InfraREIT (HIFR) 10-K 27 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Feb. 20, 2019	Jun. 29, 2018
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
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	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Public Float			$ 868.1
Entity Common Stock, Shares Outstanding		43,997,672

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current Assets
Cash and cash equivalents	$ 1,808	$ 2,867
Restricted cash	1,689	1,683
Due from affiliates	38,174	35,172
Inventory	6,903	6,759
Prepaids and other current assets	1,077	2,460
Total current assets	49,651	48,941
Electric Plant, net	1,811,317	1,772,229
Goodwill	138,384	138,384
Other Assets	31,678	34,314
Total Assets	2,031,030	1,993,868
Current Liabilities
Accounts payable and accrued liabilities	19,657	21,230
Short-term borrowings	112,500	41,000
Current portion of long-term debt	8,792	68,305
Dividends and distributions payable	15,176	15,169
Accrued taxes	1,052	5,633
Total current liabilities	157,177	151,337
Long-Term Debt, Less Deferred Financing Costs	832,455	841,215
Regulatory Liabilities	115,532	100,458
Total liabilities	1,105,164	1,093,010
Commitments and Contingencies
Equity
Common stock, $0.01 par value; 450,000,000 shares authorized; 43,974,998 and 43,796,915 issued and outstanding as of December 31, 2018 and 2017, respectively	440	438
Additional paid-in capital	708,283	706,357
Accumulated deficit	(32,022)	(49,728)
Total InfraREIT, Inc. equity	676,701	657,067
Noncontrolling interest	249,165	243,791
Total equity	925,866	900,858
Total Liabilities and Equity	$ 2,031,030	$ 1,993,868

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 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	43,974,998	43,796,915
Common stock, shares, outstanding	43,974,998	43,796,915

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Lease revenue	$ 200,354	$ 190,341	$ 172,099
Tax Cuts and Jobs Act regulatory adjustment		(55,779)
Net revenues	200,354	134,562	172,099
Operating costs and expenses
General and administrative expense	30,965	25,388	21,852
Depreciation	47,813	51,207	46,704
Gain on 2017 asset exchange transaction		(257)
Total operating costs and expenses	78,778	76,338	68,556
Income from operations	121,576	58,224	103,543
Other (expense) income
Interest expense, net	(42,122)	(40,671)	(36,920)
Other income, net	1,117	718	3,781
Total other expense	(41,005)	(39,953)	(33,139)
Income before income taxes	80,571	18,271	70,404
Income tax (benefit) expense	(4,581)	1,218	1,103
Net income	85,152	17,053	69,301
Less: Net income attributable to noncontrolling interest	23,482	4,751	19,347
Net income attributable to InfraREIT, Inc.	$ 61,670	$ 12,302	$ 49,954
Net income attributable to InfraREIT, Inc. common stockholders per share:
Basic	$ 1.40	$ 0.28	$ 1.14
Diluted	1.40	0.28	1.14
Cash dividends declared per common share	$ 1	$ 1	$ 1

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Total InfraREIT, Inc. Equity	Noncontrolling Interest
Balance at Dec. 31, 2015	$ 934,268	$ 436	$ 702,213	$ (24,526)	$ 678,123	$ 256,145
Balance, shares at Dec. 31, 2015		43,565,495
Dividends and distributions	$ (60,636)			(43,671)	(43,671)	(16,965)
Redemption of operating partnership units for common stock		$ 2	3,275		3,277	(3,277)
Redemption of operating partnership units for common stock, shares	186,496	186,496
Net income	$ 69,301			49,954	49,954	19,347
Equity based compensation	978		357		357	621
Equity based compensation, shares		20,292
Balance at Dec. 31, 2016	943,911	$ 438	705,845	(18,243)	688,040	255,871
Balance, shares at Dec. 31, 2016		43,772,283
Dividends and distributions	$ (60,676)			(43,787)	(43,787)	(16,889)
Redemption of operating partnership units for common stock			512		512	(512)
Redemption of operating partnership units for common stock, shares	24,632	24,632
Net income	$ 17,053			12,302	12,302	4,751
Equity based compensation	570					570
Balance at Dec. 31, 2017	900,858	$ 438	706,357	(49,728)	657,067	243,791
Balance, shares at Dec. 31, 2017		43,796,915
Dividends and distributions	$ (60,704)			(43,964)	(43,964)	(16,740)
Redemption of operating partnership units for common stock		$ 2	1,926		1,928	(1,928)
Redemption of operating partnership units for common stock, shares	178,083	178,083
Net income	$ 85,152			61,670	61,670	23,482
Equity based compensation	560					560
Balance at Dec. 31, 2018	$ 925,866	$ 440	$ 708,283	$ (32,022)	$ 676,701	$ 249,165
Balance, shares at Dec. 31, 2018		43,974,998

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities
Net income	$ 85,152	$ 17,053	$ 69,301
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	47,813	51,207	46,704
Amortization of deferred financing costs	2,971	4,173	4,014
Allowance for funds used during construction - other funds	(1,094)	(681)	(3,728)
Tax Cuts and Jobs Act regulatory adjustment		55,779
Gain on asset exchange transaction		(257)
Loss on inventory disposition	316
Equity based compensation	560	570	978
Changes in assets and liabilities:
Due from affiliates	(3,149)	(2,618)	(1,382)
Inventory	(460)	479	(545)
Prepaids and other current assets	(102)	(102)	(166)
Accounts payable and accrued liabilities	(7,037)	(8,021)	7,958
Net cash provided by operating activities	124,970	117,582	123,134
Cash flows from investing activities
Additions to electric plant	(69,850)	(184,435)	(231,312)
Proceeds from asset exchange transaction	1,632	17,935
Net cash used in investing activities	(68,218)	(166,500)	(231,312)
Cash flows from financing activities
Proceeds from short-term borrowings	162,500	138,500	139,500
Repayments of short-term borrowings	(91,000)	(235,000)	(56,000)
Proceeds from borrowings of long-term debt		200,000	100,000
Repayments of long-term debt	(68,305)	(7,849)	(7,423)
Deferred financing costs	(303)	(809)	(649)
Dividends and distributions paid	(60,697)	(60,668)	(59,109)
Net cash (used in) provided by financing activities	(57,805)	34,174	116,319
Net (decrease) increase in cash, cash equivalents and restricted cash	(1,053)	(14,744)	8,141
Cash, cash equivalents and restricted cash at beginning of year	4,550	19,294	11,153
Cash, cash equivalents and restricted cash at end of year	$ 3,497	$ 4,550	$ 19,294

Description of Business and Sum

Description of Business and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of Business and Summary of Significant Accounting Policies	1. Description of Business and Summary of Significant Accounting Policies Description of Business InfraREIT, Inc. (Company or InfraREIT) is a Maryland corporation that is engaged in owning and leasing rate-regulated assets in Texas. The Company is structured as a real estate investment trust (REIT) for federal income tax purposes. The Company’s subsidiaries include InfraREIT Partners, LP (Operating Partnership or InfraREIT LP), a Delaware limited partnership, of which InfraREIT is the general partner; Transmission and Distribution Company, L.L.C. (TDC); and Sharyland Distribution & Transmission Services, L.L.C. (SDTS), the Company’s regulated subsidiary. The Company has elected to be taxed as a REIT for federal income tax purposes. The Company is externally managed and advised by Hunt Utility Services, LLC (Hunt Manager), a Delaware limited liability company. Hunt Manager is responsible for managing the Company’s day-to-day affairs, subject to the oversight of the Company’s board of directors. All of the Company’s officers, including the Company’s President and Chief Executive Officer, David A. Campbell, are employees of Hunt Manager. Mr. Campbell also serves as President and Chief Executive Officer of Sharyland Utilities, L.P. (Sharyland), a Texas-based utility and the Company’s sole tenant. The Company holds 72.4% of the outstanding partnership units (OP Units) in the Operating Partnership as of December 31, 2018. The Company includes the accounts of the Operating Partnership and its subsidiaries in the consolidated financial statements. Affiliates and current or former employees of Hunt Consolidated, Inc. (Hunt) and members of the Company’s board of directors hold the other 27.6% of the outstanding OP Units as of December 31, 2018. SDTS’s assets are located in the Texas Panhandle; near Wichita Falls, Abilene and Brownwood; in the Permian Basin; and in South Texas. SDTS leases all its regulated assets under several lease agreements to Sharyland, which operates and maintains the regulated assets. SDTS and Sharyland are each subject to regulation as an electric utility by the Public Utility Commission of Texas (PUCT). SDTS is authorized to own and lease its assets to Sharyland under a certificate of convenience and necessity (CCN) granted by the PUCT. Principles of Consolidation and Presentation The consolidated financial statements include the Company’s accounts and the accounts of all other entities in which the Company has a controlling financial interest with noncontrolling interest of consolidated subsidiaries reported separately. All significant intercompany balances and transactions have been eliminated. SDTS maintains accounting records in accordance with the uniform system of accounts, as prescribed by the Federal Energy Regulatory Commission (FERC). In accordance with the applicable consolidation guidance, the Company’s consolidated financial statements reflect the effects of the different rate making principles mandated by the FERC and PUCT which regulate its subsidiaries’ operations. The accompanying historical consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (U.S. GAAP). In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. The historical financial information is not necessarily indicative of the Company’s future results of operations, financial position and cash flows. Use of Estimates The preparation of the Company’s 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. Regulation As the owner of rate-regulated assets, regulatory principles applicable to the utility industry also apply to SDTS. The financial statements reflect regulatory assets and liabilities under cost-based rate regulation in accordance with accounting standards related to the effect of certain types of regulation. Regulatory decisions can have an impact on the recovery of costs, the rate earned on invested capital and the timing and amount of assets to be recovered by rates. See Note 8, Other Assets SDTS capitalizes allowance for funds used during construction (AFUDC) during the construction of its regulated assets, and SDTS’s lease agreements with Sharyland rely on FERC definitions and accepted standards regarding capitalization of expense to define key terms in the lease such as footprint projects, which are the expenditures SDTS is obligated to fund pursuant to the leases. The amounts funded for these footprint projects include allocations of Sharyland employees’ time and overhead allocations consistent with FERC policies and U.S. GAAP. The leases define “footprint projects” to be transmission or, if applicable, distribution projects that (1) are primarily situated within the Company’s current or previous distribution service territory, as applicable; (2) physically hang from the Company’s existing transmission assets, such as the addition of another circuit to the Company’s existing transmission lines or that are physically located within one of its substations or (3) connect or are otherwise added to transmission lines or other properties that comprise a part of the 2017 Asset Exchange Transaction (as defined below). Sharyland cannot be removed as lessee without prior approval from the PUCT. SDTS transacts with Sharyland through several lease arrangements covering all the regulated assets. These lease agreements include provisions for additions and retirements of the regulated assets in the form of new construction or other capitalized projects. Cash and Cash Equivalents The Company considers all short-term, highly liquid investments with original maturities of three months or less to be cash equivalents. The Company’s account balances at one or more institutions periodically exceed the Federal Deposit Insurance Corporation (FDIC) insurance coverage and, as a result, there could be a concentration of credit risk related to amounts on deposit in excess of FDIC insurance coverage. The Company has not experienced any losses and believes the risk is not significant. Restricted Cash Restricted cash represents the principal and interest payable for two consecutive periods associated with TDC’s senior secured notes described in Note 10, Long-Term Debt Concentration of Credit Risk Sharyland is the Company’s sole tenant and all the Company’s revenue is driven by the leases with Sharyland. Inventory Inventory consists primarily of transmission and distribution parts and materials used in the construction of electric plant. Inventory is valued at average cost when it is acquired and used. Electric Plant, net Electric plant equipment is stated at the original cost of acquisition or construction, which includes the cost of contracted services, direct labor, materials, acquisition adjustments and overhead items. In accordance with the FERC uniform system of accounts guidance, SDTS recognizes, as a cost to construction work in progress (CWIP), AFUDC on other funds classified as other income (expense), net and AFUDC on borrowed funds classified as a reduction of the interest expense, net on the Consolidated Statements of Operations. The AFUDC blended rate utilized was 6.3%, 4.0% and 6.7% for the years ended December 31, 2018, 2017 and 2016, respectively. Depreciation of property, plant and equipment is calculated on a straight-line basis over the estimated service lives of the properties based on depreciation rates approved by the PUCT. Depreciation rates include plant removal costs as a component of depreciation expense, consistent with regulatory treatment. Actual removal costs incurred are charged to accumulated depreciation. When accrued removal costs exceed incurred removal costs, the difference is reclassified as a regulatory liability to retire assets in the future. The regulatory liability will be relieved as cost of removal charges are incurred upon asset retirement. Repairs are the responsibility of Sharyland as the lessee under the lease agreements. Betterments and improvements generally are the responsibility of SDTS and are capitalized. Provision for depreciation of electric plant is computed using composite straight-line rates as follows for each of the years ended December 31, 2018, 2017 and 2016: Rates Transmission plant 1.69% - Distribution plant 1.74% - 5.96% General plant 0.80% - 5.12% Impairment of Long-Lived Assets The Company evaluates impairment of its long-lived assets annually or whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. An impairment loss is recognized only if the carrying amount of a long-lived asset is not recoverable through expected future cash flows. Regulatory assets are charged to expense in the period in which they are no longer probable of future recovery. Goodwill Goodwill represents the excess of costs of an acquired business over the fair value of the assets acquired, less liabilities assumed. Goodwill is not amortized and is tested for impairment annually or more frequently if events or changes in circumstances arise. Accounting Standard Update (ASU) 2011-08, Testing of Goodwill for Impairment The Company’s annual goodwill impairment analysis, which was performed qualitatively during the fourth quarter of 2018, did not result in an impairment charge. As of December 31, 2018 and 2017, $138.4 million was recorded as goodwill on the Consolidated Balance Sheets. Investments An investment is considered impaired if the fair value of the investment is less than its cost. Generally, an impairment is considered other-than-temporary unless (1) the Company has the ability and intent to hold an investment for a reasonable period of time sufficient for an anticipated recovery of fair value up to (or beyond) the cost of the investment; and (2) evidence indicating that the cost of the investment is recoverable within a reasonable period of time outweighs evidence to the contrary. If impairment is determined to be other than temporary, then an impairment loss is recognized equal to the difference between the investment’s cost and its fair value. Deferred Financing Costs Amortization of deferred financing costs associated with the issuance of TDC’s $25.0 million senior secured notes and the revolving credit facilities is computed using the straight-line method over the life of the loan which approximates the effective interest method. Amortization of deferred financing costs associated with SDTS is computed using the straight-line method over the life of the loan in accordance with applicable regulatory guidance. Derivative Instruments The Company may use derivatives from time to time to hedge against changes in cash flows related to interest rate risk (cash flow hedging instrument). Accounting Standards Codification (ASC) Topic 815, Derivatives and Hedging Unrealized gains and losses on the effective cash flow hedging instrument are recorded as components of accumulated other comprehensive income. Realized gains and losses on the cash flow hedging instrument are recorded as adjustments to interest expense. Settlements of derivatives are included within operating activities on the Consolidated Statements of Cash Flows. Any ineffectiveness in the cash flow hedging instrument is recorded as an adjustment to interest expense in the current period. The Company did not have any derivative financial instruments during 2018, 2017 or 2016. Income Taxes The Company elected to be treated as a REIT under Sections 856 through 860 of the Internal Revenue Code of 1986, as amended, commencing with its taxable year ended December 31, 2010. As a result, the Company generally will not be subject to federal income tax on its taxable income that is distributed to its stockholders. A REIT is subject to a number of other organizational and operational requirements, including a requirement that it currently distribute at least 90% of its annual taxable income (with certain adjustments). As a REIT, the Company expects to distribute at least 100% of its taxable income. Accordingly, there is no provision for federal income taxes in the accompanying consolidated financial statements. Even if the Company maintains its qualification for taxation as a REIT, it may be subject to certain state and local taxes on its income and property, including excise taxes, and federal corporate income taxes on any undistributed income. The Company recognizes the impact of tax return positions that are more-likely-than-not to be sustained upon audit. Significant judgment is required to evaluate uncertain tax positions. The evaluation of uncertain tax positions is based upon a number of factors, including changes in facts or circumstances, changes in tax law, correspondence with tax authorities during the course of audits and effective settlement of audit issues. In December 2017, the Tax Cuts and Job Acts (TCJA) was signed into law resulting in significant changes to federal tax laws effective for taxable years beginning on or after January 1, 2018. See Note 19, Income Taxes Revenue Recognition The Company, through its subsidiaries, is the owner of regulated assets and recognizes lease revenue over the term of lease agreements with Sharyland. The Company’s lease revenue includes annual payments and additional rents based upon a percentage of revenue earned by Sharyland on the leased assets in excess of annual specified breakpoints. In accordance with the lease agreements, Sharyland, the lessee and operator of the regulated assets, is responsible for the maintenance and operation of the regulated assets and primarily responsible for compliance with all regulatory requirements of the PUCT, the FERC or any other regulatory entity with jurisdiction over the regulated assets on the Company’s behalf and with the Company’s cooperation. Each of the lease agreements with Sharyland is a net lease that obligates the lessee to pay all property related expenses, including maintenance, repairs, taxes and insurance, and to comply with the terms of the SDTS secured credit facilities and note purchase agreements. The Company recognizes base rent under these leases on a straight-line basis over the applicable lease term. The current lease agreements provide for periodic supplemental adjustments of base rent based upon capital expenditures made by SDTS. The Company recognizes supplemental adjustments of base rent as a modification under these leases on a prospective straight-line basis over the applicable lease term. The Company recognizes percentage rent under these leases once the revenue earned by Sharyland on the leased assets exceeds the annual specified breakpoints. Asset Retirement Obligations The Company has identified, but not recognized, asset retirement obligation liabilities related to the regulated assets as a result of certain easements on property on which the Company has assets. Generally, such easements are perpetual and require only the retirement and removal of the assets upon cessation of the property’s use. Management has not estimated and recorded a retirement liability for such easements because the Company plans to use the facilities indefinitely. Interest Expense, net The Company’s interest expense, net primarily consists of interest expense from the senior secured notes, senior secured term loan and credit facilities, see Note 9, Borrowings Under Credit Facilities Long-Term Debt Other Income, net AFUDC on other funds of $1.1 million, $0.7 million and $3.7 million was recognized in other income, net during the years ended December 31, 2018, 2017 and 2016, respectively. Fair Value of Financial Instruments ASC Topic 820, Fair Value Measurements and Disclosures Level 1 — Quoted prices in active markets for identical assets and liabilities. Level 2 — Valuations based on one or more quoted prices in markets that are not active; quoted prices for similar assets or liabilities in active markets; inputs that are observable other than quoted prices for the asset or the liability; or inputs that are derived principally from or corroborated by observable market data by correlation or other means. Level 3 — Valuations based on inputs that are unobservable and significant to the overall fair value measurement. Recent Accounting Guidance Recently Adopted Accounting Guidance In May 2014, the Financial Accounting Standards Board (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 230): 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 (Topic 842) Leases (Topic 842): Land Easement Practical Expedient for Transition to Topic 842 Leases (Topic 842), Narrow-Scope Improvements for Lessors Leases (Topic 842): Targeted Improvements In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement Reportable Segments U.S. GAAP establishes standards for reporting financial and descriptive information about a company’s reportable segments. Management has determined that the Company has one reportable segment, with activities related to ownership and leasing of rate-regulated assets.

