InfraREIT (HIFR) 10-Q 2 Nov 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 30, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Trading Symbol	HIFR
Entity Registrant Name	InfraREIT, Inc.
Entity Central Index Key	1,506,401
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		43,796,915

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current Assets
Cash and cash equivalents	$ 4,186	$ 17,612
Restricted cash	1,682	1,682
Due from affiliates	28,518	32,554
Inventory	7,181	7,276
Prepaids and other current assets	753	726
Total current assets	42,320	59,850
Electric Plant, net	1,752,645	1,640,820
Goodwill	138,384	138,384
Other Assets	35,378	37,646
Total Assets	1,968,727	1,876,700
Current Liabilities
Accounts payable and accrued liabilities	32,052	37,372
Short-term borrowings	35,000	137,500
Current portion of long-term debt	67,632	7,849
Dividends and distributions payable	15,169	15,161
Accrued taxes	5,288	4,415
Total current liabilities	155,141	202,297
Long-Term Debt, Less Deferred Financing Costs	843,884	709,488
Regulatory Liability	28,486	21,004
Total liabilities	1,027,511	932,789
Commitments and Contingencies
Equity
Common stock, $0.01 par value; 450,000,000 shares authorized; 43,795,632 and 43,772,283 issued and outstanding as of September 30, 2017 and December 31, 2016, respectively	438	438
Additional paid-in capital	706,337	705,845
Accumulated deficit	(20,494)	(18,243)
Total InfraREIT, Inc. equity	686,281	688,040
Noncontrolling interest	254,935	255,871
Total equity	941,216	943,911
Total Liabilities and Equity	$ 1,968,727	$ 1,876,700

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Common stock, par or stated value per share	$ 0.01	$ 0.01
Common stock, shares authorized	450,000,000	450,000,000
Common stock, shares issued	43,795,632	43,772,283
Common stock, shares, outstanding	43,795,632	43,772,283

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Lease revenue	$ 51,618	$ 49,419	$ 131,664	$ 116,869
Operating costs and expenses
General and administrative expense	6,718	5,336	19,565	15,861
Depreciation	13,328	11,828	38,997	34,312
Total operating costs and expenses	20,046	17,164	58,562	50,173
Income from operations	31,572	32,255	73,102	66,696
Other (expense) income
Interest expense, net	(10,357)	(9,379)	(30,196)	(27,276)
Other income, net	331	1,024	351	2,920
Total other expense	(10,026)	(8,355)	(29,845)	(24,356)
Income before income taxes	21,546	23,900	43,257	42,340
Income tax expense	308	299	873	778
Net income	21,238	23,601	42,384	41,562
Less: Net income attributable to noncontrolling interest	5,908	6,560	11,797	11,598
Net income attributable to InfraREIT, Inc.	$ 15,330	$ 17,041	$ 30,587	$ 29,964
Net income attributable to InfraREIT, Inc. common stockholders per share:
Basic	$ 0.35	$ 0.39	$ 0.70	$ 0.69
Diluted	0.35	0.39	0.70	0.69
Cash dividends declared per common share	$ 0.25	$ 0.25	$ 0.75	$ 0.75

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities
Net income	$ 42,384	$ 41,562
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	38,997	34,312
Amortization of deferred financing costs	3,101	3,010
Allowance for funds used during construction - other funds	(318)	(2,903)
Equity based compensation	428	750
Changes in assets and liabilities:
Due from affiliates	4,036	5,198
Inventory	95	(99)
Prepaids and other current assets	(27)	(209)
Accounts payable and accrued liabilities	334	11,327
Net cash provided by operating activities	89,030	92,948
Cash flows from investing activities
Additions to electric plant	(147,803)	(179,765)
Net cash used in investing activities	(147,803)	(179,765)
Cash flows from financing activities
Proceeds from short-term borrowings	110,500	94,500
Repayments of short-term borrowings	(213,000)	(56,000)
Proceeds from borrowings of long-term debt	200,000	100,000
Repayments of long-term debt	(5,845)	(5,528)
Deferred financing costs	(809)	(649)
Dividends and distributions paid	(45,499)	(43,948)
Net cash provided by financing activities	45,347	88,375
Net (decrease) increase in cash and cash equivalents	(13,426)	1,558
Cash and cash equivalents at beginning of period	17,612	9,471
Cash and cash equivalents at end of period	$ 4,186	$ 11,029

Description of Business and Pre

Description of Business and Presentation of Financial Statements	9 Months Ended
	Sep. 30, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of Business and Presentation of Financial Statements	1. Description of Business and Presentation of Financial Statements Basis of Presentation InfraREIT, Inc. is a Maryland corporation, which may be referred to in these financial statements as the “Company,” “we,” “us” and “our.” These unaudited interim consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. Operating results for the nine months ended September 30, 2017 are not necessarily indicative of the results that may be expected for the year ending December 31, 2017. For further information, refer to the consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2016 filed with the U.S. Securities and Exchange Commission (SEC) on February 28, 2017 (2016 Form 10-K). We held 72.2% of the outstanding partnership units (OP Units) in InfraREIT Partners, LP (Operating Partnership or InfraREIT LP) as of September 30, 2017 and are its general partner. We include the accounts of the Operating Partnership and its subsidiaries in our consolidated financial statements. Hunt Consolidated, Inc. affiliates, current or former employees and members of our board of directors held the other 27.8% of the outstanding OP Units as of September 30, 2017. Use of Estimates The preparation of our consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts in the consolidated financial statements and accompanying notes. Actual results could differ from those estimates. Recent Accounting Guidance Recent Accounting Guidance Not Yet Adopted In February 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2016-02, Leases In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Clarification of Certain Cash Receipts and Cash Payments In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 203): Restricted Cash (A Consensus of the FASB Emerging Issues Task Force) In January 2017, the FASB issued ASU 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business.

Asset Exchange Transaction

Asset Exchange Transaction	9 Months Ended
	Sep. 30, 2017
Nonmonetary Transactions [Abstract]
Asset Exchange Transaction	2 . Asset Exchange Transaction On July 21, 2017, our regulated subsidiary, Sharyland Distribution & Transmission Services, L.L.C. (SDTS), and our sole tenant, Sharyland Utilities, L.P. (Sharyland), signed a definitive agreement (Definitive Agreement) with Oncor Electric Delivery Company LLC (Oncor) to exchange SDTS’s retail distribution assets for a group of Oncor’s transmission assets located in West and Central Texas. Under the Definitive Agreement with Oncor, SDTS will exchange approximately $400 million of net distribution assets for approximately $380 million of transmission assets located in West and Central Texas and approximately $20 million in cash from Oncor, subject to customary adjustments to be made at and following the closing of the transaction. These transactions are structured to qualify, in part, as a simultaneous tax deferred like-kind exchange of assets to the extent that the assets are of “like kind” (within the meaning of Section 1031 of the Internal Revenue Code of 1986, as amended). Upon closing, Sharyland will lease these assets from SDTS and operate them under an amended certificate of convenience and necessity (CCN). Thereafter, SDTS will continue to own and lease to Sharyland certain substations related to its distribution assets, but Sharyland will exit the retail distribution business. In accordance with the Definitive Agreement, SDTS, Sharyland and Oncor filed a joint Sale-Transfer-Merger application (STM) with the (PUCT) on August 4, 2017 under Docket No. 47469 requesting PUCT approval of the asset exchange transaction. See Note 18, Subsequent Events for additional information regarding the approval of the STM. Concurrently with the execution of the Definitive Agreement, Sharyland and SDTS entered into an agreement (Rate Case Dismissal Agreement) with certain parties to their pending rate case (Rate Case), which would result in the dismissal of the Rate Case upon the completion of the asset exchange transaction with Oncor. On September 29, 2017, the PUCT issued an order dismissing the Rate Case contingent on PUCT approval of the STM and the closing of the asset exchange transaction Regulatory Matters The closing of the asset exchange transaction with Oncor and the effectiveness of the Rate Case dismissal are dependent upon each other and subject to a number of closing conditions, including the PUCT approvals discussed above as well as PUCT approval of Oncor’s rate case settlement. The closing of the asset exchange transaction is also contingent upon Oncor’s parent company obtaining consent of the U.S. Bankruptcy Court for the District of Delaware (Bankruptcy Court) and SDTS obtaining certain consents from its lenders, as well as other customary closing conditions. On August 18, 2017, SDTS received early termination of the Hart-Scott-Rodino Act waiting period applicable to the asset exchange transaction. On September 15, 2017, the Bankruptcy Court approved Oncor’s parent company’s consent for Oncor to enter into the asset exchange transaction. See Note 18, Subsequent Events

