| Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block] | NOTE 1: SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES BASIS OF PRESENTATION – The Consolidated Financial Statements include the operations of Connecticut Water Service, Inc. (the “Company”), an investor-owned holding company and its wholly-owned subsidiaries, including: The Connecticut Water Company (“Connecticut Water”) The Maine Water Company (“Maine Water”) The Heritage Village Water Company (“HVWC”) The Avon Water Company (“Avon Water”) Chester Realty, Inc. (“Chester Realty”) New England Water Utility Services, Inc. (“NEWUS”) As of December 31, 2017 , Connecticut Water, Maine Water, HVWC and Avon Water were our regulated public water utility companies (collectively the “Regulated Companies”), which together served 135,645 customers in 80 towns throughout Connecticut and Maine. Chester Realty is a real estate company whose net profits from rental of property are included in the “Other Income (Deductions), Net of Taxes” section of the Consolidated Statements of Income in the “Non-Water Sales Earnings” category. NEWUS is engaged in water-related services, including the Linebacker ® program, emergency drinking water, and contract operations. Its earnings are included in the “Non-Water Sales Earnings” category of the Consolidated Statements of Income. Intercompany accounts and transactions have been eliminated. The results for interim periods are not necessarily indicative of results to be expected for the year since the consolidated earnings are subject to seasonal factors. Effective February 27, 2017 and July 1, 2017, the Company acquired HVWC and Avon Water, respectively, discussed further in Note 15 below. As a result, the Company’s Consolidated Balance Sheet at December 31, 2016 , the Consolidated Statements of Net Income, Consolidated Statements of Comprehensive Income, and Consolidated Statements of Cash Flows for the year-ended December 31, 2016 and 2015 do not include HVWC or Avon Water. The Consolidated Statements of Net Income, Consolidated Statements of Comprehensive Income, and Consolidated Statements of Cash Flows for the year-ended December 31, 2017 do include HVWC’s and Avon Water’s results for the periods the Company owned HVWC and Avon Water. HVWC’s and Avon Water’s assets and liabilities are included in the Consolidated Balance Sheet as of December 31, 2017 . As noted in Note 15 below, HVWC serves approximately 4,700 water customers in the Towns of Southbury, Middlebury, and Oxford, Connecticut and approximately 3,000 wastewater customers in the Town of Southbury, Connecticut. The results of the wastewater line of business are included in the Company’s Water Operations segment. Additionally, as noted in Note 15, Avon Water serves approximately 4,800 water customers in the Towns of Avon, Farmington, and Simsbury, Connecticut. During the preparation of the Condensed Consolidated Financial Statements for the quarter ended June 30, 2016, the Company identified two errors related to the accounting treatment of stock based performance awards granted to officers of the Company. First, the Company had mistakenly classified certain stock based performance awards as equity awards and, secondly, incorrectly marked those awards to the market price of the Company’s common stock price at the end of each reporting period. A portion of these awards should have been classified as liability awards and only those awards should have been marked-to-market based on the Company’s common stock price. During the second quarter of 2016, the Company reversed all of the incorrectly recorded mark-to-market expense as a cumulative out-of-period adjustment resulting in a one-time benefit of approximately $2.6 million on the Operation and Maintenance line item on its Condensed Consolidated Statements of Income for the three months ended June 30, 2016. Approximately $1.6 million of the out of period adjustment pertained to years prior to 2016, with the remaining $1.0 million related to the first quarter of 2016. Additionally, the Company decreased its Common Stock Without Par Value and increased its Long-Term Compensation Arrangement line items on the Condensed Consolidated Balance Sheet as of June 30, 2016 by approximately $0.6 million to reflect both the awards that should have been classified as liability awards and their corresponding mark-to-market adjustments. The Company performed various quantitative and qualitative analyses and determined that these errors were not material to the previously reported quarterly and annual results. The Company also determined that recording these entries as an out-of- period adjustment during the second quarter of 2016 was not material to the full year ended December 31, 2016 results of operations. PUBLIC UTILITY REGULATION – Connecticut Water, HVWC and Avon Water are subject to regulation for rates and other matters by the Connecticut Public Utility Regulatory Authority (“PURA”) and follow accounting policies prescribed by PURA. Maine Water is subject to regulation for rates and other matters by the Maine Public Utilities Commission (“MPUC”). The Company prepares its financial statements in accordance with accounting principles generally accepted in the United States of America (“GAAP”), which includes the provisions of Financial Accounting Standards Board’s (“FASB”) Accounting Standards Codification (“ASC”) 980 “Regulated