Pending Corporate transactions

Pending Corporate transactions	12 Months Ended
	Dec. 31, 2018
Business Combinations [Abstract]
Pending Corporate Transactions	2. Pending Corporate Transactions Sale and Asset Exchange On October 18, 2018, InfraREIT and InfraREIT LP entered into a definitive agreement to be acquired by Oncor Electric Delivery Company LLC (Oncor) for $21.00 per share or OP Unit, as applicable, in cash, valued at approximately $1.275 billion, plus the assumption of InfraREIT’s net debt of approximately $950 million as of December 31, 2018. As a condition to Oncor’s acquisition of InfraREIT, SDTS and Oncor also signed a definitive agreement with Sharyland to exchange, immediately prior to Oncor’s acquisition, SDTS’s South Texas assets for Sharyland’s Golden Spread Electric Cooperative interconnection located in the Texas Panhandle, along with certain development projects in the Texas Panhandle and South Plains regions, including the Lubbock Power & Light interconnection. The difference between the net book value of the exchanged assets will be paid in cash at closing. SDTS and Sharyland have agreed to terminate their existing leases in connection with the asset exchange. The asset exchange with Sharyland and merger with Oncor are mutually dependent on one another, and neither will become effective without the closing of the other. Arrangements with Hunt Under the management agreement with Hunt Manager, which will be terminated upon the closing of the sale and asset exchange transaction described above, Hunt Manager is entitled to the payment of a termination fee upon the termination or non-renewal of the management agreement. The termination of the management agreement automatically triggers the termination of the development agreement between InfraREIT and Hunt. InfraREIT has agreed to pay Hunt approximately $40.5 million at the closing of the transactions to terminate the management agreement, development agreement, leases with Sharyland, and all other existing agreements between InfraREIT or its subsidiaries and Hunt, Sharyland or their affiliates. This amount is consistent with the termination fee, as calculated at the time the Company entered into the omnibus termination agreement, contractually required under the management agreement. Closing Conditions and Status The closing of the transactions is dependent upon and subject to several closing conditions, including: • PUCT approval of the transactions, including: o Exchange of assets with Sharyland; o Acquisition of InfraREIT by Oncor; and o Sempra Energy’s 50% ownership in Sharyland Holdings, LP; • other necessary regulatory approvals, including approval by FERC, the expiration or termination of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (HSR Act) and clearance by the Committee on Foreign Investment in the United States (CFIUS); • stockholder approval; • certain lender consents; and • other customary closing conditions Early termination of the 30-day waiting period required by the HSR Act was received December 14, 2018. On December 21, 2018, TDC and SDTS entered into amendments that, effective as of the closing, will satisfy the closing condition with respect to the lender consents. Additionally, a special meeting of InfraREIT’s stockholders was held on February 7, 2019, at which time the stockholders voted to approve the transaction. In accordance with the definitive agreements, SDTS, Sharyland and Oncor filed a Sale-Transfer-Merger application (STM) with the PUCT on November 30, 2018, and a hearing on the merits is scheduled for April 10-12, 2019. The 180-day deadline for the STM is May 29, 2019, although the PUCT is permitted to extend that deadline for an additional 60 days if necessary. Subject to obtaining the required regulatory approvals, the transactions are expected to close by mid-2019.

2017 Asset Exchange Transaction

2017 Asset Exchange Transaction	12 Months Ended
	Dec. 31, 2018
Nonmonetary Transactions [Abstract]
2017 Asset Exchange Transaction	3 . 2017 Asset Exchange Transaction In July 2017, SDTS and Sharyland signed a definitive agreement (2017 Asset Exchange Agreement) with 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 (2017 Asset Exchange Transaction). The 2017 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 and 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). The table below reflects the details of the Asset Exchange Transaction: (in thousands) December 31, 2017 Net assets transferred to Oncor Gross transmission plant $ 2,675 Gross distribution plant 499,381 Gross general plant 13,013 Construction work in progress 22,076 Total electric plant 537,145 Accumulated depreciation (130,712 ) Electric plant, net 406,433 Inventory 37 Regulatory liability (3,870 ) Net assets transferred to Oncor $ 402,600 Net transmission assets acquired from Oncor Gross transmission plant $ 432,560 Construction work in progress 48 Total transmission plant 432,608 Accumulated depreciation (32,778 ) Transmission plant, net 399,830 Regulatory liability (16,540 ) Net assets acquired from Oncor $ 383,290 Cash portion of purchase price from Oncor Cash $ 17,935 Receivable from Oncor 1,632 Cash portion of purchase price from Oncor $ 19,567 Gain on asset exchange transaction $ 257 Upon closing of the 2017 Asset Exchange Transaction, Sharyland leased the newly acquired assets from SDTS and began operating them under an amended CCN. SDTS continues to own and lease to Sharyland certain substations related to its wholesale distribution assets. Sharyland exited the retail distribution business when the transaction closed. Additionally, SDTS and Sharyland amended certain of their lease agreements to remove the assets that were transferred to Oncor. See Note 17, Leases

Cash, Cash Equivalents and Rest

Cash, Cash Equivalents and Restricted Cash	12 Months Ended
	Dec. 31, 2018
Cash And Cash Equivalents [Abstract]
Cash, Cash Equivalents and Restricted Cash	4 . 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: December 31, (In thousands) 2018 2017 2016 Cash and cash equivalents $ 1,808 $ 2,867 $ 17,612 Restricted cash 1,689 1,683 1,682 Total cash, cash equivalents and restricted cash shown on the Statement of Cash Flows $ 3,497 $ 4,550 $ 19,294 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, TDC, as described in Note 10, Long-Term Debt

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2018
Related Party Transactions [Abstract]
Related Party Transactions	5 . Related Party Transactions The Company, through SDTS, leases all its regulated assets to Sharyland through several lease agreements. Under the leases, the Company has agreed to fund capital expenditures for footprint projects. The Company earned lease revenues from Sharyland under these agreements of $200.4 million, $190.3 million and $172.1 million during the years ended December 31, 2018, 2017 and 2016, respectively. In connection with the Company’s leases with Sharyland, the Company had a deferred rent liability of $11.1 million and $14.7 million as of December 31, 2018 and 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 the Company, the Company 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 the Company’s regulated assets. For the years ended December 31, 2018 and 2017, the net amount of the payments the Company made to Sharyland was $68.1 million and $187.1 million, respectively. As of December 31, 2018 and 2017, accounts payable and accrued liabilities on the Consolidated Balance Sheets included $2.9 million and $2.1 million, respectively, related to amounts owed to Sharyland for construction costs incurred and property taxes paid on behalf of the Company. As of December 31, 2018 and 2017, amounts due from affiliates on the Consolidated Balance Sheets included $38.2 million and $35.2 million, respectively, related to amounts owed by Sharyland primarily associated with the Company’s leases. The management fee paid to Hunt Manager for the years ended December 31, 2018, 2017 and 2016 was $13.7 million, $17.6 million and $10.3 million, respectively. As of December 31, 2018 and 2017, there were no prepaid or accrued amounts associated with management fees on the Consolidated Balance Sheets. As of December 31, 2016, there was $3.5 million accrued for management fees on the Consolidated Balance Sheets. Additionally, during the years ended December 31, 2018, 2017 and 2016, the Company paid Hunt Manager $0.1 million, $0.3 million and $0.5 million, respectively, for reimbursement of annual software license and maintenance fees and other expenses in accordance with the management agreement. The 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 the Company’s total equity as of December 31 of the immediately preceding year, subject to a $30.0 million cap. The Company must notify Hunt Manager no later than September 30, 2019 if it intends not to renew the management agreement at the end of its current term, which expires December 31, 2019. Otherwise, the management agreement will automatically renew for successive five-year terms unless a majority of the Company’s independent directors decides to terminate the agreement. The base fees through December 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 April 1, 2019 - December 31, 2019 10.4 If the management agreement is renewed under its current terms, the Company would owe $3.5 million for the first quarter of 2020, and the management fee owed for the subsequent 12-month period would be calculated as described above. If, instead, the management agreement is terminated, the Company would owe Hunt Manager a termination fee equal to three times the current annual management fee or approximately $41.7 million. For information related to the pending sale of InfraREIT and asset exchange with Sharyland, including the proposed termination of the leases and management agreement, see Note 2, Pending Corporate Transactions 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 2017 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 2017 Asset Exchange 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 2017 Asset Exchange Transaction. For information related to the 2017 Asset Exchange Transaction, see Note 3, 2017 Asset Exchange Transaction As a condition to Oncor’s acquisition of InfraREIT, in October 2018 SDTS entered into a definitive agreement to exchange certain assets with Sharyland. See Note 2, Pending Corporate Transactions In connection with the sale of InfraREIT and related transactions, in October 2018 the Company entered into an omnibus termination agreement pursuant to which the management agreement, development agreement, leases and all other existing agreements between the Company, and Hunt, Sharyland or their affiliates will be terminated upon the closing. Under the omnibus termination agreement, the Company has agreed to pay Hunt approximately $40.5 million upon the closing. This amount is consistent with the termination fee, as calculated at the time the Company entered into the omnibus termination agreement, contractually required under the management agreement. For additional information, see Note 2, Pending Corporate Transactions