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2017
Related Party Transactions [Abstract]
Related Party Transactions	3 . Related Party Transactions Our subsidiary, SDTS, leases all our electric transmission and distribution assets (regulated assets) through several lease agreements to Sharyland, a Texas based utility and our sole tenant. Under the leases, we have agreed to fund capital expenditures for footprint projects. Our leases define “footprint projects” to be transmission or distribution projects primarily situated within our distribution service territory, or that physically hang from our existing transmission assets or that are physically located within one of our substations. We earned lease revenues from Sharyland under these agreements of $51.6 million and $49.4 million during the three months ended September 30, 2017 and 2016, respectively. We earned lease revenues of $131.7 million and $116.9 million from Sharyland during the nine months ended September 30, 2017 and 2016, respectively. In connection with our leases with Sharyland, we recorded a deferred rent liability of $18.8 million and $15.6 million as of September 30, 2017 and December 31, 2016, respectively, which is included in accounts payable and accrued liabilities on the Consolidated Balance Sheets. In addition to rent payments that Sharyland makes to us, we and Sharyland also make payments to each other under the leases that primarily consist of payments to reimburse Sharyland for the costs of gross plant and equipment added to our regulated assets. For the nine months ended September 30, 2017 and 2016, the net amount of payments we made to Sharyland was $151.2 million and $179.5 million, respectively. In connection with the Definitive Agreement, on July 21, 2017, SDTS and Sharyland entered into a letter agreement (Side Letter) in which they agreed to certain terms and conditions to address the actual or potential conflicts of interest arising between SDTS and Sharyland in connection with the transaction with Oncor. Specifically, the Side Letter includes, among other things: (a) certain representations and warranties from Sharyland that correspond to representations and warranties of SDTS under the Definitive Agreement relating to certain matters for which SDTS relies, in whole or in part, upon Sharyland under the leases and as operator of the assets; (b) a mutual covenant of SDTS and Sharyland to not take actions that would cause the other party to breach the Definitive Agreement; and (c) an allocation of expenses incurred in connection with the transactions. The Side Letter also provides that SDTS and Sharyland will amend the leases at closing of the transaction to reflect SDTS’s rights related to funding and ownership of future capital expenditure rights in the service territory previously certificated to Sharyland and cooperate to resolve other matters arising in connection with the transactions. For information related to the pending asset exchange transaction with Oncor, see Note 2, Asset Exchange Transaction As of September 30, 2017 and December 31, 2016, accounts payable and accrued liabilities on the Consolidated Balance Sheets included $4.5 million and $13.7 million, respectively, related to amounts owed to Sharyland. As of September 30, 2017 and December 31, 2016, amounts due from affiliates on the Consolidated Balance Sheets included $28.5 million and $32.6 million, respectively, related to amounts owed by Sharyland associated with our leases and the Side Letter. The management fee paid to Hunt Utility Services, LLC (Hunt Manager) for the nine months ended September 30, 2017 and 2016 was $14.1 million and $10.3 million, respectively. As of December 31, 2016, there was $3.5 million accrued associated with management fees on the Consolidated Balance Sheets. There were no prepaid or accrued amounts associated with the management fees on the Consolidated Balance Sheets as of September 30, 2017. Additionally, during the nine months ended September 30, 2017 and 2016, we paid Hunt Manager $0.2 million and $0.1 million, respectively, for reimbursement of annual software license and maintenance fees and other expenses in accordance with our management agreement. Our management agreement with Hunt Manager provided for an annual base fee, or management fee, of $13.1 million from April 1, 2015 through March 31, 2016. Effective as of April 1, 2016, the annual base fee was automatically adjusted to $14.0 million annually through March 31, 2017. Effective as of April 1, 2017, the annual base fee was automatically adjusted to $14.2 million annually through March 31, 2018. The base fee for each twelve month period beginning each April 1 thereafter will equal 1.50% of our total equity as of December 31 of the immediately preceding year, subject to a $30.0 million cap. The term of the management agreement expires December 31, 2019 and will automatically renew for successive five year terms unless a majority of our independent directors decides to terminate the agreement.

Electric Plant and Depreciation

Electric Plant and Depreciation	9 Months Ended
	Sep. 30, 2017
Public Utilities Property Plant And Equipment [Abstract]
Electric Plant and Depreciation	4 . Electric Plant and Depreciation The major classes of electric plant are as follows: (In thousands) September 30, 2017 December 31, 2016 Electric plant: Transmission plant $ 1,247,626 $ 1,203,164 Distribution plant 628,636 575,648 General plant 16,007 15,959 Total plant in service 1,892,269 1,794,771 Construction work in progress 125,539 107,189 Total electric plant 2,017,808 1,901,960 Accumulated depreciation (265,163 ) (261,140 ) Electric plant, net $ 1,752,645 $ 1,640,820 General plant consists primarily of a warehouse, buildings and associated assets. Construction work in progress (CWIP) relates to various transmission and distribution projects underway. The amounts of CWIP consist primarily of route development expenditures, labor and materials expenditures, right of way acquisitions, engineering services and legal fees. Electric plant, net includes plant acquisition adjustments of $26.9 million and $27.7 million as of September 30, 2017 and December 31, 2016, respectively. See Note 2, Asset Exchange Transaction

Goodwill

Goodwill	9 Months Ended
	Sep. 30, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill	5 . Goodwill Goodwill represents the excess of costs of an acquired business over the fair value of the assets acquired, less liabilities assumed. We conduct an impairment test of goodwill at least annually. As of September 30, 2017 and December 31, 2016, $138.4 million was recorded as goodwill on the Consolidated Balance Sheets.

Other Assets

Other Assets	9 Months Ended
	Sep. 30, 2017
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Other Assets	6 . Other Assets Other assets are as follows: September 30, 2017 December 31, 2016 (In thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Deferred financing costs on undrawn revolver $ 967 $ (542 ) $ 425 $ 967 $ (397 ) $ 570 Other regulatory assets: Deferred financing costs 28,570 (19,929 ) 8,641 27,761 (16,997 ) 10,764 Deferred costs recoverable in future years 23,793 — 23,793 23,793 — 23,793 Other regulatory assets 52,363 (19,929 ) 32,434 51,554 (16,997 ) 34,557 Investments 2,519 — 2,519 2,519 — 2,519 Other assets $ 55,849 $ (20,471 ) $ 35,378 $ 55,040 $ (17,394 ) $ 37,646 Deferred financing costs on undrawn revolver consist of costs incurred in connection with the establishment of the InfraREIT LP revolving credit facility, see Note 7, Borrowings Under Credit Facilities Other regulatory assets consist of deferred financing costs within our regulated subsidiary, SDTS. The deferred financing costs primarily consist of debt issuance costs incurred in connection with the construction of our regulated assets or the refinancing of related debt. See Note 7, Borrowings Under Credit Facilities Long-Term Debt Deferred costs recoverable in future years of $23.8 million as of September 30, 2017 and December 31, 2016 represent operating costs incurred from inception of Sharyland through 2007. We have determined that these costs are probable of recovery through future rates based on orders of the PUCT in Sharyland’s prior rate cases and regulatory precedent. In connection with the acquisition of Cap Rock Holding Corporation, we received a participation in the National Rural Utilities Cooperative Finance Corporation (NRUCFC). We account for this investment under the cost method of accounting. We believe that the investment is not impaired as of September 30, 2017 and December 31, 2016.

