Unitil (UTL) 10-Q 3 May 22 2022 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 31, 2022	Apr. 29, 2022
Document Information [Line Items]
Entity Interactive Data Current	Yes
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Amendment Flag	false
Document Period End Date	Mar. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Entity Registrant Name	UNITIL CORP
Entity Central Index Key	0000755001
Entity File Number	1-8858
Entity Tax Identification Number	02-0381573
Entity Incorporation, State or Country Code	NH
Current Fiscal Year End Date	--12-31
Entity Shell Company	false
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Current Reporting Status	Yes
Entity Emerging Growth Company	false
Entity Address, Address Line One	6 Liberty Lane West
Entity Address, City or Town	Hampton
Entity Address, Postal Zip Code	03842-1720
Entity Address, State or Province	NH
City Area Code	603
Local Phone Number	772-0775
Trading Symbol	UTL
Security Exchange Name	NYSE
Entity Common Stock, Shares Outstanding		16,031,008
Title of 12(b) Security	Common Stock

CONSOLIDATED STATEMENTS OF EARN

CONSOLIDATED STATEMENTS OF EARNINGS - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating Revenues
Total Operating Revenues	$ 192.6	$ 138.8
Operating Expenses
Operation and Maintenance	18.5	17
Depreciation and Amortization	15.5	14.9
Taxes Other than Income Taxes	6.8	6.2
Total Operating Expenses	156.8	105.4
Operating Income	35.8	33.4
Interest Expense, Net	6.2	6.7
Other Expense (Income), Net	0.7	1.3
Income Before Income Taxes	28.9	25.4
Provision For Income Taxes	7.4	6.5
Net Income	$ 21.5	$ 18.9
Net Income Per Common Share (Basic and Diluted)	$ 1.35	$ 1.26
Weighted Average Common Shares Outstanding – (Basic and Diluted)	16	15
Gas
Operating Revenues
Total Operating Revenues	$ 103.4	$ 78.7
Operating Expenses
Cost of Sales	51.4	30.9
Electric
Operating Revenues
Total Operating Revenues	89.2	60.1
Operating Expenses
Cost of Sales	$ 64.6	$ 36.4

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Current Assets:
Cash and Cash Equivalents	$ 6.5	$ 6.5	$ 6.1
Accounts Receivable, Net	81.9	66.9	73.2
Accrued Revenue	56.3	61.2	34.7
Exchange Gas Receivable	0.7	7.4	1.2
Gas Inventory	0.5	1	0.4
Materials and Supplies	9.4	8.6	9.2
Prepayments and Other	7.8	8.1	7.9
Total Current Assets	163.1	159.7	132.7
Utility Plant:
Electric	606.7	602.4	576.8
Gas	986.3	972.6	922.4
Common	66.6	66.4	64.5
Construction Work in Progress	36.5	47.5	38.3
Total Utility Plant	1,696.1	1,688.9	1,602
Less: Accumulated Depreciation	436.2	431.7	409.7
Net Utility Plant	1,259.9	1,257.2	1,192.3
Other Noncurrent Assets:
Regulatory Assets	108.1	108.9	128.7
Operating Lease Right of Use Assets	4.8	4.7	5.4
Other Assets	16.4	9.8	17.9
Total Other Noncurrent Assets	129.3	123.4	152
TOTAL ASSETS	1,552.3	1,540.3	1,477
Current Liabilities:
Accounts Payable	39	52.4	28.7
Short-Term Debt	64	64.1	37.3
Long-Term Debt, Current Portion	8.2	8.2	8.5
Regulatory Liabilities	15.6	9.5	14.7
Energy Supply Obligations	6.9	14.5	7.7
Interest Payable	6.4	4.8	6.8
Environmental Obligations	0.5	0.5	0.3
Other Current Liabilities	17.1	19.5	18.9
Total Current Liabilities	157.7	173.5	122.9
Noncurrent Liabilities:
Retirement Benefit Obligations	136.3	133.9	164.8
Deferred Income Taxes, Net	135	127.7	115.4
Cost of Removal Obligations	109.8	107.5	102.5
Regulatory Liabilities	42.1	42.6	43.5
Environmental Obligations	2.2	2.2	1.8
Other Noncurrent Liabilities	7.3	6.6	7
Total Noncurrent Liabilities	432.7	420.5	435
Capitalization:
Long-Term Debt, Less Current Portion	496.6	497.8	515.8
Stockholders' Equity:
Common Equity (Authorized: 25,000,000 and Outstanding:16,020,047, 15,041,629 and 15,977,766 Shares)	333.7	332.1	286.3
Retained Earnings	131.4	116.2	116.8
Total Common Stock Equity	465.1	448.3	403.1
Preferred Stock	0.2	0.2	0.2
Total Stockholders' Equity	465.3	448.5	403.3
Total Capitalization	961.9	946.3	919.1
Commitments and Contingencies (Notes 6 & 7)
TOTAL LIABILITIES AND CAPITALIZATION	$ 1,552.3	$ 1,540.3	$ 1,477

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - shares	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Statement of Financial Position [Abstract]
Common Stock Authorized	25,000,000	25,000,000	25,000,000
Common Equity Outstanding	16,020,047	15,977,766	15,041,629

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating Activities:
Net Income	$ 21.5	$ 18.9
Adjustments to Reconcile Net Income to Cash Provided by Operating Activities:
Depreciation and Amortization	15.5	14.9
Deferred Tax Provision	7.1	6.2
Changes in Working Capital Items:
Accounts Receivable	(15)	(11.2)
Accrued Revenue	4.9	16.2
Exchange Gas Receivable	6.7	3.7
Regulatory Liabilities	6.1	9.2
Accounts Payable	(13.4)	(4.5)
Other Changes in Working Capital Items	(2.2)	0.8
Deferred Regulatory and Other Charges	(5.9)	(7.7)
Other, net	3.8	1.2
Cash Provided by Operating Activities	29.1	47.7
Investing Activities:
Property, Plant and Equipment Additions	(15.4)	(14.1)
Cash (Used in) Investing Activities	(15.4)	(14.1)
Financing Activities:
Repayment of Short-Term Debt, Net	(0.1)	(17.4)
Repayment of Long-Term Debt	(1.3)	(7.2)
(Decrease) Increase in Capital Lease Obligations	(0.1)	0.1
Net Decrease in Exchange Gas Financing	(6.2)	(3.5)
Dividends Paid	(6.3)	(5.8)
Proceeds from Issuance of Common Stock	0.3	0.3
Cash (Used in) Financing Activities	(13.7)	(33.5)
Net Increase in Cash and Cash Equivalents	0	0.1
Cash and Cash Equivalents at Beginning of Period	6.5	6
Cash and Cash Equivalents at End of Period	6.5	6.1
Supplemental Cash Flow Information:
Interest Paid	4.7	4.9
Income Taxes Paid	0.4	0.3
Payments on Capital Leases	0.1	0.1
Non-cash Investing Activity:
Capital Expenditures Included in Accounts Payable	4.6	4.1
Right-of-Use Assets Obtained in Exchange for Lease Obligations	$ 0.6	$ 0.2

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN COMMON STOCK EQUITY - USD ($) $ in Millions	Total	Common Equity	Retained Earnings
Beginning Balance at Dec. 31, 2020	$ 389	$ 285.3	$ 103.7
Net Income	18.9		18.9
Dividends on Common Shares	(5.8)		(5.8)
Stock Compensation Plans	0.7	0.7
Issuance of Common Shares	0.3	0.3
Ending Balance at Mar. 31, 2021	403.1	286.3	116.8
Beginning Balance at Dec. 31, 2021	448.3	332.1	116.2
Net Income	21.5		21.5
Dividends on Common Shares	(6.3)		(6.3)
Stock Compensation Plans	1.3	1.3
Issuance of Common Shares	0.3	0.3
Ending Balance at Mar. 31, 2022	$ 465.1	$ 333.7	$ 131.4

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN COMMON STOCK EQUITY (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Equity [Abstract]
Dividends per Common Share	$ 0.39	$ 0.38
Common stock, shares issued	5,511	6,179

