value between an equivalent volume of oil versus an equivalent volume of natural gas. Under the full cost method of accounting, total capitalized costs of oil and natural gas properties, net of accumulated depletion, may not exceed an amount equal to the present value of future net revenues from proved reserves, discounted at 10% per annum, plus the lower of cost or fair value of unevaluated properties (the ceiling limitation). A ceiling limitation is calculated at each reporting period. If total capitalized costs, net of accumulated DD&A are greater than the ceiling limitation, a write-down or impairment of the full cost pool is required. A write-down of the carrying value of the full cost pool is a noncash charge that reduces earnings and impacts equity in the period of occurrence and typically results in lower depletion expense in future periods. Once incurred, a write-down cannot be reversed at a later date. The ceiling limitation calculation is prepared using the 12-month As of December 31, 2018 and 2017, the full cost ceiling value of our reserves was calculated based on the average posted first-day-of-the write-off
Revenue Recognition		Revenue Recognition Royalty interests represent the right to receive revenues (oil and natural gas sales), less production and operating taxes and post-production costs. Revenue is recorded when title passes to the purchaser. Royalty interests have no rights or obligations to explore, develop or operate the property and do not incur any of the costs of exploration, development and operation of the property. Brigham Minerals recognizes revenue when it is realized or realizable and earned. Revenues are considered realized or realizable and earned when: (i) persuasive evidence of an arrangement exists, (ii) delivery has occurred or services have been rendered, (iii) the seller’s price to the buyer is fixed or determinable, and (iv) collectability is reasonably assured. Pricing of oil, natural gas and NGL sales from Brigham Minerals’ properties is primarily determined by supply and demand in the marketplace and can fluctuate considerably. Brigham Minerals has no involvement or operational control over the volumes and method of sale of oil, natural gas and NGLs produced and sold from its properties. To the extent actual volumes and prices of oil, natural gas and NGLs are unavailable for a given reporting period because of timing or information not received from third parties, the expected sales volume and prices for these properties are estimated and recorded within accounts receivable in the accompanying consolidated and combined balance sheet. Receivables from new wells turned in line for which we did not receive payment at the time revenues are recognized are estimated and recognized only when public production information is available. Differences between estimates of revenue and the actual amounts are adjusted and recorded in the period that the actual amounts are known. Brigham Minerals earns lease bonus revenues and lease extension revenues (collectively referred to as “lease bonus revenue”) from leasing mineral interests to exploration and production companies in exchange for a royalty interest. Lease bonus revenues are recognized when received, at which time Brigham Minerals gives up the right to develop the land itself or to lease it to another party.
Debt Issuance Cost		Debt Issuance Cost As of December 31, 2018, capitalized debt issuance costs of $4.3 million, net of accumulated amortization of $0.3 million, was included in long-term debt on the consolidated and combined balance sheets. As of December 31, 2017, capitalized debt issuance costs of $0.4 million, net of accumulated amortization of $0.3 million, was included in other assets on the consolidated and combined balance sheets. Debt issuance costs were incurred in connection with establishing and amending credit facilities for Brigham Minerals and are amortized over the term of the credit facilities using the effective interest rate method. Amortization expense for debt issue costs was $0.7 million and $0.2 million, for the years ended December 31, 2018 and 2017. On July 27, 2018, the prior revolving credit facility was terminated and replaced with a new term loan facility. See further discussion in “Note 7—Long-Term Debt” in our consolidated financial statements.

Oil and Gas Properties (Tables)

Oil and Gas Properties (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Extractive Industries [Abstract]
Schedule of Oil and Gas Properties	Oil and gas properties as of the dates shown consisted of the following: September 30, December 31, (In thousands) Oil and gas properties, at cost, using the full cost method of accounting: Unevaluated property $ 276,888 $ 228,151 Evaluated property 423,884 289,851 Total oil and gas properties, at cost 700,772 518,002 Less accumulated depreciation, depletion, and amortization (49,488 ) (27,628 ) Total oil and gas properties, net $ 651,284 $ 490,374	Oil and gas properties consisted of the following: Years Ended December 31, 2018 2017 (in thousands, except per Oil and gas properties, at cost, using the full cost method of accounting: Not subject to depletion $ 228,151 $ 168,691 Subject to depletion 289,851 152,354 Total oil and gas properties, at cost 518,002 321,045 Less accumulated depreciation, depletion, and amortization (27,628 ) (14,210 ) Total oil and gas properties, net $ 490,374 $ 306,835 Full cost pool depletion per barrel of oil equivalent $ 9.38 $ 7.25 Costs not subject to depletion at December 31, 2018 are as follows, by the year in which such costs were incurred (in thousands) : Total 2018 2017 Prior Property Acquisition costs $ 228,151 $ 76,793 $ 68,939 $ 82,419

Acquisitions and Divestitures (

Acquisitions and Divestitures (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Schedule in Costs were Incurred in Oil and Natural Gas	During the nine months ended September 30, 2019 and 2018, Brigham Minerals entered into a number of acquisitions of mineral and royalty interests from various sellers in Texas, Oklahoma, Colorado, New Mexico, and North Dakota, as reflected in the tables below. The change in the oil and natural gas property balance is comprised of payments for acquisitions of minerals, land brokerage costs and capitalized general and administrative expenses that were funded with borrowings under its Owl Rock credit facility, the new revolving credit facility and proceeds from the IPO. Assets Acquired Cash Evaluated Unevaluated (In thousands) Quarter Ended March 31, 2019 $ 27,929 $ 13,403 $ 41,332 Quarter Ended June 30, 2019 25,050 14,925 39,975 Quarter Ended September 30, 2019 63,787 35,251 99,038 Total Acquired $ 116,766 $ 63,579 $ 180,345 Assets Acquired Cash Evaluated Unevaluated (In thousands) Quarter Ended March 31, 2018 $ 14,132 $ 11,462 $ 25,594 Quarter Ended June 30, 2018 44,706 34,711 79,417 Quarter Ended September 30, 2018 39,099 19,873 58,972 Total Acquired $ 97,937 $ 66,046 $ 163,983	The following costs were incurred in oil and natural gas producing activities: For the Year Ended 2018 2017 (in thousands) Acquisition of properties Unevaluated $ 59,460 $ 50,224 Evaluated 137,496 51,862 Total $ 196,956 $ 102,086
Series of Individually Immaterial Business Acquisitions [Member]
Schedule in Costs were Incurred in Oil and Natural Gas		During the twelve months ended December 31, 2018, Brigham Minerals entered into a number of individually insignificant acquisitions of mineral and royalty interests from various sellers in Texas, Oklahoma and North Dakota, as reflected in the table below. The change in the oil and natural gas property balance is comprised of individually insignificant payments for acquisitions of minerals, land brokerage costs and capitalized general and administrative expenses that were funded with capital contributions and borrowings under our prior revolving credit facility and our new term loan facility. Assets Acquired Consideration Paid Evaluated Unevaluated Cash (in thousands) Quarter Ended March 31, 2018 $ 14,132 $ 11,462 $ 25,594 Quarter Ended June 30, 2018 21,903 16,558 38,461 Quarter Ended Sept 30, 2018 22,982 13,946 36,928 Quarter Ended Dec 31, 2018 15,319 13,879 29,198 Total Acquired $ 74,336 $ 55,845 $ 130,181

Derivative Instruments (Tables)

Derivative Instruments (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments	As of September 30, 2019, Brigham Minerals had certain WTI fixed price swap contracts based on the NYMEX futures index. The fair values, notional quantities and weighted-average swap prices of these contracts as of September 30, 2019, are summarized in the table below. Description & Production Period Volume Weighted Average Swap Price Fair Value Asset/ (Bbl) ($/Bbl) (In thousands) Crude Oil Swaps: October 2019—December 2019 15,000 $ 63.61 $ 146 The following table summarizes Brigham Minerals’ gain (loss) on derivative instruments, net on its condensed consolidated and combined statement of operations for the three and nine months ended September 30, 2019 and 2018 (in thousands): Three Months Ended Nine Months Ended 2019 2018 2019 2018 (In thousands) Realized gain (loss) $ 119 $ (306 ) $ 356 $ (670 ) Unrealized gain (loss) (28 ) 26 (877 ) (524 ) Combined—realized/unrealized gain (loss) $ 91 $ (280 ) $ (521 ) $ (1,194 )	The fair values, notional quantities and weighted-average swap prices of these contracts as of December 31, 2018 , are summarized in the table below. Description & Production Period Volume Weighted Fair Value (Bbl) ($/Bbl) (in thousands) Crude Oil Swaps: January 2019-March 2019(1) 20,000 $ 64.60 $ 358 April 2019-June 2019 15,000 $ 63.61 $ 246 July 2019-September 2019 15,000 $ 63.61 $ 231 October 2019-December 2019 15,000 $ 63.61 $ 222 Total 65,000 $ 63.91 $ 1,057 (1) Includes swaps for 5,000 Bbl valued as an asset of $0.1 million that matured on Dec 31, 2018 and will be settled in January, 2019.
Offsetting Liabilities	The following table summarizes the location and fair value of its derivative instruments as of September 30, 2019 and December 31, 2018 (in thousands): Derivative Instruments Balance Sheet Classification Gross Amount Less Group Net Amount As of September 30, 2019 Derivative assets: Commodity swaps Current derivative assets $ 146 $ — $ 146 As of December 31, 2018 Derivative assets: Commodity swaps Current derivative assets $ 1,057 $ — $ 1,057	The following table summarizes the location and fair value of our derivative instruments as of December 31, 2018 and December 31, 2017 (in thousands): Derivative Instruments Balance Sheet Classification Gross Amount Less Group Net Amount (In thousands) As of December 31, 2018 Derivative assets: Commodity swaps Current derivative assets $ 1,057 $ — $ 1,057 As of December 31, 2017 Derivative liabilities: Commodity swaps Current derivative liabilities $ 121 $ — $ 121