Operations” (“FASB ASC 980”). FASB ASC 980 requires cost-based, rate-regulated enterprises, such as the Regulated Companies, to reflect the impact of regulatory decisions in their financial statements. The state regulators, through the rate regulation process, can create regulatory assets and liabilities that result when costs and benefits are allowed for ratemaking purposes in a period after the period in which the costs or benefits would be charged to expense by an unregulated enterprise. The Consolidated Balance Sheets include regulatory assets and liabilities as appropriate, primarily related to income taxes, post-retirement benefit costs and deferred revenues associated with the Water Revenue Adjustment (“WRA”) used by Connecticut Water and HVWC. In accordance with FASB ASC 980, costs which benefit future periods are amortized over the periods they benefit. The Company believes, based on current regulatory circumstances, that the regulatory assets recorded are probable to be recovered and that its use of regulatory accounting is appropriate and in accordance with the provisions of FASB ASC 980. Regulatory assets and liabilities are comprised of the following: (in thousands) December 31, 2017 2016 Assets: Pension Benefits and Post-Retirement Benefits Other Than Pension $ 11,455 $ 12,531 Unrecovered Income Taxes 66,631 93,264 Deferred revenue (included in Prepayments and Other Current Assets and Deferred Charges and Other Costs) 6,574 3,910 Other (included in Prepayments and Other Current Assets and Deferred Charges and Other Costs) 5,202 4,276 Total regulatory assets $ 89,862 $ 113,981 Liabilities: Other (included in Other Current Liabilities) $ 1,117 $ 1,710 Unamortized Investment Tax Credits 1,133 1,189 Refunds to Customers (including Current Portion of Refund to Customers) 64 963 Unfunded Future Income Taxes (including Other Long-Term Liabilities) 58,384 90,977 Excess Accumulated Deferred Income Tax 30,937 4,373 Total regulatory liabilities $ 91,635 $ 99,212 Pension and post-retirement benefits include costs in excess of amounts funded. The Company believes these costs will be recoverable in future years, through rates, as funding is required and has recorded regulatory assets for those costs. The recovery period is dependent on contributions made to the plans and remaining life expectancy. Certain items giving rise to deferred state income taxes, as well as a portion of deferred federal income taxes related primarily to differences between book and tax depreciation expense, are recognized for ratemaking purposes on a cash or flow-through basis and are recognized as unrecovered future income taxes that will be recovered in rates in future years as they reverse. In addition, basis differences resulting from the repair tax deduction adopted in 2013 contribute to the change in unfunded future income taxes. Unrecovered Income Taxes, Unfunded Future Income Taxes and Excess Accumulated Deferred Income Tax all changed significantly between 2016 and 2017 primarily as a result of recognition of lower corporate tax rate resulting from the adoption of the Tax Act. Deferred revenue represents a portion of the rate increase granted in Connecticut Water’s 2007 rate decision. PURA decision required the Company to defer for future collection, beginning in 2008, a portion of the increase. Additionally, revenue recorded under the WRA, discussed below, is included in deferred revenue. Regulatory liabilities include deferred investment tax credits and amounts to be refunded to customers as a result of the adoption of the tangible property regulations in Connecticut and Maine. These liabilities will be given back to customers in rates as tax deductions occur in the future. Regulatory Matters The rates we charge our water and waste water customers in Connecticut and Maine are established under the jurisdiction of and are approved by PURA and MPUC, respectively. It is our policy to seek rate relief as necessary to enable us to achieve an adequate rate of return. Connecticut Water’s allowed return on equity and return on rate base, effective as of December 31, 2017 were 9.75% and 7.32% , respectively. HVWC’s blended water and wastewater allowed return on equity and return on rate base, effective December 31, 2017 , were 10.10% and 7.19% , respectively. Avon Water’s allowed return on equity and return on rate base, effective December 31, 2017 , were 10.00% and 7.79% , respectively. Maine Water’s average allowed return on equity and return on rate base, as of December 31, 2017 were 9.50% and 7.96% , respectively. PURA establishes rates in Connecticut on a company-wide basis while the MPUC approves Maine Water’s rates on a division-by-division basis. Each of Connecticut Water, HVWC, Avon Water and Maine Water are allowed to add surcharges to customers’ bills in order to recover certain costs associated with approved capital projects in between full rate cases, as well as approved surcharges for Water Revenue Adjustments, in Connecticut, as discussed in more detail below. HVWC has not added surcharges to customers’ bills in order to recover certain approved capital projects as of December 31, 2017 , however, HVWC, as authorized by PURA, began to utilize Water Revenue Adjustments as of March 31, 2017. On January 3, 2018, PURA filed a motion to reopen the most recent rate case decisions for the Company’s Connecticut Regulated Companies to