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	NOTE 1 – SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Nature of Operations - non-regulated The Company’s earnings are seasonal and typically are higher in the first and fourth quarters when customers use gas for heating purposes. Unitil’s principal business is the local distribution of electricity in the southeastern seacoast and capital city areas of New Hampshire and the greater Fitchburg area of north central Massachusetts and the local distribution of gas in southeastern New Hampshire, portions of southern Maine to the Lewiston-Auburn area and in the greater Fitchburg area of north central Massachusetts. Unitil has three distribution utility subsidiaries, including Unitil Energy, which operates in New Hampshire; Fitchburg, which operates in Massachusetts; and Northern Utilities, which operates in New Hampshire and Maine (collectively referred to as the “distribution utilities”). Granite State is an interstate gas transmission pipeline company, operating 86 miles of underground gas transmission pipeline primarily located in Maine and New Hampshire. Granite State provides Northern Utilities with interconnection to three major gas pipelines and access to domestic gas supplies in the south and Canadian gas supplies in the north. Granite State derives its revenues principally from transportation services provided to Northern Utilities and, to a lesser extent, third-party marketers. A fifth utility subsidiary, Unitil Power, formerly functioned as the full requirements wholesale power supply provider for Unitil Energy. In connection with the implementation of electric industry restructuring in New Hampshire, on May 1, 2003 Unitil Power ceased being the wholesale supplier of Unitil Energy and divested of its long-term power supply contracts through the sale of the entitlements to the electricity associated with various electric power supply contracts it had acquired to serve Unitil Energy’s customers. In the period since, Unitil Power continued to flow revenues and expenses from remaining contracts to Unitil Energy under the Amended Unitil System Agreement. The last of those contracts expired October 31, 2020, and the Company no longer has material revenues or expenses associated with them. Unitil also has three other wholly-owned subsidiaries: Unitil Service, Unitil Realty and Unitil Resources. Unitil Service provides, at cost, a variety of administrative and professional services, including regulatory, financial, accounting, human resources, engineering, operations, technology, energy management and management services on a centralized basis to its affiliated Unitil companies. Unitil Realty owns and manages the Company’s corporate office in Hampton, New Hampshire and leases this facility to Unitil Service under a long-term lease arrangement. Unitil Resources is the Company’s wholly-owned non-regulated Basis of Presentation - 10-Q 10-K Revenue is recorded when service is rendered or energy is delivered to customers. However, the determination of energy sales to individual customers is based on the reading of their meters, which occurs on a systematic basis throughout the month. At the end of each calendar month, amounts of energy delivered to customers since the date of the last meter reading are estimated and the corresponding unbilled revenues are calculated. These unbilled revenues are estimated each month based on estimated customer usage by class and applicable customer rates, taking into account current and historical weather data, assumptions pertaining to metering patterns, billing cycle statistics, and other estimates and assumptions, and are then reversed in the following month when billed to customers. A majority of the Company’s revenue from contracts with customers continues to be recognized on a monthly basis based on applicable tariffs and customer monthly consumption. Such revenue is recognized using the invoice practical expedient, which allows an entity to recognize revenue in the amount that directly corresponds to the value transferred to the customer. The Company’s billed and unbilled revenue meets the definition of “revenues from contracts with customers” as defined in Accounting Standards Codification (ASC) 606. Revenue recognized in connection with rate adjustment mechanisms is consistent with the definition of alternative revenue programs in ASC 980-605-25-3, 980-605-25-4. In the following tables, revenue is classified by the types of goods/services rendered and market/customer type. Three Months Ended March 31, 2022 Electric and Gas Operating Revenues ($ millions): Electric Gas Total Billed and Unbilled Revenue: Residential $ 49.4 $ 45.6 $ 95.0 Commercial and Industrial 31.0 64.6 95.6 Other 4.3 3.5 7.8 Total Billed and Unbilled Revenue 84.7 113.7 198.4 Rate Adjustment Mechanism Revenue 4.5 (10.3 ) (5.8 ) Total Electric and Gas Operating Revenues $ 89.2 $ 103.4 $ 192.6 Fitchburg is subject to revenue decoupling. Revenue decoupling is the term given to the elimination of the dependency of a utility’s distribution revenue on the volume of electricity or gas sales. The difference between distribution revenue amounts billed to customers and the targeted revenue decoupling amounts is recorded as an increase or a decrease in Accrued Revenue, which forms the basis for resetting rates for future cash recoveries from, or credits to, customers. These revenue decoupling targets may be adjusted as a result of rate cases that the Company files with the Massachusetts Department of Public Utilities (MDPU). Income Taxes - Provisions for income taxes are calculated in each jurisdiction in which the Company operates, for each period for which a statement of earnings is presented. The Company accounts for income taxes in accordance with the FASB Codification guidance on Income Taxes, which requires an asset and liability approach for the financial accounting and reporting of income taxes. Significant judgments and estimates are required in determining the current and deferred tax assets and liabilities. The Company’s deferred tax assets and liabilities reflect its best assessment of estimated future taxes to be paid. In accordance with the FASB Codification, the Company periodically assesses the realization of its deferred tax assets and liabilities and adjusts the income tax provision, the current tax liability and deferred taxes in the period in which the facts and circumstances which gave rise to the revision become known. Cash and Cash Equivalents - (ISO-NE) ISO-NE. 2-1/2 ISO-NE Allowance for Doubtful Accounts - conditions, customer trends, or other factors such as the extent and duration of any shutoff or collection moratoriums. The Company also calculates the amount of written-off The Allowance for Doubtful Accounts as of March 31, 2022, March 31, 2021 and December 31, 2021, was as follows: ($ millions) March 31, December 31, 2022 2021 2021 Allowance for Doubtful Accounts $ 3.4 $ 4.4 $ 3.3 Accounts Receivable, Net includes $3.3 million, $4.3 million, and $3.1 million of the Allowance for Doubtful Accounts at March 31, 2022, March 31, 2021 and December 31, 2021, respectively. Unbilled Revenues, net (a component of Accrued Revenue) includes $0.1 million, $0.1 million and $0.2 million of the Allowance for Doubtful Accounts at March 31, 2022, March 31, 2021 and December 31, 2021, respectively. Accrued Revenue - March 31, December 31, Accrued Revenue ($ millions) 2022 2021 2021 Regulatory Assets – Current $ 45.2 $ 24.0 $ 47.4 Unbilled Revenues, net 11.1 10.7 13.8 Total Accrued Revenue $ 56.3 $ 34.7 $ 61.2 March 31, December 31, Gas Inventory ($ millions) 2022 2021 2021 Natural Gas $ — $ — $ 0.5 Propane 0.4 0.3 0.4 Liquefied Natural Gas & Other 0.1 0.1 0.1 Total Gas Inventory $ 0.5 $ 0.4 $ 1.0 Utility Plant - Leases - non-lease Regulatory Accounting - shut-off. March 31, December 31, Regulatory Assets consist of the following ($ millions) 2022 2021 2021 Retirement Benefits $ 86.5 $ 104.5 $ 86.4 Energy Supply and Other Rate Adjustment Mechanisms 41.9 20.2 44.1 Deferred Storm Charges 2.9 3.7 3.3 Environmental 4.5 5.0 4.6 Income Taxes 2.4 3.2 2.6 Other Deferred Charges 15.1 16.1 15.3 Total Regulatory Assets 153.3 152.7 156.3 Less: Current Portion of Regulatory Assets (1) 45.2 24.0 47.4 Regulatory Assets – noncurrent $ 108.1 $ 128.7 $ 108.9 (1) Reflects amounts included in the Accrued Revenue on the Company’s Consolidated Balance Sheets. March 31, December 31, Regulatory Liabilities consist of the following ($ millions) 2022 2021 2021 Income Taxes (Note 8) $ 43.9 $ 45.1 $ 44.3 Rate Adjustment Mechanisms 13.8 12.9 7.7 Other — 0.2 0.1 Total Regulatory Liabilities 57.7 58.2 52.1 Less: Current Portion of Regulatory Liabilities 15.6 14.7 9.5 Regulatory Liabilities – noncurrent $ 42.1 $ 43.5 $ 42.6 Generally, the Company receives a return on investment on its regulatory assets for which a cash outflow has been made. Included in Regulatory Assets as of March 31, 2022 are $7.8 million of environmental costs, rate case costs and other expenditures to be recovered over varying periods in the next seven years. Regulators have authorized recovery of these expenditures, but without a return. Regulatory commissions can reach different conclusions about the recovery of costs, which can have a material effect on the Company’s Consolidated Financial Statements. The Company believes it is probable that its regulated distribution and transmission utilities will recover their investments in long-lived assets, including regulatory assets. If the Company, or a portion of its assets or operations, were to cease meeting the criteria for application of these accounting rules, accounting standards for businesses in general would become applicable and immediate recognition of any previously deferred costs, or a portion of deferred costs, would be required in the year in which the criteria are no longer met, if such deferred costs were not recoverable in the portion of the business that continues to meet the criteria for application of the FASB Codification topic on Regulated Operations. If unable to continue to apply the FASB Codification provisions for Regulated Operations, the Company would be required to apply the provisions for the Discontinuation of Rate-Regulated Accounting included in the FASB Codification. In the Company’s opinion, its regulated operations will be subject to the FASB Codification provisions for Regulated Operations for the foreseeable future. Derivatives - Fitchburg has entered into power purchase agreements for which contingencies exist (see Note 6, Regulatory Matters). Until these contingencies are satisfied, these contracts will not qualify for derivative accounting. The Company believes that the power purchase obligations under these long-term contracts will have a material effect on the contractual obligations of Fitchburg. Investments in Marketable Securities - At March 31, 2022, March 31, 2021 and December 31, 2021, the fair value of the Company’s investments in these trading securities, which are recorded on the Consolidated Balance Sheets in Other Assets, w as March 31, December 31, Fair Value of Marketable Securities ($ millions) 2022 2021 2021 Money Market Funds $ 5.5 $ 5.6 $ 5.7 Total Marketable Securities $ 5.5 $ 5.6 $ 5.7 The Company also sponsors the Unitil Corporation Deferred Compensation Plan (the “DC Plan”). The DC Plan is a non-qualified tax-deferred At March 31, 2022, March 31, 2021 and December 31, 2021, the fair value of the Company’s investments in these trading securities related to the DC Plan, which are recorded on the Consolidated Balance Sheets in Other Assets, were $0.8 million, $0.6 million and $0.6 million, respectively, as shown in the following table. These investments are valued based on quoted prices from active markets and are categorized in Level 1 as they are actively traded and no valuation adjustments have been applied. Changes in the fair value of these investments are recorded in Other Expense, Net. March 31, December 31, Fair Value of Marketable Securities ($ millions) 2022 2021 2021 Equity Funds $ 0.4 $ 0.3 $ 0.2 Money Market Funds 0.4 0.3 0.4 Total Marketable Securities $ 0.8 $ 0.6 $ 0.6 Energy Supply Obligations - March 31, December 31, Energy Supply Obligations ($ millions) 2022 2021 2021 Current: Exchange Gas Obligation $ 0.5 $ 1.0 $ 6.7 Renewable Energy Portfolio Standards 6.4 6.5 7.8 Power Supply Contract Divestitures — 0.2 — Total Energy Supply Obligations $ 6.9 $ 7.7 $ 14.5 Exchange Gas Obligation - Renewable Energy Portfolio Standards - Fitchburg has entered into long-term renewable contracts for the purchase of clean energy and/or RECs pursuant to Massachusetts legislation, specifically, An Act Relative to Green Communities (Green Communities Act, 2008), An Act Relative to Competitively Priced Electricity in the Commonwealth (2012) and An Act to Promote Energy Diversity (Energy Diversity Act, 2016). The generating facilities associated with ten of these contracts have been constructed and are now operating. Three approved contracts are currently under development. These include two long-term contracts filed with the MDPU in 2018, one for offshore wind generation and one for imported hydroelectric power and associated transmission, which were approved in 2019 and another for offshore wind generation contracts filed with the MDPU during the first quarter of 2020 and approved in 2021. In compliance with An Act to Promote a Clean Energy Future (2018), in 2021 in coordination with the other electric utilities in Massachusetts, the Company issued its most recent long-term renewable solicitation seeking up to an additional 1,600 megawatts (MW) of offshore wind generation. In December 2021, a portfolio of projects comprising 1,600 MW of offshore wind capacity was selected for negotiation. Those contracts will be filed for approval with the MDPU in May 2022. Fitchburg recovers the costs associated with long-term renewable contracts on a fully reconciling basis through a MDPU-approved cost recovery mechanism. Power Supply Contract Divestitures - Subsequent Events -

DIVIDENDS DECLARED PER SHARE

DIVIDENDS DECLARED PER SHARE	3 Months Ended
	Mar. 31, 2022
DIVIDENDS DECLARED PER SHARE [Abstract]
DIVIDENDS DECLARED PER SHARE	NOTE 2 - DIVIDENDS DECLARED PER SHARE Declaration Date Shareholder of Dividend 04/27/22 05/27/22 05/13/22 $ 0.39 01/26/22 02/25/22 02/11/22 $ 0.39 10/27/21 11/29/21 11/15/21 $ 0.38 07/28/21 08/27/21 08/13/21 $ 0.38 04/28/21 05/28/21 05/14/21 $ 0.38 01/27/21 02/26/21 02/12/21 $ 0.38

SEGMENT INFORMATION

SEGMENT INFORMATION	3 Months Ended
	Mar. 31, 2022
Segment Information	NOTE 3 - SEGMENT INFORMATION The following table provides segment financial data for the three months ended March 31, 2022 and March 31, 2021 : Electric Gas Non- Regulated Other Total Three Months Ended March 31, 2022 ($ millions) Revenues: Billed and Unbilled Revenue $ 84.7 $ 113.7 $ — $ — $ 198.4 Rate Adjustment Mechanism Revenue 4.5 (10.3 ) — — (5.8 ) Total Operating Revenues 89.2 103.4 — — 192.6 Segment Profit (Loss) 3.4 18.5 — (0.4 ) 21.5 Identifiable Segment Assets 598.2 932.6 — 21.5 1,552.3 Capital Expenditures 6.3 9.0 — 0.1 15.4 Three Months Ended March 31, 2021 ($ millions) Revenues: Billed and Unbilled Revenue $ 65.8 $ 93.2 $ — $ — $ 159.0 Rate Adjustment Mechanism Revenue (5.7 ) (14.5 ) — — (20.2 ) Total Operating Revenues 60.1 78.7 — — 138.8 Segment Profit (Loss) 2.9 16.4 — (0.4 ) 18.9 Identifiable Segment Assets 574.8 881.1 — 21.1 1,477.0 Capital Expenditures 9.5 4.3 — 0.3 14.1

