InfraREIT (HIFR) 10-Q 1 Aug 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Jul. 27, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
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		43,962,167

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current Assets
Cash and cash equivalents	$ 2,102	$ 2,867
Restricted cash	1,685	1,683
Due from affiliates	32,423	35,172
Inventory	7,302	6,759
Prepaids and other current assets	1,039	2,460
Total current assets	44,551	48,941
Electric Plant, net	1,788,991	1,772,229
Goodwill	138,384	138,384
Other Assets	32,188	34,314
Total Assets	2,004,114	1,993,868
Current Liabilities
Accounts payable and accrued liabilities	22,955	21,230
Short-term borrowings	99,500	41,000
Current portion of long-term debt	7,957	68,305
Dividends and distributions payable	15,176	15,169
Accrued taxes	491	5,633
Total current liabilities	146,079	151,337
Long-Term Debt, Less Deferred Financing Costs	837,486	841,215
Regulatory Liabilities	108,023	100,458
Total liabilities	1,091,588	1,093,010
Commitments and Contingencies
Equity
Common stock, $0.01 par value; 450,000,000 shares authorized; 43,962,167 and 43,796,915 issued and outstanding as of June 30, 2018 and December 31, 2017, respectively	440	438
Additional paid-in capital	709,488	706,357
Accumulated deficit	(41,510)	(49,728)
Total InfraREIT, Inc. equity	668,418	657,067
Noncontrolling interest	244,108	243,791
Total equity	912,526	900,858
Total Liabilities and Equity	$ 2,004,114	$ 1,993,868

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2018	Dec. 31, 2017
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	43,962,167	43,796,915
Common stock, shares, outstanding	43,962,167	43,796,915

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Lease revenue	$ 47,827	$ 40,422	$ 93,483	$ 80,046
Operating costs and expenses
General and administrative expense	6,631	6,866	12,719	12,847
Depreciation	11,992	12,982	23,569	25,669
Total operating costs and expenses	18,623	19,848	36,288	38,516
Income from operations	29,204	20,574	57,195	41,530
Other (expense) income
Interest expense, net	(11,070)	(10,141)	(21,744)	(19,839)
Other income, net	374	17	1,107	20
Total other expense	(10,696)	(10,124)	(20,637)	(19,819)
Income before income taxes	18,508	10,450	36,558	21,711
Income tax (benefit) expense	(5,428)	321	(5,142)	565
Net income	23,936	10,129	41,700	21,146
Less: Net income attributable to noncontrolling interest	6,602	2,821	11,502	5,889
Net income attributable to InfraREIT, Inc.	$ 17,334	$ 7,308	$ 30,198	$ 15,257
Net income attributable to InfraREIT, Inc. common stockholders per share:
Basic	$ 0.39	$ 0.17	$ 0.69	$ 0.35
Diluted	0.39	0.17	0.69	0.35
Cash dividends declared per common share	$ 0.25	$ 0.25	$ 0.50	$ 0.50

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities
Net income	$ 41,700	$ 21,146
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	23,569	25,669
Amortization of deferred financing costs	2,142	2,030
Allowance for funds used during construction - other funds	(1,094)
Equity based compensation	320	285
Changes in assets and liabilities:
Due from affiliates	2,749	5,227
Inventory	(543)	104
Prepaids and other current assets	(211)	(296)
Accounts payable and accrued liabilities	(3,390)	1,986
Net cash provided by operating activities	65,242	56,151
Cash flows from investing activities
Additions to electric plant	(31,699)	(91,601)
Proceeds from asset exchange transaction	1,632
Net cash used in investing activities	(30,067)	(91,601)
Cash flows from financing activities
Proceeds from short-term borrowings	92,500	65,500
Repayments of short-term borrowings	(34,000)	(203,000)
Proceeds from borrowings of long-term debt		200,000
Repayments of long-term debt	(64,093)	(3,869)
Deferred financing costs		(801)
Dividends and distributions paid	(30,345)	(30,330)
Net cash (used in) provided by financing activities	(35,938)	27,500
Net decrease in cash, cash equivalents and restricted cash	(763)	(7,950)
Cash, cash equivalents and restricted cash at beginning of period	4,550	19,294
Cash, cash equivalents and restricted cash at end of period	$ 3,787	$ 11,344

Description of Business and Pre

Description of Business and Presentation of Financial Statements	6 Months Ended
	Jun. 30, 2018
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 six months ended June 30, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018. 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, 2017 filed with the U.S. Securities and Exchange Commission (SEC) on March 5, 2018 (2017 Form 10-K). We held 72.4% of the outstanding partnership units (OP Units) in InfraREIT Partners, LP (Operating Partnership or InfraREIT LP) as of June 30, 2018 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 27.6% of the outstanding OP Units as of June 30, 2018. 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 Recently Adopted Accounting Guidance In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (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) Recent Accounting Guidance Not Yet Adopted In February 2016, the FASB issued ASU 2016-02, Leases Leases (Topic 842): Land Easement Practical Expedient for Transition to Topic 842

Asset Exchange Transaction

Asset Exchange Transaction	6 Months Ended
	Jun. 30, 2018
Nonmonetary Transactions [Abstract]
Asset Exchange Transaction	2 . Asset Exchange Transaction In July 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 and certain transmission assets for a group of Oncor’s transmission assets located in Northwest and Central Texas (Asset Exchange Transaction). The Asset Exchange Transaction closed in November 2017 and, among other things, resulted in SDTS exchanging $403 million of net assets for $383 million of transmission assets owned by Oncor, $18 million of net cash and a $2 million receivable from Oncor as of December 31, 2017. The transaction resulted in a gain of $0.3 million for SDTS. The receivable from Oncor was included in prepaids and other current assets in the Consolidated Balance Sheets at December 31, 2017. The receivable from Oncor was collected during the first quarter of 2018. These transactions were 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).