Borrowings Under Credit Facilit

Borrowings Under Credit Facilities	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Borrowings Under Credit Facilities	7 . Borrowings Under Credit Facilities InfraREIT LP Revolving Credit Facility In 2014, InfraREIT LP entered into a $75.0 million revolving credit facility, led by Bank of America, N.A., as administrative agent, with up to $15.0 million available for issuance of letters of credit and a maturity date of December 10, 2019. The revolving credit facility is secured by certain assets of InfraREIT LP, including accounts and other personal property, and is guaranteed by us and Transmission and Distribution Company, L.L.C. (TDC), with the TDC guarantee secured by the assets of, and InfraREIT LP’s equity interests in, TDC on materially the same basis as TDC’s senior secured notes described below in Note 8, Long-Term Debt Borrowings and other extensions of credit under the revolving credit facility bear interest, at InfraREIT LP’s election, at a rate equal to (1) the one, two, three or six month London Interbank Offered Rate (LIBOR) plus 2.5%, or (2) a base rate (equal to the highest of (a) the Federal Funds Rate plus ½ of 1%, (b) the administrative agent’s prime rate and (c) LIBOR plus 1%) plus 1.5%. Letters of credit are subject to a letter of credit fee equal to the daily amount available to be drawn times 2.5%. InfraREIT LP is also required to pay a commitment fee and other customary fees under the revolving credit facility. InfraREIT LP may prepay amounts outstanding under the revolving credit facility in whole or in part without premium or penalty. As of September 30, 2017 and December 31, 2016, there were no borrowings or letters of credit outstanding, and there was $75.0 million of borrowing capacity available under the revolving credit facility. As of September 30, 2017 and December 31, 2016, InfraREIT LP was in compliance with all debt covenants under the credit agreement. SDTS Revolving Credit Facility In 2014, SDTS entered into the third amended and restated credit agreement led by Royal Bank of Canada, as administrative agent, with a maturity date of December 10, 2019. The credit agreement contains a revolving credit facility with a borrowing capacity up to $250.0 million with up to $25.0 million of the revolving credit facility available for issuance of letters of credit and up to $5.0 million of the revolving credit facility available for swingline loans. The revolving credit facility is secured by certain of SDTS’s regulated assets, the leases, certain accounts and TDC’s equity interests in SDTS on the same basis as SDTS’s various senior secured note obligations described below in Note 8, Long-Term Debt The interest rate for the revolving credit facility is based, at SDTS’s option, at a rate equal to either (1) a base rate, determined as the greatest of (a) the administrative agent’s prime rate, (b) the federal funds effective rate plus ½ of 1% and (c) LIBOR plus 1.00% per annum, plus a margin of either 0.75% or 1.00% per annum, depending on the total debt to capitalization ratio of SDTS on a consolidated basis or (2) the one, two, three or six month LIBOR plus a margin of either 1.75% or 2.00% per annum, depending on the total debt to capitalization ratio of SDTS on a consolidated basis. SDTS is also required to pay a commitment fee and other customary fees under its revolving credit facility. SDTS is entitled to prepay amounts outstanding under the revolving credit facility with no prepayment penalty. As of September 30, 2017, SDTS had $35.0 million of borrowings outstanding at a weighted average interest rate of 3.79%, no letters of credit outstanding and $215.0 million of borrowing capacity available under this revolving credit facility. As of December 31, 2016, SDTS had $137.5 million of borrowings outstanding at a weighted average interest rate of 2.50% with no letters of credit outstanding and $112.5 million of borrowing capacity available under this revolving credit facility. As of September 30, 2017 and December 31, 2016, SDTS was in compliance with all debt covenants under the credit agreement. The credit agreements require InfraREIT LP and SDTS to comply with customary covenants for facilities of this type, including: debt to capitalization ratios, debt service coverage ratios, limitations on additional debt, liens, investments, mergers, acquisitions, dispositions or entry into any line of business other than the business of the transmission and distribution of electric power and the provision of ancillary services and certain restrictions on the payment of dividends. The debt to capitalization ratio on the SDTS credit facility is calculated on a combined basis with Sharyland. The credit agreements also contain restrictions on the amount of Sharyland’s indebtedness and other restrictions on, and covenants applicable to, Sharyland. See Note 18, Subsequent Events The revolving credit facilities of InfraREIT LP and SDTS are subject to customary events of default. If an event of default occurs under either facility and is continuing, the lenders may accelerate amounts due under such revolving credit facility.

Long-Term Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2017
Debt Instruments [Abstract]
Long-Term Debt	8 . Long-Term Debt Long-term debt consisted of the following: September 30, 2017 December 31, 2016 (In thousands) Maturity Date Amount Outstanding Interest Rate Amount Outstanding Interest Rate TDC Senior secured notes - $25.0 million December 30, 2020 $ 16,563 8.50% $ 17,500 8.50% SDTS Senior secured notes - $60.0 million June 20, 2018 60,000 5.04% 60,000 5.04% Senior secured term loan - $200.0 million June 5, 2020 200,000 2.48% — n/a Senior secured notes - $400.0 million December 3, 2025 400,000 3.86% 400,000 3.86% Senior secured notes - $100.0 million January 14, 2026 100,000 3.86% 100,000 3.86% Senior secured notes - $53.5 million December 30, 2029 41,073 7.25% 42,600 7.25% Senior secured notes - $110.0 million September 30, 2030 93,985 6.47% 97,366 6.47% Total SDTS debt 895,058 699,966 Total long-term debt 911,621 717,466 Less unamortized deferred financing costs (105 ) (129 ) Total long-term debt, less deferred financing costs 911,516 717,337 Less current portion of long-term debt (67,632 ) (7,849 ) Debt classified as long-term debt, less deferred financing costs $ 843,884 $ 709,488 In 2010, TDC issued $25.0 million aggregate principal amount of 8.50% per annum senior secured notes to The Prudential Insurance Company of America and affiliates (TDC Notes). Principal and interest on the TDC Notes are payable quarterly, and the TDC Notes are secured by the assets of, and InfraREIT LP’s equity interest in, TDC on materially the same basis as with lenders under InfraREIT LP’s revolving credit facility described above in Note 7, Borrowings Under Credit Facilities SDTS has $60.0 million aggregate principal amount of 5.04% per annum senior secured notes issued to The Prudential Insurance Company of America and affiliates in 2011 (2011 Notes). Interest is payable quarterly while no principal payments are due until maturity. On June 5, 2017, SDTS entered into a $200.0 million senior secured term loan credit facility (2017 Term Loan) with Canadian Imperial Bank of Commerce, New York Branch (CIBC) and Mizuho Bank, Ltd., as lenders, and CIBC as administrative agent. The interest rate for the 2017 Term Loan is based, at SDTS’s option, at a rate equal to either (1) a base rate, determined as the greatest of (a) the administrative agent’s prime rate, (b) the federal funds effective rate plus 0.5% and (c) LIBOR plus 1.00% per annum, plus a margin of 0.25% per annum or (2) LIBOR plus a margin of 1.25% per annum. The LIBOR interest period may be one, two, three or six months, but interest is payable no less frequently than quarterly. Proceeds from the issuance of the 2017 Term Loan were used to repay In 2015, SDTS issued $400.0 million in 10 year senior secured notes, series A (Series A Notes), and in 2016 issued an additional $100.0 million in 10 year senior secured notes, series B (Series B Notes). These senior secured notes bear interest at a rate of 3.86% per annum, payable semi-annually. The Series A Notes are due at maturity with outstanding accrued interest payable each June and December. The Series B Notes are due at maturity with outstanding accrued interest payable each January and July. In 2009, SDTS issued $53.5 million aggregate principal amount of 7.25% per annum senior secured notes to The Prudential Insurance Company of America and affiliates (2009 Notes). Principal and interest on the 2009 Notes are payable quarterly. In 2010, SDTS issued $110.0 million aggregate principal amount of 6.47% per annum senior secured notes to The Prudential Insurance Company of America (2010 Notes). Principal and interest on the 2010 Notes are payable quarterly. SDTS and TDC are entitled to prepay amounts outstanding under their senior secured notes, subject to a prepayment penalty equal to the excess of the discounted value of the remaining scheduled payments with respect to such notes over the amount of the prepaid notes. SDTS is entitled to prepay amounts outstanding under the 2017 Term Loan with no prepayment penalty. The 2017 Term Loan is also subject to required prepayments upon the occurrence of certain events. The agreements governing the senior secured notes and 2017 Term Loan contain customary covenants, such as debt to capitalization ratios, debt service coverage ratios, limitations on liens, dispositions, mergers, entry into other lines of business, investments and the incurrence of additional indebtedness. The debt to capitalization ratios are calculated on a combined basis with Sharyland. SDTS’s Series A Notes and Series B Notes are not required to maintain a debt service coverage ratio. As of September 30, 2017 and December 31, 2016, SDTS and TDC were in compliance with all debt covenants under the applicable agreements. See Note 18, Subsequent Events SDTS’s Series A Notes, Series B Notes, 2009 Notes, 2010 Notes, 2011 Notes and 2017 Term Loan are secured by certain of SDTS’s transmission and distribution assets, the leases, certain accounts and TDC’s equity interests in SDTS on the same basis as SDTS’s revolving credit facility described above in Note 7, Borrowings Under Credit Facilities The senior secured notes of TDC and SDTS and 2017 Term Loan are subject to customary events of default. If an event of default occurs with respect to the notes and is continuing, the lenders may accelerate the applicable amounts due.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	9 . Fair Value of Financial Instruments The carrying amounts of our cash and cash equivalents, restricted cash, due from affiliates and accounts payable approximate fair value due to the short-term nature of these assets and liabilities. We had fixed interest rate borrowings totaling $711.6 million and $717.5 million under our senior secured notes with a weighted average interest rate of 4.6% per annum as of September 30, 2017 and December 31, 2016, respectively. The fair value of these borrowings is estimated using discounted cash flow analysis based on current market rates. As of September 30, 2017, we had $200.0 million of borrowings under our 2017 Term Loan that accrues interest under a floating interest rate structure, which is typically repriced every month or three months. Accordingly, the carrying value of such indebtedness approximated its fair value for the amounts outstanding. Financial instruments, measured at fair value, by level within the fair value hierarchy were as follows: Carrying Fair Value (In thousands) Value Level 1 Level 2 Level 3 September 30, 2017 Long-term debt $ 911,621 $ — $ 954,748 $ — December 31, 2016 Long-term debt $ 717,466 $ — $ 758,415 $ —