DEBT AND FINANCING ARRANGEMENTS

DEBT AND FINANCING ARRANGEMENTS	3 Months Ended
	Mar. 31, 2022
Debt And Financing Arrangements	NOTE 4 - DEBT AND FINANCING ARRANGEMENTS Details on long-term debt at March 31, 2022, March 31, 2021 and December 31, 2021 are shown in the following table: ($ millions) March 31, December 31, 2022 2021 2021 Unitil Corporation: 6.33% Senior Notes, Due May 1, 2022 $ — $ 9.0 $ — 3.70% Senior Notes, Due August 1, 2026 30.0 30.0 30.0 3.43% Senior Notes, Due December 18, 2029 30.0 30.0 30.0 Unitil Energy First Mortgage Bonds: 8.49% Senior Secured Notes, Due October 14, 2024 1.5 3.0 1.5 6.96% Senior Secured Notes, Due September 1, 2028 14.0 16.0 14.0 8.00% Senior Secured Notes, Due May 1, 2031 15.0 15.0 15.0 6.32% Senior Secured Notes, Due September 15, 2036 15.0 15.0 15.0 3.58% Senior Secured Notes, Due September 15, 2040 27.5 27.5 27.5 4.18% Senior Secured Notes, Due November 30, 2048 30.0 30.0 30.0 Fitchburg: 6.75% Senior Notes, Due November 30, 2023 — 1.9 — 6.79% Senior Notes, Due October 15, 2025 6.0 10.0 6.0 3.52% Senior Notes, Due November 1, 2027 10.0 10.0 10.0 7.37% Senior Notes, Due January 15, 2029 8.4 9.6 9.6 5.90% Senior Notes, Due December 15, 2030 15.0 15.0 15.0 7.98% Senior Notes, Due June 1, 2031 14.0 14.0 14.0 3.78% Senior Notes, Due September 15, 2040 27.5 27.5 27.5 4.32% Senior Notes, Due November 1, 2047 15.0 15.0 15.0 Northern Utilities: 3.52% Senior Notes, Due November 1, 2027 20.0 20.0 20.0 7.72% Senior Notes, Due December 3, 2038 50.0 50.0 50.0 3.78% Senior Notes, Due September 15, 2040 40.0 40.0 40.0 4.42% Senior Notes, Due October 15, 2044 50.0 50.0 50.0 4.32% Senior Notes, Due November 1, 2047 30.0 30.0 30.0 4.04% Senior Notes, Due September 12, 2049 40.0 40.0 40.0 Granite State: 3.72% Senior Notes, Due November 1, 2027 15.0 15.0 15.0 Unitil Realty Corp.: 2.64% Senior Secured Notes, Due December 18, 2030 4.4 4.7 4.5 Total Long-Term Debt 508.3 528.2 509.6 Less: Unamortized Debt Issuance Costs 3.5 3.9 3.6 Total Long-Term Debt, net of Unamortized Debt Issuance Costs 504.8 524.3 506.0 Less: Current Portion 8.2 8.5 8.2 Total Long-term Debt, Less Current Portion $ 496.6 $ 515.8 $ 497.8 Fair Value of Long-Term Debt - ($ millions) March 31, December 31, 2022 2021 2021 Estimated Fair Value of Long-Term Debt $ 524.8 $ 581.0 $ 584.9 On July 25, 2018, the Company entered into a Second Amended and Restated Credit Agreement and related documents (collectively, the Credit Facility) with a syndicate of lenders, which amended and restated in its entirety the Company’s prior credit facility. The Credit Facility has a borrowing limit of $120 million, which includes a $25 million sublimit for the issuance of standby letters of credit , extends to July 25, 2023, and, under certain conditions, allows for an increase in the borrowing limit by up to $50 million, and two one-year bear-interest one-month one-month The Company utilizes the Credit Facility for cash management purposes related to its short-term operating activities. Total gross borrowings were $96.8 million for the three months ended March 31, 2022. Total gross repayments were $96.9 million for the three months ended March 31, 2022. The following table details the borrowing limits, amounts outstanding and amounts available under the Credit Facility as of March 31 2022, March 31, 2021 and December 31, 2021: Revolving Credit Facility ($ millions) March 31, December 31, 2022 2021 2021 Limit $ 120.0 $ 120.0 $ 120.0 Short-Term Borrowings Outstanding 64.0 37.3 64.1 Available $ 56.0 $ 82.7 $ 55.9 The Credit Facility contains customary terms and conditions for credit facilities of this type, including affirmative and negative covenants. There are restrictions on, among other things, the Company’s and its subsidiaries’ ability to permit liens or incur indebtedness, and restrictions on the Company’s ability to merge or consolidate with another entity or change its line of business. The affirmative and negative covenants under the Credit Facility apply until the Credit Facility terminates and all amounts borrowed under the Credit Facility are paid in full (or with respect to letters of credit, they are cash collateralized). The only financial covenant in the Credit Facility provides that Funded Debt to Capitalization (as each term is defined in the Credit Facility) cannot exceed 65%, tested on a quarterly basis. At March 31, 2022, March 31, 2021 and December 31, 2021, the Company was in compliance with the covenants contained in the Credit Facility in effect on those dates. The average interest rates on all short-term borrowings and intercompany money pool transactions were 1.4% and 1.3% for the three months ended March 31, 2022 and March 31, 2021, respectively. The average interest rate on all short-term borrowings for the twelve months ended December 31, 2021 was 1.2%. Unitil Corporation and its utility subsidiaries, Fitchburg, Unitil Energy, Northern Utilities, and Granite State currently are rated “BBB+” by Standard & Poor’s Ratings Services. Unitil Corporation and Granite State currently are rated “Baa2”, and Fitchburg, Unitil Energy and Northern Utilities are currently rated “Baa1” by Moody’s Investors Services. Northern Utilities enters into asset management agreements under which Northern Utilities releases certain gas pipeline and storage assets, resells the gas storage inventory to an asset manager and subsequently repurchases the inventory over the course of the gas heating season at the same price at which it sold the gas inventory to the asset manager. There was $2.0 million, $1.5 million and $8.3 million of gas storage inventory at March 31, 2022, March 31, 2021 and December 31, 2021, respectively, related to these asset management agreements. The amount of gas inventory released in March 2022 and payable in April 2022 is $1.5 million and is recorded in Accounts Payable at March 31, 2022. The amount of gas inventory released in March 2021 and payable in April 2021 was $0.5 million and was recorded in Accounts Payable at March 31, 2021. The amount of gas inventory released in December 2021 and payable in January 2022 was $1.6 million and was recorded in Accounts Payable at December 31, 2021. Guarantees The Company provides limited guarantees on certain energy and gas storage management contracts entered into by the distribution utilities. The Company’s policy is to limit the duration of these guarantees. As of March 31, 2022, there were approximately $0.7 million of guarantees outstanding with a duration less than one year. Leases Unitil’s subsidiaries lease certain vehicles, machinery and office equipment under both capital and operating lease arrangements. Total rental expense under operating leases charged to operations for the three months ended March 31, 2022 and 2021 amounted to $0.5 million and $0.5 million, respectively. The balance sheet classification of the Company’s lease obligations was as follows: March 31, December 31, Lease Obligations ($ millions) 2022 2021 2021 Operating Lease Obligations: Other Current Liabilities (current portion) $ 1.6 $ 1.6 $ 1.6 Other Noncurrent Liabilities (long-term portion) 3.2 3.8 3.1 Total Operating Lease Obligations $ 4.8 $ 5.4 $ 4.7 Capital Lease Obligations: Other Current Liabilities (current portion) $ 0.1 $ 0.2 $ 0.1 Other Noncurrent Liabilities (long-term portion) 0.2 0.3 0.2 Total Capital Lease Obligations $ 0.3 $ 0.5 $ 0.3 Total Lease Obligations $ 5.1 $ 5.9 $ 5.0 Cash paid for amounts included in the measurement of operating lease obligations for the three months ended March 31, 2022 and March 31, 2021 was $0.5 million and $0.5 million , respectively, and was included in Cash Provided by Operating Activities on the Consolidated Statements of Cash Flows. Assets under capital leases amounted to approximately $0.6 million, $0.9 million and $0.7 million as of March 31, 2022, March 31, 2021 and December 31, 2021, respectively, less accumulated amortization of $0.3 million, $0.4 million and $0.3 million, respectively, and are included in Net Utility Plant on the Company’s Consolidated Balance Sheets. The following table is a schedule of future operating lease payment obligations and future minimum lease payments under capital leases as of March 31, 2022. The payments for operating leases consist of $1.6 million of current operating lease obligations, which are included in Other Current Liabilities and $3.2 million of noncurrent operating lease obligations, which are included in Other Noncurrent Liabilities, on the Company’s Consolidated Balance Sheets as of March 31, 2022. The payments for capital leases consist of $0.1 million of current capital lease obligations, which are included in Other Current Liabilities and $0.2 million of noncurrent capital lease obligations, which are included in Other Noncurrent Liabilities, on the Company’s Consolidated Balance Sheets as of March 31, 2022. Lease Payments ($000’s) Year Ending December 31, Operating Capital Rest of 2022 $ 1,340 $ 111 2023 1,515 107 2024 1,186 52 2025 620 19 2026 316 — 2027-2031 121 — Total Payments 5,098 289 Less: Interest 297 10 Amount of Lease Obligations Recorded on Consolidated Balance Sheets $ 4,801 $ 279 Operating lease obligations are based on the net present value of the remaining lease payments over the remaining lease term. In determining the present value of lease payments, the Company used the interest rate stated in each lease agreement. As of March 31, 2022, the weighted average remaining lease term is 3.5 years and the weighted average operating discount rate used to determine the operating lease obligations was 3.7%. As of March 31, 2021, the weighted average remaining lease term was 3.8 years and the weighted average operating discount rate used to determine the operating lease obligations was 4.2%.

COMMON STOCK AND PREFERRED STOC

COMMON STOCK AND PREFERRED STOCK	3 Months Ended
	Mar. 31, 2022
COMMON STOCK AND PREFERRED STOCK	NOTE 5 - COMMON STOCK AND PREFERRED STOCK Common Stock The Company’s common stock trades on the New York Stock Exchange under the symbol “UTL.” The Company had 16,020,047, 15,041,629 and 15,977,766 shares of common stock outstanding at March 31, 2022, March 31, 2021 and December 31, 2021, respectively. Dividend Reinvestment and Stock Purchase Plan - Stock Plan - manner consistent with the Stock Plan; construe and interpret the Stock Plan and any agreement or instrument entered into under the Stock Plan as they apply to participants; establish, amend, or waive rules and regulations for the Stock Plan’s administration as they apply to participants; and, subject to the provisions of the Stock Plan, amend the terms and conditions of any outstanding award to the extent such terms and conditions are within the discretion of the Compensation Committee as provided for in the Stock Plan. On April 19, 2012, the Company’s shareholders approved an amendment to the Stock Plan to, among other things, increase the maximum number of shares of common stock available for awards to plan participants. The maximum number of shares available for awards to participants under the Stock Plan is 677,500. The maximum number of shares that may be awarded in any one calendar year to any one participant is 20,000. In the event of any change in capitalization of the Company, the Compensation Committee is authorized to make an equitable adjustment to the number and kind of shares of common stock that may be delivered under the Stock Plan and, in addition, may authorize and make an equitable adjustment to the Stock Plan’s annual individual award limit. Restricted Shares Outstanding awards of Restricted Shares fully vest over a period of four years at a rate of 25% each year. During the vesting period, dividends on Restricted Shares underlying the award may be credited to a participant’s account. The Company may deduct or withhold, or require a participant to remit to the Company, an amount sufficient to satisfy any taxes required by federal, state, or local law or regulation to be withheld with respect to any taxable event arising in connection with an Award. For purposes of compensation expense, Restricted Shares vest immediately upon a participant becoming eligible for retirement, as defined in the Stock Plan. Prior to the end of the vesting period, the restricted shares are subject to forfeiture if the participant ceases to be employed by the Company other than due to the participant’s death. On January 25, 2022, 36,770 Restricted Shares were issued in conjunction with the Stock Plan with an aggregate market value at the date of issuance of approximately $1.7 million. There were 73,178 and 62,566 non-vested Restricted Stock Units Restricted Stock Units , which are issued to members of the Company’s Board of Directors, earn dividend equivalents and will generally be settled by payment to each Director as soon as practicable following the Director’s separation from service to the Company. The Restricted Stock Units will be paid such that the Director will receive (i) 70% of the shares of the Company’s common stock underlying the restricted stock units and (ii) cash in an amount equal to the fair market value of 30% of the shares of the Company’s common stock underlying the Restricted Stock Units. The equity portion of Restricted Stock Units activity during the three months ended March 31, 2022 in conjunction with the Stock Plan are presented in the following table: Restricted Stock Units (Equity Portion) Units Weighted Restricted Stock Units as of December 31, 2021 49,182 $ 41.67 Restricted Stock Units Granted — — Dividend Equivalents Earned 377 $ 50.90 Restricted Stock Units Settled — — Restricted Stock Units as of March 31, 2022 49,559 $ 41.74 There were 43,584 Restricted Stock Units outstanding as of March 31, 2021 with a weighted average stock price of $41.34. Included in Other Noncurrent Liabilities on the Company’s Consolidated Balance Sheets as of March 31, 2022, March 31, 2021 and December 31, 2021 is $1.1 million, $0.9 million and $1.0 million, respectively, representing the fair value of liabilities associated with the portion of fully vested RSUs that will be settled in cash. Preferred Stock There were $0.2 million, or 1,861 shares, of Unitil Energy’s 6.00% Series Preferred Stock outstanding as of March 31, 2022 and December 31, 2021. There were $0.2 million, or 1,887 shares, of Unitil Energy’s 6.00% Series Preferred Stock outstanding as of March 31, 2021. There were less than $0.1 million of total dividends declared on Preferred Stock in each of the three month periods ended March 31, 2022 and March 31, 2021, respectively.