determine what, if any, adjustments to rates are appropriate to account for revisions to tax laws, including corporate tax rates, contained in the Tax Cuts and Jobs Act (“Tax Act”). As discussed below, Connecticut Water has entered into a settlement agreement with the state’s consumer advocate that covers treatment of the Tax Act. On January 11, 2018, the MPUC issued a notice of investigation to determine the impact of the Tax Act on Maine Water. The investigation will allow the MPUC to determine the specific impact of the Tax Act and whether any rate adjustments are warranted. Following discovery, a technical conference is scheduled for April 19, 2018. In addition to determining the impact of the Tax Act on the justness and reasonableness of Maine Water’s rates, the MPUC will consider whether to issue an accounting order to establish a regulatory liability which defers for future flow-through to ratepayers the impact of the tax changes. Maine Water Land Sale On March 11, 2016, Maine Water entered into a purchase and sale agreement with the Coastal Mountains Land Trust, a Maine nonprofit corporation (the “Land Trust”) pursuant to which Maine Water agreed to sell two conservation easements to the Land Trust on approximately 1,300 acres of land located in the towns of Rockport, Camden and Hope, in Knox County, Maine valued in the aggregate at $3.1 million. The land had a book value of approximately $600,000 at December 31, 2015 and is included in “Utility Plant” on the Company’s Consolidated Balance Sheets. The easements and purchase prices are as follows: 1. Ragged Mountain Mirror Lake Conservation Easement: $1,875,000; and 2. Grassy Pond conservation Easement: $600,000. On October 13, 2017, an amendment to the agreement was made to extend closing of the first transaction to June 30, 2018, from December 31, 2017. This is also expected to extend the second closing into 2020. Maine Water will make a $200,000 contribution to the Land Trust upon completion of the closing of the first easement sale. Maine Water also expects to claim a charitable deduction for the $600,000 in excess of the fair market value of the second easement over the $600,000 sale price. Connecticut Rates Connecticut Water’s Water Infrastructure Conservation Adjustment (“WICA”) was 9.81%, 7.13% and 4.19% above base rates at December 31, 2017, 2016, and 2015 , respectively. As of December 31, 2017 , Avon Water’s WICA surcharge was 8.09%. As of December 31, 2017 , HVWC has not filed for a WICA surcharge. On February 6, 2018, Connecticut Water filed a petition with PURA to reopen Connecticut Water’s 2010 rate case (previously reopened in 2013) proceeding for the limited purpose of approving a Settlement Agreement entered into by Connecticut Water and the Connecticut Office of Consumer Counsel (“OCC”) (the “Agreement”). The Agreement contemplates a change in Connecticut Water’s customer rates effective for bills rendered on and after April 1, 2018 made up of the following two components: (1) the revenue requirements associated with a $36.3 million addition to rate base to reflect necessary upgrades to Connecticut Water’s Rockville Water Treatment Plant; and (2) the folding in to base rates of the Company’s present WICA surcharges. In addition, the Agreement provides that: 1. Upon implementation of new rates under the Agreement, until such time as new rates are adopted in a general rate case, through a temporary modification of the earnings sharing mechanism, Connecticut Water customers will receive one hundred percent of any earnings in excess of levels allowed by law rather than limiting such customer credits to 50% as contemplated by applicable law; 2. Connecticut Water agrees it will not file for a general increase of Connecticut Water’s base rates to be effective before January 1, 2020; 3. The pending proceeding initiated by PURA in Docket No. 09-12-11RE03, Application of The Connecticut Water Company for Amended Rates – Federal Tax Cuts and Jobs Act shall be closed; and 4. Connecticut Water shall continue to make investments in infrastructure replacement consistent with its approved WICA plan. Connecticut Water shall be allowed to continue to pursue recovery of eligible projects through WICA. The Agreement provides that, if PURA does not fully approve the Agreement in its entirety, it shall be deemed withdrawn. Accordingly, the Agreement has no operative effect unless and until it is approved by PURA. Connecticut Water is not able to predict with certainty the ultimate timing of PURA’s final action on the Agreement. No assurance can be given that PURA will approve the Agreement and permit some or all of the terms contained in the Agreement requested by the parties. PURA has agreed to the request to reopen the rate proceeding. We expect a decision by the end of the second quarter of 2018 with provisions of the Agreement becoming effective soon thereafter. Since 2013, Connecticut law has authorized a WRA to reconcile actual water demands with the demands projected in the last general rate case and allows companies to adjust rates as necessary to recover the revenues approved by PURA in the last general rate case. The WRA removes the financial disincentive for water utilities to develop and implement effective water conservation programs. The WRA allows water companies to defer on the balance sheet, as a regulatory asset or liability, for later collection