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	Our financial assets and liabilities that were accounted for at fair value on a recurring basis at September 30, 2019 and December 31, 2018 are as follows: September 30, 2019 Level 1 Level 2 Level 3 Total (In thousands) Assets—commodity derivative instruments $ — $ 146 $ — $ 146 December 31, 2018 Level 1 Level 2 Level 3 Total (In thousands) Assets—commodity derivative instruments $ — $ 1,057 $ — $ 1,057	Our financial assets and liabilities that were accounted for at fair value on a recurring basis at December 31, 2018 and December 31, 2017 are as follows (in thousands): December 31, 2018 Level 1 Level 2 Level 3 Total Assets-commodity derivative instruments $ — $ 1,057 $ — $ 1,057 December 31, 2017 Level 1 Level 2 Level 3 Total Assets-investment in equity securities $ 4,105 $ — $ — $ 4,105 Liabilities-commodity derivative instruments $ — $ 121 $ — $ 121

Shareholders' and Members' Eq_2

Shareholders' and Members' Equity (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Federal Home Loan Banks [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table reflects the allocation of net income (loss) to common stockholders and EPS computations for the period indicated based on a weighted average number of common stock outstanding for the period: Three Months Ended Nine Months Ended 2019 2018 2019 2018 (In thousands, except per share data) Basic EPS Numerator: Basic net income attributable to Brigham Minerals, Inc. shareholders $ 3,146 $ — $ 1,824 $ — Less: net income attributable to Brigham Minerals, Inc. shareholders pre-IPO — — (848 ) — Basic net income attributable to Brigham Minerals, Inc. shareholders post-IPO $ 3,146 $ — $ 976 $ — Denominator: Basic weighted average shares outstanding 21,838 — 13,299 — Basic EPS attributable to Brigham Minerals, Inc. shareholders $ 0.14 $ — $ 0.07 $ — Diluted EPS Numerator: Basic net income attributable to Brigham Minerals, Inc. shareholders post-IPO 3,146 — 976 — Effect of time-based restricted stock awards — — — — Diluted net income attributable to Brigham Minerals, Inc. shareholders $ 3,146 $ — $ 976 $ — Denominator: Basic weighted average shares outstanding 21,838 — 13,299 — Effect of dilutive securities: Time-based restricted stock awards 88 — 47 — Diluted weighted average shares outstanding 21,926 — 13,346 — Diluted EPS attributable to Brigham Minerals, Inc. shareholders $ 0.14 $ — $ 0.07 $ —
Restricted Units Issued and Outstanding		A summary of the Restricted Units issued and outstanding is as follows: Series M Units M-1 M-2 M-3 M-4 Total Beginning balance 7,520 7,520 7,520 7,520 30,080 2017 issuances — — — — — 2017 forfeitures — — — — — Outstanding at December 31, 2017 7,520 7,520 7,520 7,520 30,080 2018 issuances 1,030 1,030 1,030 1,030 4,120 2018 forfeitures — — — — — Outstanding at December 31, 2018 8,550 8,550 8,550 8,550 34,200 Series Z Units Z-1 Z-2 Z-3 Z-4 Total Beginning balance 4,328 4,328 4,328 4,328 17,312 2017 issuances — — — — — 2017 forfeitures (15 ) (15 ) (15 ) (15 ) (60 ) Outstanding at December 31, 2017 4,313 4,313 4,313 4,313 17,252 2018 issuances 485 485 485 485 1,940 2018 forfeitures (105 ) (105 ) (105 ) (105 ) (420 ) Outstanding at December 31, 2018 4,693 4,693 4,693 4,693 18,772

Temporary Equity (Tables)

Temporary Equity (Tables)	9 Months Ended
	Sep. 30, 2019
Temporary Equity Disclosure [Abstract]
Temporary Equity	redemption amount. From the date of the IPO through September 30, 2019, the Company recorded adjustments to the value of temporary equity as presented in the table below: Temporary (In thousands) Balance—April 17, 2019 $ 518,000 Net loss attribution post-IPO (2,941 ) Distribution of pre-IPO (441 ) Adjustment of temporary equity to redemption amount(2) 97,344 Balance—June 30, 2019 $ 611,962 Net income attribution 3Q, 2019 $ 5,318 Distribution to non-controlling (9,497 ) Adjustment of temporary equity to redemption amount(3) (3,797 ) Balance—September 30, 2019 $ 603,986 (1) Based on 28,777,802 shares of Class B common stock outstanding and Class A share price of $18.00 at IPO date. (2) Based on 28,777,802 shares of Class B common stock outstanding and Class A share 10-day (3) Based on 28,777,802 shares of Class B common stock outstanding and Class A share 10-day

Share-Based Compensation (Table

Share-Based Compensation (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Restricted Incentive Unit Activity	A summary of the Incentive Unit activity for the nine months ended September 30, 2019 is as follows: Incentive Units Number of Grant-date (In thousands) Outstanding—January 1, 2019 3,272 $ 1.49 Vested (3,058 ) 0.88 Outstanding—September 30, 2019 215 $ 10.04 A summary of the Incentive Unit activity for the nine months ended September 30, 2018 is as follows: Incentive Units Number of Grant-date (In thousands) Outstanding—January 1, 2018 2,918 $ 0.45 Granted 354 10.04 Vested — — Outstanding—September 30, 2018 3,272 $ 1.49
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions	Brigham LLC used the Black-Scholes option pricing valuation model with the following weighted-average assumptions: Incentive Units 2018 2015 2013 Expected volatility 28 % 33 % 40 % Expected dividend yield — — — Expected term (in years) 0.7 3.7 6.2 Risk-free interest rates 2.45 % 1.07 % 0.94 % Weighted-average grant date fair value per Incentive Unit $ 10.04 $ 0.03 $ 1.51 Performance- Expected dividend yield 8.1 % Risk-free interest rate 2.3 % Volatility 30.0 %	Brigham Resources used the Black-Scholes option pricing valuation model with the following weighted-average assumptions: Incentive Units 2018 2015 2013 Expected volatility 28 % 33 % 40 % Expected dividend yield — — — Expected term (in years) 0.7 3.7 6.2 Risk-free interest rates 2.45 % 1.07 % 0.94 % Weighted-average grant date fair value per Incentive Unit $ 10.04 $ 0.03 $ 1.51 Total grant date fair value (in thousands) $ 3,558 $ 55 $ 1,248
Schedule of Share-Based Compensation Expense	Share-based compensation cost recorded for each type of share-based compensation award, was as follows for the periods indicated: Three Months Ended Nine Months Ended 2019 2018 2019 2018 (In thousands) Incentive Units(1)(3) $ 559 $ — $ 2,726 $ — RSAs(2)(3) 285 — 3,741 — RSUs(3) 1,686 — 2,932 — PSUs(4) 622 — 1,258 — Capitalized share-based compensation(5) (1,415 ) — (2,425 ) — Total share-based compensation expense $ 1,737 $ — $ 8,232 $ — (1) Includes a cumulative effect adjustment to share-based compensation cost of $2.0 million pertaining to the period from the grant date through the IPO date. No compensation expense was recorded prior to the IPO because the IPO was not considered probable. (2) Includes $3.2 million recorded at grant date of April 23, 2019, associated with 152,742 RSAs, which vested immediately. (3) Share-based compensation expense relating to Incentive Units, restricted stock awards and time-based restricted stock units with ratable vesting is recognized on a straight-line basis over the requisite service period for the entire award. (4) Share-based compensation expense relating to PSUs with cliff-vesting is recognized on a straight-line basis over the performance period for the entire award. (5) During the three and nine months ended September 30, 2019, Brigham Minerals capitalized $1.4 million and $2.4 million, respectively, of the share-based compensation to unevaluated property on its balance sheet. Future Share-Based Compensation Expense The following table reflects the future share-based compensation expense to be recorded for the share-based compensation awards that were outstanding at September 30, 2019, a portion of which will be capitalized: Incentive RSAs RSUs PSUs Total (In thousands) 2019 $ 178 $ 285 $ 1,686 $ 723 $ 2,872 2020 712 1,129 4,217 2,869 $ 8,927 2021 712 1,129 3,891 2,868 $ 8,600 2022 533 350 — — $ 883 Total $ 2,135 $ 2,893 $ 9,794 $ 6,460 $ 21,282