REGULATORY MATTERS

REGULATORY MATTERS	3 Months Ended
	Mar. 31, 2022
REGULATORY MATTERS	NOTE 6 - REGULATORY MATTERS UNITIL’S REGULATORY MATTERS ARE DESCRIBED IN NOTE 8 TO THE FINANCIAL STATEMENTS IN ITEM 8 OF PART II OF UNITIL CORPORATION’S FORM 10-K Tax Cuts and Jobs Act of 2017 On December 22, 2017, the Tax Cuts and Jobs Act of 2017 (TCJA) was signed into law. Among other things, the TCJA substantially reduced the corporate income tax rate to 21%, effective January 1, 2018. Each state public utility commission, with jurisdiction over the areas that are served by Unitil’s electric and gas subsidiary companies, issued orders directing how the tax law changes were to be reflected in rates. Unitil has complied with these orders and has made the required changes to its rates as directed by the commissions. The FERC issued a Notice of Proposed Rulemaking that would allow it to determine which pipelines under the Natural Gas Act may be collecting unjust and unreasonable rates in light of the corporate tax reduction. This matter was resolved for Granite State in its May 2, 2018 uncontested rate settlement filing, which accounted for the effect of the TCJA. On November 21, 2019, the FERC issued Order No. 864, a final rule on Public Utility Transmission Rate Changes to Address Accumulated Deferred Income Taxes. The new rule requires public utilities with formula transmission rates to revise their formula rates to include a transparent methodology to address the TCJA and future tax law changes on customer rates by accounting for “excess” or “deficient” Accumulated Deferred Income Taxes (ADIT). The FERC also required transmission providers with stated rates to account for TCJA’s effect on ADIT in their next rate case. The Company is complying with the new rule and there is no material effect on its financial position, operating results, or cash flows. Rate Case Activity Northern Utilities - Base Rates - Maine recovery of some, but not all, of the Company’s implementation costs associated with its customer information system pending the completion of an investigation, including a third-party audit. On March 9, 2021, the MPUC opened a new docket to investigate the amount of customer information system costs that will be allowed in rates. On January 27, 2022, the Company and the Maine Office of the Public Advocate filed a stipulation in this docket. The stipulation includes no finding of imprudence or asset disallowance. The terms of the stipulation provide for recovery of the revenue requirement related to the Company’s customer information system in base rates starting November 1, 2022, which coincides with the timing of the Company’s winter cost of gas rate change. On February 9, 2022, the MPUC approved the stipulation. Northern Utilities - Targeted Infrastructure Replacement Adjustment (TIRA) - Maine million for 2021 eligible facilities, was filed with the MPUC on February 28, 2022. On April 27, 2022, the MPUC issued an order approving the filing, for rates effective May 1, 2022. Northern Utilities - Base Rates - New Hampshire Unitil Energy - Base Rates - Fitchburg - Base Rates - Electric - requirement associated with certain capital additions. On November 2, 2021, Fitchburg filed its cumulative revenue requirement of $1.6 million associated with its 2019 and 2020 capital expenditures. The Department allowed the associated rate increase to become effective on January 1, 2022, subject to further investigation and reconciliation. On April 17, 2020, the MDPU approved a settlement agreement entered into by the Company and the Massachusetts Office of the Attorney General providing for a distribution increase of $1.1 million, effective November 1, 2020. The Company’s subsequent Compliance Filing reflected an adjusted distribution increase of $0.9 million, a decrease of $0.2 million from the original settlement amount. On May 21, 2020, the MDPU approved the Company’s Compliance Filing. The agreement provides for a Return on Equity of 9.7% and a capital structure reflecting 52.45% equity and 47.55% long-term debt. Under the agreement, the Company will not increase or redesign base distribution rates to become effective prior to November 1, 2023, though the Company may seek cost recovery for certain exogenous events that meet a revenue threshold of $0.1 million. The agreement also provides for the implementation of a major storm reserve fund, whereby the Company may recover the costs of restoration for qualifying storm events. In addition, the agreement provides for the extension of the annual capital cost recovery mechanism, modified to allow the recovery of property tax on the cumulative net capital expenditures. Fitchburg - Base Rates - Gas On February 28, 2020, the MDPU approved a settlement agreement between the Company and the Massachusetts Office of the Attorney General. The agreement provides for an annual distribution revenue increase of $4.6 million to be phased in over two years: (1) an increase of $3.7 million, which became effective on March 1, 2020; and (2) an increase of $0.9 million, which became effective on March 1, 2021. Under the agreement, the Company will not increase or redesign base distribution rates to become effective prior to March 1, 2023, though the Company may seek cost recovery for certain exogenous events that meet a revenue effect threshold of $40,000. The agreement provides for a Return on Equity of 9.7% and a capital structure reflecting 52.45% equity and 47.55% long-term debt. Fitchburg - Gas System Enhancement Program million, and received final approval on April 29, 2021, effective May 1, 2021. The Company’s most recent forward-looking filing, filed on October 29, 2021, requested recovery of approximately $3.3 million. On April 28, 2022, the MDPU issued an order approving this filing for rates effective May 1, 2022. The Company considers these to be routine regulatory proceedings, and there are no material issues outstanding. Granite State - Base Rates - approximately $14.6 million on the capital cost recoverable under such filings during the term of the Settlement. Under the Settlement Agreement, Granite may not file a new general rate case earlier than April 30, 2024 with rates to be effective no earlier than November 1, 2024 based on a test year ending no earlier than December 31, 2023. On August 24, 2021, the FERC accepted Granite State’s first limited Section 4 rate adjustment pursuant to the Settlement Agreement, for an annual revenue increase of $0.1 million, effective September 1, 2021. Other Matters Fitchburg - Grid Modernization Fitchburg - Grid Modernization Cost Recovery Factor Fitchburg - Investigation into the role of gas LDCs to achieve Commonwealth 2050 climate goals - net-zero net-zero Financial Effects of COVID-19 COVID-19 shut-off 20-58, COVID-19 COVID-19 Northern Utilities / Granite State - Firm Capacity Contract one-year 12-month one-year Reconciliation Filings Fitchburg - Massachusetts Request for Proposals (RFPs) The EDCs issued the RFP for Section 83D Long-Term Contracts for Qualified Clean Energy Projects in March 2017, and after selection of final projects and negotiation, final contracts for 9,554,940 MWh of Qualified Clean Energy and associated Environmental Attributes from Hydro-Quebec Energy Services (U.S.), Inc. for hydroelectric generation were filed in July 2018 for approval by the MDPU. On June 25, 2019, the MDPU approved the power purchase agreements, including the EDCs’ proposal to sell the energy procured under the contract into the ISO-NE ISO-NE The EDCs issued the RFP pursuant to Section 83C for Long-Term Contracts for Offshore Wind Energy Generation in June 2017. The EDCs selected an 800 MW project submitted by Vineyard Wind in May 2018, contracts were signed in July 2018 and on July 23, 2018, the EDCs, including Fitchburg, filed two long-term contracts, each for 400 MW of offshore wind energy generation with the MDPU for approval. On April 12, 2019, the MDPU approved the offshore wind energy generation power purchase agreements, including the EDCs’ proposal to sell the energy procured under the contract into the ISO-NE ISO-NE customers. The MDPU also determined that the EDCs’ request for remuneration equal to 2.75% of the contract payments is reasonable and in the public interest and approved the EDCs’ proposal to amend their respective tariffs to include the recovery of costs associated with the contracts. The Company believes the power purchase obligations under these long-term contracts will have a material effect on the contractual obligations of Fitchburg, once certain conditions and contingencies are met. The EDCs issued a second RFP pursuant to Section 83C for Long-Term Contracts for Offshore Wind Energy Generation on May 23, 2019. This solicitation sought to procure the obligation remaining under 83C at the time, an additional 800 MW of offshore wind energy generation. The EDCs selected an 800 MW project submitted by Mayflower Wind Energy LLC and contracts were executed on January 10, 2020. A filing with the MDPU for approval of two long-term contracts, each for 400 MW of offshore wind energy generation, was made on February 10, 2020. On November 5, 2020, the MDPU approved the Offshore Wind Energy Generation power purchase agreements. The MDPU also determined that the EDCs’ request for remuneration equal to 2.75% is reasonable and in the public interest. The Company believes the power purchase obligations under these long-term contracts will have a material effect on the contractual obligations of Fitchburg, once certain conditions and contingencies are met. In accordance with the requirement of Chapter 227 of the Acts of 2018, An Act to Advance Clean Energy, signed August 9, 2018, Massachusetts Department of Energy Resources (MDOER) prepared a report on the necessity, benefits and costs of requiring the EDCs to competitively conduct offshore wind generation RFPs for up to an additional 1,600 MW. The MDOER filed its report with the Legislature in May, 2019, recommending that, “the EDCs should proceed with additional offshore wind solicitations for up to 1,600 MW of offshore wind in 2022 and 2024 and only enter into contracts if found to be cost-effective.” On March 10, 2021, Fitchburg, along with the other EDCs, filed a petition with the MDPU for approval of a proposed timetable and method of solicitation and execution of long-term contracts for up to an additional 1,600 MW of off shore wind generation. On May 5, 2021, the DPU approved the proposed timetable and method for the solicitation, and the RFP was issued on May 7, 2021. On December 17, 2021, the EDCs selected a 1,600 MW portfolio of offshore wind generation that includes a 1,200 MW project submitted by Vineyard Wind and a 400 MW project submitted by Mayflower Wind. Contract negotiations were the contracts will be M ay Section 83C of Chapter 169 of the Acts of 2008 was recently amended by the Acts of 2021 to increase the aggregate amount of offshore wind capacity to be procured to 5,600 MW not later than June 30, 2027. After considering the two approved offshore wind contracts of 800 MW each and the most recent selection of 1,600 MW there is another 2,400 MW of offshore wind capacity to be procured in the future. FERC Transmission Formula Rate Proceedings - ISO-New EL14-12, 14-12, The FERC Section 206 proceeding concerning the justness and reasonableness of ISO-New settlement agreement on May 22, 2019 and remanded the proceeding to the Chief Administrative Law Judge to resume hearing procedures. On May 24, 2019 the judge appointed a Dispute Resolution Facilitator to aid parties in settlement negotiations. The procedural schedule was suspended September 24, 2019 in order to allow participants to focus on settlement negotiations. On October 24, 2019, the NETOs filed an unopposed motion to suspend the procedural schedule and waiver of answer period indicating that the NETOs, Municipal Pool Transmission Facility Owners and the Commission Trial Staff have reached agreement in principle on the terms of a settlement to resolve all open issues in the proceeding. On June 15, 2020 a settlement was filed. The FERC approved the settlement agreement on December 28, 2020. Pursuant to the terms of the settlement agreement, the negotiated formula rates took effect on January 1, 2022. Fitchburg and Unitil Energy are Participating Transmission Owners, although Unitil Energy does not own transmission plant. Legal Proceedings The Company is involved in legal and administrative proceedings and claims of various types, including those which arise in the ordinary course of business. The Company believes, based upon information furnished by counsel and others, that the ultimate resolution of these claims will not have a material effect on its financial position, operating results or cash flows.

ENVIRONMENTAL MATTERS

ENVIRONMENTAL MATTERS	3 Months Ended
	Mar. 31, 2022
ENVIRONMENTAL MATTERS	NOTE 7 - ENVIRONMENTAL MATTERS UNITIL’S ENVIRONMENTAL MATTERS ARE DESCRIBED IN NOTE 8 TO THE FINANCIAL STATEMENTS IN ITEM 8 OF PART II OF UNITIL CORPORATION’S FORM 10-K The Company’s past and present operations include activities that are generally subject to extensive and complex federal and state environmental laws and regulations. The Company is in material compliance with applicable environmental and safety laws and regulations and, as of March 31, 2022, has not identified any material losses reasonably likely to be incurred in excess of recorded amounts. However, the Company cannot assure that significant costs and liabilities will not be incurred in the future. It is possible that other developments, such as increasingly stringent federal, state or local environmental laws and regulations could result in increased environmental compliance costs. Based on its current assessment of its environmental responsibilities, existing legal requirements and regulatory policies, the Company does not believe that these environmental costs will have a material adverse effect on the Company’s consolidated financial position or results of operations. Northern Utilities Manufactured Gas Plant Sites mid-1800s mid-1900s. Northern Utilities has worked with the Maine Department of Environmental Protection and New Hampshire Department of Environmental Services (NH DES) to address environmental concerns with these sites. Northern Utilities or others have completed remediation activities at all sites; however, on site monitoring continues at several sites which may result in future remedial actions as directed by the applicable regulatory agency. In July 2019, the NH DES requested that Northern Utilities review modeled expectations for groundwater contaminants against observed data at the Rochester site. In June 2020, the NH DES coupled the submittal of the review to a proposed extension of the gas distribution system by Northern Utilities. Northern Utilities submitted the review in January 2022. In anticipation of the NH DES approval of the work plan, the Company has accrued $0.8 million for estimated costs to complete the remediation at the Rochester site, which is included in Environmental Obligations. The NHPUC and MPUC have approved regulatory mechanisms for the recovery of MGP environmental costs. For Northern Utilities’ New Hampshire division, the NHPUC has approved the recovery of MGP environmental costs over succeeding seven-year periods. For Northern Utilities’ Maine division, the MPUC has authorized the recovery of environmental remediation costs over succeeding five-year periods. The Environmental Obligations table shows the amounts accrued for Northern Utilities related to estimated future cleanup costs associated with Northern Utilities’ environmental remediation obligations for former MGP sites. Corresponding Regulatory Assets were recorded to reflect that the future recovery of these environmental remediation costs is expected based on regulatory precedent and established practices. Fitchburg’s Manufactured Gas Plant Site In August 2021, the Mass DEP issued a Notice of Non-compliance Fitchburg recovers the environmental response costs incurred at this former MGP site in gas rates pursuant to the terms of a cost recovery agreement approved by the MDPU. Pursuant to this agreement, Fitchburg is authorized to amortize and recover environmental response costs from gas customers over succeeding seven-year periods. Unitil Energy - Kensington Distribution Operations Center The following table sets forth a summary of changes in the Company’s liability for Environmental Obligations for the three months ended March 31, 2022 and 2021. Environmental Obligations ($ millions) Three Months Ended March 31, 2022 2021 Total Balance at Beginning of Period $ 2.7 $ 2.1 Additions — 0.1 Less: Payments / Reductions — 0.1 Total Balance at End of Period 2.7 2.1 Less: Current Portion 0.5 0.3 Noncurrent Balance at End of Period $ 2.2 $ 1.8