from or crediting to customers the amount by which actual revenues deviate from the revenues allowed in the most recent general rate proceedings, including WICA proceedings. Additionally, projects eligible for WICA surcharges were expanded to include energy conservation projects, improvements required to comply with streamflow regulations, and improvements to acquired systems. Connecticut Water and HVWC’s allowed revenues for the year ended December 31, 2017 , as approved by PURA during each company’s last general rate case and including subsequently approved WICA surcharges, were approximately $80.7 million. Through normal billing for the year ended December 31, 2017 operating revenue for Connecticut Water and HVWC would have been approximately $76.4 million had the WRA not been implemented. As a result of the implementation of the WRA, Connecticut Water and HVWC recorded $4.3 million in additional revenue for the year ended December 31, 2017 . During the years ended December 31, 2016 and 2015 , Connecticut Water recorded $1.1 million and $1.6 million , respectively, in additional revenue related to the WRA. Avon Water does not currently use the WRA mechanism. Maine Rates In Maine, the overall, approved cumulative Water Infrastructure Charge (“WISC”) for all of Maine Water’s divisions was 5.6%, 4.7% and 1.6% above base rates as of December 31, 2017, 2016, and 2015 , respectively. Five pending WISC filings as of December 31, 2017 have since been approved in the first quarter of 2018, bringing the total to 6.9%. The WISC rates for the Biddeford and Saco division were reset to zero with the approval of the general rate increase discussed below. On June 29, 2017, Maine Water filed for a rate increase in its Biddeford and Saco division. The rate request was for an approximate $1.6 million, or 25.1%, increase in revenues. The rate request is designed to recover higher operating expenses, depreciation and property taxes since Biddeford and Saco’s last rate increase in 2015. Maine Water and the Maine Office of the Public Advocate reached an agreement that increases annual revenue by $1.56 million. The agreement was approved by the MPUC on December 5, 2017, with new rates effective December 1, 2017. In 2014 and 2015, Maine Water petitioned the MPUC for approval of accounting orders that would address (1) the return to its customers a federal income tax refund stemming from the adoption of the Internal Revenue Service (“IRS”) Revenue Procedure 2012-19 (“Repair Regulations”), and (2) the treatment of any benefit resulting from the elimination of deferred tax liabilities previously recorded on these qualifying fixed assets that are now deducted under the Repair Regulations. On February 26, 2015, the MPUC approved a stipulation between Maine Water and the Office of the Public Advocate that refunds $2.9 million to the customers of the eight divisions over a two-year period starting no later than July 1, 2015, and allows the flow-through treatment of the repair deduction as of January 1, 2014. In addition, Maine Water agreed not to file a general rate case during the two-year refund period in any of the eight divisions that were allowed the refund. On June 22, 2015, the MPUC approved a settlement agreement between Maine Water and the Office of the Public Advocate that allowed for the amortization of the deferred tax liabilities over a one to nine year period, depending on the division. Maine Water commenced amortization per the agreed upon schedule. With the completion of these two dockets, Maine Water recorded in the quarter ended June 30, 2015 the retroactive benefit associated with the flow-through of the Repair Regulations from January 1, 2014. The 2014 benefit, reflected in the second quarter of 2015, was approximately $931,000, or $0.09 per basic share outstanding. A water revenue adjustment mechanism law in Maine became available to regulated water utilities in Maine on October 15, 2015. Maine Water is currently precluded from seeking new rates in the Biddeford and Saco division due to provisions in the settlement agreement with the MPUC. As the stay-out periods for other divisions expire, Maine Water expects to request usage of this mechanism as Maine Water file rate cases for those divisions. USE OF ESTIMATES – The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from these estimates. REVENUES – The Company’s accounting policies regarding revenue recognition by segment are as follows: Water Operations – Most of our water customers are billed quarterly, with the exception of larger commercial and industrial customers, as well as certain public and private fire protection customers who are billed monthly. Most customers, except fire protection customers, are metered. Revenues from metered customers are based on their water usage multiplied by approved, regulated rates and are earned when water is delivered. Public fire protection revenues are based on the length of the water main, and number of hydrants in service and are earned on a monthly basis. Private fire protection charges are based on the diameter of the connection to the water main. Our Regulated Companies accrue an estimate for metered customers for the amount of revenues earned relating to water delivered but unbilled at the end of each quarter, which is reflected as “Accrued Unbilled Revenues” in the accompanying Consolidated Balance Sheets. Beginning in 