| **Capitalization**            | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               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| **Capitalization [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                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| Capitalization                | Note 6 – Capitalization 
Private Placement 

On March 29, 2019, the Company entered into a Stock Purchase Agreement (the “Stock Purchase Agreement”) with Canada Pension Plan Investment Board (the “Investor”), pursuant to which the Company has agreed to issue and sell to the Investor in a private placement (the “Private Placement”) 21,661,095 newly issued shares of common stock, par value $0.50 per share (the “Common Stock”).  On March 16, 2020, in connection with the closing of the Peoples Gas Acquisition the Company closed on the Private Placement and received gross proceeds of $749,907, less expenses of $19,772.  The Investor has agreed to certain transfer restrictions for a period of 15 months from the closing date of the Peoples Gas Acquisition.

The shares issued and sold to the Investor pursuant to the Private Placement were to be priced at the lower of (1) $34.62, which represents a 4.5% discount to the trailing 20 consecutive trading day volume weighted average price of the Common Stock ending on, and including, March 28, 2019, and (2) the volume weighted average price per share in the Company’s subsequent public offering of Common Stock to fund a portion of the Peoples Gas Acquisition.  Based on the common stock offering noted below, the Private Placement was priced at $34.62 per share.

The Stock Purchase Agreement contains customary representations, warranties and covenants of the Company and the Investor, and the parties have agreed to indemnify each other for losses related to breaches of their respective representations and warranties.  At the closing of the Private Placement, the Company reimbursed the Investor for reasonable out-of-pocket diligence expenses of $4,000.  

Common Stock / Tangible Equity Unit Issuances

On April 23, 2019, the Company issued $1,293,750, less expenses of $30,651, of its common stock and $690,000, less expenses of $16,358, of its tangible equity units (the “Units”), with a stated amount of $50 per unit.  These issuances were part of the permanent financing to close the Peoples Gas Acquisition.  The common stock was issued at $34.62 per share and thus the Private Placement noted above was priced at $34.62 per share.    

Each Unit consists of a prepaid stock purchase contract and an amortizing note due April 30, 2022, each issued by the Company.  Unless earlier settled or redeemed, each stock purchase contract will automatically settle on April 30, 2022 (subject to postponement in limited circumstances) for between 1.1790 and 1.4442 shares of the Company’s common stock, subject to adjustment, based upon the applicable market value of the common stock, as described in the final prospectus supplement relating to the Units.  During the first quarter of 2020, 1,979,570 stock purchase contracts were early settled by the holders of the contracts, resulting in the issuance of 2,335,654 shares of the Company’s common stock.  The balance of stock purchase contracts is 7,711,138.  The amortizing notes have an initial principal amount of $8.62909, or $119,081 in aggregate, and bear interest at a rate of 3.00% per year, and pay equal quarterly cash installments of $0.75000 per amortizing note (except for the July 30, 2019 installment payment, which was $0.80833 per amortizing note), that will constitute a payment of interest and a partial repayment of principal, and which cash payment in the aggregate will be equivalent to 6.00% per year with respect to each $50 stated amount of the Units.  The amortizing notes represent unsecured senior obligations of the Company.  

The issuance of the common stock and the Units (including the component stock purchase contracts and amortizing notes) were separate public issuances made by means of separate prospectus supplements pursuant to the Company’s universal “pay as you go” shelf registration statement, filed with the SEC in February 2018, which allows for the potential future offer and sale by us, from time to time, in one or more public offerings, of an indeterminate amount of the Company’s common stock, preferred stock, debt securities, and other securities specified therein at indeterminate prices.   

The Company recorded the issuance of the purchase contract portion of the Units as additional paid-in-capital of $570,919, less allocable issuance costs of $13,530, in our financial statements.  The Company recorded the amortizing notes portion of the Units of $119,081 as long-term debt and recorded allocable issuance costs of $2,828 as debt issuance costs.    