Cash, Cash Equivalents and Rest

Cash, Cash Equivalents and Restricted Cash	6 Months Ended
	Jun. 30, 2018
Cash And Cash Equivalents [Abstract]
Cash, Cash Equivalents and Restricted Cash	3 . Cash, Cash Equivalents and Restricted Cash The following table provides a reconciliation of cash, cash equivalents and restricted cash within the Consolidated Balance Sheets that sum to the total of the same such amounts shown on the Consolidated Statements of Cash Flows: June 30, (In thousands) 2018 2017 Cash $ 2,102 $ 9,662 Restricted cash 1,685 1,682 Total cash, cash equivalents and restricted cash shown on the Statement of Cash Flows $ 3,787 $ 11,344 Amounts included in restricted cash represent the principal and interest payable for two consecutive periods associated with the $25.0 million senior secured notes of the Operating Partnership’s wholly-owned subsidiary, Transmission and Distribution Company, L.L.C. (TDC), as described in Note 9, Long-Term Debt

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2018
Related Party Transactions [Abstract]
Related Party Transactions	4 . Related Party Transactions We lease, through SDTS, all our regulated assets to Sharyland through several lease agreements. Under the leases, we have agreed to fund capital expenditures for footprint projects. Our leases define “footprint projects” to be transmission or, if applicable, distribution projects that (1) are primarily situated within our current or previous distribution service territory, as applicable; (2) physically hang from our existing transmission assets, such as the addition of another circuit to our existing transmission lines, or that are physically located within one of our substations or (3) connect or are otherwise added to transmission lines or other properties that comprise a part of the transmission assets acquired in the Asset Exchange Transaction. We earned lease revenue from Sharyland under these agreements of $47.8 million and $40.4 million during the three months ended June 30, 2018 and 2017, respectively. We earned lease revenue of $93.5 million and $80.0 million from Sharyland during the six months ended June 30, 2018 and 2017, respectively. In connection with our leases with Sharyland, we had a deferred rent liability of $14.5 million and $14.7 million as of June 30, 2018 and December 31, 2017, 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 six months ended June 30, 2018 and 2017, the net amount of payments we made to Sharyland was $31.1 million and $93.9 million, respectively. In July 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 Asset Exchange Transaction. Specifically, the Side Letter includes, among other things, 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 and an allocation of expenses incurred in connection with the transactions. For information related to Asset Exchange Transaction, see Note 2, Asset Exchange Transaction As part of the Asset Exchange Transaction, we incurred $0.2 million in legal fees related to us obtaining the lenders’ consents to complete the Asset Exchange Transaction. These costs are eligible to be recovered through rates collected from customers during the 24-month period starting January 2018 through December 2019. We sold the recoverable costs to Sharyland in exchange for 24 equal monthly payments beginning January 2018 through December 2019. The equal monthly payments from Sharyland will be received through the CREZ lease. As of June 30, 2018, Sharyland had made six monthly payments related to the recoverable legal fees. As of December 31, 2017, there were no payments due from Sharyland related to the legal fees and no payments had been received. These fees are included in due from affiliates on the Consolidated Balance Sheets. As of June 30, 2018 and December 31, 2017, accounts payable and accrued liabilities on the Consolidated Balance Sheets included $2.7 million and $2.1 million, respectively, related to amounts owed to Sharyland for construction costs incurred and property taxes paid on our behalf. As of June 30, 2018 and December 31, 2017, amounts due from affiliates on the Consolidated Balance Sheets included $32.4 million and $35.2 million, respectively, related to amounts owed by Sharyland primarily associated with our leases. The management fee paid to Hunt Utility Services, LLC (Hunt Manager) for the six months ended June 30, 2018 and 2017 was $6.9 million and $10.5 million, respectively. There were no prepaid or accrued amounts associated with the management fees on the Consolidated Balance Sheets as of June 30, 2018 and December 31, 2017. As of December 31, 2016, there was $3.5 million accrued associated with management fees on the Consolidated Balance Sheets. Additionally, during the six months ended June 30, 2018 and 2017, we paid Hunt Manager $0.1 million and $0.2 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 provides for an annual base fee, or management fee. The base fee for each 12 month period beginning each April 1 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. The annual base fees through March 31, 2019 are as follows: (In millions) Base Fee April 1, 2016 - March 31, 2017 $ 14.0 April 1, 2017 - March 31, 2018 14.2 April 1, 2018 - March 31, 2019 13.5

Electric Plant and Depreciation

Electric Plant and Depreciation	6 Months Ended
	Jun. 30, 2018
Public Utilities Property Plant And Equipment [Abstract]
Electric Plant and Depreciation	5 . Electric Plant and Depreciation The major classes of electric plant are as follows: (In thousands) June 30, 2018 December 31, 2017 Electric plant: Transmission plant $ 1,779,123 $ 1,685,466 Distribution plant 150,034 143,865 General plant 3,023 3,023 Total plant in service 1,932,180 1,832,354 Construction work in progress 46,701 113,643 Total electric plant 1,978,881 1,945,997 Accumulated depreciation (189,890 ) (173,768 ) Electric plant, net $ 1,788,991 $ 1,772,229 General plant consists primarily of a warehouse, buildings and associated assets. Construction work in progress (CWIP) relates to various projects underway related to our regulated assets. The capitalized 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 $28.8 million and $29.4 million as of June 30, 2018 and December 31, 2017, respectively.

Goodwill

Goodwill	6 Months Ended
	Jun. 30, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill	6 . 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 June 30, 2018 and December 31, 2017, $138.4 million was recorded as goodwill on the Consolidated Balance Sheets.

Other Assets

Other Assets	6 Months Ended
	Jun. 30, 2018
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Other Assets	7 . Other Assets Other assets are as follows: June 30, 2018 December 31, 2017 (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 $ (688 ) $ 279 $ 967 $ (591 ) $ 376 Other regulatory assets: Deferred financing costs 10,365 (4,768 ) 5,597 28,570 (20,944 ) 7,626 Deferred costs recoverable in future years 23,793 — 23,793 23,793 — 23,793 Other regulatory assets 34,158 (4,768 ) 29,390 52,363 (20,944 ) 31,419 Investments 2,519 — 2,519 2,519 — 2,519 Other assets $ 37,644 $ (5,456 ) $ 32,188 $ 55,849 $ (21,535 ) $ 34,314 Deferred financing costs on undrawn revolver consist of costs incurred in connection with the establishment of the InfraREIT LP revolving credit facility. See Note 8, 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 SDTS’s regulated assets or the refinancing of related debt. These assets are classified as regulatory assets and amortized over the length of the related loan. These costs are recovered through rates established in rate cases. The $18.2 million gross deferred financing costs associated with our 2011 Notes (defined below) were fully amortized in June 2018 and removed from our Consolidated Balance Sheets when the 2011 Notes were repaid at maturity. See Note 9, Long-Term Debt Deferred costs recoverable in future years of $23.8 million as of June 30, 2018 and December 31, 2017 represent operating costs incurred from the 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. We account for this investment under the cost method of accounting. We believe that the investment is not impaired as of June 30, 2018 and December 31, 2017.