INCOME TAXES

INCOME TAXES	3 Months Ended
	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 8: INCOME TAXES The differences between the Company’s provisions for Income Taxes and the provisions calculated at the statutory federal tax rate, expressed in percentages, are shown in the following table: Three Months Ended March 31, 2022 2021 Statutory Federal Income Tax Rate 21 % 21 % Income Tax Effects of: State Income Taxes, net 6 6 Utility Plant Differences (1 ) (1 ) Other, net — — Effective Income Tax Rate 26 % 26 % Under the Company’s Tax Sharing Agreement (the Agreement) which was approved upon the formation of Unitil as a public utility holding company, the Company files consolidated Federal and State tax returns and Unitil Corporation and each of its utility operating subsidiaries recognize the results of their operations in its tax returns as if it were a stand-alone taxpayer. The Agreement provides that the Company will account for income taxes in compliance with U.S. GAAP and regulatory accounting principles. The Company has evaluated its tax positions at March 31, 2022 in accordance with the FASB Codification, and has concluded that no adjustment for recognition, de-recognition, Income tax filings for the year ended December 31, 2020 have been filed with the IRS, Massachusetts Department of Revenue, the Maine Revenue Service, and the New Hampshire Department of Revenue Administration. In the Company’s federal tax returns for the year ended December 31, 2020, which were filed with the IRS in October 2021, the Company generated federal Net Operating Loss Carryforward (NOLC) assets of $7.7 million, principally due to tax repairs expense and tax depreciation. As of December 31, 2021, the Company recognized the utilization of approximately $3.6 million of the NOLC asset to offset current taxes payable. In addition, at December 31, 2021, the Company had $0.7 million of cumulative state tax credit carryforwards to offset future income taxes payable. If unused, the Company’s state tax credit carryforwards will begin to expire in 2024. In March 2020, the Coronavirus Aid, Relief and Economic Security (CARES) Act was signed into law. The CARES Act included several tax changes as part of its economic package. These changes principally related to expanded Net Operating Loss carryback periods, increases to interest deductibility limitations, and accelerated Alternative Minimum Tax refunds. Additionally, the CARES Act enacted the Employee Retention Credit (ERC) to incentivize companies to retain employees. The ERC is a 50% credit on employee wages for employees that are retained and cannot perform their job duties at 100% capacity as a result of coronavirus pandemic restrictions. In December 2020, the Consolidated Appropriations Act, 2021 (CAA) was signed into law. The CAA included additional funding through tax credits as part of its economic package for 2021. These changes include the temporary removal of deduction limitations on business meals through December 2022 and additional funding for the ERC with expanded benefits extended through June 30, 2021. The expanded ERC is a 70% credit on employee wages for employees that are retained and cannot perform their job duties at 100% capacity as a result of coronavirus pandemic restrictions. In March 2021, the American Rescue Plan Act of 2021 (ARPA) was signed into law. The ARPA included certain provisions that provide economic relief for the ongoing COVID-19 The Company has evaluated each of the CARES, CAA and ARPA provisions and determined that they do not have a material effect on the Company’s financial statements as of March 31, 2022. In December 2017, the Tax Cuts and Jobs Act (TCJA), which included a reduction to the corporate federal income tax rate to 21% effective January 1, 2018, was signed into law. In accordance with FASB Codification Topic 740, the Company revalued its Accumulated Deferred Income Taxes (ADIT) at the new 21% tax rate at which the ADIT will be reversed in future periods. Based on communications received by the Company from its state regulators in rate cases and other regulatory proceedings in the first quarter of 2018 and as prescribed in the TCJA, FERC guidance and IRS normalization rules, the benefit of protected excess ADIT amounts will be subject to flow back to customers in future utility rates according to the Average Rate Assumption Method (ARAM). ARAM reconciles excess ADIT at the reversal rate of the underlying book/tax temporary timing differences. The Company estimates the ARAM flow back period for protected and unprotected excess ADIT to be between fifteen