Electric Plant and Depreciation

Electric Plant and Depreciation	12 Months Ended
	Dec. 31, 2018
Public Utilities Property Plant And Equipment [Abstract]
Electric Plant and Depreciation	6 . Electric Plant and Depreciation The major classes of electric plant are as follows: December 31, (In thousands) 2018 2017 Electric plant: Transmission plant $ 1,794,438 $ 1,685,466 Distribution plant 151,698 143,865 General plant 3,023 3,023 Total plant in service 1,949,159 1,832,354 Construction work in progress 66,121 113,643 Total electric plant 2,015,280 1,945,997 Accumulated depreciation (203,963 ) (173,768 ) Electric plant, net $ 1,811,317 $ 1,772,229 General plant consists primarily of a warehouse, buildings and associated assets. CWIP reflects the regulated asset projects in various stages of construction prior to being placed in service. 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 $28.5 million and $29.4 million at December 31, 2018 and 2017, respectively.

Goodwill

Goodwill	12 Months Ended
	Dec. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill	7 . Goodwill Goodwill represents the excess of costs of an acquired business over the fair value of the assets acquired, less liabilities assumed. The Company conducts an impairment test of goodwill at least annually. The Company’s 2018 impairment test did not result in an impairment charge. As of December 31, 2018 and 2017, $138.4 million was recorded as goodwill on the Consolidated Balance Sheets.

Other Assets

Other Assets	12 Months Ended
	Dec. 31, 2018
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Other Assets	8 . Other Assets Other assets are as follows: December 31, 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 $ 1,025 $ (779 ) $ 246 $ 967 $ (591 ) $ 376 Other regulatory assets: Deferred financing costs 10,610 (5,490 ) 5,120 28,570 (20,944 ) 7,626 Deferred costs recoverable in future years 23,793 — 23,793 23,793 — 23,793 Other regulatory assets 34,403 (5,490 ) 28,913 52,363 (20,944 ) 31,419 Investments 2,519 — 2,519 2,519 — 2,519 Other assets $ 37,947 $ (6,269 ) $ 31,678 $ 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 9, Borrowings Under Credit Facilities Other regulatory assets consist of deferred financing costs within the Company’s regulated subsidiary, SDTS. These 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 SDTS’s 2011 Notes (defined below) were fully amortized in June 2018 and removed from the Company’s Consolidated Balance Sheets when the 2011 Notes were repaid at maturity. See Note 10, Long-Term Debt Deferred costs recoverable in future years of $23.8 million at December 31, 2018 and 2017 represent operating costs incurred from inception of Sharyland through 2007. The Company has 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, the Company received a participation in the National Rural Utilities Cooperative Finance Corporation. The Company accounts for this investment under the cost method of accounting. The Company believes that the investment is not impaired as of December 31, 2018 and 2017.

Borrowings Under Credit Facilit

Borrowings Under Credit Facilities	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Borrowings Under Credit Facilities	9 . 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. In December 2018, InfraREIT LP entered into an amendment to its revolving credit facility that extended the maturity date with respect to $67.0 million of the available revolving credit facility to December 10, 2020. The remaining $8.0 million of the available revolving credit facility will continue to mature on 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 the Company 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 10, 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 also is 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 December 31, 2018 and 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 December 31, 2018 and 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. In December 2018, SDTS entered into an amendment to its revolving credit agreement that extended the maturity date from December 10, 2019 to December 10, 2020. 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 in Note 10, 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 also is 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 December 31, 2018, SDTS had $112.5 million of borrowings outstanding at a weighted average interest rate of 4.59%, no letters of credit outstanding and $137.5 million of remaining borrowing capacity available under this revolving credit facility. As of December 31, 2017, SDTS had $41.0 million of borrowings outstanding at a weighted average interest rate of 3.12% with no letters of credit outstanding and $209.0 million of borrowing capacity available under this revolving credit facility. As of December 31, 2018 and 2017, 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. 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	12 Months Ended
	Dec. 31, 2018
Debt Instruments [Abstract]
Long-Term Debt	10 . Long-Term Debt Long-term debt consisted of the following: December 31, 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 $ 15,000 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 3.73% 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 38,338 7.25% 40,546 7.25% Senior secured notes - $110.0 million September 30, 2030 87,973 6.47% 92,821 6.47% Total SDTS debt 826,311 893,367 Total long-term debt 841,311 909,617 Less unamortized deferred financing costs (64 ) (97 ) Total long-term debt, less deferred financing costs 841,247 909,520 Less current portion of long-term debt (8,792 ) (68,305 ) Debt classified as long-term debt, less deferred financing costs $ 832,455 $ 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 9, Borrowings Under Credit Facilities SDTS had $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 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 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 are due at maturity and bear interest at a rate of 3.86% per annum, payable semi-annually. The outstanding accrued interest payable on the Series A Notes is due each June and December while the accrued interest payable on the Series B Notes is due 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, limitation 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 December 31, 2018 and 2017, SDTS and TDC were in compliance with all debt covenants under the applicable agreements. See Note 2, Pending Corporate Transaction 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 9, 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. Future maturities of long-term debt are as follows for the years ending December 31: (In thousands) Total 2019 $ 8,792 2020 221,813 2021 8,621 2022 9,216 2023 9,853 Thereafter 583,016 Total $ 841,311

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	11 . Fair Value of Financial Instruments The carrying amounts of the Company’s 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. The Company had fixed rate borrowings totaling $641.3 million and $709.6 million under senior secured notes with a weighted average interest rate of 4.5% and 4.6% per annum as of December 31, 2018 and 2017, respectively. The fair value of these borrowings was estimated using discounted cash flow analysis based on current market rates. As of December 31, 2018 and 2017, the Company had $200.0 million of borrowings under the 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 December 31, 2018 Long-term debt $ 841,311 $ — $ 864,281 $ — December 31, 2017 Long-term debt $ 909,617 $ — $ 950,522 $ —

Regulatory Matters

Regulatory Matters	12 Months Ended
	Dec. 31, 2018
Public Utilities Rate Matters [Abstract]
Regulatory Matters	1 2 . Regulatory Matters Regulatory Liabilities Regulatory liabilities are as follows: December 31, (In thousands) 2018 2017 Cost of removal $ 59,753 $ 44,679 Excess accumulated deferred federal income tax 55,779 55,779 Regulatory liabilities $ 115,532 $ 100,458 The Company’s regulatory liability related to cost of removal is established through depreciation rates and represents amounts that the Company expects 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, the Company 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 its assets. Prior to the enactment of the TCJA in December 2017, this ADFIT was calculated based on a 35% corporate federal income tax rate but was not recorded on its consolidated balance sheets or income statements due to the expectation that the Company would not pay corporate federal income taxes as a result of its REIT structure. With the passage of the 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, during the fourth quarter of 2017, the Company 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 Setting The Company has separated, between Sharyland and SDTS, the functionality that is typically combined under one commonly owned group in an integrated utility. SDTS is generally responsible for financing and funding asset additions while Sharyland is responsible for construction management, operation and maintenance of the Company’s regulated assets. Accordingly, the PUCT’s order approving the restructuring of the Company into a REIT structure required Sharyland and SDTS to be regulated on a combined basis, and Sharyland, as the holder of the CCN required to operate the Company’s regulated assets, historically has made all regulatory filings related to the Company’s assets with the PUCT. As part of the rate case in Docket No. 45414 related to SDTS’s assets (2016 Rate Case), the PUCT raised certain questions indicating that this regulatory construct might change in the future, including the potential regulation of the leases between Sharyland and SDTS as tariffs. In November 2017, the 2016 Rate Case was dismissed upon the completion of the 2017 Asset Exchange Transaction (Rate Case Dismissal), but the dismissal preserved the right of the parties to the 2016 Rate Case to address in a future proceeding all issues not mooted by the Rate Case Dismissal. Additionally, as part of the PUCT order approving the 2017 Asset Exchange Transaction, SDTS was granted a separate CCN to continue to own and lease its assets to Sharyland. The regulatory parameters in Sharyland’s rates and applicable to the Company’s regulated assets provide 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. Additionally, Sharyland’s rates also reflect the recovery of an income tax allowance, with respect to the Company’s transmission assets, at the 21% corporate federal income tax rate and, with respect to the Company’s wholesale distribution assets, at the prior 35% corporate federal income tax rate. Under existing PUCT orders, SDTS and Sharyland are required to file a new rate case by July 1, 2020 using a test year ending December 31, 2019. If the sale of InfraREIT is not completed and the Company is required to move forward with the 2020 rate case, the outcome of that rate case will result in an adjustment to many of the current parameters applicable to the Company’s regulated assets.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	1 3 . Commitments and Contingencies From time to time, the Company is a party to various legal proceedings arising in the ordinary course of business. Although the Company cannot predict the outcome of any such legal proceedings, the Company does not believe the resolution of these proceedings, individually or in the aggregate, will have a material impact on the Company’s business, financial condition or results of operations, liquidity or cash flows.

Equity

Equity	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Equity	1 4 . Equity The Company and the Operating Partnership declared cash dividends on common stock and distributions on OP Units of $1.00 per share during each of the years ended December 31, 2018, 2017 and 2016. The Company paid a total of $60.7 million, $60.7 million and $59.1 million in dividends and distributions during the years ended December 31, 2018, 2017 and 2016, respectively. For federal income tax purposes, the dividends declared in 2018, 2017 and 2016 were classified as ordinary income. The Company is required to distribute at least 90% of its taxable income (excluding net capital gains) to maintain its status as a REIT. Management believes that the Company has distributed at least 100% of its taxable income.

Noncontrolling Interest

Noncontrolling Interest	12 Months Ended
	Dec. 31, 2018
Noncontrolling Interest [Abstract]
Noncontrolling Interest	1 5 . Noncontrolling Interest The Company presents as a noncontrolling interest the portion of any equity in entities that it controls and consolidates but does not own. Generally, OP Units of the 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 the Company’s option, it may satisfy this redemption with cash or by exchanging shares of the Company’s common stock on a one-for-one basis. As of December 31, 2018 and 2017, there were a total of 16.7 million and 16.9 million, respectively, OP Units held by the limited partners of the Operating Partnership. During the years ended December 31, 2018, 2017 and 2016, an aggregate of 28,952, 31,633 and 29,722 long-term incentive units (LTIP Units), respectively, were issued by the Operating Partnership to members of the Company’s board of directors. For additional information, refer to Note 18, Share-Based Compensation The Company follows the guidance issued by the FASB regarding the classification and measurement of redeemable securities. Accordingly, the Company has determined that the OP Units meet the requirements to be classified as permanent equity. During the year ended December 31, 2018, the Company redeemed 178,083 OP Units with the issuance of 178,083 shares of common stock. The Company redeemed 24,632 OP Units with the issuance of 24,632 shares of common stock during the year ended December 31, 2017. During the year ended December 31, 2016, the Company redeemed 186,496 OP Units with the issuance of 186,496 shares of common stock.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Share	1 6 . 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 the Company’s common stock, if such redemption were dilutive. The redemption of OP Units would have been anti-dilutive during the years ended December 31, 2018, 2017 and 2016. Earnings per share are calculated as follows: Years Ended December 31, (In thousands, except per share data) 2018 2017 2016 Basic net income per share: Net income attributable to InfraREIT, Inc. $ 61,670 $ 12,302 $ 49,954 Weighted average common shares outstanding 43,930 43,783 43,668 Basic net income per share $ 1.40 $ 0.28 $ 1.14 Diluted net income per share: Net income attributable to InfraREIT, Inc. $ 61,670 $ 12,302 $ 49,954 Weighted average common shares outstanding 43,930 43,783 43,668 Redemption of Operating Partnership units — — — Weighted average dilutive shares outstanding 43,930 43,783 43,668 Diluted net income per share $ 1.40 $ 0.28 $ 1.14 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 $ 23,482 $ 4,751 $ 19,347 Redemption of Operating Partnership units 16,774 16,892 16,968