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Lease Commitments	Future minimum lease commitments under noncancelable operating leases at September 30, 2019 are presented below: Commitment (In thousands) Year 2019 $ 160 2020 970 2021 1,275 2022 1,312 2023 1,349 Thereafter 5,020 Total $ 10,086	Future minimum lease commitments under noncancelable operating leases at December 31, 2018 are presented below (in thousands): Year Commitment 2019 $ 538 2020 654 2021 672 2022 689 2023 474 2024 111 Total $ 3,138

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Summary of Concentration Of Oil and Gas Sales to Significant Customers	Concentrations of oil and gas sales to significant customers (operators) are presented in the table below. For the year ended December 31, 2018 2017 Anadarko Petroleum Corp. 15 % — Continental Resources, Inc. 10 % 10 % Noble Energy, Inc. 9 % 13 %

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	During the year ended December 31, 2018, Brigham Minerals recorded current tax expense of $0.1 million and deferred tax expense of $0.2 million. During the year ended December 31, 2017, Brigham Minerals recorded current tax expense of $0.7 million and deferred tax expense of $0.3 million as indicated in the table below (in thousands): 2018 2017 State Income Tax Current (benefit)/expense (23 ) 713 Deferred (benefit)/expense (138 ) 295 Federal Income Tax Current expense 114 — Deferred expense 374 — Totals: 327 1,008 Total current income taxes 91 713 Total deferred income taxes 236 295 Totals: 327 1,008 The following table reconciles the income tax provision with income tax expense at the federal statutory rate for the periods indicated (in thousands): 2018 2017 Income before income taxes 33,142 116,620 Less: income before income taxes attributable to predecessor 30,805 116,620 Income before income taxes attributable to shareholders 2,337 — Income tax at the federal statutory rate 491 — State income taxes, net of federal benefit (150 ) 1,008 Percentage depletion in excess of basis (14 ) — Total income tax provision 327 1,008
Schedule of Deferred Tax Assets and Liabilities	Brigham Minerals had $3.7 million and $0.4 million recorded as deferred tax liability at December 31, 2018 and 2017, respectively. The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities were are follows (in thousands): 2018 2017 Noncurrent: Deferred tax assets: — — Total noncurrent deferred tax assets: — — Deferred tax liabilities: Oil and gas properties (208 ) (391 ) Investment in subsidiary (3,476 ) — Total noncurrent deferred tax liabilities (3,684 ) (391 ) Net noncurrent deferred tax liabilities (3,684 ) (391 )

Quarterly Financial Informati_2

Quarterly Financial Information-Unaudited (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	2018 Quarters Total Fourth Third Second First Total revenues $ 67,264 $ 17,591 $ 18,701 $ 16,889 $ 14,083 Income from operations $ 39,231 $ 8,732 $ 11,716 $ 10,564 $ 8,219 Net Income $ 32,815 $ 7,114 $ 8,153 $ 9,351 $ 8,197 2017 Quarters Total Fourth Third Second First Total revenues $ 40,908 $ 12,404 $ 8,380 $ 8,201 $ 11,923 Income from operations $ 121,214 $ 7,697 $ 5,044 $ 5,127 $ 103,346 Net income $ 115,612 $ 7,234 $ 654 $ 5,024 $ 102,700

Reserve and Related Financial_2

Reserve and Related Financial Data (SMOG)-Unaudited (Tables)	12 Months Ended
	Dec. 31, 2018
Text Block [Abstract]
Schedule of Reserve Quantity of Resources	Crude Oil Natural Gas NGL Total Proved reserve quantities, December 31, 2016 7,174 22,991 2,356 13,363 Sales of minerals-in-place (1,291 ) (815 ) (200 ) (1,627 ) Extentions and discoveries 1,548 6,012 709 3,259 Acquisitions 2,141 9,380 1,116 4,820 Revisions of previous estimates (394 ) 2,601 108 147 Production (454 ) (1,768 ) (109 ) (858 ) Proved reserve quantities, December 31, 2017 8,724 38,401 3,980 19,104 Sales of minerals-in-place — — — — Extentions and discoveries 1,765 5,285 562 3,208 Acquisitions 3,669 13,862 1,374 7,354 Revisions of previous estimates (390 ) (3,245 ) (577 ) (1,508 ) Production (777 ) (2,507 ) (222 ) (1,417 ) Proved reserve quantities, December 31, 2018 12,991 51,796 5,117 26,741 Proved developed reserve quantities: December 31, 2017 2,804 13,028 1,185 6,160 December 31, 2018 6,067 21,735 1,898 11,588 Proved undeveloped reserve quantities: December 31, 2017 5,920 25,373 2,795 12,944 December 31, 2018 6,924 30,061 3,219 15,153
Schedule of Future Cash Flows of Oil and Gas Reserves	The following summary sets forth the future net cash flows relating to proved oil and gas reserves based on the standardized measure prescribed in ASC Topic 932: For the Year Ended 2018 2017 (in thousands) Future crude oil, natural gas and NGL sales $ 1,049,141 $ 595,874 Future severance tax and ad valorem taxes (70,248 ) (40,225 ) Future income tax expense (144,421 ) (1,151 ) Future net cash flows 834,472 554,498 10% annual discount (391,013 ) (238,030 ) Standardized measure of discounted future net cash flows $ 443,459 $ 316,468
Schedule of Cost Used in Determining of Standardized Measure	The following prices were used in the determination of standardized measure: For the Year Ended 2018 2017 Oil (per Bbl) $ 61.31 $ 47.80 Natural gas (per MMBtu) 2.51 2.74 NGLs (per Bbl) 23.98 18.56
Schedule of Change in Standardized Measure of Discounted Future net Cash Flows	The principal sources of change in the standardized measure of discounted future net cash flows are: For the Year Ended 2018 2017 (in thousands) Standardized measure of discounted future net cash flows, beginning of the year $ 316,468 $ 185,752 Changes in the year resulting from: Sales, less production costs and taxes (52,278 ) (26,711 ) Revisions of previous quantity estimates (22,942 ) 4,894 Extensions, discoveries and other additions 71,668 56,511 Net change in prices and production costs 71,770 30,565 Accretion of discount 31,713 18,612 Purchase of reserves in place 148,580 79,190 Divestitures of reserves in place — (26,742 ) Net change in income Tax (75,369 ) (298 ) Timing differences and other (46,151 ) (5,305 ) Standardized measure of discounted future net cash flows, end of the year $ 443,459 $ 316,468
Aggregate Amounts of Costs Capitalized for Oil and Natural Gas Producing Activities	The aggregate amounts of costs capitalized for oil and natural gas producing activities and related aggregate amounts of accumulated depletion follow: For the Year Ended 2018 2017 (in thousands) Oil and gas properties, at cost, using full cost method of accounting: Not subject to depletion $ 228,151 $ 168,691 Subject to depletion 289,851 152,354 Total oil and gas properties, at cost 518,002 321,045 Less accumulated depreciation, depletion and amortization (27,628 ) (14,210 ) Total oil and gas properties, net $ 490,374 $ 306,835

Business and Basis of Presentat

Business and Basis of Presentation - Additional Information (Detail)

May 07, 2019USD ($)

Apr. 17, 2019USD ($)$ / sharesshares

Jun. 30, 2019USD ($)

Sep. 30, 2019USD ($)Segment

Sep. 30, 2018USD ($)

Dec. 31, 2018USD ($)

Dec. 31, 2017USD ($)

Sep. 30, 2019USD ($)

Nov. 07, 2019USD ($)

May 31, 2019USD ($)

May 16, 2019USD ($)

Jul. 27, 2018USD ($)

Jul. 16, 2018

Schedule of Equity Method Investments [Line Items]

Unamortized debt issuance costs written off

$ 4,000,000

Prepayment premium paid

$ 2,091,000

Loss on extinguished of debt

(6,900,000)

(6,933,000)

Capitalized issuance costs

5,100,000

$ 3,600,000

$ 8,700,000

Capitalized share-based compensation expense

2,425,000

Stock compensation expense

8,200,000

Share based compensation expense

$ 21,300,000

$ 21,282,000

Number of operating segments | Segment

1

Equity securities distributed

$ (3,313,000)

3,313,000

$ (20,092,000)

(Gain) on sale of oil and gas properties

94,551,000

Term Loan Facility

Schedule of Equity Method Investments [Line Items]

Long-term line of credit

200,000,000

175,000,000

Prepayment premium paid

2,100,000

Legal fees paid

$ 800,000

Line of credit, borrowing base

$ 125,000,000

Existing Owners of Brigham Minerals

Schedule of Equity Method Investments [Line Items]

Sale of stock, ownership percentage

10.50%

Investors in Offering

Schedule of Equity Method Investments [Line Items]

Sale of stock, ownership percentage

32.80%

Initial Public Offering

Schedule of Equity Method Investments [Line Items]

Consideration received

$ 273,300,000

$ 273,300,000

Class A Common Stock | Existing Owners of Brigham Minerals

Schedule of Equity Method Investments [Line Items]

Sale of stock, ownership percentage

24.20%

Number of shares owned (in shares) | shares

5,322,198

Class A Common Stock | Investors in Offering

Schedule of Equity Method Investments [Line Items]

Sale of stock, ownership percentage

75.80%

Class A Common Stock | Initial Public Offering

Schedule of Equity Method Investments [Line Items]

Sale of stock, number of shares issued (in shares) | shares

16,675,000

Share price (in dollars per share) | $ / shares

$ 18

Class B Common Stock

Schedule of Equity Method Investments [Line Items]