RETIREMENT BENEFIT OBLIGATIONS

RETIREMENT BENEFIT OBLIGATIONS	3 Months Ended
	Mar. 31, 2022
Retirement Benefits [Abstract]
Retirement Benefit Plans	NOTE 9: RETIREMENT BENEFIT OBLIGATIONS The Company sponsors the following retirement benefit plans to provide certain pension and post-retirement benefits for its retirees and current employees as follows: • The Unitil Corporation Retirement Plan (Pension Plan) - non-union • The Unitil Retiree Health and Welfare Benefits Plan (PBOP Plan) - • The Unitil Corporation Supplemental Executive Retirement Plan (SERP) - non-qualified See Note 10 (Retirement Benefit Plans) to the Consolidated Financial Statements in the Company’s Form 10-K The following table includes the key weighted average assumptions used in determining the Company’s benefit plan costs and obligations: Used to Determine Plan Costs 2022 2021 Discount Rate 2.85 % 2.50 % Rate of Compensation Increase 3.00 % 3.00 % Expected Long-term rate of return on plan assets 7.50 % 7.50 % Health Care Cost Trend Rate Assumed for Next Year 6.20 % 6.60 % Ultimate Health Care Cost Trend Rate 4.50 % 4.50 % Year that Ultimate Health Care Cost Trend Rate is reached 2029 2029 The following table provides the components of the Company’s Retirement plan costs ($000’s): Pension Plan PBOP Plan SERP Three Months Ended March 31, 2022 2021 2022 2021 2022 2021 Service Cost $ 791 $ 868 $ 722 $ 758 $ 68 $ 89 Interest Cost 1,371 1,251 799 685 118 114 Expected Return on Plan Assets (2,720 ) (2,423 ) (854 ) (627 ) — — Prior Service Cost Amortization 89 75 273 302 14 14 Actuarial Loss Amortization 1,377 2,022 255 262 199 372 Sub-total 908 1,793 1,195 1,380 399 589 Amounts Capitalized and Deferred (156 ) (713 ) (511 ) (662 ) (118 ) (178 ) Net Periodic Benefit Cost Recognized $ 752 $ 1,080 $ 684 $ 718 $ 281 $ 411 Employer Contributions As of March 31, 2022, the Company had not made any contributions to its Pension Plan and PBOP Plan, respectively, in 2022. The Company, along with its subsidiaries, expects to make contributions to its Pension and PBOP Plans in 2022 and future years at minimum required and discretionary funding levels consistent with the amounts recovered in the distribution utilities’ rates for these Pension and PBOP Plan costs. As of March 31, 2022, the Company had made $0.2 million of benefit payments under the SERP Plan in 2022. The Company presently anticipates making an additional $0.4 million of benefit payments under the SERP Plan in 2022.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Nature of Operations	Nature of Operations - non-regulated The Company’s earnings are seasonal and typically are higher in the first and fourth quarters when customers use gas for heating purposes. Unitil’s principal business is the local distribution of electricity in the southeastern seacoast and capital city areas of New Hampshire and the greater Fitchburg area of north central Massachusetts and the local distribution of gas in southeastern New Hampshire, portions of southern Maine to the Lewiston-Auburn area and in the greater Fitchburg area of north central Massachusetts. Unitil has three distribution utility subsidiaries, including Unitil Energy, which operates in New Hampshire; Fitchburg, which operates in Massachusetts; and Northern Utilities, which operates in New Hampshire and Maine (collectively referred to as the “distribution utilities”). Granite State is an interstate gas transmission pipeline company, operating 86 miles of underground gas transmission pipeline primarily located in Maine and New Hampshire. Granite State provides Northern Utilities with interconnection to three major gas pipelines and access to domestic gas supplies in the south and Canadian gas supplies in the north. Granite State derives its revenues principally from transportation services provided to Northern Utilities and, to a lesser extent, third-party marketers. A fifth utility subsidiary, Unitil Power, formerly functioned as the full requirements wholesale power supply provider for Unitil Energy. In connection with the implementation of electric industry restructuring in New Hampshire, on May 1, 2003 Unitil Power ceased being the wholesale supplier of Unitil Energy and divested of its long-term power supply contracts through the sale of the entitlements to the electricity associated with various electric power supply contracts it had acquired to serve Unitil Energy’s customers. In the period since, Unitil Power continued to flow revenues and expenses from remaining contracts to Unitil Energy under the Amended Unitil System Agreement. The last of those contracts expired October 31, 2020, and the Company no longer has material revenues or expenses associated with them. Unitil also has three other wholly-owned subsidiaries: Unitil Service, Unitil Realty and Unitil Resources. Unitil Service provides, at cost, a variety of administrative and professional services, including regulatory, financial, accounting, human resources, engineering, operations, technology, energy management and management services on a centralized basis to its affiliated Unitil companies. Unitil Realty owns and manages the Company’s corporate office in Hampton, New Hampshire and leases this facility to Unitil Service under a long-term lease arrangement. Unitil Resources is the Company’s wholly-owned non-regulated
Basis of Presentation	Basis of Presentation - 10-Q 10-K
Utility Revenue Recognition	Revenue is recorded when service is rendered or energy is delivered to customers. However, the determination of energy sales to individual customers is based on the reading of their meters, which occurs on a systematic basis throughout the month. At the end of each calendar month, amounts of energy delivered to customers since the date of the last meter reading are estimated and the corresponding unbilled revenues are calculated. These unbilled revenues are estimated each month based on estimated customer usage by class and applicable customer rates, taking into account current and historical weather data, assumptions pertaining to metering patterns, billing cycle statistics, and other estimates and assumptions, and are then reversed in the following month when billed to customers. A majority of the Company’s revenue from contracts with customers continues to be recognized on a monthly basis based on applicable tariffs and customer monthly consumption. Such revenue is recognized using the invoice practical expedient, which allows an entity to recognize revenue in the amount that directly corresponds to the value transferred to the customer. The Company’s billed and unbilled revenue meets the definition of “revenues from contracts with customers” as defined in Accounting Standards Codification (ASC) 606. Revenue recognized in connection with rate adjustment mechanisms is consistent with the definition of alternative revenue programs in ASC 980-605-25-3, 980-605-25-4. In the following tables, revenue is classified by the types of goods/services rendered and market/customer type. Three Months Ended March 31, 2022 Electric and Gas Operating Revenues ($ millions): Electric Gas Total Billed and Unbilled Revenue: Residential $ 49.4 $ 45.6 $ 95.0 Commercial and Industrial 31.0 64.6 95.6 Other 4.3 3.5 7.8 Total Billed and Unbilled Revenue 84.7 113.7 198.4 Rate Adjustment Mechanism Revenue 4.5 (10.3 ) (5.8 ) Total Electric and Gas Operating Revenues $ 89.2 $ 103.4 $ 192.6 Fitchburg is subject to revenue decoupling. Revenue decoupling is the term given to the elimination of the dependency of a utility’s distribution revenue on the volume of electricity or gas sales. The difference between distribution revenue amounts billed to customers and the targeted revenue decoupling amounts is recorded as an increase or a decrease in Accrued Revenue, which forms the basis for resetting rates for future cash recoveries from, or credits to, customers. These revenue decoupling targets may be adjusted as a result of rate cases that the Company files with the Massachusetts Department of Public Utilities (MDPU).
Income Taxes	Income Taxes - Provisions for income taxes are calculated in each jurisdiction in which the Company operates, for each period for which a statement of earnings is presented. The Company accounts for income taxes in accordance with the FASB Codification guidance on Income Taxes, which requires an asset and liability approach for the financial accounting and reporting of income taxes. Significant judgments and estimates are required in determining the current and deferred tax assets and liabilities. The Company’s deferred tax assets and liabilities reflect its best assessment of estimated future taxes to be paid. In accordance with the FASB Codification, the Company periodically assesses the realization of its deferred tax assets and liabilities and adjusts the income tax provision, the current tax liability and deferred taxes in the period in which the facts and circumstances which gave rise to the revision become known.
Cash and Cash Equivalents	Cash and Cash Equivalents - (ISO-NE) ISO-NE. 2-1/2 ISO-NE
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts - conditions, customer trends, or other factors such as the extent and duration of any shutoff or collection moratoriums. The Company also calculates the amount of written-off The Allowance for Doubtful Accounts as of March 31, 2022, March 31, 2021 and December 31, 2021, was as follows: ($ millions) March 31, December 31, 2022 2021 2021 Allowance for Doubtful Accounts $ 3.4 $ 4.4 $ 3.3 Accounts Receivable, Net includes $3.3 million, $4.3 million, and $3.1 million of the Allowance for Doubtful Accounts at March 31, 2022, March 31, 2021 and December 31, 2021, respectively. Unbilled Revenues, net (a component of Accrued Revenue) includes $0.1 million, $0.1 million and $0.2 million of the Allowance for Doubtful Accounts at March 31, 2022, March 31, 2021 and December 31, 2021, respectively.
Accrued Revenue	Accrued Revenue - March 31, December 31, Accrued Revenue ($ millions) 2022 2021 2021 Regulatory Assets – Current $ 45.2 $ 24.0 $ 47.4 Unbilled Revenues, net 11.1 10.7 13.8 Total Accrued Revenue $ 56.3 $ 34.7 $ 61.2
Exchange Gas Receivable	Exchange Gas Receivable - March 31, December 31, Exchange Gas Receivable ($ millions) 2022 2021 2021 Northern Utilities $ 0.5 $ 1.0 $ 6.7 Fitchburg 0.2 0.2 0.7 Total Exchange Gas Receivable $ 0.7 $ 1.2 $ 7.4
Gas Inventory	Gas Inventory - March 31, December 31, Gas Inventory ($ millions) 2022 2021 2021 Natural Gas $ — $ — $ 0.5 Propane 0.4 0.3 0.4 Liquefied Natural Gas & Other 0.1 0.1 0.1 Total Gas Inventory $ 0.5 $ 0.4 $ 1.0
Utility Plant	Utility Plant -
Leases	Leases - non-lease
Regulatory Accounting	Regulatory Accounting - shut-off. March 31, December 31, Regulatory Assets consist of the following ($ millions) 2022 2021 2021 Retirement Benefits $ 86.5 $ 104.5 $ 86.4 Energy Supply and Other Rate Adjustment Mechanisms 41.9 20.2 44.1 Deferred Storm Charges 2.9 3.7 3.3 Environmental 4.5 5.0 4.6 Income Taxes 2.4 3.2 2.6 Other Deferred Charges 15.1 16.1 15.3 Total Regulatory Assets 153.3 152.7 156.3 Less: Current Portion of Regulatory Assets (1) 45.2 24.0 47.4 Regulatory Assets – noncurrent $ 108.1 $ 128.7 $ 108.9 (1) Reflects amounts included in the Accrued Revenue on the Company’s Consolidated Balance Sheets. March 31, December 31, Regulatory Liabilities consist of the following ($ millions) 2022 2021 2021 Income Taxes (Note 8) $ 43.9 $ 45.1 $ 44.3 Rate Adjustment Mechanisms 13.8 12.9 7.7 Other — 0.2 0.1 Total Regulatory Liabilities 57.7 58.2 52.1 Less: Current Portion of Regulatory Liabilities 15.6 14.7 9.5 Regulatory Liabilities – noncurrent $ 42.1 $ 43.5 $ 42.6 Generally, the Company receives a return on investment on its regulatory assets for which a cash outflow has been made. Included in Regulatory Assets as of March 31, 2022 are $7.8 million of environmental costs, rate case costs and other expenditures to be recovered over varying periods in the next seven years. Regulators have authorized recovery of these expenditures, but without a return. Regulatory commissions can reach different conclusions about the recovery of costs, which can have a material effect on the Company’s Consolidated Financial Statements. The Company believes it is probable that its regulated distribution and transmission utilities will recover their investments in long-lived assets, including regulatory assets. If the Company, or a portion of its assets or operations, were to cease meeting the criteria for application of these accounting rules, accounting standards for businesses in general would become applicable and immediate recognition of any previously deferred costs, or a portion of deferred costs, would be required in the year in which the criteria are no longer met, if such deferred costs were not recoverable in the portion of the business that continues to meet the criteria for application of the FASB Codification topic on Regulated Operations. If unable to continue to apply the FASB Codification provisions for Regulated Operations, the Company would be required to apply the provisions for the Discontinuation of Rate-Regulated Accounting included in the FASB Codification. In the Company’s opinion, its regulated operations will be subject to the FASB Codification provisions for Regulated Operations for the foreseeable future.
Derivatives	Derivatives - Fitchburg has entered into power purchase agreements for which contingencies exist (see Note 6, Regulatory Matters). Until these contingencies are satisfied, these contracts will not qualify for derivative accounting. The Company believes that the power purchase obligations under these long-term contracts will have a material effect on the contractual obligations of Fitchburg.
Investments in Marketable Securities	Investments in Marketable Securities - At March 31, 2022, March 31, 2021 and December 31, 2021, the fair value of the Company’s investments in these trading securities, which are recorded on the Consolidated Balance Sheets in Other Assets, w as March 31, December 31, Fair Value of Marketable Securities ($ millions) 2022 2021 2021 Money Market Funds $ 5.5 $ 5.6 $ 5.7 Total Marketable Securities $ 5.5 $ 5.6 $ 5.7 The Company also sponsors the Unitil Corporation Deferred Compensation Plan (the “DC Plan”). The DC Plan is a non-qualified tax-deferred At March 31, 2022, March 31, 2021 and December 31, 2021, the fair value of the Company’s investments in these trading securities related to the DC Plan, which are recorded on the Consolidated Balance Sheets in Other Assets, were $0.8 million, $0.6 million and $0.6 million, respectively, as shown in the following table. These investments are valued based on quoted prices from active markets and are categorized in Level 1 as they are actively traded and no valuation adjustments have been applied. Changes in the fair value of these investments are recorded in Other Expense, Net. March 31, December 31, Fair Value of Marketable Securities ($ millions) 2022 2021 2021 Equity Funds $ 0.4 $ 0.3 $ 0.2 Money Market Funds 0.4 0.3 0.4 Total Marketable Securities $ 0.8 $ 0.6 $ 0.6
Energy Supply Obligations	Energy Supply Obligations - March 31, December 31, Energy Supply Obligations ($ millions) 2022 2021 2021 Current: Exchange Gas Obligation $ 0.5 $ 1.0 $ 6.7 Renewable Energy Portfolio Standards 6.4 6.5 7.8 Power Supply Contract Divestitures — 0.2 — Total Energy Supply Obligations $ 6.9 $ 7.7 $ 14.5 Exchange Gas Obligation - Renewable Energy Portfolio Standards - Fitchburg has entered into long-term renewable contracts for the purchase of clean energy and/or RECs pursuant to Massachusetts legislation, specifically, An Act Relative to Green Communities (Green Communities Act, 2008), An Act Relative to Competitively Priced Electricity in the Commonwealth (2012) and An Act to Promote Energy Diversity (Energy Diversity Act, 2016). The generating facilities associated with ten of these contracts have been constructed and are now operating. Three approved contracts are currently under development. These include two long-term contracts filed with the MDPU in 2018, one for offshore wind generation and one for imported hydroelectric power and associated transmission, which were approved in 2019 and another for offshore wind generation contracts filed with the MDPU during the first quarter of 2020 and approved in 2021. In compliance with An Act to Promote a Clean Energy Future (2018), in 2021 in coordination with the other electric utilities in Massachusetts, the Company issued its most recent long-term renewable solicitation seeking up to an additional 1,600 megawatts (MW) of offshore wind generation. In December 2021, a portfolio of projects comprising 1,600 MW of offshore wind capacity was selected for negotiation. Those contracts will be filed for approval with the MDPU in May 2022. Fitchburg recovers the costs associated with long-term renewable contracts on a fully reconciling basis through a MDPU-approved cost recovery mechanism. Power Supply Contract Divestitures -
Subsequent Events	Subsequent Events -

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	3 Months Ended
	Mar. 31, 2022
Components of Gas and Electric Operating Revenue	In the following tables, revenue is classified by the types of goods/services rendered and market/customer type. Three Months Ended March 31, 2022 Electric and Gas Operating Revenues ($ millions): Electric Gas Total Billed and Unbilled Revenue: Residential $ 49.4 $ 45.6 $ 95.0 Commercial and Industrial 31.0 64.6 95.6 Other 4.3 3.5 7.8 Total Billed and Unbilled Revenue 84.7 113.7 198.4 Rate Adjustment Mechanism Revenue 4.5 (10.3 ) (5.8 ) Total Electric and Gas Operating Revenues $ 89.2 $ 103.4 $ 192.6
Allowance for Doubtful Accounts Included in Accounts Receivable Net	The Allowance for Doubtful Accounts as of March 31, 2022, March 31, 2021 and December 31, 2021, was as follows: ($ millions) March 31, December 31, 2022 2021 2021 Allowance for Doubtful Accounts $ 3.4 $ 4.4 $ 3.3
Components of Accrued Revenue	The following table shows the components of Accrued Revenue as of March 31, 2022, March 31, 2021 and December 31, 2021. March 31, December 31, Accrued Revenue ($ millions) 2022 2021 2021 Regulatory Assets – Current $ 45.2 $ 24.0 $ 47.4 Unbilled Revenues, net 11.1 10.7 13.8 Total Accrued Revenue $ 56.3 $ 34.7 $ 61.2
Components of Exchange Gas Receivable	The following table shows the components of Exchange Gas Receivable as of March 31, 2022, March 31, 2021 and December 31, 2021. March 31, December 31, Exchange Gas Receivable ($ millions) 2022 2021 2021 Northern Utilities $ 0.5 $ 1.0 $ 6.7 Fitchburg 0.2 0.2 0.7 Total Exchange Gas Receivable $ 0.7 $ 1.2 $ 7.4
Components of Gas Inventory	The following table shows the components of Gas Inventory as of March 31, 2022, March 31, 2021 and December 31, 2021. March 31, December 31, Gas Inventory ($ millions) 2022 2021 2021 Natural Gas $ — $ — $ 0.5 Propane 0.4 0.3 0.4 Liquefied Natural Gas & Other 0.1 0.1 0.1 Total Gas Inventory $ 0.5 $ 0.4 $ 1.0
Regulatory Assets	March 31, December 31, Regulatory Assets consist of the following ($ millions) 2022 2021 2021 Retirement Benefits $ 86.5 $ 104.5 $ 86.4 Energy Supply and Other Rate Adjustment Mechanisms 41.9 20.2 44.1 Deferred Storm Charges 2.9 3.7 3.3 Environmental 4.5 5.0 4.6 Income Taxes 2.4 3.2 2.6 Other Deferred Charges 15.1 16.1 15.3 Total Regulatory Assets 153.3 152.7 156.3 Less: Current Portion of Regulatory Assets (1) 45.2 24.0 47.4 Regulatory Assets – noncurrent $ 108.1 $ 128.7 $ 108.9 (1) Reflects amounts included in the Accrued Revenue on the Company’s Consolidated Balance Sheets.
Regulatory Liabilities	March 31, December 31, Regulatory Liabilities consist of the following ($ millions) 2022 2021 2021 Income Taxes (Note 8) $ 43.9 $ 45.1 $ 44.3 Rate Adjustment Mechanisms 13.8 12.9 7.7 Other — 0.2 0.1 Total Regulatory Liabilities 57.7 58.2 52.1 Less: Current Portion of Regulatory Liabilities 15.6 14.7 9.5 Regulatory Liabilities – noncurrent $ 42.1 $ 43.5 $ 42.6
Fair Value of Marketable Securities	Changes in the fair value of these investments are recorded in Other Expense, Net. March 31, December 31, Fair Value of Marketable Securities ($ millions) 2022 2021 2021 Money Market Funds $ 5.5 $ 5.6 $ 5.7 Total Marketable Securities $ 5.5 $ 5.6 $ 5.7
Components of Energy Supply Obligations	Energy Supply Obligations - March 31, December 31, Energy Supply Obligations ($ millions) 2022 2021 2021 Current: Exchange Gas Obligation $ 0.5 $ 1.0 $ 6.7 Renewable Energy Portfolio Standards 6.4 6.5 7.8 Power Supply Contract Divestitures — 0.2 — Total Energy Supply Obligations $ 6.9 $ 7.7 $ 14.5
Deferred Compensation Plan [Member]
Fair Value of Marketable Securities	Changes in the fair value of these investments are recorded in Other Expense, Net. March 31, December 31, Fair Value of Marketable Securities ($ millions) 2022 2021 2021 Equity Funds $ 0.4 $ 0.3 $ 0.2 Money Market Funds 0.4 0.3 0.4 Total Marketable Securities $ 0.8 $ 0.6 $ 0.6