Borrowings Under Credit Facilit

Borrowings Under Credit Facilities	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Borrowings Under Credit Facilities	8 . 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 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 9, 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 June 30, 2018 and December 31, 2017, 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 June 30, 2018 and December 31, 2017, 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 9, 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) 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 June 30, 2018, SDTS had $99.5 million of borrowings outstanding at an interest rate of 4.10%, no letters of credit outstanding and $150.5 million of borrowing capacity available under this revolving credit facility. During June 2018, $60.0 million in borrowings were used to repay the outstanding balance on the 2011 Notes. See Note 9, Long-Term Debt 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. 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	6 Months Ended
	Jun. 30, 2018
Debt Instruments [Abstract]
Long-Term Debt	9 . Long-Term Debt Long-term debt consisted of the following: June 30, 2018 December 31, 2017 (Dollar amounts in thousands) Maturity Date Amount Outstanding Interest Rate Amount Outstanding Interest Rate TDC Senior secured notes - $25.0 million December 30, 2020 $ 15,625 8.50% $ 16,250 8.50% SDTS Senior secured notes - $60.0 million June 20, 2018 — n/a 60,000 5.04% Senior secured term loan - $200.0 million June 5, 2020 200,000 3.34% 200,000 2.71% 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 39,462 7.25% 40,546 7.25% Senior secured notes - $110.0 million September 30, 2030 90,436 6.47% 92,821 6.47% Total SDTS debt 829,898 893,367 Total long-term debt 845,523 909,617 Less unamortized deferred financing costs (80 ) (97 ) Total long-term debt, less deferred financing costs 845,443 909,520 Less current portion of long-term debt (7,957 ) (68,305 ) Debt classified as long-term debt, less deferred financing costs $ 837,486 $ 841,215 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 had $60.0 million aggregate principal amount of 5.04% per annum senior secured notes that were issued to The Prudential Insurance Company of America and affiliates in 2011 (2011 Notes). Interest was payable quarterly while no principal payments were due until maturity. These notes were paid in full at maturity during June 2018 with proceeds from SDTS’s revolving credit facility. In June 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. In 2015, SDTS issued $400.0 million series A senior secured notes (Series A Notes), and in 2016 issued an additional $100.0 million series B senior secured notes (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 June 30, 2018 and December 31, 2017, SDTS and TDC were in compliance with all debt covenants under the applicable agreements. SDTS’s Series A Notes, Series B Notes, 2009 Notes, 2010 Notes and 2017 Term Loan are, and the 2011 Notes were, 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 revolving credit facility described above in Note 8, 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	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	10 . 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 $645.5 million and $709.6 million under our senior secured notes with a weighted average interest rate of 4.6% per annum as of June 30, 2018 and December 31, 2017, respectively. The fair value of these borrowings is estimated using discounted cash flow analysis based on current market rates. As of June 30, 2018 and December 31, 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 June 30, 2018 Long-term debt $ 845,523 $ — $ 861,272 $ — December 31, 2017 Long-term debt $ 909,617 $ — $ 950,522 $ —

Regulatory Matters

Regulatory Matters	6 Months Ended
	Jun. 30, 2018
Public Utilities Rate Matters [Abstract]
Regulatory Matters	1 1 . Regulatory Matters Regulatory Liability Regulatory liabilities are as follows: (In thousands) June 30, 2018 December 31, 2017 Cost of removal $ 52,244 $ 44,679 Excess ADFIT 55,779 55,779 Regulatory liabilities $ 108,023 $ 100,458 Our regulatory liability related to cost of removal is established through depreciation rates and represents amounts that we expect to incur in the future. The regulatory liability is recorded as a long-term liability net of actual removal costs incurred. As an owner of regulated utility assets, we established an accumulated deferred federal income tax (ADFIT) balance for regulatory purposes primarily associated with the difference between U.S. GAAP and federal income tax depreciation on our assets. This ADFIT was calculated based on a 35% corporate federal income tax rate but was not recorded on our consolidated balance sheets or income statements due to the expectation that we would not pay corporate federal income taxes as a result of our REIT structure. With the passage of the Tax Cuts and Jobs Act (TCJA), the corporate federal income tax rate was reduced to 21% effective for tax years beginning on or after January 1, 2018. Regulatory accounting rules require utilities to revalue their ADFIT balances based on a change in corporate federal income tax rates, to remove the difference from ADFIT and to create a regulatory liability for the reduction in ADFIT. Therefore, we reduced the ADFIT by $55.8 million and created a regulatory liability for regulatory purposes. Additionally, in accordance with ASC Topic 980, Regulated Operations Liabilities Rate Case Filing In January 2014, the PUCT approved a rate case (2013 Rate Case) filed by Sharyland applicable to our regulated assets providing for a capital structure consisting of 55% debt and 45% equity; a cost of debt of 6.73%; a return on equity of 9.70%; and a return on invested capital of 8.06% in calculating rates. The new rates became effective May 1, 2014. Under the order approving the 2013 Rate Case, Sharyland was required to file its next rate case in 2016 (2016 Rate Case). In November 2017, the 2016 Rate Case was dismissed, which resulted in the 2013 Rate Case regulatory parameters remaining in place. As part of the PUCT order approving the Asset Exchange Transaction, the PUCT also granted SDTS a CCN to continue to own and lease its assets to Sharyland. SDTS and Sharyland are required to file a new rate case by July 1, 2020 with a test year ending December 31, 2019.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	1 2 . Commitments and Contingencies 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	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Equity	1 3 . Equity We and the Operating Partnership declared cash dividends on common stock and distributions on OP Units of $0.50 per share or unit, as applicable, during each of the six months ended June 30, 2018 and 2017. We paid a total of $30.3 million in dividends and distributions during each of the six months ended June 30, 2018 and 2017.