2013, Connecticut Water began to record deferred revenue related to the WRA, which represent under collection from customers based upon allowed revenues as approved by PURA. On March 31, 2017, HVWC calculated its actual revenues compared to allowed revenues dating back to May 1, 2015, for collection from customers, as allowed by a PURA order. More detailed information, including revenues, costs and income taxes associated with the segment can be found in Note 14, “Segment Reporting”. Real Estate Transactions – Revenues are recorded when a sale or other transaction has been completed and title to the real estate has been transferred. Net income from the Real Estate Transactions segment is shown net in the “Other Income (Deductions), Net of Taxes” portion of the Company’s Consolidated Statements of Income. More detailed information, including revenues, costs and income taxes associated with the segment can be found in Note 14, “Segment Reporting”. Services and Rentals – Revenues are recorded when the Company has delivered the services called for by contractual obligation. Net income from the Services and Rentals segment is shown net in the “Other Income (Deductions), Net of Taxes” portion of the Company’s Consolidated Statements of Income. More detailed information, including revenues, costs and income taxes associated with the segment can be found in Note 14, “Segment Reporting”. UTILITY PLANT – Utility plant is stated at the original cost of such property when first devoted to public service. Utility plant accounts are charged with the cost of improvements and replacements of property including an Allowance for Funds Used During Construction (“AFUDC”). Retired or disposed depreciable plant is charged to accumulated provision for depreciation together with any costs applicable to retirement, less any salvage received. Maintenance of utility plant is charged to expense. Accounting policies relating to other areas of utility plant are listed below: Allowance For Funds Used During Construction – AFUDC is the cost of debt and equity funds used to finance the construction of utility plant. The amount shown on the Consolidated Statements of Income relates to the equity portion. The debt portion is included as an offset to “Other Interest Income, Net”. Generally, utility plant under construction is not recognized as part of rate base for ratemaking purposes until facilities are placed into service, and accordingly, AFUDC is charged to the construction cost of utility plant. Capitalized AFUDC, which does not represent current cash income, is recovered through rates over the service lives of the assets. Our Regulated Companies’ allowed rate of return on rate base is used to calculate AFUDC. Customers’ Advances For Construction, Contributed Plant and Contributions In Aid Of Construction –Under the terms of construction contracts with real estate developers and others, the Regulated Companies periodically receive either advances for the costs of new main installations or title to the main after it is constructed and financed by the developer. Refunds are made, without interest, as services are connected to the main, over periods not exceeding fifteen years and not in excess of the original advance. Unrefunded balances, at the end of the contract period, are credited to contributions in aid of construction (“CIAC”) and are no longer refundable. Utility Plant is added in two ways. The majority of the Company’s plant additions occur from direct investment of Company funds that originated through operating or financings activities. The Company manages the construction of these plant additions. These plant additions are part of the Company’s depreciable utility plant and are generally part of rate base. The Company’s rate base is a key component of how its regulated rates are set, and is recovered through the depreciation component of the Company’s rates. The second way in which plant additions occur are through developer advances and contributions. Under this scenario either the developer funds the additions through payments to the Company, who in turn manages the construction of the project, or the developer pays for the plant construction directly and contributes the asset to the Company after it is complete. Plant additions that are financed by a developer, either directly or indirectly, are excluded from the Company’s rate base and not recovered through the rates process, and are also not depreciated. The components that comprise net additions to Utility Plant during the last three years ending December 31 are as follows: (in thousands) 2017 2016 2015 Additions to Utility Plant: Company Financed $ 51,543 $ 66,339 $ 47,774 Allowance for Funds Used During Construction 774 1,198 530 Subtotal – Utility Plant Increase to Rate Base 52,317 67,537 48,304 Advances from Others for Construction 1,479 350 251 Net Additions to Utility Plant $ 53,796 $ 67,887 $ 48,555 Depreciation – Depreciation is computed on a straight-line basis at various rates as approved by the state regulators on a company by company basis. Depreciation allows the Company to recover the investment in utility plant over its useful life. The overall consolidated company depreciation rate, based on the average balances of depreciable property, was 2.0% , 1.9% , and 1.9% for 2017 , 2016 , and 2015 , respectively. INCOME TAXES – The Company provides income tax expense for its utility