Share price (in dollars per share) | $ / shares

$ 18

Class B Common Stock | Existing Owners of Brigham Minerals

Schedule of Equity Method Investments [Line Items]

Sale of stock, ownership percentage

56.70%

Subsequent Event | New Revolving Credit Facility

Schedule of Equity Method Investments [Line Items]

Line of credit, borrowing base

$ 150,000,000

Previously Reported

Schedule of Equity Method Investments [Line Items]

Equity securities distributed

$ 37,988,000

Brigham Resources, LLC

Schedule of Equity Method Investments [Line Items]

Percentage of voting rights owned

100.00%

Ownership percentage by subsidiary

43.30%

Cash collateral posted for existing swap contracts

$ 1,600,000

$ 1,600,000

$ 1,400,000

Brigham Resources, LLC | New Revolving Credit Facility

Schedule of Equity Method Investments [Line Items]

Long-term line of credit

45,000,000

45,000,000

Line of credit, borrowing base

$ 135,000,000

$ 135,000,000

$ 120,000,000

Brigham Resources, LLC | Existing Owners of Brigham Minerals

Schedule of Equity Method Investments [Line Items]

Sale of stock, ownership percentage

67.20%

Brigham Resources, LLC

Schedule of Equity Method Investments [Line Items]

Equity method investment, ownership percentage

16.50%

Summary of Significant Accounti

Summary of Significant Accounting Policies - Additional Information (Detail) $ in Thousands	Apr. 17, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Jun. 30, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)$ / Barrel$ / Mcf	Dec. 31, 2017USD ($)$ / Barrel$ / Mcf
Debt Instrument [Line Items]
Share based compensation expense						$ 21,300	$ 21,282
Deferred tax asset arising from the IPO	$ 13,700			$ 13,664	$ 13,700
Restricted cash		$ 400							$ 400
Allowance for doubtful accounts		400	$ 0						400	$ 0
Debt issuance costs capitalized		4,300	400						4,300	400
Accumulated amortization debt issuance costs		300	300						300	300
Amortization of debt issuance costs		$ 700	$ 200				$ 354	$ 501	$ 690	$ 121
Existing Owners of Brigham Minerals
Debt Instrument [Line Items]
Sale of stock, ownership percentage	10.50%
Class B Common Stock | Existing Owners of Brigham Minerals
Debt Instrument [Line Items]
Sale of stock, ownership percentage	56.70%
Natural Gas Liquids [Member]
Debt Instrument [Line Items]
Percentage of price variation									22.00%	41.00%
Average product prices | $ / Barrel									23.98	18.56
Oil [Member]
Debt Instrument [Line Items]
Percentage of price variation									19.00%	42.00%
Average product prices | $ / Barrel									61.31	47.80
Gas [Member]
Debt Instrument [Line Items]
Average product prices | $ / Mcf									2.51	2.74
Maximum
Debt Instrument [Line Items]
Percentage of sale reserve									25.00%
Present value of future net revenues from proved reserve									10.00%

Oil and Gas Properties - Schedu

Oil and Gas Properties - Schedule of Oil and Gas Properties (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)$ / Barrel	Dec. 31, 2017USD ($)$ / Barrel	Sep. 30, 2019USD ($)
Oil and gas properties, at cost, using the full cost method of accounting:
Not subject to depletion	$ 228,151	$ 168,691	$ 276,888
Evaluated property	289,851	152,354	423,884
Total oil and gas properties, at cost	518,002	321,045	700,772
Less accumulated depreciation, depletion, and amortization	(27,628)	(14,210)	(49,488)
Oil and gas properties-net	$ 490,374	$ 306,835	$ 651,284
Full cost pool depletion per barrel of oil equivalent | $ / Barrel	9.38	7.25

Oil and Gas Properties - Additi

Oil and Gas Properties - Additional Information (Detail) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019USD ($)$ / Boe	Sep. 30, 2018USD ($)$ / Boe	Sep. 30, 2019USD ($)$ / Boe	Sep. 30, 2018USD ($)$ / Boe	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Extractive Industries [Abstract]
Depletion expense	$ 8.3	$ 3.7	$ 19.9	$ 9.1	$ 13.3	$ 6.2
Average depletion of proved properties (in dollars per Boe) | $ / Boe	11.49	10.17	10.91	9.18
Capitalized costs	$ 2.3	$ 0.6	$ 5	$ 2	$ 2.7	$ 2.1

Acquisitions and Divestitures -

Acquisitions and Divestitures - Schedule of Acquisitions (Details) (Detail) - USD ($) $ in Thousands	3 Months Ended							9 Months Ended		12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Assets acquired, evaluated	$ 63,787	$ 25,050	$ 27,929		$ 39,099	$ 44,706	$ 14,132	$ 116,766	$ 97,937	$ 137,496	$ 51,862
Assets acquired, unevaluated	35,251	14,925	13,403		19,873	34,711	11,462	63,579	66,046	59,460	50,224
Cash consideration paid	$ 99,038	$ 39,975	$ 41,332		58,972	79,417	25,594	$ 180,345	$ 163,983	196,956	$ 102,086
Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Assets acquired, evaluated				$ 15,319	22,982	21,903	14,132			74,336
Assets acquired, unevaluated				13,879	13,946	16,558	11,462			55,845
Cash consideration paid				$ 29,198	$ 36,928	$ 38,461	$ 25,594			$ 130,181

Derivative Instruments - Additi

Derivative Instruments - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	May 31, 2019	Jul. 27, 2018
Derivative [Line Items]
Realized gain (losses) on oil swap contracts	$ 91	$ (280)	$ (521)	$ (1,194)	$ (800)
Unrealized gain (losses) on oil swap contracts					1,200	$ (100)
Brigham Resources, LLC
Derivative [Line Items]
Cash collateral posted for existing swap contracts					$ 1,600		$ 1,600	$ 1,400

Derivative Instruments - Summar

Derivative Instruments - Summary of Notional Amounts of Derivatives (Detail) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019USD ($)$ / bblbbl	Dec. 31, 2018USD ($)$ / Barrelbbl
Derivative [Line Items]
Volume | bbl		65,000
Weighted Average Swap Price | $ / Barrel		63.91
Fair Value Asset/ (Liability) | $		$ 1,057
October 2019 - December 2019
Derivative [Line Items]
Volume | bbl	15,000
Weighted Average Swap Price | $ / bbl	63.61
Fair Value Asset/ (Liability) | $	$ 146
January 2019 - March 2019
Derivative [Line Items]
Volume | bbl		20,000
Weighted Average Swap Price | $ / Barrel		64.60
Fair Value Asset/ (Liability) | $		$ 358
April 2019 - June 2019
Derivative [Line Items]
Volume | bbl		15,000
Weighted Average Swap Price | $ / Barrel		63.61
Fair Value Asset/ (Liability) | $		$ 246
July 2019 - September 2019
Derivative [Line Items]
Volume | bbl		15,000
Weighted Average Swap Price | $ / Barrel		63.61
Fair Value Asset/ (Liability) | $		$ 231
October 2019 - December 2019
Derivative [Line Items]
Volume | bbl		15,000
Weighted Average Swap Price | $ / Barrel		63.61
Fair Value Asset/ (Liability) | $		$ 222
December 2018 - January 2019
Derivative [Line Items]
Volume | bbl		5,000
Fair Value Asset/ (Liability) | $		$ 100

Derivative Instruments - Summ_2

Derivative Instruments - Summary of Location and Fair Value of Derivative Instruments (Detail) - Commodity swaps - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Current derivative assets
Derivatives, Fair Value [Line Items]
Gross Amount Recognized, Assets	$ 146	$ 1,057
Less Group Amount of Offset, Assets	0	0
Net Amount Recognized, Assets	$ 146	$ 1,057
Derivative Liabilities Current
Derivatives, Fair Value [Line Items]
Gross Amount Recognized, Liability			$ 121
Less Group Amount of Offset, Liability			0
Net Amount Recognized, Liability			$ 121

Derivative Instruments - Schedu

Derivative Instruments - Schedule of Gains (Losses) on Derivatives (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Realized Gain (Loss) on Derivatives	$ 119	$ (306)	$ 356	$ (670)
Unrealized Gain (Loss) on Derivatives	(28)	26	(877)	(524)
Derivative, Gain (Loss) on Derivative, Net	$ 91	$ (280)	$ (521)	$ (1,194)	$ (800)

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets-commodity derivative instruments	$ 146	$ 1,057
Assets-investment in equity securities			$ 4,105
Liabilities-commodity derivative instruments			121
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets-commodity derivative instruments	0	0
Assets-investment in equity securities			4,105
Liabilities-commodity derivative instruments			0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets-commodity derivative instruments	146	1,057
Assets-investment in equity securities			0
Liabilities-commodity derivative instruments			121
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets-commodity derivative instruments	$ 0	$ 0
Assets-investment in equity securities			0
Liabilities-commodity derivative instruments			$ 0

Long-Term Debt (Detail)

Long-Term Debt (Detail)

May 16, 2019USD ($)

May 07, 2019USD ($)

Jul. 27, 2018USD ($)

Sep. 30, 2018USD ($)