Noncontrolling Interest

Noncontrolling Interest	6 Months Ended
	Jun. 30, 2018
Noncontrolling Interest [Abstract]
Noncontrolling Interest	1 4 . 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 requirement with cash or by exchanging shares of InfraREIT, Inc. common stock on a one-for-one basis. As of June 30, 2018 and December 31, 2017, there were a total of 16.7 million and 16.9 million OP Units, respectively, held by the limited partners of the Operating Partnership. During the six months ended June 30, 2018 and 2017, an aggregate of 28,952 and 31,633 long-term incentive units (LTIP Units), respectively, were issued by the Operating Partnership to members of our board of directors. For additional information, refer to Note 17, 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. During the six months ended June 30, 2018, we redeemed 165,252 OP Units with the issuance of 165,252 shares of common stock. We redeemed 6,207 OP Units with the issuance of 6,207 shares of common stock during the six months ended June 30, 2017.

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Share	1 5 . 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 six months ended June 30, 2018 and 2017. Earnings per share are calculated as follows: Three Months Ended June 30, Six Months Ended June 30, (In thousands, except per share data) 2018 2017 2018 2017 Basic net income per share: Net income attributable to InfraREIT, Inc. $ 17,334 $ 7,308 $ 30,198 $ 15,257 Weighted average common shares outstanding 43,961 43,778 43,897 43,776 Basic net income per share $ 0.39 $ 0.17 $ 0.69 $ 0.35 Diluted net income per share: Net income attributable to InfraREIT, Inc. $ 17,334 $ 7,308 $ 30,198 $ 15,257 Weighted average common shares outstanding 43,961 43,778 43,897 43,776 Redemption of Operating Partnership units — — — — Weighted average dilutive shares outstanding 43,961 43,778 43,897 43,776 Diluted net income per share $ 0.39 $ 0.17 $ 0.69 $ 0.35 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 $ 6,602 $ 2,821 $ 11,502 $ 5,889 Redemption of Operating Partnership units 16,743 16,897 16,807 16,899

Leases

Leases	6 Months Ended
	Jun. 30, 2018
Leases [Abstract]
Leases	1 6 . Leases The following table shows the composition of our lease revenue: Three Months Ended June 30, Six Months Ended June 30, (In thousands) 2018 2017 2018 2017 Base rent (straight-line) $ 47,827 $ 40,422 $ 93,483 $ 80,046 Percentage rent — — — — Total lease revenue $ 47,827 $ 40,422 $ 93,483 $ 80,046 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, 2019 through December 31, 2022. Our leases primarily consist of base rent, but certain lease supplements contain percentage rent as well. The lease supplements governing the Stanton Transmission Loop, Permian Basin assets and assets acquired in the Asset Exchange Transaction, which are part of the CREZ assets, only provide for base rent. Rent for the assets in McAllen and the CREZ assets not acquired in the Asset Exchange Transaction is comprised primarily of base rent but also includes percentage rent. Prior to its termination on December 31, 2017, the lease that previously covered the Permian Basin assets as well as the assets in Brady and Celeste, Texas that were transferred to Oncor in the Asset Exchange Transaction also included a percentage rent component. Percentage rent under our leases is based on a percentage of Sharyland’s annual gross revenue, as defined in the applicable lease, in excess of annual specified breakpoints, which are at least equal to the base rent under each lease. The rate used for percentage rent for the reported time periods varies by lease and ranges from a high of 31% 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 that little to no percentage rent will be recognized in the first and second quarters of each year, with the largest amounts of percentage rent recognized during the third and fourth quarters of each year.

Share Based Compensation

Share Based Compensation	6 Months Ended
	Jun. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Compensation	1 7 . Share-Based Compensation We currently utilize the InfraREIT, Inc. 2015 Equity Incentive Plan primarily for the annual compensation of the non-executive directors for their service on our board of directors. The following table shows the aggregate LTIP Units issued to members of our board of directors during the six months ended June 30, 2018 and 2017: Grant Date LTIP Units Grant Date Fair Value per LTIP Unit Aggregate Fair Value (in thousands) Vesting Date January 2017 31,633 $ 18.02 $ 570 January 2018 January 2018 28,952 18.61 539 January 2019 As part of our board of directors’ quarterly compensation, each non-executive director can, subject to certain exceptions, elect to receive part of their compensation in our common stock instead of cash with full vesting upon issuance. During 2017 and 2018, all directors received their quarterly compensation in cash. 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 each of the three months ended June 30, 2018 and 2017, $0.2 million 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 $0.3 million of compensation expense during each of the six months ended June 30, 2018 and 2017. The unamortized compensation expense related to these grants was $0.2 million as of June 30, 2018.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	18. Income Taxes Historically, we have accrued for potential taxes, penalties and interest related to Texas state franchise taxes on our rental income on our Consolidated Balance Sheets. However, during the second quarter of 2018, we reached a settlement with the state of Texas in which no franchise taxes were owed on lease revenue for all tax years through 2017. As a result, the accrued liability for these potential taxes of $4.9 million and penalties and interest of $0.7 million were removed from our Consolidated Balance Sheets and recognized as an income tax benefit on our Consolidated Statements of Operations during the second quarter of 2018. The tax portion of the liability represented unrecognized tax benefits that, if recognized, would have impacted our effective tax rate. A reconciliation of the beginning and ending amount of unrecognized tax benefits follows: (In thousands) June 30, 2018 December 31, 2017 Balance at beginning of period $ 4,864 $ 3,827 Additions based on tax positions related to the current year — 1,037 Settlements (4,864 ) — Balance at end of period $ — $ 4,864 Effective January 1, 2018, we will begin accruing and paying Texas franchise tax on our gross lease revenues.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	6 Months Ended
	Jun. 30, 2018
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Information	1 9 . Supplemental Cash Flow Information Supplemental cash flow information and non-cash investing and financing activities are as follows: Six Months Ended June 30, (In thousands) 2018 2017 Supplemental cash flow information Cash paid for interest $ 20,794 $ 19,007 Non-cash investing and financing activities Change in accrued additions to electric plant (95 ) 3,912 Allowance for funds used during construction - debt 1,228 1,557 Redemption of operating partnership units for common stock 3,133 110 Dividends and distributions payable 15,176 15,169