DIVIDENDS DECLARED PER SHARE (T

DIVIDENDS DECLARED PER SHARE (Tables)	3 Months Ended
	Mar. 31, 2022
DIVIDENDS DECLARED PER SHARE [Abstract]
Schedule of Dividends Declared	Declaration Date Shareholder of Dividend 04/27/22 05/27/22 05/13/22 $ 0.39 01/26/22 02/25/22 02/11/22 $ 0.39 10/27/21 11/29/21 11/15/21 $ 0.38 07/28/21 08/27/21 08/13/21 $ 0.38 04/28/21 05/28/21 05/14/21 $ 0.38 01/27/21 02/26/21 02/12/21 $ 0.38

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2022
Significant Segment Financial Data	The following table provides segment financial data for the three months ended March 31, 2022 and March 31, 2021 : Electric Gas Non- Regulated Other Total Three Months Ended March 31, 2022 ($ millions) Revenues: Billed and Unbilled Revenue $ 84.7 $ 113.7 $ — $ — $ 198.4 Rate Adjustment Mechanism Revenue 4.5 (10.3 ) — — (5.8 ) Total Operating Revenues 89.2 103.4 — — 192.6 Segment Profit (Loss) 3.4 18.5 — (0.4 ) 21.5 Identifiable Segment Assets 598.2 932.6 — 21.5 1,552.3 Capital Expenditures 6.3 9.0 — 0.1 15.4 Three Months Ended March 31, 2021 ($ millions) Revenues: Billed and Unbilled Revenue $ 65.8 $ 93.2 $ — $ — $ 159.0 Rate Adjustment Mechanism Revenue (5.7 ) (14.5 ) — — (20.2 ) Total Operating Revenues 60.1 78.7 — — 138.8 Segment Profit (Loss) 2.9 16.4 — (0.4 ) 18.9 Identifiable Segment Assets 574.8 881.1 — 21.1 1,477.0 Capital Expenditures 9.5 4.3 — 0.3 14.1

DEBT AND FINANCING ARRANGEMEN_2

DEBT AND FINANCING ARRANGEMENTS (Tables)	3 Months Ended
	Mar. 31, 2022
Details on Long Term Debt	Details on long-term debt at March 31, 2022, March 31, 2021 and December 31, 2021 are shown in the following table: ($ millions) March 31, December 31, 2022 2021 2021 Unitil Corporation: 6.33% Senior Notes, Due May 1, 2022 $ — $ 9.0 $ — 3.70% Senior Notes, Due August 1, 2026 30.0 30.0 30.0 3.43% Senior Notes, Due December 18, 2029 30.0 30.0 30.0 Unitil Energy First Mortgage Bonds: 8.49% Senior Secured Notes, Due October 14, 2024 1.5 3.0 1.5 6.96% Senior Secured Notes, Due September 1, 2028 14.0 16.0 14.0 8.00% Senior Secured Notes, Due May 1, 2031 15.0 15.0 15.0 6.32% Senior Secured Notes, Due September 15, 2036 15.0 15.0 15.0 3.58% Senior Secured Notes, Due September 15, 2040 27.5 27.5 27.5 4.18% Senior Secured Notes, Due November 30, 2048 30.0 30.0 30.0 Fitchburg: 6.75% Senior Notes, Due November 30, 2023 — 1.9 — 6.79% Senior Notes, Due October 15, 2025 6.0 10.0 6.0 3.52% Senior Notes, Due November 1, 2027 10.0 10.0 10.0 7.37% Senior Notes, Due January 15, 2029 8.4 9.6 9.6 5.90% Senior Notes, Due December 15, 2030 15.0 15.0 15.0 7.98% Senior Notes, Due June 1, 2031 14.0 14.0 14.0 3.78% Senior Notes, Due September 15, 2040 27.5 27.5 27.5 4.32% Senior Notes, Due November 1, 2047 15.0 15.0 15.0 Northern Utilities: 3.52% Senior Notes, Due November 1, 2027 20.0 20.0 20.0 7.72% Senior Notes, Due December 3, 2038 50.0 50.0 50.0 3.78% Senior Notes, Due September 15, 2040 40.0 40.0 40.0 4.42% Senior Notes, Due October 15, 2044 50.0 50.0 50.0 4.32% Senior Notes, Due November 1, 2047 30.0 30.0 30.0 4.04% Senior Notes, Due September 12, 2049 40.0 40.0 40.0 Granite State: 3.72% Senior Notes, Due November 1, 2027 15.0 15.0 15.0 Unitil Realty Corp.: 2.64% Senior Secured Notes, Due December 18, 2030 4.4 4.7 4.5 Total Long-Term Debt 508.3 528.2 509.6 Less: Unamortized Debt Issuance Costs 3.5 3.9 3.6 Total Long-Term Debt, net of Unamortized Debt Issuance Costs 504.8 524.3 506.0 Less: Current Portion 8.2 8.5 8.2 Total Long-term Debt, Less Current Portion $ 496.6 $ 515.8 $ 497.8
Fair Value of Long Term Debt	($ millions) March 31, December 31, 2022 2021 2021 Estimated Fair Value of Long-Term Debt $ 524.8 $ 581.0 $ 584.9
Borrowing Limits Amounts Outstanding and Amounts Available under Credit Facility	The following table details the borrowing limits, amounts outstanding and amounts available under the Credit Facility as of March 31 2022, March 31, 2021 and December 31, 2021: Revolving Credit Facility ($ millions) March 31, December 31, 2022 2021 2021 Limit $ 120.0 $ 120.0 $ 120.0 Short-Term Borrowings Outstanding 64.0 37.3 64.1 Available $ 56.0 $ 82.7 $ 55.9
Classification of the Company Lease Obligations	The balance sheet classification of the Company’s lease obligations was as follows: March 31, December 31, Lease Obligations ($ millions) 2022 2021 2021 Operating Lease Obligations: Other Current Liabilities (current portion) $ 1.6 $ 1.6 $ 1.6 Other Noncurrent Liabilities (long-term portion) 3.2 3.8 3.1 Total Operating Lease Obligations $ 4.8 $ 5.4 $ 4.7 Capital Lease Obligations: Other Current Liabilities (current portion) $ 0.1 $ 0.2 $ 0.1 Other Noncurrent Liabilities (long-term portion) 0.2 0.3 0.2 Total Capital Lease Obligations $ 0.3 $ 0.5 $ 0.3 Total Lease Obligations $ 5.1 $ 5.9 $ 5.0 Cash paid for amounts included in the measurement of operating lease obligations for the three months ended March 31, 2022 and March 31, 2021 was $0.5 million and $0.5 million , respectively, and was included in Cash Provided by Operating Activities on the Consolidated Statements of Cash Flows.
Future Operating Lease Payment Obligations and Future Minimum Lease Payments under Capital Leases	The following table is a schedule of future operating lease payment obligations and future minimum lease payments under capital leases as of March 31, 2022. The payments for operating leases consist of $1.6 million of current operating lease obligations, which are included in Other Current Liabilities and $3.2 million of noncurrent operating lease obligations, which are included in Other Noncurrent Liabilities, on the Company’s Consolidated Balance Sheets as of March 31, 2022. The payments for capital leases consist of $0.1 million of current capital lease obligations, which are included in Other Current Liabilities and $0.2 million of noncurrent capital lease obligations, which are included in Other Noncurrent Liabilities, on the Company’s Consolidated Balance Sheets as of March 31, 2022. Lease Payments ($000’s) Year Ending December 31, Operating Capital Rest of 2022 $ 1,340 $ 111 2023 1,515 107 2024 1,186 52 2025 620 19 2026 316 — 2027-2031 121 — Total Payments 5,098 289 Less: Interest 297 10 Amount of Lease Obligations Recorded on Consolidated Balance Sheets $ 4,801 $ 279

COMMON STOCK AND PREFERRED ST_2

COMMON STOCK AND PREFERRED STOCK (Tables)	3 Months Ended
	Mar. 31, 2022
Table Text Block Supplement [Abstract]
Restricted Stock Units Issued	The equity portion of Restricted Stock Units activity during the three months ended March 31, 2022 in conjunction with the Stock Plan are presented in the following table: Restricted Stock Units (Equity Portion) Units Weighted Restricted Stock Units as of December 31, 2021 49,182 $ 41.67 Restricted Stock Units Granted — — Dividend Equivalents Earned 377 $ 50.90 Restricted Stock Units Settled — — Restricted Stock Units as of March 31, 2022 49,559 $ 41.74

ENVIRONMENTAL MATTERS (Tables)

ENVIRONMENTAL MATTERS (Tables)	3 Months Ended
	Mar. 31, 2022
Environmental Obligations Recognized by Company	The following table sets forth a summary of changes in the Company’s liability for Environmental Obligations for the three months ended March 31, 2022 and 2021. Environmental Obligations ($ millions) Three Months Ended March 31, 2022 2021 Total Balance at Beginning of Period $ 2.7 $ 2.1 Additions — 0.1 Less: Payments / Reductions — 0.1 Total Balance at End of Period 2.7 2.1 Less: Current Portion 0.5 0.3 Noncurrent Balance at End of Period $ 2.2 $ 1.8

INCOME TAXES (Tables)

INCOME TAXES (Tables)	3 Months Ended
	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Differences Between Provisions for Income Taxes and Provisions Calculated at Statutory Federal Tax Rate	The differences between the Company’s provisions for Income Taxes and the provisions calculated at the statutory federal tax rate, expressed in percentages, are shown in the following table: Three Months Ended March 31, 2022 2021 Statutory Federal Income Tax Rate 21 % 21 % Income Tax Effects of: State Income Taxes, net 6 6 Utility Plant Differences (1 ) (1 ) Other, net — — Effective Income Tax Rate 26 % 26 %

RETIREMENT BENEFIT OBLIGATIONS

RETIREMENT BENEFIT OBLIGATIONS (Tables)	3 Months Ended
	Mar. 31, 2022
Key Weighted Average Assumptions Used in Determining Benefit Plan Costs and Obligations	The following table includes the key weighted average assumptions used in determining the Company’s benefit plan costs and obligations: Used to Determine Plan Costs 2022 2021 Discount Rate 2.85 % 2.50 % Rate of Compensation Increase 3.00 % 3.00 % Expected Long-term rate of return on plan assets 7.50 % 7.50 % Health Care Cost Trend Rate Assumed for Next Year 6.20 % 6.60 % Ultimate Health Care Cost Trend Rate 4.50 % 4.50 % Year that Ultimate Health Care Cost Trend Rate is reached 2029 2029
Components of Retirement Plan Costs	The following table provides the components of the Company’s Retirement plan costs ($000’s): Pension Plan PBOP Plan SERP Three Months Ended March 31, 2022 2021 2022 2021 2022 2021 Service Cost $ 791 $ 868 $ 722 $ 758 $ 68 $ 89 Interest Cost 1,371 1,251 799 685 118 114 Expected Return on Plan Assets (2,720 ) (2,423 ) (854 ) (627 ) — — Prior Service Cost Amortization 89 75 273 302 14 14 Actuarial Loss Amortization 1,377 2,022 255 262 199 372 Sub-total 908 1,793 1,195 1,380 399 589 Amounts Capitalized and Deferred (156 ) (713 ) (511 ) (662 ) (118 ) (178 ) Net Periodic Benefit Cost Recognized $ 752 $ 1,080 $ 684 $ 718 $ 281 $ 411