Regulatory Matters

Regulatory Matters	9 Months Ended
	Sep. 30, 2017
Public Utilities Rate Matters [Abstract]
Regulatory Matters	10 . Regulatory Matters Regulatory Liability Our regulatory liability is established through depreciation rates related to cost of removal and represents amounts that we expect to incur in the future. As of September 30, 2017 and December 31, 2016, we recorded on the Consolidated Balance Sheets as a long-term liability $28.5 million and $21.0 million, respectively, net of actual removal costs incurred. Rate Case Filing On April 29, 2016, Sharyland filed a system-wide rate proceeding with the PUCT to update its rates (April Rate Case Filing). Pursuant to a restructuring order issued by the PUCT in 2008 allowing us to utilize a REIT structure, the April Rate Case Filing was prepared using the audited books and records of both Sharyland and SDTS and proposed rates to be set on a combined basis. However, as a result of a preliminary order issued by the PUCT in October 2016, Sharyland and SDTS filed an amended rate case application and rate filing packages (December Rate Case Filing) on December 30, 2016 with the PUCT, which superseded the April Rate Case Filing. On September 29, 2017, the PUCT issued an order dismissing the Rate Case contingent on PUCT approval of the STM and the closing of the asset exchange transaction. e Note 2, Asset Exchange Transaction and Note 18, Subsequent Events for additional information regarding the pending asset exchange transaction and the status of the key closing conditions. Once the Rate Case dismissal becomes effective, SDTS and Sharyland will continue operating under their existing regulatory structure, and the current regulatory parameters will remain in place until the next rate case, including an allowed return on equity of 9.7%, a capital structure of 55% debt and 45% equity and a cost of debt of 6.73%. Sharyland and SDTS will be required to file a new rate case in the calendar year 2020 with a test year ending December 31, 2019.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2017
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	1 1 . Commitments and Contingencies SDTS and Sharyland filed the December Rate Case Filing with the PUCT on December 30, 2016. For further information regarding the Rate Case, see Note 10, Regulatory Matters In addition, from time to time, we are a party to various legal proceedings arising in the ordinary course of business. Although we cannot predict the outcome of any such legal proceedings, we do not believe the resolution of these proceedings, individually or in the aggregate, will have a material impact on our business, financial condition or results of operations, liquidity and cash flows.

Equity

Equity	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Equity	1 2 . Equity We and the Operating Partnership declared cash dividends on common stock and distributions on OP Units of $0.75 per share or unit, as applicable, during each of the nine months ended September 30, 2017 and 2016. We paid a total of $45.5 million and $43.9 million in dividends and distributions during the nine months ended September 30, 2017 and 2016, respectively.

Noncontrolling Interest

Noncontrolling Interest	9 Months Ended
	Sep. 30, 2017
Noncontrolling Interest [Abstract]
Noncontrolling Interest	1 3 . Noncontrolling Interest We present as a noncontrolling interest the portion of any equity in entities that we control and consolidate but do not own. Generally, OP Units of our Operating Partnership participate in net income allocations and distributions and entitle their holder to the right, subject to the terms set forth in the partnership agreement, to require the Operating Partnership to redeem all or a portion of the OP Units held by such limited partner. At our option, we may satisfy this redemption with cash or by exchanging shares of InfraREIT, Inc. common stock on a one-for-one basis. As of September 30, 2017 and December 31, 2016, there were a total of 16.9 million OP Units held by the limited partners of the Operating Partnership. During the nine months ended September 30, 2017 and 2016, an aggregate of 31,633 and 29,722 long-term incentive units (LTIP Units), respectively, were issued by our Operating Partnership to members of our board of directors. For additional information, refer to Note 16, Share-Based Compensation We follow the guidance issued by the FASB regarding the classification and measurement of redeemable securities. Accordingly, we have determined that the OP Units meet the requirements to be classified as permanent equity. We redeemed 23,349 OP Units with the issuance of 23,349 shares of common stock during the nine months ended September 30, 2017. During the nine months ended September 30, 2016, we redeemed 183,496 OP Units with the issuance of 183,496 shares of common stock.

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Earnings Per Share	1 4 . Earnings Per Share Basic earnings per share is calculated by dividing net earnings after noncontrolling interest by the weighted average shares outstanding. Diluted earnings per share is calculated similarly, except that it includes the dilutive effect of the assumed redemption of OP Units for shares of our common stock, if such redemption were dilutive. The redemption of OP Units would have been anti-dilutive during the three and nine months ended September 30, 2017 and 2016. Earnings per share are calculated as follows: Three Months Ended September 30, Nine Months Ended September 30, (In thousands, except per share data) 2017 2016 2017 2016 Basic net income per share: Net income attributable to InfraREIT, Inc. $ 15,330 $ 17,041 $ 30,587 $ 29,964 Weighted average common shares outstanding 43,784 43,755 43,779 43,634 Basic net income per share $ 0.35 $ 0.39 $ 0.70 $ 0.69 Diluted net income per share: Net income attributable to InfraREIT, Inc. $ 15,330 $ 17,041 $ 30,587 $ 29,964 Weighted average common shares outstanding 43,784 43,755 43,779 43,634 Redemption of Operating Partnership units — — — — Weighted average dilutive shares outstanding 43,784 43,755 43,779 43,634 Diluted net income per share $ 0.35 $ 0.39 $ 0.70 $ 0.69 Due to the anti-dilutive effect, the computation of diluted earnings per share does not reflect the following adjustments: Net income attributable to noncontrolling interest $ 5,908 $ 6,560 $ 11,797 $ 11,598 Redemption of Operating Partnership units 16,891 16,884 16,896 16,999