Description of Business and P25

Description of Business and Presentation of Financial Statements (Policies)	6 Months Ended
	Jun. 30, 2018
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 six months ended June 30, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018. 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, 2017 filed with the U.S. Securities and Exchange Commission (SEC) on March 5, 2018 (2017 Form 10-K). We held 72.4% of the outstanding partnership units (OP Units) in InfraREIT Partners, LP (Operating Partnership or InfraREIT LP) as of June 30, 2018 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 27.6% of the outstanding OP Units as of June 30, 2018.
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 Recently Adopted Accounting Guidance In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (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) Recent Accounting Guidance Not Yet Adopted In February 2016, the FASB issued ASU 2016-02, Leases Leases (Topic 842): Land Easement Practical Expedient for Transition to Topic 842

Cash, Cash Equivalents and Re26

Cash, Cash Equivalents and Restricted Cash (Tables)	6 Months Ended
	Jun. 30, 2018
Cash And Cash Equivalents [Abstract]
Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash within Consolidated Balance Sheets	The following table provides a reconciliation of cash, cash equivalents and restricted cash within the Consolidated Balance Sheets that sum to the total of the same such amounts shown on the Consolidated Statements of Cash Flows: June 30, (In thousands) 2018 2017 Cash $ 2,102 $ 9,662 Restricted cash 1,685 1,682 Total cash, cash equivalents and restricted cash shown on the Statement of Cash Flows $ 3,787 $ 11,344

Related Party Transactions (Tab

Related Party Transactions (Tables)	6 Months Ended
	Jun. 30, 2018
Related Party Transactions [Abstract]
Schedule of Annual Base Fees	The annual base fees through March 31, 2019 are as follows: (In millions) Base Fee April 1, 2016 - March 31, 2017 $ 14.0 April 1, 2017 - March 31, 2018 14.2 April 1, 2018 - March 31, 2019 13.5

Electric Plant and Depreciati28

Electric Plant and Depreciation (Tables)	6 Months Ended
	Jun. 30, 2018
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) June 30, 2018 December 31, 2017 Electric plant: Transmission plant $ 1,779,123 $ 1,685,466 Distribution plant 150,034 143,865 General plant 3,023 3,023 Total plant in service 1,932,180 1,832,354 Construction work in progress 46,701 113,643 Total electric plant 1,978,881 1,945,997 Accumulated depreciation (189,890 ) (173,768 ) Electric plant, net $ 1,788,991 $ 1,772,229

Other Assets (Tables)

Other Assets (Tables)	6 Months Ended
	Jun. 30, 2018
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Summary of Other Assets	Other assets are as follows: June 30, 2018 December 31, 2017 (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 $ (688 ) $ 279 $ 967 $ (591 ) $ 376 Other regulatory assets: Deferred financing costs 10,365 (4,768 ) 5,597 28,570 (20,944 ) 7,626 Deferred costs recoverable in future years 23,793 — 23,793 23,793 — 23,793 Other regulatory assets 34,158 (4,768 ) 29,390 52,363 (20,944 ) 31,419 Investments 2,519 — 2,519 2,519 — 2,519 Other assets $ 37,644 $ (5,456 ) $ 32,188 $ 55,849 $ (21,535 ) $ 34,314

Long-Term Debt (Tables)

Long-Term Debt (Tables)	6 Months Ended
	Jun. 30, 2018
Debt Instruments [Abstract]
Components of Long-Term Debt	Long-term debt consisted of the following: June 30, 2018 December 31, 2017 (Dollar amounts in thousands) Maturity Date Amount Outstanding Interest Rate Amount Outstanding Interest Rate TDC Senior secured notes - $25.0 million December 30, 2020 $ 15,625 8.50% $ 16,250 8.50% SDTS Senior secured notes - $60.0 million June 20, 2018 — n/a 60,000 5.04% Senior secured term loan - $200.0 million June 5, 2020 200,000 3.34% 200,000 2.71% 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 39,462 7.25% 40,546 7.25% Senior secured notes - $110.0 million September 30, 2030 90,436 6.47% 92,821 6.47% Total SDTS debt 829,898 893,367 Total long-term debt 845,523 909,617 Less unamortized deferred financing costs (80 ) (97 ) Total long-term debt, less deferred financing costs 845,443 909,520 Less current portion of long-term debt (7,957 ) (68,305 ) Debt classified as long-term debt, less deferred financing costs $ 837,486 $ 841,215

Fair Value of Financial Instr31

Fair Value of Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2018
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 June 30, 2018 Long-term debt $ 845,523 $ — $ 861,272 $ — December 31, 2017 Long-term debt $ 909,617 $ — $ 950,522 $ —

Regulatory Matters (Tables)

Regulatory Matters (Tables)	6 Months Ended
	Jun. 30, 2018
Public Utilities Rate Matters [Abstract]
Summary of Regulatory Liabilities	Regulatory liabilities are as follows: (In thousands) June 30, 2018 December 31, 2017 Cost of removal $ 52,244 $ 44,679 Excess ADFIT 55,779 55,779 Regulatory liabilities $ 108,023 $ 100,458

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Computation of Earnings Per Share	Earnings per share are calculated as follows: Three Months Ended June 30, Six Months Ended June 30, (In thousands, except per share data) 2018 2017 2018 2017 Basic net income per share: Net income attributable to InfraREIT, Inc. $ 17,334 $ 7,308 $ 30,198 $ 15,257 Weighted average common shares outstanding 43,961 43,778 43,897 43,776 Basic net income per share $ 0.39 $ 0.17 $ 0.69 $ 0.35 Diluted net income per share: Net income attributable to InfraREIT, Inc. $ 17,334 $ 7,308 $ 30,198 $ 15,257 Weighted average common shares outstanding 43,961 43,778 43,897 43,776 Redemption of Operating Partnership units — — — — Weighted average dilutive shares outstanding 43,961 43,778 43,897 43,776 Diluted net income per share $ 0.39 $ 0.17 $ 0.69 $ 0.35 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 $ 6,602 $ 2,821 $ 11,502 $ 5,889 Redemption of Operating Partnership units 16,743 16,897 16,807 16,899