Leases

Leases	12 Months Ended
	Dec. 31, 2018
Leases [Abstract]
Leases	1 7 . Leases The following table shows the composition of the Company’s lease revenue: Years Ended December 31, (In thousands) 2018 2017 2016 Base rent (straight-line) $ 191,319 $ 165,264 $ 145,030 Percentage rent 9,035 25,077 27,069 Total lease revenue $ 200,354 $ 190,341 $ 172,099 SDTS has entered into various leases with Sharyland for all of the Company’s placed in service regulated assets. The master lease agreements, as amended, expire at various dates from December 31, 2019 through December 31, 2022. The Company’s 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 2017 Asset Exchange Transaction, which are part of the competitive renewable energy zones (CREZ) assets, only provide for base rent. Rent for the assets in McAllen and the CREZ assets not acquired in the 2017 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 2017 Asset Exchange Transaction also included a percentage rent component. All of the rent with respect to the capital expenditures to be placed in service in 2019 consists only of base rent. Percentage rent under the Company’s leases is based on a percentage of Sharyland’s annual gross revenues, as defined in the applicable lease, in excess of an annual breakpoint specified in each lease, which is 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 32% to a low of 23%. The percentage rent rates for 2019 through the expiration of the leases range from 24% to 30%. Because an annual specified breakpoint must be met under the leases before the Company can recognize any percentage rent, the Company anticipates that revenue will grow over the year with little to no percentage rent recognized in the first and second quarters of each year, with the largest amounts recognized during the third and fourth quarters of each year. Future minimum rent revenue expected in accordance with these lease agreements is as follows for the years ending December 31: (In thousands) Total 2019 $ 194,068 2020 184,438 2021 9,089 2022 4,954 2023 — Thereafter — Total $ 392,549 See Note 2, Pending Corporate Transactions

Share Based Compensation

Share Based Compensation	12 Months Ended
	Dec. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Compensation	1 8 . Share-Based Compensation InfraREIT, Inc. 2015 Equity Incentive Plan The InfraREIT, Inc. 2015 Equity Incentive Plan (2015 Equity Incentive Plan) permits the Company to provide equity based compensation to certain personnel who provide services to the Company, Hunt Manager or an affiliate of either, in the form of stock options, stock appreciation rights, dividend equivalent rights, restricted stock, stock units, performance based awards, unrestricted stock, LTIP Units and other equity based awards up to an aggregate of 375,000 shares. The 2015 Equity Incentive Plan provides that no participant in the plan will be permitted to acquire, or will have any right to acquire, shares if such acquisition would be prohibited by the ownership limits contained in the Company’s charter or bylaws or would impair the Company’s status as a REIT. As of December 31, 2018, 236,401 shares were reserved for issuance under the 2015 Equity Incentive Plan. The Company currently utilizes the 2015 Equity Incentive Plan primarily for annual compensation to the non-executive directors for their service on the Company’s board of directors. The following table shows the aggregate LTIP Units issued to members of the Company’s board of directors for the years ended December 31, 2018, 2017 and 2016: Grant Date LTIP Units Grant Date Fair Value per LTIP Unit Aggregate Fair Value (in thousands) Vesting Date January 2016 29,722 $ 18.58 $ 552 January 2017 January 2017 31,633 18.02 570 January 2018 January 2018 28,952 18.61 539 January 2019 See Note 22, Subsequent Events As part of the Company’s board of directors’ quarterly compensation, each non-executive director can, subject to certain exceptions, elect to receive part of their compensation in the Company’s common stock instead of cash with full vesting upon issuance. During 2017 and 2018, all directors received their quarterly compensation in cash. During 2016, certain directors elected to receive their quarterly compensation in the Company’s common stock. The following table shows the shares of common stock issued to members of the board of directors during the year ended December 31, 2016: Grant Date Shares of Common Stock Grant Date Value per Share Aggregate Fair Value (in thousands) January 2016 4,735 $ 18.58 $ 88 April 2016 5,497 16.81 92 July 2016 5,248 17.58 92 October 2016 4,812 17.84 86 The compensation expense, which represents the fair value of the common 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 years ended December 31, 2018, 2017 and 2016, $0.6 million, $0.6 million and $1.0 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. There was no unamortized compensation expense related to these grants at December 31, 2018. InfraREIT, Inc. Non-Qualified 2015 Employee Stock Purchase Plan The InfraREIT, Inc. 2015 Non-Qualified Employee Stock Purchase Plan (ESPP) allows employees of Hunt Manager or its affiliates whose principal duties include the management and operation of the Company’s business to purchase shares of the Company’s common stock at a discount. Pursuant to the management agreement, Hunt Manager is obligated to fund all the costs associated with the ESPP, including the funds necessary to purchase shares of the Company’s common stock in the open market pursuant to the plan. A total of 250,000 shares of common stock are reserved for sale and authorized for issuance under the ESPP. As of December 31, 2018, no shares have been purchased or offered for purchase under the ESPP.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	1 9 . Income Taxes Net Operating Loss Carryforwards At December 31, 2017, the Company had net operating loss carryforwards for federal income tax purposes of $108.1 million. There were no net operating losses used for the year ended December 31, 2018. The estimated net operating loss carryforward for federal tax purposes was $108.1 million at December 31, 2018 and will begin expiring in 2026. Unrecognized Tax Benefits Historically, the Company has accrued for potential taxes, penalties and interest related to Texas state franchise taxes on its rental income on its Consolidated Balance Sheets. However, during the second quarter of 2018, the Company 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 the Company’s Consolidated Balance Sheets and recognized as an income tax benefit on its 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 the Company’s effective tax rate. A reconciliation of the beginning and ending amount of unrecognized tax benefits follows: Years Ended December 31, (In thousands) 2018 2017 Balance at January 1 $ 4,864 $ 3,827 Additions based on tax positions related to the current year — 1,037 Settlements (4,864 ) — Balance at December 31 $ — $ 4,864 As a result of the Texas franchise tax settlement, the Company began accruing and paying Texas franchise tax on its gross lease revenues effective January 1, 2018. During each of the years ended December 31, 2017 and 2016, the Company recognized interest and penalties of $0.2 million. The Company did not recognize any interest or penalties during the year ended December 31, 2018. The Company had accrued interest and penalties of $0.8 million at December 31, 2017. There were no accrued interest and penalties at December 31, 2018. With few exceptions, the Company is no longer subject to U.S. federal, state and local income tax examinations by tax authorities for years prior to 2015. Tax Cuts and Jobs Act In December 2017, the TCJA was signed into law reducing the corporate federal income tax rate from 35% to 21%, effective for taxable years beginning on or after January 1, 2018. The TCJA also includes provisions that reduce the tax rates applicable to individuals and that treat dividends paid to REIT shareholders as income eligible for the new 20% deduction for business income earned from passthrough entities. These changes will have the effect of reducing the maximum income tax rate applicable to REIT dividends paid to individual REIT shareholders from 39.6% to 29.6%. These provisions, other than the reduction in the corporate federal income tax rate, are set to expire after 2025. The Company recorded $55.8 million as a regulatory liability on its Consolidated Balance Sheets as of December 31, 2017 related to the creation of excess ADFIT, related to the Company’s assets, due to the reduction in the corporate federal income tax rate. See Note 12, Regulatory Matters

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	12 Months Ended
	Dec. 31, 2018
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Information	20 . Supplemental Cash Flow Information Supplemental cash flow information and non-cash investing and financing activities are as follows: Years Ended December 31, (In thousands) 2018 2017 2016 Supplemental cash flow information Cash paid for interest $ 41,721 $ 39,020 $ 33,972 Non-cash investing and financing activities Change in accrued additions to electric plant (908 ) 11,298 4,113 Allowance for funds used during construction - debt 2,807 3,040 3,142 Redemption of operating partnership units for common stock 1,928 512 3,277 Dividends and distributions payable 15,176 15,169 15,161

Quarterly Financial Information

Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information (Unaudited)	21 . Quarterly Financial Information (Unaudited) Summarized unaudited consolidated quarterly information for the years ended December 31 follows: (In thousands, except per share data) 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Year 2018 Lease revenue $ 45,656 $ 47,827 $ 48,926 $ 57,945 $ 200,354 Tax Cuts and Jobs Act regulatory adjustment — — — — — General and administrative expense (6,088 ) (6,631 ) (6,787 ) (11,459 ) (30,965 ) Depreciation (11,577 ) (11,992 ) (12,063 ) (12,181 ) (47,813 ) Gain on 2017 Asset Exchange Transaction — — — — — Interest expense, net (10,674 ) (11,070 ) (10,120 ) (10,258 ) (42,122 ) Other income 733 374 7 3 1,117 Income tax expense (286 ) 5,428 (257 ) (304 ) 4,581 Net income 17,764 23,936 19,706 23,746 85,152 Less: Net income attributable to noncontrolling interest 4,900 6,602 5,435 6,545 23,482 Net income attributable to InfraREIT, Inc. $ 12,864 $ 17,334 $ 14,271 $ 17,201 $ 61,670 Basic EPS $ 0.29 $ 0.39 $ 0.32 $ 0.39 $ 1.40 Diluted EPS $ 0.29 $ 0.39 $ 0.32 $ 0.39 $ 1.40 2017 Lease revenue $ 39,624 $ 40,422 $ 51,618 $ 58,677 $ 190,341 Tax Cuts and Jobs Act regulatory adjustment — — — (55,779 ) (55,779 ) General and administrative expense (5,981 ) (6,866 ) (6,718 ) (5,823 ) (25,388 ) Depreciation (12,687 ) (12,982 ) (13,328 ) (12,210 ) (51,207 ) Gain on 2017 Asset Exchange Transaction — — — 257 257 Interest expense, net (9,698 ) (10,141 ) (10,357 ) (10,475 ) (40,671 ) Other income 3 17 331 367 718 Income tax expense (244 ) (321 ) (308 ) (345 ) (1,218 ) Net income (loss) 11,017 10,129 21,238 (25,331 ) 17,053 Less: Net income (loss) attributable to noncontrolling interest 3,068 2,821 5,908 (7,046 ) 4,751 Net income (loss) attributable to InfraREIT, Inc. $ 7,949 $ 7,308 $ 15,330 $ (18,285 ) $ 12,302 Basic EPS $ 0.18 $ 0.17 $ 0.35 $ (0.42 ) $ 0.28 Diluted EPS $ 0.18 $ 0.17 $ 0.35 $ (0.42 ) $ 0.28 (1) Basic and diluted net income per common share are computed independently for each quarter and full year based on the respective average number of common shares outstanding; therefore, the sum of the quarterly net income per common share data may not equal the net income per common share for the year.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	22 . Subsequent Events Stockholders’ Equity On January 2, 2019, the Company issued an aggregate of 22,674 shares of common stock to members of the Company’s board of directors with a grant date fair value of $21.15 per common stock and a fair value of $0.5 million. The shares of common stock are scheduled to vest in January 2020, subject to continued service. The fair value of each common stock award, or compensation expense, is measured based on the grant date market price of the Company’s common stock and is amortized over the respective vesting period on a straight-line basis. On February 26, 2019, the Company’s board of directors declared a quarterly dividend of $0.25 per share of common stock payable on April 18, 2019 to holders of record as of March 29, 2019. The Company’s board of directors also authorized the Operating Partnership to make a distribution of $0.25 per OP Unit to the partners in the Operating Partnership, which includes affiliates of Hunt. SDTS Services Agreement and Management Agreement Amendment On February 26, 2019, SDTS and Hunt Manager entered into a services agreement pursuant to which SDTS will begin to directly reimburse Hunt Manager for the compensation expenses incurred by Hunt Manager in providing certain services directly to SDTS. None of these reimbursable expenses relate to the compensation of any of the Company’s executive officers. The services otherwise remain subject to the terms of the management agreement. In connection with the execution of the services agreement, on February 26, 2019, InfraREIT, Inc. and the Operating Partnership entered into an amendment to the management agreement with Hunt Manager (Second Amendment). As a result of the Second Amendment, the amount of the quarterly base fee installment due under the management agreement in any particular quarter will be reduced by any amounts payable by SDTS under the services agreement with respect to the corresponding quarter. As a result, the total amount of the base compensation payable by the Company with respect to services provided by Hunt Manager to InfraREIT, Inc. and its subsidiaries remains unchanged. The Second Amendment also modified certain notice periods required by the management agreement in connection with the expiration of the initial term of the management agreement on December 31, 2019. These modifications included extending the date by which notice must be given of any decision on the Company’s behalf to terminate the management agreement upon its expiration. As amended, if the Company’s independent directors decide to terminate the management agreement upon the expiration of the initial term, the Company must give Hunt Manager notice of the termination no later than September 30, 2019 and otherwise comply with the existing termination provisions of the management agreement.