Sep. 30, 2019USD ($)

Dec. 31, 2018USD ($)

Dec. 31, 2019

Dec. 06, 2019USD ($)

Nov. 07, 2019USD ($)

Jul. 26, 2018USD ($)

Jun. 30, 2018USD ($)

Dec. 31, 2017USD ($)

Debt Instrument [Line Items]

Unamortized debt issuance costs written off

$ 4,000,000

Loss on extinguishment of debt

(6,900,000)

$ (6,933,000)

Prepayment premium paid

2,091,000

Term Loan Facility

Debt Instrument [Line Items]

Line of credit, borrowing base

$ 125,000,000

Prepayment premium paid

2,100,000

Legal fees paid

800,000

Long-term line of credit

$ 200,000,000

$ 175,000,000

Debt instrument, covenant, total net leverage ratio, maximum

2,000,000

5.50

Debt instrument, amortization, quarterly installments, percent

5.00%

Debt instrument, covenant, asset coverage ratio, minimum

1.75

Total net leverage ratio, maximum cash reduction to ratio

$ 25,000,000

Debt instrument, covenant, debt to capitalization ratio, maximum

0.40

Term Loan Facility | Base Rate

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

4.50%

Term Loan Facility | London Interbank Offered Rate (LIBOR)

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

5.50%

Term Loan Facility | London Interbank Offered Rate (LIBOR) | Minimum

Debt Instrument [Line Items]

Interest rate, floor (as a percent)

1.00%

Delayed Draw Term Loan

Debt Instrument [Line Items]

Line of credit, borrowing base

$ 75,000,000

Revolving Credit Facility

Debt Instrument [Line Items]

Line of credit, borrowing base

$ 150,000,000

Line of credit facility available

70,000,000

$ 70,000,000

$ 50,000,000

Unamortized debt issuance costs written off

$ 300,000

Long-term debt outstanding

70,000,000

Debt instrument, covenant, current ratio, minimum

1,000,000

Debt instrument, covenant, total net funded debt to consolidated EBITDA ratio, maximum

4,000,000

Line of credit outstanding

$ 70,000,000

$ 27,000,000

Revolving Credit Facility | Minimum

Debt Instrument [Line Items]

Commitment fee, percentage

0.375%

Revolving Credit Facility | Maximum

Debt Instrument [Line Items]

Commitment fee, percentage

0.50%

Revolving Credit Facility | London Interbank Offered Rate (LIBOR)

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

1.00%

Revolving Credit Facility | London Interbank Offered Rate (LIBOR) | Minimum

Debt Instrument [Line Items]

Applicable margin on variable rate

2.50%

Revolving Credit Facility | London Interbank Offered Rate (LIBOR) | Maximum

Debt Instrument [Line Items]

Applicable margin on variable rate

3.50%

Revolving Credit Facility | Adjusted Base Rate | Minimum

Debt Instrument [Line Items]

Applicable margin on variable rate

1.50%

Revolving Credit Facility | Adjusted Base Rate | Maximum

Debt Instrument [Line Items]

Applicable margin on variable rate

2.50%

Revolving Credit Facility | Federal Funds Effective Swap Rate [Member]

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

0.50%

Revolving Credit Facility | Term Loan Facility

Debt Instrument [Line Items]

Line of credit, borrowing base

$ 10,000,000

Brigham Resources, LLC | New Revolving Credit Facility

Debt Instrument [Line Items]

Line of credit, borrowing base

$ 120,000,000

135,000,000

Line of credit facility available

90,000,000

Long-term line of credit

$ 45,000,000

Debt instrument, covenant, current ratio, minimum

1

Debt instrument, covenant, total net funded debt to consolidated EBITDA ratio, maximum

4

Brigham Resources, LLC | New Revolving Credit Facility | Minimum

Debt Instrument [Line Items]

Commitment fee, percentage

0.375%

Brigham Resources, LLC | New Revolving Credit Facility | Maximum

Debt Instrument [Line Items]

Commitment fee, percentage

0.50%

Brigham Resources, LLC | New Revolving Credit Facility | London Interbank Offered Rate (LIBOR) | Minimum

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

1.75%

Brigham Resources, LLC | New Revolving Credit Facility | London Interbank Offered Rate (LIBOR) | Maximum

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

2.75%

Brigham Resources, LLC | New Revolving Credit Facility | Adjusted Base Rate | Minimum

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

0.75%

Brigham Resources, LLC | New Revolving Credit Facility | Adjusted Base Rate | Maximum

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

1.75%

Subsequent Event | New Revolving Credit Facility

Debt Instrument [Line Items]

Line of credit, borrowing base

$ 150,000,000

Subsequent Event | Brigham Resources, LLC | New Revolving Credit Facility

Debt Instrument [Line Items]

Line of credit outstanding

$ 80,000,000

Scenario, Forecast | Term Loan Facility

Debt Instrument [Line Items]

Debt instrument, covenant, total net leverage ratio, maximum

4

Brigham Operating

Debt Instrument [Line Items]

Long-term debt outstanding

$ 7,000,000

Debt instrument, interest

7.00%

Shareholders and Members Equity

Shareholders and Members Equity - Narrative (Detail)	May 08, 2015$ / sharesshares	Apr. 05, 2013Vote$ / sharesshares	Sep. 30, 2019Voteshares	Dec. 31, 2018USD ($)shares	Dec. 31, 2017USD ($)shares	Dec. 31, 2014shares
Performance-Based Restricted Stock Units
Class of Stock [Line Items]
Shares granted during period (in shares)			753,546
Class A Common Stock
Class of Stock [Line Items]
Common stock outstanding (in shares)			21,997,198
Number of votes per share (vote) | Vote			1
Class B Common Stock
Class of Stock [Line Items]
Common stock outstanding (in shares)			28,777,802
Number of votes per share (vote) | Vote			1
Series A Units
Class of Stock [Line Items]
Units subscriptions to purchase		64,840,000
Units authorized for issuance, price per unit | $ / shares		$ 10
Units subscriptions, purchase period		5 years
Number of votes per unit | Vote		1
Units subscribed, liquidation preference cumulative return in addition to total invested capital		7.00%
Series AZ Common Units
Class of Stock [Line Items]
Units subscriptions to purchase	41,176,471
Units authorized for issuance, price per unit | $ / shares	$ 8.50
Number of votes per unit	1
Units subscribed, liquidation preference cumulative return in addition to total invested capital	7.00%
Units issued				5,411,764	4,352,941
Proceed from issuance of units | $				$ 45,999,995	$ 37,000,002
Series M1 Restricted Units
Class of Stock [Line Items]
Units authorized for issuance			10,000
Units vested				7,726	7,520
Units threshold value | $				$ 0
Series M2 Restricted Units
Class of Stock [Line Items]
Units authorized for issuance			10,000
Units vested				7,726	7,520
Units threshold value | $				$ 2.25
Series M3 Restricted Units
Class of Stock [Line Items]
Units authorized for issuance			10,000
Units vested				7,726	7,520
Units threshold value | $				$ 6.50
Series M4 Restricted Units
Class of Stock [Line Items]
Units authorized for issuance			10,000
Units vested				7,726	7,520
Units threshold value | $				$ 14
Series M Restricted Units [Member]
Class of Stock [Line Items]
Units vested				30,904	30,080
Series Z1 Restricted Units
Class of Stock [Line Items]
Units authorized for issuance			10,000
Units vested				3,808	2,596
Units threshold value | $				$ 0
Series Z2 Restricted Units
Class of Stock [Line Items]
Units authorized for issuance			10,000
Units vested				3,808	2,596
Units threshold value | $				$ 1.91
Series Z3 Restricted Units
Class of Stock [Line Items]
Units authorized for issuance			10,000
Units vested				3,808	2,596
Units threshold value | $				$ 5.53
Series Z4 Restricted Units
Class of Stock [Line Items]
Units authorized for issuance			10,000
Units vested				3,808	2,596
Units threshold value | $				$ 11.90
Series Z Restricted Units
Class of Stock [Line Items]
Units vested				15,232	10,386
Series A-M Units
Class of Stock [Line Items]
Units authorized for issuance, price per unit | $ / shares		$ 10
Units subscribed, liquidation preference cumulative return in addition to total invested capital					7.00%
Units authorized for issuance		460,000
Units issued		160,000				300,000
Units available for issuance		300,000
Units, vested percentage					100.00%
Restricted Equity Units
Class of Stock [Line Items]
Units authorized for issuance			120,000
Units, vested percentage			20.00%
Units, vesting percentage on each of four anniversary			20.00%