operations in accordance with the regulatory accounting policies of the applicable jurisdictions. The Company’s income tax provision is calculated on a separate return basis. For Connecticut Water , PURA requires the flow-through method of accounting for most state tax temporary differences as well as for certain federal temporary differences. For Avon Water , PURA requires the flow-through method of accounting for most state temporary differences and normalized accounting for most federal temporary differences. PURA has allowed the flow-through method of accounting stemming from Avon Water’s adoption of the IRS’ Repair Regulations. For HVWC, PURA requires normalized accounting for federal and state temporary differences. The MPUC requires the flow-through method of accounting for most state temporary differences and normalized accounting for most federal temporary differences. In its approvals of the stipulation agreements between Maine Water and the Office of the Public Advocate, issued in 2015, the MPUC has allowed the flow-through method of accounting stemming from Maine Water’s adoption of the IRS’ Repair Regulations in all of its divisions. The Company computes deferred tax liabilities for all temporary book-tax differences using the liability method prescribed in FASB ASC 740 “Income Taxes” (“FASB ASC 740”). Under the liability method, deferred income taxes are recognized at currently enacted income tax rates to reflect the tax effect of temporary differences between the financial reporting and tax bases of assets and liabilities. Such temporary differences are the result of provisions in the income tax law that either require or permit certain items to be reported on the income tax return in a different period than they are reported in the financial statements. Deferred tax liabilities that have not been reflected in tax expense due to regulatory treatment are reflected as Unfunded Future Income Taxes, and are expected to be included in future years’ rates. During the quarter ended December 31, 2017 the Company recorded the impact of the Tax Cuts and Jobs Act (“Tax Act”). As a result, the Company re-measured Deferred Tax Assets and Liabilities to reflect the enacted legislation and recorded a Regulatory Liability of $27.1 million to capture the excess accumulated deferred income taxes for items included in rates that follow the normalized method of accounting. Unrecovered Income Taxes and Unfunded Future Income Taxes were written down by $32 million to reflect the reduced tax rate for items that follow the flow-through method of accounting. Pursuant to ASU 2018-02, the Company has elected to reclassify the stranded tax effects of the 2017 Tax Act from AOCI to Retained Earnings in the amount of $70,482. These stranded taxes relate to post-retirement obligations of the Company. For more information on the Tax Act, please see Note 2. The Company believes that deferred income tax assets, net of provisions, will be realized in the future. The majority of Unfunded Future Income Taxes, prior to 2013, relate to deferred state income taxes regarding book to tax depreciation differences. Beginning in 2013, basis differences resulting from the repair tax deduction contributed to the change in unfunded income taxes. Deferred Federal and State Income Taxes include amounts that have been provided for accelerated depreciation subsequent to 1981, as required by federal income tax regulations, as well as the basis differences associated with expenditures qualifying for repair tax deductions as clarified by the IRS in regulations issued in 2013. Deferred taxes have also been provided for temporary differences in the recognition of certain expenses for tax and financial statement purposes as allowed by regulatory ratemaking policies. MUNICIPAL TAXES – Municipal taxes are reflected as “Taxes Other Than Income Taxes” and are generally expensed over the twelve-month period beginning on July 1 following the lien date, corresponding with the period in which the municipal services are provided. UNAMORTIZED DEBT ISSUANCE EXPENSE – The issuance costs of long-term debt, including the remaining balance of issuance costs on long-term debt issues that have been refinanced prior to maturity, and related call premiums, are amortized over the respective lives of the outstanding debt, as approved by PURA and the MPUC. GOODWILL – As part of the purchase of regulated water companies, the Company recorded goodwill of $67.0 million and $30.4 million as of December 31, 2017 and 2016 , respectively, representing the amount of the purchase price over net book value of the assets acquired. The increase of $36.6 million during 2017 is related to the acquisitions of HVWC and Avon Water during the year. The Company accounts for goodwill in accordance with Accounting Standards Codification 350 “Intangibles – Goodwill and Other” (“FASB ASC 350”). As part of FASB ASC 350, the Company is required to perform an annual review of goodwill for any potential impairment, which we perform as of December 31 each year. We update the assessment between the annual testing if events or circumstances occur that would more likely than not reduce the fair value of a reporting unit below its carrying value. The Company performed a quantitative analysis of impairment as of December 31, 2017, which concluded that the estimated fair value of the Water Operations reporting unit |