Schedule III - Electric Plant a

Schedule III - Electric Plant and Accumulated Depreciation	12 Months Ended
	Dec. 31, 2018
Real Estate And Accumulated Depreciation Disclosure [Abstract]
Schedule III - Electric Plant and Accumulated Depreciation	InfraREIT, Inc. DECEMBER 31, 2018 (In thousands) Description (1) Encumbrances Initial Cost to Company (2) Cost Subsequent to Acquisition Gross Amount Carried at Period Close (3) Accumulated Depreciation Date of Construction (4) Date Acquired Depreciation Life in Latest Income Statements is Computed (5) Electric Plant Improvements Carrying Cost Electric Plant Total McAllen assets $ 56,931 $ 136,426 $ — $ — $ 136,426 $ (26,584 ) (4) (4) (5) Permian assets 241,996 484,337 — — 484,337 (17,437 ) (4) (4) (5) CREZ assets 598,443 1,256,089 — — 1,256,089 (101,469 ) (4) (4) (5) Stanton Transmission Loop assets 15,305 83,906 — — 83,906 (54,377 ) (4) (4) (5) ERCOT Transmission assets 26,136 54,522 — — 54,522 (4,096 ) (4) (4) (5) (1) Asset descriptions correspond to asset groups under individual leases. (2) Because the Company’s assets consist entirely of electric plant assets, which are regulated by the PUCT, electric plant is stated at original cost, which includes cost of contracted services, direct labor, materials, acquisition adjustments, capitalized interest and overhead items. (3) See reconciliation on next page. (4) Because additions and improvements to the regulated assets are ongoing, construction and acquisition dates are not applicable. (5) Provision for depreciation of electric plant is computed using straight-lines rates as follows: Transmission plant 1.69% - 3.15% Distribution plant 1.74% - 5.96% General plant 0.80% - 5.12% InfraREIT, Inc. SCHEDULE III – ELECTRIC PLANT AND ACCUMULATED DEPRECIATION FIXED ASSET RECONCILATION (In thousands) December 31, 2018 2017 Electric plant Beginning balance $ 1,945,997 $ 1,901,960 Additions 71,852 173,820 Acquired from Oncor — 432,608 Retirements (2,569 ) (25,246 ) Transferred to Oncor — (537,145 ) Ending balance 2,015,280 1,945,997 Accumulated depreciation Beginning balance 173,768 261,140 Depreciation expense 47,813 51,207 Acquired from Oncor — 32,778 Retirements (2,569 ) (25,246 ) Cost of removal (15,049 ) (15,399 ) Transferred to Oncor — (130,712 ) Ending balance 203,963 173,768 Electric plant, net $ 1,811,317 $ 1,772,229

Description of Business and S_2

Description of Business and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of Business	Description of Business InfraREIT, Inc. (Company or InfraREIT) is a Maryland corporation that is engaged in owning and leasing rate-regulated assets in Texas. The Company is structured as a real estate investment trust (REIT) for federal income tax purposes. The Company’s subsidiaries include InfraREIT Partners, LP (Operating Partnership or InfraREIT LP), a Delaware limited partnership, of which InfraREIT is the general partner; Transmission and Distribution Company, L.L.C. (TDC); and Sharyland Distribution & Transmission Services, L.L.C. (SDTS), the Company’s regulated subsidiary. The Company has elected to be taxed as a REIT for federal income tax purposes. The Company is externally managed and advised by Hunt Utility Services, LLC (Hunt Manager), a Delaware limited liability company. Hunt Manager is responsible for managing the Company’s day-to-day affairs, subject to the oversight of the Company’s board of directors. All of the Company’s officers, including the Company’s President and Chief Executive Officer, David A. Campbell, are employees of Hunt Manager. Mr. Campbell also serves as President and Chief Executive Officer of Sharyland Utilities, L.P. (Sharyland), a Texas-based utility and the Company’s sole tenant. The Company holds 72.4% of the outstanding partnership units (OP Units) in the Operating Partnership as of December 31, 2018. The Company includes the accounts of the Operating Partnership and its subsidiaries in the consolidated financial statements. Affiliates and current or former employees of Hunt Consolidated, Inc. (Hunt) and members of the Company’s board of directors hold the other 27.6% of the outstanding OP Units as of December 31, 2018. SDTS’s assets are located in the Texas Panhandle; near Wichita Falls, Abilene and Brownwood; in the Permian Basin; and in South Texas. SDTS leases all its regulated assets under several lease agreements to Sharyland, which operates and maintains the regulated assets. SDTS and Sharyland are each subject to regulation as an electric utility by the Public Utility Commission of Texas (PUCT). SDTS is authorized to own and lease its assets to Sharyland under a certificate of convenience and necessity (CCN) granted by the PUCT.
Principles of Consolidation and Presentation	Principles of Consolidation and Presentation The consolidated financial statements include the Company’s accounts and the accounts of all other entities in which the Company has a controlling financial interest with noncontrolling interest of consolidated subsidiaries reported separately. All significant intercompany balances and transactions have been eliminated. SDTS maintains accounting records in accordance with the uniform system of accounts, as prescribed by the Federal Energy Regulatory Commission (FERC). In accordance with the applicable consolidation guidance, the Company’s consolidated financial statements reflect the effects of the different rate making principles mandated by the FERC and PUCT which regulate its subsidiaries’ operations. The accompanying historical consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (U.S. GAAP). In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. The historical financial information is not necessarily indicative of the Company’s future results of operations, financial position and cash flows.
Use of Estimates	Use of Estimates The preparation of the Company’s 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.
Regulation	Regulation As the owner of rate-regulated assets, regulatory principles applicable to the utility industry also apply to SDTS. The financial statements reflect regulatory assets and liabilities under cost-based rate regulation in accordance with accounting standards related to the effect of certain types of regulation. Regulatory decisions can have an impact on the recovery of costs, the rate earned on invested capital and the timing and amount of assets to be recovered by rates. See Note 8, Other Assets SDTS capitalizes allowance for funds used during construction (AFUDC) during the construction of its regulated assets, and SDTS’s lease agreements with Sharyland rely on FERC definitions and accepted standards regarding capitalization of expense to define key terms in the lease such as footprint projects, which are the expenditures SDTS is obligated to fund pursuant to the leases. The amounts funded for these footprint projects include allocations of Sharyland employees’ time and overhead allocations consistent with FERC policies and U.S. GAAP. The leases define “footprint projects” to be transmission or, if applicable, distribution projects that (1) are primarily situated within the Company’s current or previous distribution service territory, as applicable; (2) physically hang from the Company’s existing transmission assets, such as the addition of another circuit to the Company’s existing transmission lines or that are physically located within one of its substations or (3) connect or are otherwise added to transmission lines or other properties that comprise a part of the 2017 Asset Exchange Transaction (as defined below). Sharyland cannot be removed as lessee without prior approval from the PUCT. SDTS transacts with Sharyland through several lease arrangements covering all the regulated assets. These lease agreements include provisions for additions and retirements of the regulated assets in the form of new construction or other capitalized projects.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all short-term, highly liquid investments with original maturities of three months or less to be cash equivalents. The Company’s account balances at one or more institutions periodically exceed the Federal Deposit Insurance Corporation (FDIC) insurance coverage and, as a result, there could be a concentration of credit risk related to amounts on deposit in excess of FDIC insurance coverage. The Company has not experienced any losses and believes the risk is not significant.
Restricted Cash	Restricted Cash Restricted cash represents the principal and interest payable for two consecutive periods associated with TDC’s senior secured notes described in Note 10, Long-Term Debt
Concentration of Credit Risk	Concentration of Credit Risk Sharyland is the Company’s sole tenant and all the Company’s revenue is driven by the leases with Sharyland.
Inventory	Inventory Inventory consists primarily of transmission and distribution parts and materials used in the construction of electric plant. Inventory is valued at average cost when it is acquired and used.
Electric Plant, net	Electric Plant, net Electric plant equipment is stated at the original cost of acquisition or construction, which includes the cost of contracted services, direct labor, materials, acquisition adjustments and overhead items. In accordance with the FERC uniform system of accounts guidance, SDTS recognizes, as a cost to construction work in progress (CWIP), AFUDC on other funds classified as other income (expense), net and AFUDC on borrowed funds classified as a reduction of the interest expense, net on the Consolidated Statements of Operations. The AFUDC blended rate utilized was 6.3%, 4.0% and 6.7% for the years ended December 31, 2018, 2017 and 2016, respectively. Depreciation of property, plant and equipment is calculated on a straight-line basis over the estimated service lives of the properties based on depreciation rates approved by the PUCT. Depreciation rates include plant removal costs as a component of depreciation expense, consistent with regulatory treatment. Actual removal costs incurred are charged to accumulated depreciation. When accrued removal costs exceed incurred removal costs, the difference is reclassified as a regulatory liability to retire assets in the future. The regulatory liability will be relieved as cost of removal charges are incurred upon asset retirement. Repairs are the responsibility of Sharyland as the lessee under the lease agreements. Betterments and improvements generally are the responsibility of SDTS and are capitalized. Provision for depreciation of electric plant is computed using composite straight-line rates as follows for each of the years ended December 31, 2018, 2017 and 2016: Rates Transmission plant 1.69% - Distribution plant 1.74% - 5.96% General plant 0.80% - 5.12%
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company evaluates impairment of its long-lived assets annually or whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. An impairment loss is recognized only if the carrying amount of a long-lived asset is not recoverable through expected future cash flows. Regulatory assets are charged to expense in the period in which they are no longer probable of future recovery.
Goodwill	Goodwill Goodwill represents the excess of costs of an acquired business over the fair value of the assets acquired, less liabilities assumed. Goodwill is not amortized and is tested for impairment annually or more frequently if events or changes in circumstances arise. Accounting Standard Update (ASU) 2011-08, Testing of Goodwill for Impairment The Company’s annual goodwill impairment analysis, which was performed qualitatively during the fourth quarter of 2018, did not result in an impairment charge. As of December 31, 2018 and 2017, $138.4 million was recorded as goodwill on the Consolidated Balance Sheets.
Investments	Investments An investment is considered impaired if the fair value of the investment is less than its cost. Generally, an impairment is considered other-than-temporary unless (1) the Company has the ability and intent to hold an investment for a reasonable period of time sufficient for an anticipated recovery of fair value up to (or beyond) the cost of the investment; and (2) evidence indicating that the cost of the investment is recoverable within a reasonable period of time outweighs evidence to the contrary. If impairment is determined to be other than temporary, then an impairment loss is recognized equal to the difference between the investment’s cost and its fair value.
Deferred Financing Costs	Deferred Financing Costs Amortization of deferred financing costs associated with the issuance of TDC’s $25.0 million senior secured notes and the revolving credit facilities is computed using the straight-line method over the life of the loan which approximates the effective interest method. Amortization of deferred financing costs associated with SDTS is computed using the straight-line method over the life of the loan in accordance with applicable regulatory guidance.
Derivative Instruments	Derivative Instruments The Company may use derivatives from time to time to hedge against changes in cash flows related to interest rate risk (cash flow hedging instrument). Accounting Standards Codification (ASC) Topic 815, Derivatives and Hedging Unrealized gains and losses on the effective cash flow hedging instrument are recorded as components of accumulated other comprehensive income. Realized gains and losses on the cash flow hedging instrument are recorded as adjustments to interest expense. Settlements of derivatives are included within operating activities on the Consolidated Statements of Cash Flows. Any ineffectiveness in the cash flow hedging instrument is recorded as an adjustment to interest expense in the current period. The Company did not have any derivative financial instruments during 2018, 2017 or 2016.
Income Taxes	Income Taxes The Company elected to be treated as a REIT under Sections 856 through 860 of the Internal Revenue Code of 1986, as amended, commencing with its taxable year ended December 31, 2010. As a result, the Company generally will not be subject to federal income tax on its taxable income that is distributed to its stockholders. A REIT is subject to a number of other organizational and operational requirements, including a requirement that it currently distribute at least 90% of its annual taxable income (with certain adjustments). As a REIT, the Company expects to distribute at least 100% of its taxable income. Accordingly, there is no provision for federal income taxes in the accompanying consolidated financial statements. Even if the Company maintains its qualification for taxation as a REIT, it may be subject to certain state and local taxes on its income and property, including excise taxes, and federal corporate income taxes on any undistributed income. The Company recognizes the impact of tax return positions that are more-likely-than-not to be sustained upon audit. Significant judgment is required to evaluate uncertain tax positions. The evaluation of uncertain tax positions is based upon a number of factors, including changes in facts or circumstances, changes in tax law, correspondence with tax authorities during the course of audits and effective settlement of audit issues. In December 2017, the Tax Cuts and Job Acts (TCJA) was signed into law resulting in significant changes to federal tax laws effective for taxable years beginning on or after January 1, 2018. See Note 19, Income Taxes
Revenue Recognition	Revenue Recognition The Company, through its subsidiaries, is the owner of regulated assets and recognizes lease revenue over the term of lease agreements with Sharyland. The Company’s lease revenue includes annual payments and additional rents based upon a percentage of revenue earned by Sharyland on the leased assets in excess of annual specified breakpoints. In accordance with the lease agreements, Sharyland, the lessee and operator of the regulated assets, is responsible for the maintenance and operation of the regulated assets and primarily responsible for compliance with all regulatory requirements of the PUCT, the FERC or any other regulatory entity with jurisdiction over the regulated assets on the Company’s behalf and with the Company’s cooperation. Each of the lease agreements with Sharyland is a net lease that obligates the lessee to pay all property related expenses, including maintenance, repairs, taxes and insurance, and to comply with the terms of the SDTS secured credit facilities and note purchase agreements. The Company recognizes base rent under these leases on a straight-line basis over the applicable lease term. The current lease agreements provide for periodic supplemental adjustments of base rent based upon capital expenditures made by SDTS. The Company recognizes supplemental adjustments of base rent as a modification under these leases on a prospective straight-line basis over the applicable lease term. The Company recognizes percentage rent under these leases once the revenue earned by Sharyland on the leased assets exceeds the annual specified breakpoints.
Asset Retirement Obligations	Asset Retirement Obligations The Company has identified, but not recognized, asset retirement obligation liabilities related to the regulated assets as a result of certain easements on property on which the Company has assets. Generally, such easements are perpetual and require only the retirement and removal of the assets upon cessation of the property’s use. Management has not estimated and recorded a retirement liability for such easements because the Company plans to use the facilities indefinitely.
Interest Expense, net	Interest Expense, net The Company’s interest expense, net primarily consists of interest expense from the senior secured notes, senior secured term loan and credit facilities, see Note 9, Borrowings Under Credit Facilities Long-Term Debt
Other Income, net	Other Income, net AFUDC on other funds of $1.1 million, $0.7 million and $3.7 million was recognized in other income, net during the years ended December 31, 2018, 2017 and 2016, respectively.
Fair Value of Financial Instruments	Fair Value of Financial Instruments ASC Topic 820, Fair Value Measurements and Disclosures Level 1 — Quoted prices in active markets for identical assets and liabilities. Level 2 — Valuations based on one or more quoted prices in markets that are not active; quoted prices for similar assets or liabilities in active markets; inputs that are observable other than quoted prices for the asset or the liability; or inputs that are derived principally from or corroborated by observable market data by correlation or other means. Level 3 — Valuations based on inputs that are unobservable and significant to the overall fair value measurement.
Recent Accounting Guidance	Recent Accounting Guidance Recently Adopted Accounting Guidance In May 2014, the Financial Accounting Standards Board (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 230): 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 (Topic 842) Leases (Topic 842): Land Easement Practical Expedient for Transition to Topic 842 Leases (Topic 842), Narrow-Scope Improvements for Lessors Leases (Topic 842): Targeted Improvements In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement
Reportable Segments	Reportable Segments U.S. GAAP establishes standards for reporting financial and descriptive information about a company’s reportable segments. Management has determined that the Company has one reportable segment, with activities related to ownership and leasing of rate-regulated assets.