Shareholders' and Members' Eq_3

Shareholders' and Members' Equity - Schedule of Earnings per Share, Basic and Diluted (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Numerator:
Basic net income attributable to Brigham Minerals, Inc. shareholders	$ 3,146	$ 891	$ 1,824	$ 891	$ 1,839
Less: net income attributable to Brigham Minerals, Inc. shareholders pre-IPO	0	0	(848)	0
Basic net income attributable to Brigham Minerals, Inc. shareholders post-IPO	$ 3,146	$ 0	$ 976	$ 0
Denominator:
Diluted weighted average shares outstanding (in shares)	21,838	0	13,299	0
Diluted EPS attributable to Brigham Minerals, Inc. stockholders (in dollars per share)	$ 0.14	$ 0	$ 0.07	$ 0
Numerator:
Basic net income attributable to Brigham Minerals, Inc. shareholders post-IPO	$ 3,146	$ 0	$ 976	$ 0
Effect of time-based restricted stock awards	0	0	0	0
Diluted net income attributable to Brigham Minerals, Inc. shareholders	$ 3,146	$ 0	$ 976	$ 0
Denominator:
Basic weighted average shares outstanding (in shares)	21,838	0	13,299	0
Effect of dilutive securities:
Time-based restricted stock awards	88	0	47	0
Diluted weighted average shares outstanding	21,926	0	13,346	0
Diluted EPS attributable to Brigham Minerals, Inc. shareholders	$ 0.14	$ 0	$ 0.07	$ 0

Temporary Equity (Detail)

Temporary Equity (Detail) $ / shares in Units, $ in Thousands	Apr. 17, 2019USD ($)$ / sharesshares	Jun. 30, 2019USD ($)	Sep. 30, 2019USD ($)$ / shares	Sep. 30, 2019USD ($)Vote$ / shares	Jun. 28, 2019$ / shares
Increase (Decrease) in Temporary Equity [Roll Forward]
Beginning balance	$ 518,000	$ 518,000	$ 611,962
Net income (loss)		(2,941)	5,318
Distributions		(441)	(9,497)
Adjustment of temporary equity to redemption amount		97,344	(3,797)
Ending balance		$ 611,962	$ 603,986	$ 603,986
Class B Common Stock
Temporary Equity [Line Items]
Number of votes per share | Vote				1
Increase (Decrease) in Temporary Equity [Roll Forward]
Temporary equity (in shares) | shares	28,777,802
Share price (in dollars per share) | $ / shares	$ 18
Temporary equity, share price (in dollars per share) | $ / shares			$ 20.99	$ 20.99	$ 21.27
Existing Owners of Brigham Minerals
Temporary Equity [Line Items]
Sale of stock, ownership percentage	10.50%
Existing Owners of Brigham Minerals | Class B Common Stock
Temporary Equity [Line Items]
Sale of stock, ownership percentage	56.70%

Share-Based Compensation - Narr

Share-Based Compensation - Narrative (Detail) - $ / shares	Apr. 23, 2019	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	May 08, 2015
Incentive Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)					120,000
Award vesting percentage at grant (as a percent)			20.00%
Award vesting percentage on each anniversary (as a percent)			20.00%
Shares granted during period, grant date fair value (in dollars per share)				$ 10.04
Shares granted during period (in shares)				354,000
Shares vested during period (in shares)			3,058,000	0
RSAs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted during period, grant date fair value (in dollars per share)	$ 21.25
Shares granted during period (in shares)	312,189
Shares vested during period (in shares)		152,742
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted during period, grant date fair value (in dollars per share)	$ 21.25
Shares granted during period (in shares)	598,891
Performance-Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted during period, grant date fair value (in dollars per share)	$ 20.36
Shares granted during period (in shares)			753,546
Performance shares earned (in shares)	379,107
Performance-Based Restricted Stock Units | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage at grant (as a percent)	0.00%
Performance-Based Restricted Stock Units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage at grant (as a percent)	200.00%
Long Term Incentive Plan | Class A Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)		5,999,600	5,999,600	5,999,600
Shares available for future grants (in shares)		4,334,974	4,334,974	4,334,974

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Restricted Stock Unit Activity (Detail) - Incentive Units - $ / shares shares in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Number of Incentive Units
Beginning balance (in shares)	3,272	2,918
Granted (in shares)		354
Vested (in shares)	3,058	0
Ending balance (in shares)	215	3,272
Grant-date Fair Value
Beginning balance (in dollars per share)	$ 1.49	$ 0.45
Grant-date fair value, Granted (in dollars per share)		10.04
Grant-date fair value, Vested (in dollars per share)	0.88
Ending balance (in dollars per share)	$ 10.04	$ 1.49

Share-Based Compensation - Weig

Share-Based Compensation - Weighted Average Assumptions (Detail) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Incentive Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value per Incentive Unit	$ 10.04	$ 1.49	$ 1.49	$ 0.45
Performance-Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	30.00%
Expected dividend yield	8.10%
Risk-free interest rates	2.30%
2018 Awards | Incentive Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	28.00%	28.00%
Expected dividend yield	$ 0	$ 0
Expected term (in years)	8 months 12 days	8 months 12 days
Risk-free interest rates	2.45%	2.45%
Weighted-average grant date fair value per Incentive Unit	$ 10.04	$ 10.04
Total grant date fair value		$ 3,558,000
2015 Awards | Incentive Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	33.00%	33.00%
Expected dividend yield	$ 0	$ 0
Expected term (in years)	3 years 8 months 12 days	3 years 8 months 12 days
Risk-free interest rates	1.07%	1.07%
Weighted-average grant date fair value per Incentive Unit	$ 0.03	$ 0.03
Total grant date fair value		$ 55,000
2013 Awards | Incentive Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	40.00%	40.00%
Expected dividend yield	$ 0	$ 0
Expected term (in years)	6 years 2 months 12 days	6 years 2 months 12 days
Risk-free interest rates	0.94%	0.94%
Weighted-average grant date fair value per Incentive Unit	$ 1.51	$ 1.51
Total grant date fair value		$ 1,248,000

Share-Based Compensation - Sche

Share-Based Compensation - Schedule of Compensation Expense and Future Stock Compensation Expense (Detail) - USD ($) $ in Thousands	Apr. 17, 2019	Sep. 30, 2019	Sep. 30, 2018	Jun. 30, 2019	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Capitalized share-based compensation		$ (1,415)	$ 0		$ (2,425)	$ 0
Total share-based compensation expense		1,737	0		8,232	0
Future share-based compensation expense				$ 21,300	21,282
2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future share-based compensation expense					2,872
2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future share-based compensation expense					8,927
2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future share-based compensation expense					8,600
2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future share-based compensation expense					883
Incentive Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation cost		559	0		$ 2,726	$ 0
Compensation expense, cumulative effect adjustment at IPO	$ 2,000
Shares vested during period (in shares)					3,058,000	0
Future share-based compensation expense					$ 2,135
Incentive Units | 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future share-based compensation expense					178
Incentive Units | 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future share-based compensation expense					712
Incentive Units | 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future share-based compensation expense					712
Incentive Units | 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future share-based compensation expense					533
RSAs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation cost		285	0		3,741	$ 0
Compensation expense, cumulative effect adjustment at IPO		$ 3,200
Shares vested during period (in shares)		152,742
Future share-based compensation expense					2,893
RSAs | 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future share-based compensation expense					285
RSAs | 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future share-based compensation expense					1,129
RSAs | 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future share-based compensation expense					1,129
RSAs | 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future share-based compensation expense					350
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation cost		$ 1,686	0		2,932	0
Future share-based compensation expense					9,794
Restricted stock units | 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future share-based compensation expense					1,686
Restricted stock units | 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future share-based compensation expense					4,217
Restricted stock units | 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future share-based compensation expense					3,891
Restricted stock units | 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future share-based compensation expense					0
Performance-Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation cost		$ 622	$ 0		1,258	$ 0
Future share-based compensation expense					6,460
Performance-Based Restricted Stock Units | 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future share-based compensation expense					723
Performance-Based Restricted Stock Units | 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future share-based compensation expense					2,869
Performance-Based Restricted Stock Units | 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future share-based compensation expense					2,868
Performance-Based Restricted Stock Units | 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future share-based compensation expense					$ 0

Income Taxes (Detail)

Income Taxes (Detail) - USD ($) $ / shares in Units, $ in Thousands	Apr. 17, 2019	Jun. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Jul. 31, 2018
Operating Loss Carryforwards [Line Items]
Deferred tax liability								$ 3,684	$ 391	$ 3,100
Deferred tax asset arising from the IPO	$ 13,700	$ 13,664			$ 13,700
Effective income tax rate (as a percent)						7.90%		22.90%
Total income tax provision			$ 807	$ 428		$ 1,114	$ 456	$ 327	1,008
Federal statutory tax rate (as a percent)						21.00%
Current tax expense								91	713
Deferred tax expense								$ 236	$ 295
Class A Common Stock | Initial Public Offering
Operating Loss Carryforwards [Line Items]
Sale of stock, number of shares issued (in shares)	16,675,000
Share price (in dollars per share)	$ 18

Commitments and Contingencies_2

Commitments and Contingencies (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Rent expense	$ 200	$ 100	$ 400	$ 200	$ 300	$ 200
2019	160		160
2020	970		970		654
2021	1,275		1,275		672
2022	1,312		1,312		689
2023	1,349		1,349		474
2024	5,020		5,020		111
Total	$ 10,086		$ 10,086		3,138
2019					$ 538

Related Party Transactions Rela

Related Party Transactions Related Party Transactions (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Due to related party		$ 7,000,000		$ 7,000,000
Interest rate borrowings		7.00%		7.00%
Ben M. Brigham
Related Party Transaction [Line Items]
Amount received from related party	$ 0	$ 0	$ 400,000	$ 0	$ 0	$ 600,000
Brigham Resources, LLC
Related Party Transaction [Line Items]
Land brokerage services payments					$ 100,000	$ 600,000