Long-term Debt and Loans Payable

Subsequent to the period ended March 31, 2020, on April 3, 2020, the Company entered into a credit agreement that provided the Company with short-term borrowing capacity of up to $500,000 in unsecured term loans, which matures on April 2, 2021.  The Company borrowed the full $500,000 on April 3, 2020, which is to be used for general corporate purposes and to strengthen its liquidity and cash position, and maximize its financial flexibility in light of the uncertainty surrounding the impact of the COVID-19 pandemic.  The proceeds remain on deposit, and the Company will evaluate the timing of repayment based on the development of COVID-19 and its impact on the business.  The term loans bear interest at either the Adjusted LIBO Rate or the Alternate Base Rate, as each such term is defined in the Term Loan Agreement.  Amounts under the term loan cannot be re-borrowed upon repayment.  Additionally, on April 13, 2020, the Company issued $1,100,000 of long-term debt, less expenses of approximately $10,900, of which $500,000 is due in 2030, and $600,000 is due in 2050 with interest rates of 2.704% and 3.351%, respectively.  The Company used the proceeds from this issuance to repay in full the borrowings of $181,000 of short-term debt assumed in the Peoples Gas Acquisition, $150,000 of short-term debt issued on March 13, 2020, and to repay borrowings under its existing five year unsecured revolving credit agreement.  Further, on May 1, 2020, Aqua Pennsylvania issued $175,000 of first mortgage bonds, of which $75,000 is due in 2051, $50,000 is due in 2055, and $50,000 is due in 2056 with interest rates of 3.49%, 3.54%, and 3.55%, respectively.  The proceeds from these bonds were used to repay existing indebtedness and for general corporate purposes.  

On March 13, 2020, in connection with the closing of the Peoples Gas Acquisition, the Company amended its existing five year unsecured revolving credit agreement, which expires in December 2023, to provide the Company with an additional $300,000 of borrowing capacity, and pursuant to the terms of the revolving credit facility, our borrowing capacity thereunder was further increased by $150,000 upon the completion of the Peoples Gas Acquisition on March 16, 2020.  As a result of these increases, our total borrowing capacity increased to $1,000,000.  Further, on March 13, 2020, the Company entered into a 364 day $150,000 credit agreement pursuant to which the Company borrowed $150,000, which was used to fund a portion of the Peoples Gas Acquisition in lieu of additional borrowings under our revolving credit facility, which was subsequently repaid with the proceeds from the Company’s April 2020 long-term debt issuance noted above.      

The Company completed the Peoples Gas Acquisition on March 16, 2020, which resulted in the assumption of $1,101,091 of indebtedness, which includes $920,091 of senior notes and $181,000 of short-term debt.  The senior notes have maturities ranging from 2020 to 2032 and interest rates that range from 2.90% to 6.42%.  The short-term debt assumed at closing was repaid with the proceeds from the Company’s April 2020 long-term debt issuance noted above.

On April 26, 2019, the Company issued $900,000 of long-term debt (the “Senior Notes”), less expenses of $7,931, of which $400,000 is due in 2029, and $500,000 is due in 2049 with interest rates of 3.566% and 4.276%, respectively.    

The Company used the net proceeds from the April 2019 issuance of Senior Notes, together with the net proceeds from the common stock offering and tangible equity unit offering noted above, as well as the proceeds from the Private Placement of common stock noted above, to (1) secure funding for the Peoples Gas Acquisition, (2) complete the redemption of $313,500 aggregate principal amount of certain of the Company’s outstanding notes noted below, (3) pay related costs and expenses, and (4) for general corporate purposes.    

On May 18, 2019, the Company redeemed $313,500 of the Company’s outstanding notes (the “Company Debt Refinancing”) that had maturities ranging from 2019-2037 and interest rates ranging from 3.57-5.83%.  Additionally, the Company Debt Refinancing was subject to a make whole payment of $25,237, and $18,528 of this payment was expensed in 2019 and was presented in the consolidated statements of operations and comprehensive income on the line item “loss on debt extinguishment.”  The balance of the payment, or $6,709, was deferred as a regulatory asset, as it represents an amount by which the Company expects to receive prospective rate recovery. |

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