Description of Business and S_3

Description of Business and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Schedule of Provision for Depreciation of Electric Plant	Provision for depreciation of electric plant is computed using composite straight-line rates as follows for each of the years ended December 31, 2018, 2017 and 2016: Rates Transmission plant 1.69% - Distribution plant 1.74% - 5.96% General plant 0.80% - 5.12%

2017 Asset Exchange Transacti_2

2017 Asset Exchange Transaction (Tables)	12 Months Ended
	Dec. 31, 2018
Nonmonetary Transactions [Abstract]
Schedule of 2017 Asset Exchange Transaction	The table below reflects the details of the Asset Exchange Transaction: (in thousands) December 31, 2017 Net assets transferred to Oncor Gross transmission plant $ 2,675 Gross distribution plant 499,381 Gross general plant 13,013 Construction work in progress 22,076 Total electric plant 537,145 Accumulated depreciation (130,712 ) Electric plant, net 406,433 Inventory 37 Regulatory liability (3,870 ) Net assets transferred to Oncor $ 402,600 Net transmission assets acquired from Oncor Gross transmission plant $ 432,560 Construction work in progress 48 Total transmission plant 432,608 Accumulated depreciation (32,778 ) Transmission plant, net 399,830 Regulatory liability (16,540 ) Net assets acquired from Oncor $ 383,290 Cash portion of purchase price from Oncor Cash $ 17,935 Receivable from Oncor 1,632 Cash portion of purchase price from Oncor $ 19,567 Gain on asset exchange transaction $ 257

Cash, Cash Equivalents and Re_2

Cash, Cash Equivalents and Restricted Cash (Tables)	12 Months Ended
	Dec. 31, 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: December 31, (In thousands) 2018 2017 2016 Cash and cash equivalents $ 1,808 $ 2,867 $ 17,612 Restricted cash 1,689 1,683 1,682 Total cash, cash equivalents and restricted cash shown on the Statement of Cash Flows $ 3,497 $ 4,550 $ 19,294

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2018
Related Party Transactions [Abstract]
Schedule of Annual Base Fees	The base fees through December 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 April 1, 2019 - December 31, 2019 10.4

Electric Plant and Depreciati_2

Electric Plant and Depreciation (Tables)	12 Months Ended
	Dec. 31, 2018
Public Utilities Property Plant And Equipment [Abstract]
Schedule of Major Classes of Electric Plant	The major classes of electric plant are as follows: December 31, (In thousands) 2018 2017 Electric plant: Transmission plant $ 1,794,438 $ 1,685,466 Distribution plant 151,698 143,865 General plant 3,023 3,023 Total plant in service 1,949,159 1,832,354 Construction work in progress 66,121 113,643 Total electric plant 2,015,280 1,945,997 Accumulated depreciation (203,963 ) (173,768 ) Electric plant, net $ 1,811,317 $ 1,772,229

Other Assets (Tables)

Other Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Summary of Other Assets	Other assets are as follows: December 31, 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 $ 1,025 $ (779 ) $ 246 $ 967 $ (591 ) $ 376 Other regulatory assets: Deferred financing costs 10,610 (5,490 ) 5,120 28,570 (20,944 ) 7,626 Deferred costs recoverable in future years 23,793 — 23,793 23,793 — 23,793 Other regulatory assets 34,403 (5,490 ) 28,913 52,363 (20,944 ) 31,419 Investments 2,519 — 2,519 2,519 — 2,519 Other assets $ 37,947 $ (6,269 ) $ 31,678 $ 55,849 $ (21,535 ) $ 34,314

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Instruments [Abstract]
Components of Long-Term Debt	Long-term debt consisted of the following: December 31, 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 $ 15,000 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 3.73% 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 38,338 7.25% 40,546 7.25% Senior secured notes - $110.0 million September 30, 2030 87,973 6.47% 92,821 6.47% Total SDTS debt 826,311 893,367 Total long-term debt 841,311 909,617 Less unamortized deferred financing costs (64 ) (97 ) Total long-term debt, less deferred financing costs 841,247 909,520 Less current portion of long-term debt (8,792 ) (68,305 ) Debt classified as long-term debt, less deferred financing costs $ 832,455 $ 841,215
Schedule of Future Maturities of Long-Term Debt	Future maturities of long-term debt are as follows for the years ending December 31: (In thousands) Total 2019 $ 8,792 2020 221,813 2021 8,621 2022 9,216 2023 9,853 Thereafter 583,016 Total $ 841,311

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 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 December 31, 2018 Long-term debt $ 841,311 $ — $ 864,281 $ — December 31, 2017 Long-term debt $ 909,617 $ — $ 950,522 $ —

Regulatory Matters (Tables)

Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2018
Public Utilities Rate Matters [Abstract]
Summary of Regulatory Liabilities	Regulatory liabilities are as follows: December 31, (In thousands) 2018 2017 Cost of removal $ 59,753 $ 44,679 Excess accumulated deferred federal income tax 55,779 55,779 Regulatory liabilities $ 115,532 $ 100,458

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Computation of Earnings Per Share	Earnings per share are calculated as follows: Years Ended December 31, (In thousands, except per share data) 2018 2017 2016 Basic net income per share: Net income attributable to InfraREIT, Inc. $ 61,670 $ 12,302 $ 49,954 Weighted average common shares outstanding 43,930 43,783 43,668 Basic net income per share $ 1.40 $ 0.28 $ 1.14 Diluted net income per share: Net income attributable to InfraREIT, Inc. $ 61,670 $ 12,302 $ 49,954 Weighted average common shares outstanding 43,930 43,783 43,668 Redemption of Operating Partnership units — — — Weighted average dilutive shares outstanding 43,930 43,783 43,668 Diluted net income per share $ 1.40 $ 0.28 $ 1.14 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 $ 23,482 $ 4,751 $ 19,347 Redemption of Operating Partnership units 16,774 16,892 16,968

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2018
Leases [Abstract]
Schedule of Composition of Lease Revenue	The following table shows the composition of the Company’s lease revenue: Years Ended December 31, (In thousands) 2018 2017 2016 Base rent (straight-line) $ 191,319 $ 165,264 $ 145,030 Percentage rent 9,035 25,077 27,069 Total lease revenue $ 200,354 $ 190,341 $ 172,099
Schedule of Future Minimum Rent Revenue Expected in Accordance with Lease Agreement	Future minimum rent revenue expected in accordance with these lease agreements is as follows for the years ending December 31: (In thousands) Total 2019 $ 194,068 2020 184,438 2021 9,089 2022 4,954 2023 — Thereafter — Total $ 392,549

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 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 the Company’s board of directors for the years ended December 31, 2018, 2017 and 2016: Grant Date LTIP Units Grant Date Fair Value per LTIP Unit Aggregate Fair Value (in thousands) Vesting Date January 2016 29,722 $ 18.58 $ 552 January 2017 January 2017 31,633 18.02 570 January 2018 January 2018 28,952 18.61 539 January 2019
Shares of Common Stock Issued to Board of Directors	The following table shows the shares of common stock issued to members of the board of directors during the year ended December 31, 2016: Grant Date Shares of Common Stock Grant Date Value per Share Aggregate Fair Value (in thousands) January 2016 4,735 $ 18.58 $ 88 April 2016 5,497 16.81 92 July 2016 5,248 17.58 92 October 2016 4,812 17.84 86

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits	The tax portion of the liability represented unrecognized tax benefits that, if recognized, would have impacted the Company’s effective tax rate. A reconciliation of the beginning and ending amount of unrecognized tax benefits follows: Years Ended December 31, (In thousands) 2018 2017 Balance at January 1 $ 4,864 $ 3,827 Additions based on tax positions related to the current year — 1,037 Settlements (4,864 ) — Balance at December 31 $ — $ 4,864

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 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: Years Ended December 31, (In thousands) 2018 2017 2016 Supplemental cash flow information Cash paid for interest $ 41,721 $ 39,020 $ 33,972 Non-cash investing and financing activities Change in accrued additions to electric plant (908 ) 11,298 4,113 Allowance for funds used during construction - debt 2,807 3,040 3,142 Redemption of operating partnership units for common stock 1,928 512 3,277 Dividends and distributions payable 15,176 15,169 15,161

Quarterly Financial Informati_2

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Summarized Unaudited Consolidated Quarterly Information	Summarized unaudited consolidated quarterly information for the years ended December 31 follows: (In thousands, except per share data) 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Year 2018 Lease revenue $ 45,656 $ 47,827 $ 48,926 $ 57,945 $ 200,354 Tax Cuts and Jobs Act regulatory adjustment — — — — — General and administrative expense (6,088 ) (6,631 ) (6,787 ) (11,459 ) (30,965 ) Depreciation (11,577 ) (11,992 ) (12,063 ) (12,181 ) (47,813 ) Gain on 2017 Asset Exchange Transaction — — — — — Interest expense, net (10,674 ) (11,070 ) (10,120 ) (10,258 ) (42,122 ) Other income 733 374 7 3 1,117 Income tax expense (286 ) 5,428 (257 ) (304 ) 4,581 Net income 17,764 23,936 19,706 23,746 85,152 Less: Net income attributable to noncontrolling interest 4,900 6,602 5,435 6,545 23,482 Net income attributable to InfraREIT, Inc. $ 12,864 $ 17,334 $ 14,271 $ 17,201 $ 61,670 Basic EPS $ 0.29 $ 0.39 $ 0.32 $ 0.39 $ 1.40 Diluted EPS $ 0.29 $ 0.39 $ 0.32 $ 0.39 $ 1.40 2017 Lease revenue $ 39,624 $ 40,422 $ 51,618 $ 58,677 $ 190,341 Tax Cuts and Jobs Act regulatory adjustment — — — (55,779 ) (55,779 ) General and administrative expense (5,981 ) (6,866 ) (6,718 ) (5,823 ) (25,388 ) Depreciation (12,687 ) (12,982 ) (13,328 ) (12,210 ) (51,207 ) Gain on 2017 Asset Exchange Transaction — — — 257 257 Interest expense, net (9,698 ) (10,141 ) (10,357 ) (10,475 ) (40,671 ) Other income 3 17 331 367 718 Income tax expense (244 ) (321 ) (308 ) (345 ) (1,218 ) Net income (loss) 11,017 10,129 21,238 (25,331 ) 17,053 Less: Net income (loss) attributable to noncontrolling interest 3,068 2,821 5,908 (7,046 ) 4,751 Net income (loss) attributable to InfraREIT, Inc. $ 7,949 $ 7,308 $ 15,330 $ (18,285 ) $ 12,302 Basic EPS $ 0.18 $ 0.17 $ 0.35 $ (0.42 ) $ 0.28 Diluted EPS $ 0.18 $ 0.17 $ 0.35 $ (0.42 ) $ 0.28 (1) Basic and diluted net income per common share are computed independently for each quarter and full year based on the respective average number of common shares outstanding; therefore, the sum of the quarterly net income per common share data may not equal the net income per common share for the year.