Leases

Leases	9 Months Ended
	Sep. 30, 2017
Leases [Abstract]
Leases	1 5 . Leases The following table shows the composition of our lease revenue: Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2017 2016 2017 2016 Base rent (straight-line) $ 42,336 $ 38,629 $ 122,382 $ 106,079 Percentage rent 9,282 10,790 9,282 10,790 Total lease revenue $ 51,618 $ 49,419 $ 131,664 $ 116,869 SDTS has entered into various leases with Sharyland for all our placed in service regulated assets. The master lease agreements, as amended, expire at various dates from December 31, 2017 through December 31, 2022. Each agreement includes annual base rent, while all but one agreement includes additional percentage rent (based on an agreed upon percentage of the gross revenue of Sharyland, as defined in the lease agreements, in excess of annual specified breakpoints). The rate used for percentage rent for the reported time periods varies by lease and ranges from a high of 32% to a low of 23%. Because an annual specified breakpoint must be met under our leases before we can recognize any percentage rent, we anticipate our revenue will grow over the year with little to no percentage rent recognized in the first and second quarters of each year and with the largest amounts recognized during the third and fourth quarters of each year. For details on our December Rate Case Filing and the leases proposed in that filing, see Note 10, Regulatory Matters Regulatory Matters

Share Based Compensation

Share Based Compensation	9 Months Ended
	Sep. 30, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Compensation	1 6 . Share-Based Compensation We currently utilize the InfraREIT, Inc. 2015 Equity Incentive Plan (2015 Equity Incentive Plan) primarily to compensate the non-employee directors for their service on our board of directors. In January 2017, we issued an aggregate of 31,633 LTIP Units to members of our board of directors with a grant date fair value of $18.02 per LTIP Unit and an aggregate fair value of $0.6 million. The 31,633 LTIP Units will vest in January 2018, subject to continued service. In January 2016, we issued an aggregate of 4,735 shares of common stock and 29,722 LTIP Units to members of our board of directors with a grant date fair value of $18.58 per common share or LTIP Unit and an aggregate fair value of $0.6 million. The 29,722 LTIP Units vested in January 2017, and the 4,735 shares of common stock fully vested upon issuance. In April 2016, we issued 5,497 shares of common stock to members of our board of directors with a grant date fair value of $16.81 per common share and an aggregate fair value of $0.1 million. In July 2016, we issued 5,248 shares of common stock to members of our board of directors with a grant date fair value of $17.58 per common share and an aggregate fair value of $0.1 million. The April and July 2016 grants of shares of common stock fully vested upon issuance. The compensation expense, which represents the fair value of the stock or LTIP Unit measured at market price at the date of grant, is recognized on a straight-line basis over the vesting period. For the three months ended September 30, 2017 and 2016, $0.1 million and $0.2 million, respectively, was recognized as compensation expense related to these grants and is included in general and administrative expense on the Consolidated Statements of Operations. We recognized $0.4 million and $0.8 million of compensation expense during the nine months ended September 30, 2017 and 2016, respectively. The unamortized compensation expense related to these grants was $0.1 million as of September 30, 2017.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	9 Months Ended
	Sep. 30, 2017
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Information	1 7 . Supplemental Cash Flow Information Supplemental cash flow information and non-cash investing and financing activities are as follows: Nine Months Ended September 30, (In thousands) 2017 2016 Supplemental cash flow information Cash paid during the period for interest $ 26,004 $ 21,879 Non-cash investing and financing activities Change in accrued additions to electric plant 8,901 3,383 Allowance for funds used during construction - debt 2,261 2,517 Redemption of operating partnership units for common stock 492 3,226 Dividends and distributions payable 15,169 15,160

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2017
Subsequent Events [Abstract]
Subsequent Events	1 8 . Subsequent Events On October 13, 2017, the PUCT issued an order approving the STM for the asset exchange transaction and granting SDTS a CCN authorizing SDTS to continue to own and lease its assets to Sharyland and also issued an order approving the settlement of Oncor’s rate case. The PUCT’s approval of the STM and Oncor’s rate case settlement are both conditions to the closing of the asset exchange transaction. On November 1, 2017, SDTS entered into agreements with respect to certain of the documents governing its outstanding indebtedness pursuant to which SDTS’s lenders consented to the asset exchange transaction and, effective upon closing of the asset exchange transaction, agreed to release all liens and security interests related to the assets being transferred to Oncor and to a modification of the asset sale covenants contained in SDTS’s revolving credit facility, 2017 Term Loan and various senior secured notes, in each case in a manner that provides additional flexibility to SDTS in the event of future asset sales. Closing of the asset exchange transaction and the effectiveness of the Rate Case dismissal are expected during November 2017.

Description of Business and P24

Description of Business and Presentation of Financial Statements (Policies)	9 Months Ended
	Sep. 30, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation InfraREIT, Inc. is a Maryland corporation, which may be referred to in these financial statements as the “Company,” “we,” “us” and “our.” These unaudited interim consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. Operating results for the nine months ended September 30, 2017 are not necessarily indicative of the results that may be expected for the year ending December 31, 2017. For further information, refer to the consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2016 filed with the U.S. Securities and Exchange Commission (SEC) on February 28, 2017 (2016 Form 10-K). We held 72.2% of the outstanding partnership units (OP Units) in InfraREIT Partners, LP (Operating Partnership or InfraREIT LP) as of September 30, 2017 and are its general partner. We include the accounts of the Operating Partnership and its subsidiaries in our consolidated financial statements. Hunt Consolidated, Inc. affiliates, current or former employees and members of our board of directors held the other 27.8% of the outstanding OP Units as of September 30, 2017.
Use of Estimates	Use of Estimates The preparation of our consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts in the consolidated financial statements and accompanying notes. Actual results could differ from those estimates.
Recent Accounting Guidance	Recent Accounting Guidance Recent Accounting Guidance Not Yet Adopted In February 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2016-02, Leases In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Clarification of Certain Cash Receipts and Cash Payments In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 203): Restricted Cash (A Consensus of the FASB Emerging Issues Task Force) In January 2017, the FASB issued ASU 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business.

Electric Plant and Depreciati25

Electric Plant and Depreciation (Tables)	9 Months Ended
	Sep. 30, 2017
Public Utilities Property Plant And Equipment [Abstract]
Schedule of Major Classes of Electric Plant	The major classes of electric plant are as follows: (In thousands) September 30, 2017 December 31, 2016 Electric plant: Transmission plant $ 1,247,626 $ 1,203,164 Distribution plant 628,636 575,648 General plant 16,007 15,959 Total plant in service 1,892,269 1,794,771 Construction work in progress 125,539 107,189 Total electric plant 2,017,808 1,901,960 Accumulated depreciation (265,163 ) (261,140 ) Electric plant, net $ 1,752,645 $ 1,640,820

Other Assets (Tables)

Other Assets (Tables)	9 Months Ended
	Sep. 30, 2017
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Summary of Other Assets	Other assets are as follows: September 30, 2017 December 31, 2016 (In thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Deferred financing costs on undrawn revolver $ 967 $ (542 ) $ 425 $ 967 $ (397 ) $ 570 Other regulatory assets: Deferred financing costs 28,570 (19,929 ) 8,641 27,761 (16,997 ) 10,764 Deferred costs recoverable in future years 23,793 — 23,793 23,793 — 23,793 Other regulatory assets 52,363 (19,929 ) 32,434 51,554 (16,997 ) 34,557 Investments 2,519 — 2,519 2,519 — 2,519 Other assets $ 55,849 $ (20,471 ) $ 35,378 $ 55,040 $ (17,394 ) $ 37,646

Long-Term Debt (Tables)

Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2017
Debt Instruments [Abstract]
Components of Long-Term Debt	Long-term debt consisted of the following: September 30, 2017 December 31, 2016 (In thousands) Maturity Date Amount Outstanding Interest Rate Amount Outstanding Interest Rate TDC Senior secured notes - $25.0 million December 30, 2020 $ 16,563 8.50% $ 17,500 8.50% SDTS Senior secured notes - $60.0 million June 20, 2018 60,000 5.04% 60,000 5.04% Senior secured term loan - $200.0 million June 5, 2020 200,000 2.48% — n/a Senior secured notes - $400.0 million December 3, 2025 400,000 3.86% 400,000 3.86% Senior secured notes - $100.0 million January 14, 2026 100,000 3.86% 100,000 3.86% Senior secured notes - $53.5 million December 30, 2029 41,073 7.25% 42,600 7.25% Senior secured notes - $110.0 million September 30, 2030 93,985 6.47% 97,366 6.47% Total SDTS debt 895,058 699,966 Total long-term debt 911,621 717,466 Less unamortized deferred financing costs (105 ) (129 ) Total long-term debt, less deferred financing costs 911,516 717,337 Less current portion of long-term debt (67,632 ) (7,849 ) Debt classified as long-term debt, less deferred financing costs $ 843,884 $ 709,488

Fair Value of Financial Instr28

Fair Value of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Financial Instruments Measured at Fair Value	Financial instruments, measured at fair value, by level within the fair value hierarchy were as follows: Carrying Fair Value (In thousands) Value Level 1 Level 2 Level 3 September 30, 2017 Long-term debt $ 911,621 $ — $ 954,748 $ — December 31, 2016 Long-term debt $ 717,466 $ — $ 758,415 $ —

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Computation of Earnings Per Share	Earnings per share are calculated as follows: Three Months Ended September 30, Nine Months Ended September 30, (In thousands, except per share data) 2017 2016 2017 2016 Basic net income per share: Net income attributable to InfraREIT, Inc. $ 15,330 $ 17,041 $ 30,587 $ 29,964 Weighted average common shares outstanding 43,784 43,755 43,779 43,634 Basic net income per share $ 0.35 $ 0.39 $ 0.70 $ 0.69 Diluted net income per share: Net income attributable to InfraREIT, Inc. $ 15,330 $ 17,041 $ 30,587 $ 29,964 Weighted average common shares outstanding 43,784 43,755 43,779 43,634 Redemption of Operating Partnership units — — — — Weighted average dilutive shares outstanding 43,784 43,755 43,779 43,634 Diluted net income per share $ 0.35 $ 0.39 $ 0.70 $ 0.69 Due to the anti-dilutive effect, the computation of diluted earnings per share does not reflect the following adjustments: Net income attributable to noncontrolling interest $ 5,908 $ 6,560 $ 11,797 $ 11,598 Redemption of Operating Partnership units 16,891 16,884 16,896 16,999

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2017
Leases [Abstract]
Schedule of Composition of Lease Revenue	The following table shows the composition of our lease revenue: Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2017 2016 2017 2016 Base rent (straight-line) $ 42,336 $ 38,629 $ 122,382 $ 106,079 Percentage rent 9,282 10,790 9,282 10,790 Total lease revenue $ 51,618 $ 49,419 $ 131,664 $ 116,869

Supplemental Cash Flow Inform31

Supplemental Cash Flow Information (Tables)	9 Months Ended
	Sep. 30, 2017
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Information and Non-cash Investing and Financing Activities	Supplemental cash flow information and non-cash investing and financing activities are as follows: Nine Months Ended September 30, (In thousands) 2017 2016 Supplemental cash flow information Cash paid during the period for interest $ 26,004 $ 21,879 Non-cash investing and financing activities Change in accrued additions to electric plant 8,901 3,383 Allowance for funds used during construction - debt 2,261 2,517 Redemption of operating partnership units for common stock 492 3,226 Dividends and distributions payable 15,169 15,160

Description of Business and P32

Description of Business and Presentation of Financial Statements - Additional Information (Details)	9 Months Ended
	Sep. 30, 2017
Description Of Business And Presentation Of Financial Statements [Line Items]
Percentage of partnership units outstanding	72.20%
Hunt Consolidated, Inc.
Description Of Business And Presentation Of Financial Statements [Line Items]
Percentage of partnership units outstanding	27.80%

Asset Exchange Transaction - Ad

Asset Exchange Transaction - Additional Information (Details) - Sharyland Distribution & Transmission Services, L.L.C. - Definitive Agreement - Oncor Electric Delivery Company LLC $ in Millions	Jul. 21, 2017USD ($)
Nonmonetary Transaction [Line Items]
Distribution assets	$ 400
Customary adjustments made in cash	20
West and Central Texas
Nonmonetary Transaction [Line Items]
Transmission assets	$ 380

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Related Party Transaction [Line Items]
Due from affiliates	$ 28,518,000		$ 28,518,000					$ 32,554,000
Hunt Utility Services, LLC
Related Party Transaction [Line Items]
Payment for management fee			14,100,000	$ 10,300,000
Prepaid management fee	0		0
Accrued management fee	$ 0		$ 0					3,500,000
Management fee						$ 14,000,000	$ 13,100,000
Management agreement expiration date			Dec. 31, 2019
Agreement successive renewal terms			5 years
Management fee, description			The base fee for each twelve month period beginning each April 1 thereafter will equal 1.50% of our total equity as of December 31 of the immediately preceding year, subject to a $30.0 million cap
Investment management fee equity multiplier	1.50%		1.50%
Management fee cap	$ 30,000,000		$ 30,000,000
Hunt Utility Services, LLC | Scenario, Forecast
Related Party Transaction [Line Items]
Management fee					$ 14,200,000
Maximum | Hunt Utility Services, LLC
Related Party Transaction [Line Items]
Reimbursement of annual software license and maintenance fees and other expenses			200,000	100,000
Sharyland
Related Party Transaction [Line Items]
Lease revenue from related party	51,600,000	$ 49,400,000	131,700,000	116,900,000
Deferred rent liability	18,800,000		18,800,000					15,600,000
Payments to acquire plant, and equipment			151,200,000	$ 179,500,000
Accounts payable and accrued liabilities	4,500,000		4,500,000					13,700,000
Due from affiliates	$ 28,500,000		$ 28,500,000					$ 32,600,000

Electric Plant and Depreciati35

Electric Plant and Depreciation - Schedule of Major Classes of Electric Plant (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Electric plant:
Transmission plant	$ 1,247,626	$ 1,203,164
Distribution plant	628,636	575,648
General plant	16,007	15,959
Total plant in service	1,892,269	1,794,771
Construction work in progress	125,539	107,189
Total electric plant	2,017,808	1,901,960
Accumulated depreciation	(265,163)	(261,140)
Electric plant, net	$ 1,752,645	$ 1,640,820

Electric Plant and Depreciati36

Electric Plant and Depreciation - Additional Information (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Public Utilities Property Plant And Equipment [Abstract]
Electric plant, net includes plant acquisition adjustments	$ 26.9	$ 27.7

Goodwill (Details)

Goodwill (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill	$ 138,384	$ 138,384

Other Assets - Summary of Other

Other Assets - Summary of Other Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Other Assets Noncurrent [Abstract]
Deferred financing costs on undrawn revolver, Gross Carrying Amount	$ 967	$ 967
Other regulatory assets Deferred financing costs, Gross Carrying Amount	28,570	27,761
Other regulatory assets Deferred costs recoverable in future years, Gross Carrying Amount	23,793	23,793
Other regulatory assets, Gross Carrying Amount	52,363	51,554
Investments, Gross Carrying Amount	2,519	2,519
Other assets, Gross Carrying Amount	55,849	55,040
Deferred financing costs on undrawn revolver, Accumulated Amortization	(542)	(397)
Other regulatory assets Deferred financing costs, Accumulated Amortization	(19,929)	(16,997)
Other regulatory assets, Accumulated Amortization	(19,929)	(16,997)
Other assets, Accumulated Amortization	(20,471)	(17,394)
Deferred financing costs on undrawn revolver, Net Carrying Amount	425	570
Other regulatory assets Deferred financing costs, Net Carrying Amount	8,641	10,764
Other regulatory assets Deferred costs recoverable in future years, Net Carrying Amount	23,793	23,793
Other regulatory assets, Net Carrying Amount	32,434	34,557
Investments, Net Carrying Amount	2,519	2,519
Other assets, Net Carrying Amount	$ 35,378	$ 37,646

Other Assets - Additional Infor

Other Assets - Additional Information (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Other Assets Noncurrent [Abstract]
Deferred costs recoverable in future years	$ 23,793,000	$ 23,793,000
Investment impaired	$ 0	$ 0