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2018
Leases [Abstract]
Schedule of Composition of Lease Revenue	The following table shows the composition of our lease revenue: Three Months Ended June 30, Six Months Ended June 30, (In thousands) 2018 2017 2018 2017 Base rent (straight-line) $ 47,827 $ 40,422 $ 93,483 $ 80,046 Percentage rent — — — — Total lease revenue $ 47,827 $ 40,422 $ 93,483 $ 80,046

Share-Based Compensation (Table

Share-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Aggregate LTIP Units Issued to Board of Directors	The following table shows the aggregate LTIP Units issued to members of our board of directors during the six months ended June 30, 2018 and 2017: Grant Date LTIP Units Grant Date Fair Value per LTIP Unit Aggregate Fair Value (in thousands) Vesting Date January 2017 31,633 $ 18.02 $ 570 January 2018 January 2018 28,952 18.61 539 January 2019

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits	The tax portion of the liability represented unrecognized tax benefits that, if recognized, would have impacted our effective tax rate. A reconciliation of the beginning and ending amount of unrecognized tax benefits follows: (In thousands) June 30, 2018 December 31, 2017 Balance at beginning of period $ 4,864 $ 3,827 Additions based on tax positions related to the current year — 1,037 Settlements (4,864 ) — Balance at end of period $ — $ 4,864

Supplemental Cash Flow Inform37

Supplemental Cash Flow Information (Tables)	6 Months Ended
	Jun. 30, 2018
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: Six Months Ended June 30, (In thousands) 2018 2017 Supplemental cash flow information Cash paid for interest $ 20,794 $ 19,007 Non-cash investing and financing activities Change in accrued additions to electric plant (95 ) 3,912 Allowance for funds used during construction - debt 1,228 1,557 Redemption of operating partnership units for common stock 3,133 110 Dividends and distributions payable 15,176 15,169

Description of Business and P38

Description of Business and Presentation of Financial Statements - Additional Information (Details)	6 Months Ended
	Jun. 30, 2018
Description Of Business And Presentation Of Financial Statements [Line Items]
Percentage of partnership units outstanding	72.40%
Hunt Consolidated, Inc.
Description Of Business And Presentation Of Financial Statements [Line Items]
Percentage of partnership units outstanding	27.60%

Asset Exchange Transaction - Ad

Asset Exchange Transaction - Additional Information (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Nonmonetary Transaction [Line Items]
Proceeds from asset exchange transaction	$ 1,632
Sharyland Distribution & Transmission Services, L.L.C. | Definitive Agreement | Oncor Electric Delivery Company LLC
Nonmonetary Transaction [Line Items]
Net assets exchanged		$ 403,000
Transmission assets		383,000
Proceeds from asset exchange transaction		18,000
Gain on asset exchange transaction		300
Sharyland Distribution & Transmission Services, L.L.C. | Definitive Agreement | Oncor Electric Delivery Company LLC | Prepaids and Other Current Assets
Nonmonetary Transaction [Line Items]
Receivable under asset exchange transaction		$ 2,000

Cash, Cash Equivalents and Re40

Cash, Cash Equivalents and Restricted Cash - Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash within Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Cash And Cash Equivalents [Abstract]
Cash and cash equivalents	$ 2,102	$ 2,867	$ 9,662
Restricted cash	1,685	1,683	1,682
Total cash, cash equivalents and restricted cash shown on the Statement of Cash Flows	$ 3,787	$ 4,550	$ 11,344	$ 19,294

Cash, Cash Equivalents and Re41

Cash, Cash Equivalents and Restricted Cash - Additional Information (Details) $ in Millions	Jun. 30, 2018USD ($)
Transmission and Distribution Company, L.L.C | Senior Secured Notes, 8.50%
Restricted Cash And Cash Equivalents Items [Line Items]
Long-term debt, face amount	$ 25

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Due from affiliates	$ 32,423,000		$ 32,423,000		$ 35,172,000
Hunt Utility Services, LLC
Related Party Transaction [Line Items]
Payment for management fee			6,900,000	$ 10,500,000
Prepaid management fee	0		0		0
Accrued management fee	$ 0		$ 0		0	$ 3,500,000
Management agreement expiration date			Dec. 31, 2019
Agreement successive renewal terms			5 years
Management fee, description			The base fee for each 12 month period beginning each April 1 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 | License and Maintenence Fees
Related Party Transaction [Line Items]
Reimbursement of annual software license and maintenance fees and other expenses			100,000	200,000
Sharyland
Related Party Transaction [Line Items]
Lease revenue from related party	47,800,000	$ 40,400,000	93,500,000	80,000,000
Deferred rent liability	14,500,000		14,500,000		14,700,000
Payments to acquire plant, and equipment			31,100,000	$ 93,900,000
Due from affiliates	32,400,000		32,400,000		35,200,000
Accounts payable and accrued liabilities	$ 2,700,000		2,700,000		2,100,000
Sharyland | Asset Exchange Transaction
Related Party Transaction [Line Items]
Legal fees			$ 200,000
Transaction, description			These costs are eligible to be recovered through rates collected from customers during the 24-month period starting January 2018 through December 2019. We sold the recoverable costs to Sharyland in exchange for 24 equal monthly payments beginning January 2018 through December 2019.
Due from affiliates					0
Payments received from affiliates					$ 0

Related Party Transactions - Sc

Related Party Transactions - Schedule of Annual Base Fees (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Related Party Transaction [Line Items]
Annual base fees		$ 14.2	$ 14
Scenario, Forecast
Related Party Transaction [Line Items]
Annual base fees	$ 13.5

Electric Plant and Depreciati44

Electric Plant and Depreciation - Schedule of Major Classes of Electric Plant (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Electric plant:
Transmission plant	$ 1,779,123	$ 1,685,466
Distribution plant	150,034	143,865
General plant	3,023	3,023
Total plant in service	1,932,180	1,832,354
Construction work in progress	46,701	113,643
Total electric plant	1,978,881	1,945,997
Accumulated depreciation	(189,890)	(173,768)
Electric plant, net	$ 1,788,991	$ 1,772,229

Electric Plant and Depreciati45

Electric Plant and Depreciation - Additional Information (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Public Utilities Property Plant And Equipment [Abstract]
Electric plant, net includes plant acquisition adjustments	$ 28.8	$ 29.4

Goodwill (Details)