Description of Business and S_4

Description of Business and Summary of Significant Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2018USD ($)Segment	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Derivative financial instruments	$ 0	$ 0	$ 0
AFUDC rate	6.30%	4.00%	6.70%
Goodwill	$ 138,384,000	$ 138,384,000
Percentage of taxable income for distribution	90.00%
Percentage of taxable income distributed	100.00%
Asset retirement obligation liabilities	$ 0
AFUDC on Borrowed Funds	2,800,000	3,000,000	$ 3,100,000
AFUDC on Other Funds	$ 1,100,000	$ 700,000	$ 3,700,000
Number of reportable segment | Segment	1
InfraREIT, L.L.C.
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Percentage of taxable income for distribution	90.00%
Percentage of taxable income distributed	100.00%
Provision for federal income taxes	$ 0
Senior Secured Notes, 8.50%
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Issuance of senior secured notes	$ 25,000,000
InfraREIT LP
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Percentage of partnership units outstanding	72.40%
Hunt Consolidated, Inc. | InfraREIT LP
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Percentage of partnership units outstanding	27.60%

Description of Business and S_5

Description of Business and Summary of Significant Accounting Policies - Schedule of Provision for Depreciation of Electric Plant (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Transmission Plant | Minimum
Public Utility Property Plant And Equipment [Line Items]
Depreciation rate	1.69%	1.69%	1.69%
Transmission Plant | Maximum
Public Utility Property Plant And Equipment [Line Items]
Depreciation rate	3.15%	3.15%	3.15%
Distribution Plant | Minimum
Public Utility Property Plant And Equipment [Line Items]
Depreciation rate	1.74%	1.74%	1.74%
Distribution Plant | Maximum
Public Utility Property Plant And Equipment [Line Items]
Depreciation rate	5.96%	5.96%	5.96%
General Plant | Minimum
Public Utility Property Plant And Equipment [Line Items]
Depreciation rate	0.80%	0.80%	0.80%
General Plant | Maximum
Public Utility Property Plant And Equipment [Line Items]
Depreciation rate	5.12%	5.12%	5.12%

Pending Corporate Transactions

Pending Corporate Transactions - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2018	Oct. 18, 2018
Sharyland Holdings, LP | Sempra Energy
Business Acquisition [Line Items]
Equity interest percentage	50.00%
Hunt Consolidated, Inc.
Business Acquisition [Line Items]
Termination fee related to Sale of InfraREIT, Inc	$ 40.5
Oncor Electric Delivery Company LLC | Definitive Agreement
Business Acquisition [Line Items]
Business acquisition, share price		$ 21
Business acquisition, value in cash		$ 1,275
Business combination, assumption of net debt	$ 950

2017 Asset Exchange Transacti_3

2017 Asset Exchange Transaction - Additional Information (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Nonmonetary Transaction [Line Items]
Proceeds from asset exchange transaction			$ 1,632	$ 17,935
Gain on asset exchange transaction		$ 257		257
2017 Asset Exchange Agreement | Oncor Electric Delivery Company LLC
Nonmonetary Transaction [Line Items]
Net assets exchanged	$ 402,600	402,600		402,600
Transmission assets	399,830	399,830		399,830
Proceeds from asset exchange transaction	17,935
Receivable under asset exchange transaction	1,632	1,632		1,632
Gain on asset exchange transaction	257
Sharyland Distribution & Transmission Services, L.L.C. | 2017 Asset Exchange Agreement | Oncor Electric Delivery Company LLC
Nonmonetary Transaction [Line Items]
Net assets exchanged	403,000	403,000		403,000
Transmission assets	383,000	383,000		383,000
Proceeds from asset exchange transaction				18,000
Gain on asset exchange transaction				300
Sharyland Distribution & Transmission Services, L.L.C. | 2017 Asset Exchange Agreement | Oncor Electric Delivery Company LLC | Prepaids and Other Current Assets
Nonmonetary Transaction [Line Items]
Receivable under asset exchange transaction	$ 2,000	$ 2,000		$ 2,000

2017 Asset Exchange Transacti_4

2017 Asset Exchange Transaction - Schedule of 2017 Asset Exchange Transaction (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Cash portion of purchase price from Oncor
Cash			$ 1,632	$ 17,935
Gain on asset exchange transaction		$ 257		257
2017 Asset Exchange Agreement | Oncor Electric Delivery Company LLC
Net assets transferred to Oncor
Gross transmission plant	$ 2,675	2,675		2,675
Gross distribution plant	499,381	499,381		499,381
Gross general plant	13,013	13,013		13,013
Construction work in progress	22,076	22,076		22,076
Total electric plant	537,145	537,145		537,145
Accumulated depreciation	(130,712)	(130,712)		(130,712)
Electric plant, net	406,433	406,433		406,433
Inventory	37	37		37
Regulatory liability	(3,870)	(3,870)		(3,870)
Net assets transferred to Oncor	402,600	402,600		402,600
Net transmission assets acquired from Oncor
Gross transmission plant	432,560	432,560		432,560
Construction work in progress	48	48		48
Total transmission plant	432,608	432,608		432,608
Accumulated depreciation	(32,778)	(32,778)		(32,778)
Transmission plant, net	399,830	399,830		399,830
Regulatory liability	(16,540)	(16,540)		(16,540)
Net assets acquired from Oncor	383,290	383,290		383,290
Cash portion of purchase price from Oncor
Cash	17,935
Receivable from Oncor	1,632	1,632		1,632
Cash portion of purchase price from Oncor	19,567	$ 19,567		$ 19,567
Gain on asset exchange transaction	$ 257

Cash, Cash Equivalents and Re_3

Cash, Cash Equivalents and Restricted Cash - Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash within Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash And Cash Equivalents [Abstract]
Cash and cash equivalents	$ 1,808	$ 2,867	$ 17,612
Restricted cash	1,689	1,683	1,682
Total cash, cash equivalents and restricted cash shown on the Statement of Cash Flows	$ 3,497	$ 4,550	$ 19,294	$ 11,153

Cash, Cash Equivalents and Re_4

Cash, Cash Equivalents and Restricted Cash - Additional Information (Details) - Senior Secured Notes, 8.50% - USD ($)	Dec. 31, 2018	Dec. 31, 2010
Restricted Cash And Cash Equivalents Items [Line Items]
Long-term debt, face amount	$ 25,000,000
Transmission and Distribution Company, L.L.C
Restricted Cash And Cash Equivalents Items [Line Items]
Long-term debt, face amount	$ 25,000,000	$ 25,000,000

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Mar. 31, 2020
Related Party Transaction [Line Items]
Due from affiliates	$ 38,174,000	$ 35,172,000
Hunt Utility Services, LLC
Related Party Transaction [Line Items]
Payment for management fee	13,700,000	17,600,000	$ 10,300,000
Prepaid management fee	0	0
Accrued management fee	0	0	3,500,000
Reimbursement of annual software license and maintenance fees and other expenses	$ 100,000	$ 300,000	$ 500,000
Type of Cost, Good or Service [Extensible List]	us-gaap:LicenseAndMaintenanceMember	us-gaap:LicenseAndMaintenanceMember	us-gaap:LicenseAndMaintenanceMember
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 the Company’s 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%
Management fee cap	$ 30,000,000
Hunt Utility Services, LLC | Scenario, Forecast
Related Party Transaction [Line Items]
Due to related parties				$ 3,500,000
Sharyland
Related Party Transaction [Line Items]
Lease revenue from related party	200,400,000	$ 190,300,000	$ 172,100,000
Deferred rent liability	11,100,000	14,700,000
Payments to acquire plant, and equipment	68,100,000	187,100,000
Accounts payable and accrued liabilities	2,900,000	2,100,000
Due from affiliates	38,200,000	$ 35,200,000
Termination Fee | Hunt Utility Services, LLC
Related Party Transaction [Line Items]
Due to related parties	41,700,000
Hunt Consolidated, Inc.
Related Party Transaction [Line Items]
Termination fee related to Sale of InfraREIT, Inc	$ 40,500,000

Related Party Transactions - Sc

Related Party Transactions - Schedule of Annual Base Fees (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Dec. 31, 2019	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	$ 10.4	$ 13.5

Electric Plant and Depreciati_3

Electric Plant and Depreciation - Schedule of Major Classes of Electric Plant (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Electric plant:
Transmission plant	$ 1,794,438	$ 1,685,466
Distribution plant	151,698	143,865
General plant	3,023	3,023
Total plant in service	1,949,159	1,832,354
Construction work in progress	66,121	113,643
Total electric plant	2,015,280	1,945,997
Accumulated depreciation	(203,963)	(173,768)
Electric plant, net	$ 1,811,317	$ 1,772,229

Electric Plant and Depreciati_4

Electric Plant and Depreciation - Additional Information (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Public Utilities Property Plant And Equipment [Abstract]
Electric plant, net includes plant acquisition adjustments	$ 28.5	$ 29.4

Goodwill (Details)

Goodwill (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill impairment charge	$ 0
Goodwill	$ 138,384,000	$ 138,384,000

Other Assets - Summary of Other

Other Assets - Summary of Other Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Other Assets Noncurrent [Abstract]
Deferred financing costs on undrawn revolver, Gross Carrying Amount	$ 1,025	$ 967
Other regulatory assets Deferred financing costs, Gross Carrying Amount	10,610	28,570
Other regulatory assets Deferred costs recoverable in future years, Gross Carrying Amount	23,793	23,793
Other regulatory assets, Gross Carrying Amount	34,403	52,363
Investments, Gross Carrying Amount	2,519	2,519
Other assets, Gross Carrying Amount	37,947	55,849
Deferred financing costs on undrawn revolver, Accumulated Amortization	(779)	(591)
Other regulatory assets Deferred financing costs, Accumulated Amortization	(5,490)	(20,944)
Other regulatory assets, Accumulated Amortization	(5,490)	(20,944)
Other assets, Accumulated Amortization	(6,269)	(21,535)
Deferred financing costs on undrawn revolver, Net Carrying Amount	246	376
Other regulatory assets Deferred financing costs, Net Carrying Amount	5,120	7,626
Other regulatory assets Deferred costs recoverable in future years, Net Carrying Amount	23,793	23,793
Other regulatory assets, Net Carrying Amount	28,913	31,419
Investments, Net Carrying Amount	2,519	2,519
Other assets, Net Carrying Amount	$ 31,678	$ 34,314

Other Assets - Additional Infor

Other Assets - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Other Assets [Line Items]
Other regulatory assets Deferred financing costs, Gross Carrying Amount	$ 10,610,000	$ 28,570,000
Deferred costs recoverable in future years	23,793,000	23,793,000
Investment impaired	0	$ 0
Senior Secured Notes, 5.04% | SDTS
Other Assets [Line Items]
Other regulatory assets Deferred financing costs, Gross Carrying Amount	$ 18,200,000

Borrowings Under Credit Facil_2

Borrowings Under Credit Facilities - Additional Information (Details) - USD ($)	1 Months Ended		12 Months Ended
	Dec. 31, 2018	Nov. 30, 2018	Dec. 31, 2018	Dec. 31, 2014	Dec. 31, 2017
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			Dec. 10, 2019
Credit facility, remaining borrowing capacity	$ 75,000,000		$ 75,000,000		$ 75,000,000
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
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 | Amendment
Line Of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity	$ 67,000,000		67,000,000
Credit facility, maturity date	Dec. 10, 2020
Credit facility, remaining borrowing capacity	$ 8,000,000		8,000,000
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, 2020	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]
Credit facility, remaining borrowing capacity	$ 137,500,000		$ 137,500,000		209,000,000
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	$ 112,500,000		$ 112,500,000		$ 41,000,000
Debt, weighted average interest rate	4.59%		4.59%		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	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Debt Instrument [Line Items]
Long-term debt, Amount Outstanding	$ 841,311	$ 909,617
Less unamortized deferred financing costs	(64)	(97)
Total long-term debt, less deferred financing costs	841,247	909,520
Less current portion of long-term debt	(8,792)	(68,305)
Debt classified as long-term debt, less deferred financing costs	$ 832,455	$ 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	$ 15,000	$ 16,250
Interest bearing note, maturity date	Dec. 30, 2020
SDTS
Debt Instrument [Line Items]
Long-term debt, Amount Outstanding	$ 826,311	$ 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	$ 38,338	$ 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	$ 87,973	$ 92,821
Interest bearing note, maturity date	Sep. 30, 2030
SDTS | Senior Secured Term Loan
Debt Instrument [Line Items]
Long-term debt, Amount Outstanding	$ 200,000	$ 200,000
Interest bearing note, maturity date	Jun. 5, 2020
Long-term debt, Interest Rate	3.73%	2.71%

Long-Term Debt - Components o_2

Long-Term Debt - Components of Long-Term Debt (Parenthetical) (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Senior Secured Notes, 8.50%
Debt Instrument [Line Items]
Long-term debt, face amount	$ 25,000,000
TDC | Senior Secured Notes, 8.50%
Debt Instrument [Line Items]
Long-term debt, face amount	25,000,000		$ 25,000,000
SDTS | Senior Secured Notes, 5.04%
Debt Instrument [Line Items]
Long-term debt, face amount	60,000,000	$ 60,000,000
SDTS | Senior Secured Term Loan
Debt Instrument [Line Items]
Long-term debt, face amount	200,000,000
SDTS | Senior Secured Notes, 3.86%
Debt Instrument [Line Items]
Long-term debt, face amount	400,000,000
SDTS | Senior Secured Notes, 3.86% Maturing in 2026
Debt Instrument [Line Items]
Long-term debt, face amount	100,000,000
SDTS | Senior Secured Notes, 7.25%
Debt Instrument [Line Items]
Long-term debt, face amount	53,500,000			$ 53,500,000
SDTS | Senior Secured Notes, 6.47%
Debt Instrument [Line Items]
Long-term debt, face amount	$ 110,000,000		$ 110,000,000

Long-Term Debt - Additional Inf

Long-Term Debt - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 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	$ 246,000	$ 376,000
Senior Secured Notes, 8.50%
Debt Instrument [Line Items]
Long-term debt, face amount	25,000,000
2017 Term Loan
Debt Instrument [Line Items]
Long-term debt, face amount	200,000,000	$ 200,000,000
TDC | Senior Secured Notes, 8.50%
Debt Instrument [Line Items]
Long-term debt, face amount	$ 25,000,000					$ 25,000,000
Long-term debt, stated interest rate	8.50%	8.50%				8.50%
Deferred financing costs, Net Carrying Amount	$ 100,000	$ 100,000
SDTS | Senior Secured Notes, 5.04%
Debt Instrument [Line Items]
Long-term debt, face amount	$ 60,000,000				$ 60,000,000
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		$ 200,000,000
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	$ 53,500,000						$ 53,500,000
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	$ 110,000,000					$ 110,000,000
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				$ 400,000,000
Long-term debt, stated interest rate				3.86%
SDTS Credit Agreements | Series B Notes
Debt Instrument [Line Items]
Long-term debt, face amount			$ 100,000,000
Long-term debt, stated interest rate			3.86%

Long-Term Debt - Schedule of Fu

Long-Term Debt - Schedule of Future Maturities of Long-Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
2,019	$ 8,792
2,020	221,813
2,021	8,621
2,022	9,216
2,023	9,853
Thereafter	583,016
Total	$ 841,311	$ 909,617