Borrowings Under Credit Facil40

Borrowings Under Credit Facilities - Additional Information (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2014	Dec. 31, 2016
InfraREIT LP Revolving Credit Facility
Line Of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity		$ 75,000,000
Credit facility, maturity date		Dec. 10, 2019
Revolving credit facility, interest rate description	a rate equal to (1) the one, two, three or six month London Interbank Offered Rate (LIBOR) plus 2.5%, or (2) a base rate (equal to the highest of (a) the Federal Funds Rate plus ½ of 1%, (b) the administrative agent’s prime rate and (c) LIBOR plus 1%) plus 1.5%. Letters of credit are subject to a letter of credit fee equal to the daily amount available to be drawn times 2.5%.
Letter of credit fee multiplier		2.50%
Amount of revolving credit facility under agreement	$ 0		$ 0
Letters of credit outstanding amount	0		0
Line of credit facility, remaining borrowing capacity	$ 75,000,000		75,000,000
InfraREIT LP Revolving Credit Facility | One, Two, Three or Six Month London Interbank Offered Rate (LIBOR)
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate		2.50%
InfraREIT LP Revolving Credit Facility | Federal Funds Rate
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate		0.50%
InfraREIT LP Revolving Credit Facility | LIBOR
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate		1.00%
InfraREIT LP Revolving Credit Facility | Base Rate
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate		1.50%
InfraREIT LP Revolving Credit Facility | Letter Of Credit
Line Of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity		$ 15,000,000
Third Amended and Restated Credit Agreement | SDTS Credit Agreements
Line Of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity		$ 250,000,000
Credit facility, maturity date		Dec. 10, 2019
Third Amended and Restated Credit Agreement | Letter Of Credit | SDTS Credit Agreements
Line Of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity		$ 25,000,000
Third Amended and Restated Credit Agreement | Swingline Loans | SDTS Credit Agreements
Line Of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity		$ 5,000,000
Revolving Credit Facility | SDTS Credit Agreements
Line Of Credit Facility [Line Items]
Revolving credit facility, interest rate description	a rate equal to either (1) a base rate, determined as the greatest of (a) the administrative agent’s prime rate, (b) the federal funds effective rate plus ½ of 1% and (c) LIBOR plus 1.00% per annum, plus a margin of either 0.75% or 1.00% per annum, depending on the total debt to capitalization ratio of SDTS on a consolidated basis or (2) the one, two, three or six month LIBOR plus a margin of either 1.75% or 2.00% per annum
Amount of revolving credit facility under agreement	$ 35,000,000		137,500,000
Line of credit facility, remaining borrowing capacity	$ 215,000,000		$ 112,500,000
Debt, weighted average interest rate	3.79%		2.50%
Revolving Credit Facility | One, Two, Three or Six Month London Interbank Offered Rate (LIBOR) | SDTS Credit Agreements | Minimum
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate		1.75%
Revolving Credit Facility | One, Two, Three or Six Month London Interbank Offered Rate (LIBOR) | SDTS Credit Agreements | Maximum
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate		2.00%
Revolving Credit Facility | Federal Funds Rate | SDTS Credit Agreements
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate		0.50%
Revolving Credit Facility | LIBOR | SDTS Credit Agreements
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate		1.00%
Revolving Credit Facility | Base Rate | SDTS Credit Agreements | Minimum
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate		0.75%
Revolving Credit Facility | Base Rate | SDTS Credit Agreements | Maximum
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate		1.00%
Revolving Credit Facility | Letter Of Credit | SDTS Credit Agreements
Line Of Credit Facility [Line Items]
Amount of revolving credit facility under agreement	$ 0		$ 0

Long-Term Debt - Components of

Long-Term Debt - Components of Long-Term Debt (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Debt Instrument [Line Items]
Long-term debt, Amount Outstanding	$ 911,621	$ 717,466
Less unamortized deferred financing costs	(105)	(129)
Total long-term debt, less deferred financing costs	911,516	717,337
Less current portion of long-term debt	(67,632)	(7,849)
Debt classified as long-term debt, less deferred financing costs	$ 843,884	$ 709,488
TDC | Senior Secured Notes, 8.50%
Debt Instrument [Line Items]
Long-term debt, Interest Rate	8.50%	8.50%		8.50%
Long-term debt, Amount Outstanding	$ 16,563	$ 17,500
Interest bearing note, maturity date	Dec. 30, 2020
SDTS Credit Agreements
Debt Instrument [Line Items]
Long-term debt, Amount Outstanding	$ 895,058	$ 699,966
SDTS Credit Agreements | Senior Secured Notes, 5.04%
Debt Instrument [Line Items]
Long-term debt, Interest Rate	5.04%	5.04%	5.04%
Long-term debt, Amount Outstanding	$ 60,000	$ 60,000
Interest bearing note, maturity date	Jun. 20, 2018
SDTS Credit Agreements | Senior Secured Term Loan, 2.48%
Debt Instrument [Line Items]
Long-term debt, Interest Rate	2.48%
Long-term debt, Amount Outstanding	$ 200,000
Interest bearing note, maturity date	Jun. 5, 2020
SDTS Credit Agreements | Senior Secured Notes, 3.86%
Debt Instrument [Line Items]
Long-term debt, Interest Rate	3.86%	3.86%
Long-term debt, Amount Outstanding	$ 400,000	$ 400,000
Interest bearing note, maturity date	Dec. 3, 2025
SDTS Credit Agreements | Senior Secured Notes, 3.86% Maturing in 2026
Debt Instrument [Line Items]
Long-term debt, Interest Rate	3.86%	3.86%
Long-term debt, Amount Outstanding	$ 100,000	$ 100,000
Interest bearing note, maturity date	Jan. 14, 2026
SDTS Credit Agreements | Senior Secured Notes, 7.25%
Debt Instrument [Line Items]
Long-term debt, Interest Rate	7.25%	7.25%			7.25%
Long-term debt, Amount Outstanding	$ 41,073	$ 42,600
Interest bearing note, maturity date	Dec. 30, 2029
SDTS Credit Agreements | Senior Secured Notes, 6.47%
Debt Instrument [Line Items]
Long-term debt, Interest Rate	6.47%	6.47%		6.47%
Long-term debt, Amount Outstanding	$ 93,985	$ 97,366
Interest bearing note, maturity date	Sep. 30, 2030

Long-Term Debt - Components o42

Long-Term Debt - Components of Long-Term Debt (Parenthetical) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
TDC | Senior Secured Notes, 8.50%
Debt Instrument [Line Items]
Long-term debt, face amount	$ 25		$ 25
SDTS Credit Agreements | Senior Secured Notes, 5.04%
Debt Instrument [Line Items]
Long-term debt, face amount	60	$ 60
SDTS Credit Agreements | Senior Secured Term Loan, 2.48%
Debt Instrument [Line Items]
Long-term debt, face amount	200
SDTS Credit Agreements | Senior Secured Notes, 3.86%
Debt Instrument [Line Items]
Long-term debt, face amount	400
SDTS Credit Agreements | Senior Secured Notes, 3.86% Maturing in 2026
Debt Instrument [Line Items]
Long-term debt, face amount	100
SDTS Credit Agreements | Senior Secured Notes, 7.25%
Debt Instrument [Line Items]
Long-term debt, face amount	53.5			$ 53.5
SDTS Credit Agreements | Senior Secured Notes, 6.47%
Debt Instrument [Line Items]
Long-term debt, face amount	$ 110		$ 110