Subsequent Events (Detail)

Subsequent Events (Detail) - USD ($)	Nov. 07, 2019	Aug. 05, 2019	May 16, 2019	May 07, 2019	Apr. 17, 2019	Jul. 27, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 06, 2019
Subsequent Event [Line Items]
Repayment of outstanding borrowings							$ 195,404,000	$ 70,000,000	$ 70,000,000	$ 15,000,000
Loss on extinguishment of debt				$ (6,900,000)			(6,933,000)
Capitalized issuance costs				4,000,000
Prepayment premium paid							2,091,000
Existing Owners of Brigham Minerals
Subsequent Event [Line Items]
Sale of stock, ownership percentage					10.50%
Existing Owners of Brigham Minerals | Brigham Resources, LLC
Subsequent Event [Line Items]
Sale of stock, ownership percentage					67.20%
Initial Public Offering
Subsequent Event [Line Items]
Consideration received					$ 273,300,000		273,300,000
Class A Common Stock
Subsequent Event [Line Items]
Dividends declared		$ 0.33
Dividends declared, payable date		Aug. 29, 2019
Dividends declared, record date		Aug. 22, 2019
Class A Common Stock | Existing Owners of Brigham Minerals
Subsequent Event [Line Items]
Sale of stock, ownership percentage					24.20%
Class A Common Stock | Subsequent Event
Subsequent Event [Line Items]
Dividends declared	$ 0.33
Dividends declared, payable date	Nov. 27, 2019
Dividends declared, record date	Nov. 20, 2019
Class A Common Stock | Initial Public Offering
Subsequent Event [Line Items]
Sale of stock, number of shares issued (in shares)					16,675,000
Share price (in dollars per share)					$ 18
New Revolving Credit Facility | Brigham Resources, LLC
Subsequent Event [Line Items]
Line of credit, borrowing base			$ 120,000,000				$ 135,000,000
Revolving credit facility, maturity period			May 16, 2024
New Revolving Credit Facility | Subsequent Event
Subsequent Event [Line Items]
Line of credit, borrowing base	$ 150,000,000
New Revolving Credit Facility | Subsequent Event | Brigham Resources, LLC
Subsequent Event [Line Items]
Line of credit outstanding											$ 80,000,000
New Revolving Credit Facility | Minimum | Brigham Resources, LLC
Subsequent Event [Line Items]
Commitment fee, percentage			0.375%
New Revolving Credit Facility | Minimum | Brigham Resources, LLC | Adjusted Base Rate
Subsequent Event [Line Items]
Basis spread on variable rate			0.75%
New Revolving Credit Facility | Minimum | Brigham Resources, LLC | London Interbank Offered Rate (LIBOR)
Subsequent Event [Line Items]
Basis spread on variable rate			1.75%
New Revolving Credit Facility | Maximum | Brigham Resources, LLC
Subsequent Event [Line Items]
Commitment fee, percentage			0.50%
New Revolving Credit Facility | Maximum | Brigham Resources, LLC | Adjusted Base Rate
Subsequent Event [Line Items]
Basis spread on variable rate			1.75%
New Revolving Credit Facility | Maximum | Brigham Resources, LLC | London Interbank Offered Rate (LIBOR)
Subsequent Event [Line Items]
Basis spread on variable rate			2.75%
Term Loan Facility
Subsequent Event [Line Items]
Line of credit, borrowing base						$ 125,000,000
Repayment of outstanding borrowings					$ 200,000,000
Prepayment premium paid				2,100,000
Legal fees paid				$ 800,000
Term Loan Facility | London Interbank Offered Rate (LIBOR)
Subsequent Event [Line Items]
Basis spread on variable rate						5.50%

Summary of Significant Accoun_2

Summary of Significant Accounting Policies - Summary of Concentration Of Oil and Gas Sales to Significant Customers (Detail) - Sales Revenue, Net [Member] - Customer Concentration Risk [Member]	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Anadarko Petroleum Corp.
Concentration Risk [Line Items]
Concentration risk, percentage	15.00%
Continental Resources, Inc.
Concentration Risk [Line Items]
Concentration risk, percentage	10.00%	10.00%
Noble Energy, Inc.
Concentration Risk [Line Items]
Concentration risk, percentage	9.00%	13.00%

Oil and Gas Properties - Sche_2

Oil and Gas Properties - Schedule of Property Acquisition Costs (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Property Acquisition costs	$ 276,888	$ 228,151	$ 168,691
2018
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Property Acquisition costs		76,793
2017
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Property Acquisition costs		68,939
Prior
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Property Acquisition costs		$ 82,419

Acquisitions and Divestitures_2

Acquisitions and Divestitures - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended							9 Months Ended		12 Months Ended
	Jun. 30, 2018	Aug. 31, 2017	Feb. 28, 2017	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Cash consideration paid				$ 99,038	$ 39,975	$ 41,332		$ 58,972	$ 79,417	$ 25,594	$ 180,345	$ 163,983	$ 196,956	$ 102,086
Assets acquired, evaluated				63,787	25,050	27,929		39,099	44,706	14,132	116,766	97,937	137,496	51,862
Assets acquired, unevaluated				$ 35,251	$ 14,925	$ 13,403		19,873	$ 34,711	$ 11,462	63,579	66,046	59,460	50,224
Proceeds for sale of mineral and royalty interests											$ 2,001	$ 125	$ 125	$ 111,024
Loving County, Texas and Lea County, New Mexico
Business Acquisition [Line Items]
Cash consideration paid	$ 41,000
Assets acquired, evaluated	22,800
Assets acquired, unevaluated	18,200
Reeves, Loving and Ward Counties
Business Acquisition [Line Items]
Cash consideration paid	25,800						$ 3,800	$ 22,000
Assets acquired, evaluated	18,400
Assets acquired, unevaluated	$ 7,400
Delaware Basin [Member]
Business Acquisition [Line Items]
Cash consideration paid		$ 29,200
Assets acquired, evaluated		8,700
Assets acquired, unevaluated		$ 20,500
Sale of mineral and royalty interests			$ 156,700
Proceeds for sale of mineral and royalty interests			111,100
Share value			$ 45,600
Percentage of royalties			12.00%
Gain of sale of minerals and royalty interests			$ 94,600

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Cost basis available for sale securities			$ 3.4
Unrealized gain on securities	$ 0.8		0.7
Fair value of available for sale securities			$ 4.1
Unrealized gains on available for sale securities		$ 0.1
Distribution of securities	3.3
Sale of Securities	$ 0.9

Summary of Restricted Units Iss

Summary of Restricted Units Issued and Outstanding (Detail) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Series M1 Restricted Units
Capital Unit [Line Items]
Beginning balance	7,520	7,520
Issuances	1,030
Ending balance	8,550	7,520
Series M2 Restricted Units
Capital Unit [Line Items]
Beginning balance	7,520	7,520
Issuances	1,030
Ending balance	8,550	7,520
Series M3 Restricted Units
Capital Unit [Line Items]
Beginning balance	7,520	7,520
Issuances	1,030
Ending balance	8,550	7,520
Series M4 Restricted Units
Capital Unit [Line Items]
Beginning balance	7,520	7,520
Issuances	1,030
Ending balance	8,550	7,520
Series M Restricted Units [Member]
Capital Unit [Line Items]
Beginning balance	30,080	30,080
Issuances	4,120
Ending balance	34,200	30,080
Series Z1 Restricted Units
Capital Unit [Line Items]
Beginning balance	4,313	4,328
Issuances	485
Forfeitures	(105)	(15)
Ending balance	4,693	4,313
Series Z2 Restricted Units
Capital Unit [Line Items]
Beginning balance	4,313	4,328
Issuances	485
Forfeitures	(105)	(15)
Ending balance	4,693	4,313
Series Z3 Restricted Units
Capital Unit [Line Items]
Beginning balance	4,313	4,328
Issuances	485
Forfeitures	(105)	(15)
Ending balance	4,693	4,313
Series Z4 Restricted Units
Capital Unit [Line Items]
Beginning balance	4,313	4,328
Issuances	485
Forfeitures	(105)	(15)
Ending balance	4,693	4,313
Series Z Restricted Units
Capital Unit [Line Items]
Beginning balance	17,252	17,312
Issuances	1,940
Forfeitures	(420)	(60)
Ending balance	18,772	17,252

Employee Benefit Plan - Additio

Employee Benefit Plan - Additional Information (Detail) - Benefit Plan, 401K [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Defined Contribution Plan Disclosure [Line Items]
Employer's matching contribution	100.00%
Contribution to Employee benefit plan	$ 0.2	$ 0.1
Maximum
Defined Contribution Plan Disclosure [Line Items]
Employee's total compensation, contribution percentage	6.00%

Income Taxes - Schedule of Fede

Income Taxes - Schedule of Federal and State Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
State Income Tax
Current (benefit)/expense					$ (23)	$ 713
Deferred (benefit)/expense					(138)	295
Federal Income Tax
Current expense					114
Deferred expense					374
Total income tax provision	$ 807	$ 428	$ 1,114	$ 456	327	1,008
Total current income taxes					91	713
Total deferred income taxes					236	295
Total income tax provision	$ 807	$ 428	$ 1,114	$ 456	$ 327	$ 1,008