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Additional Information (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term Debt	$ 832,455	$ 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	$ 641,300	$ 709,600
Debt, weighted average interest rate	4.50%	4.60%

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Financial Instruments Measured at Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Carrying Value
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-term debt	$ 841,311	$ 909,617
Level 2 | Fair Value
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-term debt	$ 864,281	$ 950,522

Regulatory Matters - Summary of

Regulatory Matters - Summary of Regulatory Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Public Utilities General Disclosures [Line Items]
Regulatory Liabilities	$ 115,532	$ 100,458
Cost of Removal
Public Utilities General Disclosures [Line Items]
Regulatory Liabilities	59,753	44,679
Excess Accumulated Deferred Federal Income Tax
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	Dec. 31, 2017	Dec. 31, 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		$ 55,779		$ 55,779
Regulatory liabilities		100,458	$ 115,532	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	$ 55,779

Equity - Additional Information

Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity [Abstract]
Cash dividends declared per share to shareholders	$ 1	$ 1	$ 1
Cash distributions declared to unit holders, per unit	$ 1	$ 1	$ 1
Dividends and distributions paid	$ 60,697	$ 60,668	$ 59,109
Percentage of taxable income for distribution	90.00%
Percentage of taxable income distributed	100.00%

Noncontrolling Interest - Addit

Noncontrolling Interest - Additional Information (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	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	16,700,000	16,900,000
Operating partnership units redeem	178,083	24,632	186,496
Common shares issued	178,083	24,632	186,496
LTIP Units
Minority Interest [Line Items]
Operating partnership units issued	28,952	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								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Basic net income per share:
Net income attributable to InfraREIT, Inc.	$ 17,201	$ 14,271	$ 17,334	$ 12,864	$ (18,285)	$ 15,330	$ 7,308	$ 7,949	$ 61,670	$ 12,302	$ 49,954
Weighted average common shares outstanding									43,930	43,783	43,668
Basic net income per share	$ 0.39	$ 0.32	$ 0.39	$ 0.29	$ (0.42)	$ 0.35	$ 0.17	$ 0.18	$ 1.40	$ 0.28	$ 1.14
Diluted net income per share:
Net income attributable to InfraREIT, Inc.	$ 17,201	$ 14,271	$ 17,334	$ 12,864	$ (18,285)	$ 15,330	$ 7,308	$ 7,949	$ 61,670	$ 12,302	$ 49,954
Weighted average common shares outstanding									43,930	43,783	43,668
Weighted average dilutive shares outstanding									43,930	43,783	43,668
Diluted net income per share	$ 0.39	$ 0.32	$ 0.39	$ 0.29	$ (0.42)	$ 0.35	$ 0.17	$ 0.18	$ 1.40	$ 0.28	$ 1.14
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	$ 6,545	$ 5,435	$ 6,602	$ 4,900	$ (7,046)	$ 5,908	$ 2,821	$ 3,068	$ 23,482	$ 4,751	$ 19,347
Redemption of Operating Partnership units									16,774	16,892	16,968

Leases - Schedule of Compositio

Leases - Schedule of Composition of Lease Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Leases [Abstract]
Base rent (straight-line)									$ 191,319	$ 165,264	$ 145,030
Percentage rent									9,035	25,077	27,069
Total lease revenue	$ 57,945	$ 48,926	$ 47,827	$ 45,656	$ 58,677	$ 51,618	$ 40,422	$ 39,624	$ 200,354	$ 190,341	$ 172,099

Leases - Additional Information

Leases - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Operating Leased Assets [Line Items]
Operating leases placed in services dates description		SDTS has entered into various leases with Sharyland for all of the Company’s 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		32.00%
Minimum
Operating Leased Assets [Line Items]
Rate of rent used, Percentage		23.00%
Scenario, Forecast | Maximum
Operating Leased Assets [Line Items]
Rate of rent used, Percentage	30.00%
Scenario, Forecast | Minimum
Operating Leased Assets [Line Items]
Rate of rent used, Percentage	24.00%

Leases - Future Minimum Rent Re

Leases - Future Minimum Rent Revenue Expected in Accordance with Lease Agreement (Details) $ in Thousands	Dec. 31, 2018USD ($)
Leases [Abstract]
2,019	$ 194,068
2,020	184,438
2,021	9,089
2,022	4,954
Total	$ 392,549

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
2015 Equity Incentive Plan
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Equity based compensation	375,000
Common stock reserved for future Issuance	236,401
Unamortized stock compensation expense	$ 0
2015 Equity Incentive Plan | General And Administrative Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Compensation expenses	$ 600,000	$ 600,000	$ 1,000,000
Non-Qualified 2015 Employee Stock Purchase Plan
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Equity based compensation	250,000
Common stock reserved for future Issuance	250,000
Shares purchased under ESPP	0

Share-Based Compensation - Aggr

Share-Based Compensation - Aggregate LTIP Units Issued to Board of Directors (Details) - 2015 Equity Incentive Plan - Director - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Oct. 31, 2016	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Grant Date			2016-10	2016-07	2016-04	2016-01
Grant Date Fair Value per Share			$ 17.84	$ 17.58	$ 16.81	$ 18.58
Aggregate Fair Value			$ 86	$ 92	$ 92	$ 88
LTIP Units
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Grant Date	2018-01	2017-01				2016-01
LTIP Units	28,952	31,633				29,722
Grant Date Fair Value per Share	$ 18.61	$ 18.02				$ 18.58
Aggregate Fair Value	$ 539	$ 570				$ 552
Vesting Date	2019-01	2018-01				2017-01

Share-Based Compensation - Shar

Share-Based Compensation - Shares of Common Stock Issued to Board of Directors (Details) - 2015 Equity Incentive Plan - Director - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended
	Oct. 31, 2016	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Grant Date	2016-10	2016-07	2016-04	2016-01
Shares of Common Stock	4,812	5,248	5,497	4,735
Grant Date Fair Value per Share	$ 17.84	$ 17.58	$ 16.81	$ 18.58
Aggregate Fair Value	$ 86	$ 92	$ 92	$ 88

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	Dec. 31, 2017	Jun. 30, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Contingency [Line Items]
Accrued liability for potential taxes				$ 4,864,000
Penalties and interest expense				0	$ 200,000	$ 200,000
Penalties and interest accrued	$ 800,000		$ 800,000	$ 0	$ 800,000
Corporate federal income tax rate				21.00%	35.00%
Regulatory liability related to creation of excess accumulated deferred federal income tax			55,779,000		$ 55,779,000
InfraREIT, L.L.C.
Income Tax Contingency [Line Items]
Percentage of tax deduction for dividend paid to REIT shareholders	20.00%
Maximum | InfraREIT, L.L.C.
Income Tax Contingency [Line Items]
Percentage of tax rate on dividend paid to individual REIT shareholders	39.60%
Minimum | InfraREIT, L.L.C.
Income Tax Contingency [Line Items]
Percentage of tax rate on dividend paid to individual REIT shareholders	29.60%
Texas
Income Tax Contingency [Line Items]
Franchise taxes on lease revenue		$ 0			0
Accrued liability for potential taxes		4,900,000
Penalties and interest		$ 700,000
Federal Income Tax
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 108,100,000		$ 108,100,000	$ 108,100,000	$ 108,100,000
Net operating loss carryforwards used				$ 0
Net operating loss carryyforwards expiration year				2,026

Income Taxes - Unrecognized Tax

Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 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 Inform_3

Supplemental Cash Flow Information - Supplemental Cash Flow Information and Non-cash Investing and Financing Activities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplemental cash flow information
Cash paid for interest	$ 41,721	$ 39,020	$ 33,972
Non-cash investing and financing activities
Change in accrued additions to electric plant	(908)	11,298	4,113
Allowance for funds used during construction - debt	2,807	3,040	3,142
Redemption of operating partnership units for common stock	1,928	512	3,277
Dividends and distributions payable	$ 15,176	$ 15,169	$ 15,161

Quarterly Financial Informati_3

Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Lease revenue	$ 57,945	$ 48,926	$ 47,827	$ 45,656	$ 58,677	$ 51,618	$ 40,422	$ 39,624	$ 200,354	$ 190,341	$ 172,099
Tax Cuts and Jobs Act regulatory adjustment					(55,779)					(55,779)
General and administrative expense	(11,459)	(6,787)	(6,631)	(6,088)	(5,823)	(6,718)	(6,866)	(5,981)	(30,965)	(25,388)	(21,852)
Depreciation	(12,181)	(12,063)	(11,992)	(11,577)	(12,210)	(13,328)	(12,982)	(12,687)	(47,813)	(51,207)	(46,704)
Gain on 2017 Asset Exchange Transaction					257					257
Interest expense, net	(10,258)	(10,120)	(11,070)	(10,674)	(10,475)	(10,357)	(10,141)	(9,698)	(42,122)	(40,671)	(36,920)
Other income	3	7	374	733	367	331	17	3	1,117	718	3,781
Income tax expense	(304)	(257)	5,428	(286)	(345)	(308)	(321)	(244)	4,581	(1,218)	(1,103)
Net income	23,746	19,706	23,936	17,764	(25,331)	21,238	10,129	11,017	85,152	17,053	69,301
Less: Net income attributable to noncontrolling interest	6,545	5,435	6,602	4,900	(7,046)	5,908	2,821	3,068	23,482	4,751	19,347
Net income attributable to InfraREIT, Inc.	$ 17,201	$ 14,271	$ 17,334	$ 12,864	$ (18,285)	$ 15,330	$ 7,308	$ 7,949	$ 61,670	$ 12,302	$ 49,954
Basic	$ 0.39	$ 0.32	$ 0.39	$ 0.29	$ (0.42)	$ 0.35	$ 0.17	$ 0.18	$ 1.40	$ 0.28	$ 1.14
Diluted	$ 0.39	$ 0.32	$ 0.39	$ 0.29	$ (0.42)	$ 0.35	$ 0.17	$ 0.18	$ 1.40	$ 0.28	$ 1.14

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	Feb. 26, 2019	Jan. 02, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Subsequent Event [Line Items]
Dividend declared date			Feb. 26, 2019
Cash dividends declared per common share			$ 1	$ 1	$ 1
Dividend payable date			Apr. 18, 2019
Dividend record date			Mar. 29, 2019
Subsequent Event
Subsequent Event [Line Items]
Cash distributions to units holders	$ 0.25
Subsequent Event | Quarterly Dividend
Subsequent Event [Line Items]
Cash dividends declared per common share	$ 0.25
Subsequent Event | Director | Common Stock
Subsequent Event [Line Items]
Common stock issued to directors		22,674
Grant date fair value per share		$ 21.15
Grant date fair value		$ 0.5
Vesting period of common stock		2020-01

Schedule III - Electric Plant_2

Schedule III - Electric Plant and Accumulated Depreciation - Components of Electric Plant and Accumulated Depreciation (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Real Estate And Accumulated Depreciation [Line Items]
Gross Amount Carried at Period Close	$ 2,015,280	$ 1,945,997	$ 1,901,960
Accumulated Depreciation	(203,963)	$ (173,768)	$ (261,140)
McAllen Assets
Real Estate And Accumulated Depreciation [Line Items]
Encumbrances	56,931
Initial Cost to Company	136,426
Gross Amount Carried at Period Close	136,426
Accumulated Depreciation	(26,584)
Permian Assets
Real Estate And Accumulated Depreciation [Line Items]
Encumbrances	241,996
Initial Cost to Company	484,337
Gross Amount Carried at Period Close	484,337
Accumulated Depreciation	(17,437)
Competitive Renewable Energy Zones Assets
Real Estate And Accumulated Depreciation [Line Items]
Encumbrances	598,443
Initial Cost to Company	1,256,089
Gross Amount Carried at Period Close	1,256,089
Accumulated Depreciation	(101,469)
Stanton Transmission Loop Assets
Real Estate And Accumulated Depreciation [Line Items]
Encumbrances	15,305
Initial Cost to Company	83,906
Gross Amount Carried at Period Close	83,906
Accumulated Depreciation	(54,377)
ERCOT Transmission Assets
Real Estate And Accumulated Depreciation [Line Items]
Encumbrances	26,136
Initial Cost to Company	54,522
Gross Amount Carried at Period Close	54,522
Accumulated Depreciation	$ (4,096)

Schedule III - Electric Plant_3

Schedule III - Electric Plant and Accumulated Depreciation - Components of Electric Plant and Accumulated Depreciation (Parenthetical) (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Transmission Plant | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Depreciation rate	1.69%	1.69%	1.69%
Transmission Plant | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Depreciation rate	3.15%	3.15%	3.15%
Distribution Plant | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Depreciation rate	1.74%	1.74%	1.74%
Distribution Plant | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Depreciation rate	5.96%	5.96%	5.96%
General Plant | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Depreciation rate	0.80%	0.80%	0.80%
General Plant | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Depreciation rate	5.12%	5.12%	5.12%

Schedule III - Electric Plant_4

Schedule III - Electric Plant and Accumulated Depreciation - Components of Electric Plant and Accumulated Depreciation Fixed Asset Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Electric plant
Beginning balance	$ 1,945,997	$ 1,901,960
Additions	71,852	173,820
Retirements	(2,569)	(25,246)
Ending balance	2,015,280	1,945,997
Accumulated depreciation
Beginning balance	173,768	261,140
Depreciation expense	47,813	51,207
Retirements	(2,569)	(25,246)
Cost of removal	(15,049)	(15,399)
Ending balance	203,963	173,768
Electric plant, net	$ 1,811,317	1,772,229
Oncor Electric Delivery Company LLC
Electric plant
Acquired from Oncor		432,608
Transferred to Oncor		(537,145)
Accumulated depreciation
Acquired from Oncor		32,778
Transferred to Oncor		$ (130,712)