Goodwill (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
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	Jun. 30, 2018	Dec. 31, 2017
Other Assets Noncurrent [Abstract]
Deferred financing costs on undrawn revolver, Gross Carrying Amount	$ 967	$ 967
Other regulatory assets Deferred financing costs, Gross Carrying Amount	10,365	28,570
Other regulatory assets Deferred costs recoverable in future years, Gross Carrying Amount	23,793	23,793
Other regulatory assets, Gross Carrying Amount	34,158	52,363
Investments, Gross Carrying Amount	2,519	2,519
Other assets, Gross Carrying Amount	37,644	55,849
Deferred financing costs on undrawn revolver, Accumulated Amortization	(688)	(591)
Other regulatory assets Deferred financing costs, Accumulated Amortization	(4,768)	(20,944)
Other regulatory assets, Accumulated Amortization	(4,768)	(20,944)
Other assets, Accumulated Amortization	(5,456)	(21,535)
Deferred financing costs on undrawn revolver, Net Carrying Amount	279	376
Other regulatory assets Deferred financing costs, Net Carrying Amount	5,597	7,626
Other regulatory assets Deferred costs recoverable in future years, Net Carrying Amount	23,793	23,793
Other regulatory assets, Net Carrying Amount	29,390	31,419
Investments, Net Carrying Amount	2,519	2,519
Other assets, Net Carrying Amount	$ 32,188	$ 34,314

Other Assets - Additional Infor

Other Assets - Additional Information (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Other Assets [Line Items]
Other regulatory assets Deferred financing costs, Gross Carrying Amount	$ 10,365,000	$ 28,570,000
Deferred costs recoverable in future years	23,793,000	23,793,000
Investment impaired	0	$ 0
Senior Secured Notes, 5.04%
Other Assets [Line Items]
Other regulatory assets Deferred financing costs, Gross Carrying Amount	$ 18,200,000

Borrowings Under Credit Facil49

Borrowings Under Credit Facilities - Additional Information (Details) - USD ($)	1 Months Ended	6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2014	Dec. 31, 2017	Dec. 31, 2011
Line Of Credit Facility [Line Items]
Repayments of long-term debt		$ 64,093,000	$ 3,869,000
SDTS | Senior Secured Notes, 5.04%
Line Of Credit Facility [Line Items]
Debt, interest rate					5.04%	5.04%
Repayments of long-term debt	$ 60,000,000
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			$ 0
Letters of credit outstanding amount	0	0			0
Line of credit facility, remaining borrowing capacity	75,000,000	$ 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
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
Line Of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity				$ 25,000,000
Third Amended and Restated Credit Agreement | Swingline Loans | SDTS
Line Of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity				$ 5,000,000
Revolving Credit Facility | SDTS
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) LIBOR plus a margin of either 1.75% or 2.00% per annum
Amount of revolving credit facility under agreement	99,500,000	$ 99,500,000			41,000,000
Line of credit facility, remaining borrowing capacity	$ 150,500,000	$ 150,500,000			$ 209,000,000
Debt, interest rate	4.10%	4.10%
Debt, weighted average interest rate					3.12%
Revolving Credit Facility | Federal Funds Rate | SDTS
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate				0.50%
Revolving Credit Facility | LIBOR | SDTS
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate				1.00%
Revolving Credit Facility | LIBOR | SDTS | Minimum
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate				1.75%
Revolving Credit Facility | LIBOR | SDTS | Maximum
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate				2.00%
Revolving Credit Facility | Base Rate | SDTS | Minimum
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate				0.75%
Revolving Credit Facility | Base Rate | SDTS | Maximum
Line Of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate				1.00%
Revolving Credit Facility | Letter Of Credit | SDTS
Line Of Credit Facility [Line Items]
Amount of revolving credit facility under agreement	$ 0	$ 0			$ 0

Long-Term Debt - Components of

Long-Term Debt - Components of Long-Term Debt (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Debt Instrument [Line Items]
Long-term debt, Amount Outstanding	$ 845,523	$ 909,617
Less unamortized deferred financing costs	(80)	(97)
Total long-term debt, less deferred financing costs	845,443	909,520
Less current portion of long-term debt	(7,957)	(68,305)
Debt classified as long-term debt, less deferred financing costs	$ 837,486	$ 841,215
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	$ 15,625	$ 16,250
Interest bearing note, maturity date	Dec. 30, 2020
SDTS
Debt Instrument [Line Items]
Long-term debt, Amount Outstanding	$ 829,898	$ 893,367
SDTS | Senior Secured Notes, 5.04%
Debt Instrument [Line Items]
Long-term debt, Interest Rate		5.04%	5.04%
Long-term debt, Amount Outstanding		$ 60,000
Interest bearing note, maturity date	Jun. 20, 2018
SDTS | 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 | 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 | 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	$ 39,462	$ 40,546
Interest bearing note, maturity date	Dec. 30, 2029
SDTS | 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	$ 90,436	$ 92,821
Interest bearing note, maturity date	Sep. 30, 2030
SDTS | Senior Secured Term Loan, 3.34%
Debt Instrument [Line Items]
Long-term debt, Interest Rate	3.34%
Long-term debt, Amount Outstanding	$ 200,000
Interest bearing note, maturity date	Jun. 5, 2020
SDTS | Senior Secured Term Loan, 2.71%
Debt Instrument [Line Items]
Long-term debt, Interest Rate		2.71%
Long-term debt, Amount Outstanding		$ 200,000

Long-Term Debt - Components o51

Long-Term Debt - Components of Long-Term Debt (Parenthetical) (Details) - USD ($) $ in Millions	Jun. 30, 2018	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 | Senior Secured Notes, 5.04%
Debt Instrument [Line Items]
Long-term debt, face amount	60	$ 60
SDTS | Senior Secured Term Loan, 3.34%
Debt Instrument [Line Items]
Long-term debt, face amount	200
SDTS | Senior Secured Notes, 3.86%
Debt Instrument [Line Items]
Long-term debt, face amount	400
SDTS | Senior Secured Notes, 3.86% Maturing in 2026
Debt Instrument [Line Items]
Long-term debt, face amount	100
SDTS | Senior Secured Notes, 7.25%
Debt Instrument [Line Items]
Long-term debt, face amount	53.5			$ 53.5
SDTS | 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	1 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2018	Dec. 31, 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		$ 279	$ 376
2017 Term Loan
Debt Instrument [Line Items]
Long-term debt, face amount		200,000	$ 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 | 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%
SDTS | 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 | 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 | 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 | 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 | 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 | 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 | 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%
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%