Long-Term Debt - Additional Inf

Long-Term Debt - Additional Information (Details) - USD ($) $ in Thousands	Jun. 05, 2017	Sep. 30, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Debt Instrument [Line Items]
Deferred financing costs, Net Carrying Amount		$ 425	$ 570
2017 Term Loan
Debt Instrument [Line Items]
Long-term debt, face amount		200,000
TDC | Senior Secured Notes, 8.50%
Debt Instrument [Line Items]
Long-term debt, face amount		$ 25,000				$ 25,000
Long-term debt, stated interest rate		8.50%	8.50%			8.50%
Deferred financing costs, Net Carrying Amount		$ 100	$ 100
SDTS Credit Agreements | Senior Secured Notes, 5.04%
Debt Instrument [Line Items]
Long-term debt, face amount		$ 60,000			$ 60,000
Long-term debt, stated interest rate		5.04%	5.04%		5.04%
SDTS Credit Agreements | 2017 Term Loan | Canadian Imperial Bank of Commerce, New York Branch and Mizuho Bank, Ltd.
Debt Instrument [Line Items]
Long-term debt, face amount	$ 200,000
Interest rate description		The interest rate for the 2017 Term Loan is based, at SDTS’s option, at a rate equal to either (1) a base rate, determined as the greatest of (a) the administrative agent’s prime rate, (b) the federal funds effective rate plus 0.5% and (c) LIBOR plus 1.00% per annum, plus a margin of 0.25% per annum or (2) LIBOR plus a margin of 1.25% per annum. The LIBOR interest period may be one, two, three or six months, but interest is payable no less frequently than quarterly.
SDTS Credit Agreements | 2017 Term Loan | Canadian Imperial Bank of Commerce, New York Branch and Mizuho Bank, Ltd. | Federal Funds Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.50%
SDTS Credit Agreements | 2017 Term Loan | Canadian Imperial Bank of Commerce, New York Branch and Mizuho Bank, Ltd. | LIBOR
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.00%
SDTS Credit Agreements | 2017 Term Loan | Canadian Imperial Bank of Commerce, New York Branch and Mizuho Bank, Ltd. | Base Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.25%
SDTS Credit Agreements | 2017 Term Loan | Canadian Imperial Bank of Commerce, New York Branch and Mizuho Bank, Ltd. | One, Two, Three or Six Month London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.25%
SDTS Credit Agreements | Senior Secured Notes, 7.25%
Debt Instrument [Line Items]
Long-term debt, face amount		$ 53,500					$ 53,500
Long-term debt, stated interest rate		7.25%	7.25%				7.25%
SDTS Credit Agreements | Senior Secured Notes, 6.47%
Debt Instrument [Line Items]
Long-term debt, face amount		$ 110,000				$ 110,000
Long-term debt, stated interest rate		6.47%	6.47%			6.47%
SDTS Credit Agreements | Series A Notes
Debt Instrument [Line Items]
Long-term debt, face amount				$ 400,000
Long-term debt, stated interest rate				3.86%
Long-Term Debt Maturity Period				10 years
SDTS Credit Agreements | Series B Notes
Debt Instrument [Line Items]
Long-term debt, face amount			$ 100,000
Long-term debt, stated interest rate			3.86%
Long-Term Debt Maturity Period			10 years

Fair Value of Financial Instr44

Fair Value of Financial Instruments - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term Debt	$ 843,884	$ 709,488
2017 Term Loan
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, face amount	200,000
Senior Secured Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term Debt	$ 711,600	$ 717,500
Debt, weighted average interest rate	4.60%	4.60%

Fair Value of Financial Instr45

Fair Value of Financial Instruments - Financial Instruments Measured at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Carrying Value
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-term debt	$ 911,621	$ 717,466
Level 2 | Fair Value
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-term debt	$ 954,748	$ 758,415

Regulatory Matters - Additional

Regulatory Matters - Additional Information (Details) - USD ($) $ in Thousands	Jul. 21, 2017	Sep. 30, 2017	Dec. 31, 2016
Public Utilities General Disclosures [Line Items]
Regulatory Liability		$ 28,486	$ 21,004
Sharyland | Sharyland Distribution & Transmission Services, L.L.C.
Public Utilities General Disclosures [Line Items]
Public utilities, allowed return on equity, percentage	9.70%
Sharyland and SDTS
Public Utilities General Disclosures [Line Items]
Public utilities, requested capital structure, debt percentage	55.00%
Public utilities, requested capital structure, equity percentage	45.00%
Public utilities cost of debt percentage	6.73%

Equity - Additional Information

Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Equity [Abstract]
Cash dividends declared per share to shareholders	$ 0.25	$ 0.25	$ 0.75	$ 0.75
Cash distributions declared to unit holders, per unit			$ 0.75	$ 0.75
Dividends and distributions paid			$ 45,499	$ 43,948

Noncontrolling Interest - Addit

Noncontrolling Interest - Additional Information (Details) - shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Minority Interest [Line Items]
Description of units redeemed for cash or, at option, exchanged for common shares	one-for-one basis
OP Units held by the limited partners	16,900,000		16,900,000
Operating partnership units redeem	23,349	183,496
Common shares issued	23,349	183,496
LTIP Units
Minority Interest [Line Items]
Operating partnership units issued	31,633	29,722

Earnings Per Share - Computatio

Earnings Per Share - Computation of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Basic net income per share:
Net income attributable to InfraREIT, Inc.	$ 15,330	$ 17,041	$ 30,587	$ 29,964
Weighted average common shares outstanding	43,784	43,755	43,779	43,634
Basic net income per share	$ 0.35	$ 0.39	$ 0.70	$ 0.69
Diluted net income per share:
Net income attributable to InfraREIT, Inc.	$ 15,330	$ 17,041	$ 30,587	$ 29,964
Weighted average common shares outstanding	43,784	43,755	43,779	43,634
Weighted average dilutive shares outstanding	43,784	43,755	43,779	43,634
Diluted net income per share	$ 0.35	$ 0.39	$ 0.70	$ 0.69
Due to the anti-dilutive effect, the computation of diluted earnings per share does not reflect the following adjustments:
Net income attributable to noncontrolling interest	$ 5,908	$ 6,560	$ 11,797	$ 11,598
Redemption of Operating Partnership units	16,891	16,884	16,896	16,999

Leases - Schedule of Compositio

Leases - Schedule of Composition of Lease Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Leases [Abstract]
Base rent (straight-line)	$ 42,336	$ 38,629	$ 122,382	$ 106,079
Percentage rent	9,282	10,790	9,282	10,790
Total lease revenue	$ 51,618	$ 49,419	$ 131,664	$ 116,869

Leases - Additional Information

Leases - Additional Information (Details)	9 Months Ended
	Sep. 30, 2017
Operating Leased Assets [Line Items]
Operating leases placed in services dates description	SDTS has entered into various leases with Sharyland for all our placed in service regulated assets. The master lease agreements, as amended, expire at various dates from December 31, 2017 through December 31, 2022.
Lease expiration date range, start date	Dec. 31, 2017
Lease expiration date range, end date	Dec. 31, 2022
Lease expiration date	Dec. 31, 2020
Maximum
Operating Leased Assets [Line Items]
Rate of rent used, Percentage	32.00%
Minimum
Operating Leased Assets [Line Items]
Rate of rent used, Percentage	23.00%

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details) - 2015 Equity Incentive Plan - USD ($)	1 Months Ended				3 Months Ended		9 Months Ended
	Jan. 31, 2017	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Unamortized stock compensation expense					$ 100,000		$ 100,000
General And Administrative Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Compensation expenses					$ 100,000	$ 200,000	$ 400,000	$ 800,000
Director
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Grant date fair value per share		$ 17.58	$ 16.81
Grant date fair value		$ 100,000	$ 100,000
Aggregate common stock shares issued to directors		5,248	5,497	4,735
Director | LTIP Units
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
LTIP Units issued to directors	31,633			29,722
Grant date fair value per share	$ 18.02			$ 18.58
Grant date fair value	$ 600,000			$ 600,000
Vesting period of LTIP Units	Jan. 31, 2018			Jan. 31, 2017

Supplemental Cash Flow Inform53

Supplemental Cash Flow Information - Supplemental Cash Flow Information and Non-cash Investing and Financing Activities (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Supplemental cash flow information
Cash paid during the period for interest	$ 26,004	$ 21,879
Non-cash investing and financing activities
Change in accrued additions to electric plant	8,901	3,383
Allowance for funds used during construction - debt	2,261	2,517
Redemption of operating partnership units for common stock	492	3,226
Dividends and distributions payable	$ 15,169	$ 15,160	$ 15,161