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Income Tax Expense with Income Tax Provision (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income before income taxes					$ 33,142	$ 116,620
Less: income before income taxes attributable to predecessor					30,805	116,620
Income before income taxes attributable to shareholders					2,337
Income tax at the federal statutory rate					491
State income taxes, net of federal benefit					(150)	1,008
Percentage depletion in excess of basis					(14)
Total income tax provision	$ 807	$ 428	$ 1,114	$ 456	$ 327	$ 1,008

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Jul. 31, 2018	Dec. 31, 2017
Noncurrent:
Deferred tax assets:	$ 0		$ 0
Total noncurrent deferred tax assets:	0		0
Deferred tax liabilities:
Oil and gas properties	(208)		(391)
Investment in subsidiary	(3,476)
Total noncurrent deferred tax liabilities	(3,684)		(391)
Net noncurrent deferred tax liabilities	$ (3,684)	$ (3,100)	$ (391)

Quarterly Financial Informati_3

Quarterly Financial Information - Schedule of Quarterly Financial Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended										9 Months Ended		12 Months Ended
	Apr. 16, 2019	Sep. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Total revenues		$ 25,107		$ 17,591	$ 18,701	$ 16,889	$ 14,083	$ 12,404	$ 8,380	$ 8,201	$ 11,923	$ 67,901	$ 49,673	$ 67,264	$ 40,908
Income from operations		9,115		8,732	11,716	10,564	8,219	7,697	5,044	5,127	103,346	22,856	30,499	39,231	121,214
Net income	$ 314	$ 8,464	$ 534	$ 7,114	$ 8,153	$ 9,351	$ 8,197	$ 7,234	$ 654	$ 5,024	$ 102,700	$ 9,293	$ 25,701	$ 32,815	$ 115,612

Reserve and Related Financial_3

Reserve and Related Financial Data - Schedule of Reserve Quantity of Resources (Detail)	12 Months Ended
	Dec. 31, 2018MBoeMMcfMBbls	Dec. 31, 2017MBoeMMcfMBbls
Oil Equivalent [Member]
Reserve Quantities [Line Items]
Total Proved reserve quantities, beginning balance | MBoe	19,104	13,363
Sales of minerals-in-place | MBoe		(1,627)
Extentions and discoveries | MBoe	3,208	3,259
Acquisitions | MBoe	7,354	4,820
Revisions of previous estimates | MBoe	(1,508)	147
Production | MBoe	(1,417)	(858)
Total Proved reserve quantities, ending balance | MBoe	26,741	19,104
Proved developed reserve quantities | MBoe	11,588	6,160
Proved undeveloped reserve quantities | MBoe	15,153	12,944
Oil [Member]
Reserve Quantities [Line Items]
Total Proved reserve quantities, beginning balance	8,724	7,174
Sales of minerals-in-place		(1,291)
Extentions and discoveries	1,765	1,548
Acquisitions	3,669	2,141
Revisions of previous estimates	(390)	(394)
Production	(777)	(454)
Total Proved reserve quantities, ending balance	12,991	8,724
Proved developed reserve quantities	6,067	2,804
Proved undeveloped reserve quantities	6,924	5,920
Natural Gas [Member]
Reserve Quantities [Line Items]
Total Proved reserve quantities, beginning balance | MMcf	38,401	22,991
Sales of minerals-in-place | MMcf		(815)
Extentions and discoveries | MMcf	5,285	6,012
Acquisitions | MMcf	13,862	9,380
Revisions of previous estimates | MMcf	(3,245)	2,601
Production | MMcf	(2,507)	(1,768)
Total Proved reserve quantities, ending balance | MMcf	51,796	38,401
Proved developed reserve quantities | MMcf	21,735	13,028
Proved undeveloped reserve quantities | MMcf	30,061	25,373
Natural Gas Liquids [Member]
Reserve Quantities [Line Items]
Total Proved reserve quantities, beginning balance	3,980	2,356
Sales of minerals-in-place		(200)
Extentions and discoveries	562	709
Acquisitions	1,374	1,116
Revisions of previous estimates	(577)	108
Production	(222)	(109)
Total Proved reserve quantities, ending balance	5,117	3,980
Proved developed reserve quantities	1,898	1,185
Proved undeveloped reserve quantities	3,219	2,795

Reserve and Related Financial_4

Reserve and Related Financial Data - Additional Information (Detail) - MBoe	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Reserve Quantities [Line Items]
Annual discount factor	10.00%
Minimum
Reserve Quantities [Line Items]
Pricing percentage	22.00%
Maximum
Reserve Quantities [Line Items]
Pricing percentage	41.00%
Oil Equivalent [Member]
Reserve Quantities [Line Items]
Acquisition of additional mineral and royalty interests	7,354	4,820
Extensions and discoveries	3,208	3,259
Revisions of previous estimates	(1,508)	147
Sales of minerals-in-place		(1,627)
Oil Equivalent [Member] | Aquisitions Located in Permian, DJ, Anadarko and Williston Basins
Reserve Quantities [Line Items]
Acquisition of additional mineral and royalty interests		4,820
Oil Equivalent [Member] | Pricing Adjustment
Reserve Quantities [Line Items]
Revisions of previous estimates	536
Oil Equivalent [Member] | Operate or Development Timing
Reserve Quantities [Line Items]
Revisions of previous estimates	(1,100)
Oil Equivalent [Member] | Unit Configuration And EUR Adjustments To Existing Proved Locations
Reserve Quantities [Line Items]
Revisions of previous estimates	944
Oil Equivalent [Member] | Royalty Interests
Reserve Quantities [Line Items]
Revisions of previous estimates		2,581
Oil Equivalent [Member] | Operate or Development Timing and revision of existing proved locations
Reserve Quantities [Line Items]
Revisions of previous estimates		(2,434)

Reserve and Related Financial_5

Reserve and Related Financial Data - Schedule of Future Cash Flows of Oil and Gas Reserves (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Oil and Gas Property [Abstract]
Future crude oil, natural gas and NGL sales	$ 1,049,141	$ 595,874
Future severance tax and ad valorem taxes	(70,248)	(40,225)
Future income tax expense	(144,421)	(1,151)
Future net cash flows	834,472	554,498
10% annual discount	(391,013)	(238,030)
Standardized measure of discounted future net cash flows	$ 443,459	$ 316,468	$ 185,752

Reserve and Related Financial_6

Reserve and Related Financial Data - Schedule of Cost Used in Determining of Standardized Measure (Detail)	12 Months Ended
	Dec. 31, 2018$ / Barrel$ / MMBTU	Dec. 31, 2017$ / Barrel$ / MMBTU
Oil [Member]
Amortization Expense Per Equivalent Unit of Production or Per Dollar of Gross Revenue [Line Items]
Sale prices	61.31	47.80
Natural Gas [Member]
Amortization Expense Per Equivalent Unit of Production or Per Dollar of Gross Revenue [Line Items]
Sale prices | $ / MMBTU	2.51	2.74
Natural Gas Liquids [Member]
Amortization Expense Per Equivalent Unit of Production or Per Dollar of Gross Revenue [Line Items]
Sale prices	23.98	18.56

Reserve and Related Financial_7

Reserve and Related Financial Data - Schedule of Change in Standardized Measure of Discounted Future net Cash Flows (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Oil and Gas Property [Abstract]
Standardized measure of discounted future net cash flows, beginning of the year	$ 316,468	$ 185,752
Sales, less production costs and taxes	(52,278)	(26,711)
Revisions of previous quantity estimates	(22,942)	4,894
Extensions, discoveries and other additions	71,668	56,511
Net change in prices and production costs	71,770	30,565
Accretion of discount	31,713	18,612
Purchase of reserves in place	148,580	79,190
Divestitures of reserves in place		(26,742)
Net change in income Tax	(75,369)	(298)
Timing differences and other	(46,151)	(5,305)
Standardized measure of discounted future net cash flows, end of the year	$ 443,459	$ 316,468

Reserve and Related Financial_8

Reserve and Related Financial Data - Aggregate Amounts of Costs Capitalized for Oil and Natural Gas Producing Activities (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Oil and Gas Property [Abstract]
Not subject to depletion	$ 276,888	$ 228,151	$ 168,691
Subject to depletion	423,884	289,851	152,354
Total oil and gas properties, at cost	700,772	518,002	321,045
Less accumulated depreciation, depletion and amortization	(49,488)	(27,628)	(14,210)
Total oil and gas properties, net	$ 651,284	$ 490,374	$ 306,835

Reserve and Related Financial_9

Reserve and Related Financial Data - Schedule in Costs were Incurred in Oil and Natural Gas (Detail) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended		12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Oil and Gas Property [Abstract]
Unevaluated	$ 35,251	$ 14,925	$ 13,403	$ 19,873	$ 34,711	$ 11,462	$ 63,579	$ 66,046	$ 59,460	$ 50,224
Evaluated	63,787	25,050	27,929	39,099	44,706	14,132	116,766	97,937	137,496	51,862
Total	$ 99,038	$ 39,975	$ 41,332	$ 58,972	$ 79,417	$ 25,594	$ 180,345	$ 163,983	$ 196,956	$ 102,086