Fair Value of Financial Instr53

Fair Value of Financial Instruments - Additional Information (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term Debt	$ 837,486	$ 841,215
2017 Term Loan
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, face amount	200,000	200,000
Senior Secured Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term Debt	$ 645,500	$ 709,600
Debt, weighted average interest rate	4.60%	4.60%

Fair Value of Financial Instr54

Fair Value of Financial Instruments - Financial Instruments Measured at Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Carrying Value
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-term debt	$ 845,523	$ 909,617
Level 2 | Fair Value
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-term debt	$ 861,272	$ 950,522

Regulatory Matters - Summary of

Regulatory Matters - Summary of Regulatory Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Public Utilities General Disclosures [Line Items]
Regulatory Liabilities	$ 108,023	$ 100,458
Cost of Removal
Public Utilities General Disclosures [Line Items]
Regulatory Liabilities	52,244	44,679
Excess ADFIT
Public Utilities General Disclosures [Line Items]
Regulatory Liabilities	$ 55,779	$ 55,779

Regulatory Matters - Additional

Regulatory Matters - Additional Information (Details) - USD ($) $ in Thousands	May 01, 2014	Jun. 30, 2018	Dec. 31, 2017
Public Utilities General Disclosures [Line Items]
Corporate federal income tax rate		21.00%	35.00%
Regulatory liability related to creation of excess accumulated deferred federal income tax		$ 55,800
Regulatory liabilities		108,023	$ 100,458
Sharyland
Public Utilities General Disclosures [Line Items]
Public utilities, approved capital structure, debt percentage	55.00%
Public utilities, approved capital structure, equity percentage	45.00%
Public utilities, approved cost of debt percentage	6.73%
Public utilities, approved return on equity, percentage	9.70%
Public utilities, approved return on invested capital, percentage	8.06%
Excess ADFIT
Public Utilities General Disclosures [Line Items]
Regulatory liabilities		$ 55,779	$ 55,779

Equity - Additional Information

Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Equity [Abstract]
Cash dividends declared per share to shareholders	$ 0.25	$ 0.25	$ 0.50	$ 0.50
Cash distributions declared to unit holders, per unit			$ 0.50	$ 0.50
Dividends and distributions paid			$ 30,345	$ 30,330

Noncontrolling Interest - Addit

Noncontrolling Interest - Additional Information (Details) - shares	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
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	16,700,000		16,900,000
Operating partnership units redeem	165,252	6,207
Common shares issued	165,252	6,207
LTIP Units
Minority Interest [Line Items]
Operating partnership units issued	28,952	31,633

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		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Basic net income per share:
Net income attributable to InfraREIT, Inc.	$ 17,334	$ 7,308	$ 30,198	$ 15,257
Weighted average common shares outstanding	43,961	43,778	43,897	43,776
Basic net income per share	$ 0.39	$ 0.17	$ 0.69	$ 0.35
Diluted net income per share:
Net income attributable to InfraREIT, Inc.	$ 17,334	$ 7,308	$ 30,198	$ 15,257
Weighted average common shares outstanding	43,961	43,778	43,897	43,776
Weighted average dilutive shares outstanding	43,961	43,778	43,897	43,776
Diluted net income per share	$ 0.39	$ 0.17	$ 0.69	$ 0.35
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	$ 6,602	$ 2,821	$ 11,502	$ 5,889
Redemption of Operating Partnership units	16,743	16,897	16,807	16,899

Leases - Schedule of Compositio

Leases - Schedule of Composition of Lease Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Leases [Abstract]
Base rent (straight-line)	$ 47,827	$ 40,422	$ 93,483	$ 80,046
Total lease revenue	$ 47,827	$ 40,422	$ 93,483	$ 80,046

Leases - Additional Information

Leases - Additional Information (Details)	6 Months Ended
	Jun. 30, 2018
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, 2019 through December 31, 2022.
Lease expiration date range, start date	Dec. 31, 2019
Lease expiration date range, end date	Dec. 31, 2022
S/B/C Lease
Operating Leased Assets [Line Items]
Lease terminated date	Dec. 31, 2017
Maximum
Operating Leased Assets [Line Items]
Rate of rent used, Percentage	31.00%
Minimum
Operating Leased Assets [Line Items]
Rate of rent used, Percentage	23.00%

Share-Based Compensation - Aggr

Share-Based Compensation - Aggregate LTIP Units Issued to Board of Directors (Details) - 2015 Equity Incentive Plan - Director - LTIP Units - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended
	Jan. 31, 2018	Jan. 31, 2017
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Grant Date	2018-01	2017-01
LTIP Units	28,952	31,633
Grant Date Fair Value per Share	$ 18.61	$ 18.02
Aggregate Fair Value	$ 539	$ 570
Vesting Date	2019-01	2018-01

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details) - 2015 Equity Incentive Plan - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Unamortized stock compensation expense	$ 200,000		$ 200,000
General And Administrative Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Compensation expenses	$ 200,000	$ 200,000	$ 300,000	$ 300,000

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Income Tax Contingency [Line Items]
Accrued liability for potential taxes		$ 4,864
Texas
Income Tax Contingency [Line Items]
Franchise taxes on lease revenue		$ 0	$ 0
Accrued liability for potential taxes	$ 4,900
Penalties and interest	$ 700

Income Taxes - Unrecognized Tax

Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Balance at beginning of period	$ 4,864	$ 3,827
Additions based on tax positions related to the current year		1,037
Settlements	$ (4,864)
Balance at end of period		$ 4,864

Supplemental Cash Flow Inform66

Supplemental Cash Flow Information - Supplemental Cash Flow Information and Non-cash Investing and Financing Activities (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Supplemental cash flow information
Cash paid for interest	$ 20,794	$ 19,007
Non-cash investing and financing activities
Change in accrued additions to electric plant	(95)	3,912
Allowance for funds used during construction - debt	1,228	1,557
Redemption of operating partnership units for common stock	3,133	110
Dividends and distributions payable	$ 15,176	$ 15,169	$ 15,169