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2022USD ($)Subsidiarymi	Dec. 31, 2021USD ($)	Mar. 31, 2021USD ($)
Significant Accounting Policies [Line Items]
Number of Subsidiaries | Entity | Subsidiary	3
Length Of Pipeline | mi	86
Cost of removal obligation	$ 109.8	$ 107.5	$ 102.5
Investments in trading securities	5.5	5.7	5.6
Allowance for doubtful accounts	3.4	3.3	4.4
Regulatory assets	153.3	156.3	152.7
Other Deferred Charges [Member]
Significant Accounting Policies [Line Items]
Regulatory assets	15.1	15.3	16.1
Unbilled Revenues [member]
Significant Accounting Policies [Line Items]
Allowance for doubtful accounts	0.1	0.2	0.1
Accounts Receivable [member]
Significant Accounting Policies [Line Items]
Allowance for doubtful accounts	$ 3.3	3.1	4.3
Utilities
Significant Accounting Policies [Line Items]
Number of Subsidiaries | Entity | Subsidiary	3
Unitil Service; Unitil Realty; and Unitil Resources
Significant Accounting Policies [Line Items]
Number of Subsidiaries | Entity | Subsidiary	3
Fitchburg Gas And Electric Light Company [Member] | Other Deferred Charges [Member] | Electric And Gas Division [Member]
Significant Accounting Policies [Line Items]
Hardship accounts in regulatory assets	$ 7.9	7.9	8
Environmental and Rate Case Costs and Other Expenditures | Recovered over the next seven years
Significant Accounting Policies [Line Items]
Regulatory assets	7.8
ISO-NE Obligations
Significant Accounting Policies [Line Items]
Cash Deposits	$ 2.9	2.7	2.2
Maximum
Significant Accounting Policies [Line Items]
Lease term	12 months
Deferred Compensation Plan [Member]
Significant Accounting Policies [Line Items]
Investments in trading securities	$ 0.8	$ 0.6	$ 0.6

Components of Gas and Electric

Components of Gas and Electric Operating Revenue (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	$ 192.6	$ 138.8
Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	198.4	159
Rate Adjustment Mechanism Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	(5.8)	(20.2)
Electric
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	89.2	60.1
Electric | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	84.7	65.8
Electric | Rate Adjustment Mechanism Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	4.5	(5.7)
Gas Segment
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	103.4	78.7
Gas Segment | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	113.7	93.2
Gas Segment | Rate Adjustment Mechanism Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	(10.3)	(14.5)
Residential | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	95	75.8
Residential | Electric | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	49.4	38.1
Residential | Gas Segment | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	45.6	37.7
Commercial & Industrial | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	95.6	76
Commercial & Industrial | Electric | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	31	25.9
Commercial & Industrial | Gas Segment | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	64.6	50.1
Other | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	7.8	7.2
Other | Electric | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	4.3	1.8
Other | Gas Segment | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	$ 3.5	$ 5.4

Allowance for Doubtful Accounts

Allowance for Doubtful Accounts Included in Accounts Receivable Net (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Allowance for Doubtful Accounts Included in Accounts Receivable Net Detail [Abstract]
Allowance for Doubtful Accounts	$ 3.4	$ 3.3	$ 4.4

Components of Accrued Revenue (

Components of Accrued Revenue (Detail) - USD ($) $ in Millions		Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Deferred Revenue Arrangement [Line Items]
Regulatory Assets – Current	[1]	$ 45.2	$ 47.4	$ 24
Total Accrued Revenue		56.3	61.2	34.7
Unbilled Revenues
Deferred Revenue Arrangement [Line Items]
Regulatory Assets – Current		11.1	13.8	10.7
Regulatory Assets
Deferred Revenue Arrangement [Line Items]
Regulatory Assets – Current		$ 45.2	$ 47.4	$ 24
[1]	Reflects amounts included in the Accrued Revenue on the Company’s Consolidated Balance Sheets.

Components of Exchange Gas Rece

Components of Exchange Gas Receivable (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Receivables [Line Items]
Total Exchange Gas Receivable	$ 0.7	$ 7.4	$ 1.2
Northern Utilities Inc
Receivables [Line Items]
Total Exchange Gas Receivable	0.5	6.7	1
Fitchburg
Receivables [Line Items]
Total Exchange Gas Receivable	$ 0.2	$ 0.7	$ 0.2

Components of Gas Inventory (De

Components of Gas Inventory (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Public Utilities, Inventory [Line Items]
Weighted average cost inventory amount	$ 0.5	$ 1	$ 0.4
Liquefied Natural Gas & Other
Public Utilities, Inventory [Line Items]
Weighted average cost inventory amount	0.1	0.1	0.1
Natural Gas
Public Utilities, Inventory [Line Items]
Weighted average cost inventory amount		0.5
Propane
Public Utilities, Inventory [Line Items]
Weighted average cost inventory amount	$ 0.4	$ 0.4	$ 0.3

Regulatory Assets (Detail)

Regulatory Assets (Detail) - USD ($) $ in Millions		Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Regulatory Assets [Line Items]
Regulatory Assets		$ 153.3	$ 156.3	$ 152.7
Less: Current Portion of Regulatory Assets	[1]	45.2	47.4	24
Regulatory Assets – noncurrent		108.1	108.9	128.7
Environmental Matters
Regulatory Assets [Line Items]
Regulatory Assets		4.5	4.6	5
Other Deferred Charges
Regulatory Assets [Line Items]
Regulatory Assets		15.1	15.3	16.1
Retirement Benefits
Regulatory Assets [Line Items]
Regulatory Assets		86.5	86.4	104.5
Deferred Storm Charges
Regulatory Assets [Line Items]
Regulatory Assets		2.9	3.3	3.7
Income Taxes
Regulatory Assets [Line Items]
Regulatory Assets		2.4	2.6	3.2
Energy Supply and Other Rate Adjustment Mechanisms
Regulatory Assets [Line Items]
Regulatory Assets		$ 41.9	$ 44.1	$ 20.2
[1]	Reflects amounts included in the Accrued Revenue on the Company’s Consolidated Balance Sheets.

Regulatory Liabilities (Detail)

Regulatory Liabilities (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Regulatory Liabilities [Line Items]
Regulatory Liabilities	$ 57.7	$ 52.1	$ 58.2
Less: Current Portion of Regulatory Liabilities	15.6	9.5	14.7
Regulatory Liabilities – noncurrent	42.1	42.6	43.5
Income Taxes
Regulatory Liabilities [Line Items]
Regulatory Liabilities	43.9	44.3	45.1
Rate Adjustment Mechanisms
Regulatory Liabilities [Line Items]
Regulatory Liabilities	13.8	7.7	12.9
Other
Regulatory Liabilities [Line Items]
Regulatory Liabilities	$ 0	$ 0.1	$ 0.2

Fair Value of Marketable Securi

Fair Value of Marketable Securities (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities	$ 5.5	$ 5.7	$ 5.6
Deferred Compensation Plan [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities	0.8	0.6	0.6
Fair Value, Inputs, Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities	5.5	5.7	5.6
Fair Value, Inputs, Level 1 | Deferred Compensation Plan [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities	0.8	0.6	0.6
Fair Value, Inputs, Level 1 | Equity Funds | Deferred Compensation Plan [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities	0.4	0.2	0.3
Fair Value, Inputs, Level 1 | Money Market Funds
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities	5.5	5.7	5.6
Fair Value, Inputs, Level 1 | Money Market Funds | Deferred Compensation Plan [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities	$ 0.4	$ 0.4	$ 0.3

Components of Energy Supply Obl

Components of Energy Supply Obligations (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Contractual Obligation [Line Items]
Energy Supply Obligations-Current	$ 6.9	$ 14.5	$ 7.7
Exchange Gas Obligation
Contractual Obligation [Line Items]
Energy Supply Obligations-Current	0.5	6.7	1
Renewable Energy Portfolio Standards
Contractual Obligation [Line Items]
Energy Supply Obligations-Current	6.4	$ 7.8	6.5
Power Supply Contract Divestitures
Contractual Obligation [Line Items]
Energy Supply Obligations-Current	$ 0		$ 0.2

Dividends Declared Per Share (D

Dividends Declared Per Share (Detail) - $ / shares	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Dividends Payable [Line Items]
Dividend Amount	$ 0.39	$ 0.38
Group One
Dividends Payable [Line Items]
Declaration Date	Apr. 27, 2022
Date Paid (Payable)	May 27, 2022
Shareholder of Record Date	May 13, 2022
Dividend Amount	$ 0.39
Group Two
Dividends Payable [Line Items]
Declaration Date	Jan. 26, 2022
Date Paid (Payable)	Feb. 25, 2022
Shareholder of Record Date	Feb. 11, 2022
Dividend Amount	$ 0.39
Group Three
Dividends Payable [Line Items]
Declaration Date	Oct. 27, 2021
Date Paid (Payable)	Nov. 29, 2021
Shareholder of Record Date	Nov. 15, 2021
Dividend Amount	$ 0.38
Group Four
Dividends Payable [Line Items]
Declaration Date	Jul. 28, 2021
Date Paid (Payable)	Aug. 27, 2021
Shareholder of Record Date	Aug. 13, 2021
Dividend Amount	$ 0.38
Group Five
Dividends Payable [Line Items]
Declaration Date	Apr. 28, 2021
Date Paid (Payable)	May 28, 2021
Shareholder of Record Date	May 14, 2021
Dividend Amount	$ 0.38
Group Six
Dividends Payable [Line Items]
Declaration Date	Jan. 27, 2021
Date Paid (Payable)	Feb. 26, 2021
Shareholder of Record Date	Feb. 12, 2021
Dividend Amount	$ 0.38

Significant Segment Financial D

Significant Segment Financial Data (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	$ 192.6	$ 138.8
Segment Profit (Loss)	21.5	18.9
Identifiable Segment Assets	1,552.3	1,477	$ 1,540.3
Capital Expenditures	15.4	14.1
Billed and Unbilled Revenue
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	198.4	159
Rate Adjustment Mechanism Revenue
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	(5.8)	(20.2)
Gas Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	103.4	78.7
Segment Profit (Loss)	18.5	16.4
Identifiable Segment Assets	932.6	881.1
Capital Expenditures	9	4.3
Gas Segment | Billed and Unbilled Revenue
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	113.7	93.2
Gas Segment | Rate Adjustment Mechanism Revenue
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	(10.3)	(14.5)
Electric
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	89.2	60.1
Segment Profit (Loss)	3.4	2.9
Identifiable Segment Assets	598.2	574.8
Capital Expenditures	6.3	9.5
Electric | Billed and Unbilled Revenue
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	84.7	65.8
Electric | Rate Adjustment Mechanism Revenue
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	4.5	(5.7)
All Other Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Segment Profit (Loss)	(0.4)	(0.4)
Identifiable Segment Assets	21.5	21.1
Capital Expenditures	$ 0.1	0.3
Non- Regulated Operation
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Identifiable Segment Assets		$ 0

Details on Long Term Debt (Deta

Details on Long Term Debt (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Debt Instrument [Line Items]
Total Long-Term Debt	$ 508.3	$ 509.6	$ 528.2
Less: Unamortized Debt Issuance Costs	3.5	3.6	3.9
Long-Term Debt	504.8	506	524.3
Less: Current Portion	8.2	8.2	8.5
Total Long-Term Debt, Less Current Portion	496.6	497.8	515.8
6.33% Senior Notes, Due May 1, 2022
Debt Instrument [Line Items]
Total Long-Term Debt	0	0	9
3.70% Senior Notes, Due August 1, 2026
Debt Instrument [Line Items]
Total Long-Term Debt	30	30	30
3.43% Senior Notes, Due December 18, 2029
Debt Instrument [Line Items]
Total Long-Term Debt	30	30	30
Unitil Energy Systems Inc | First Mortgage Bonds 8.49% Senior Secured Notes, Due October 14, 2024
Debt Instrument [Line Items]
Total Long-Term Debt	1.5	1.5	3
Unitil Energy Systems Inc | First Mortgage Bonds 6.96% Senior Secured Notes, Due September 1, 2028
Debt Instrument [Line Items]
Total Long-Term Debt	14	14	16
Unitil Energy Systems Inc | First Mortgage Bonds 8.00% Senior Secured Notes, Due May 1, 2031
Debt Instrument [Line Items]
Total Long-Term Debt	15	15	15
Unitil Energy Systems Inc | First Mortgage Bonds 6.32% Senior Secured Notes, Due September 15, 2036
Debt Instrument [Line Items]
Total Long-Term Debt	15	15	15
Unitil Energy Systems Inc | First Mortgage Bonds 4.18% Senior Secured Notes Due November 30, 2048
Debt Instrument [Line Items]
Total Long-Term Debt	30	30	30
Unitil Energy Systems Inc | 3.58% Senior Secured Notes, Due September 15, 2040
Debt Instrument [Line Items]
Total Long-Term Debt	27.5	27.5	27.5
Fitchburg Gas and Electric Light Company | 6.75% Senior Notes, Due November 30, 2023
Debt Instrument [Line Items]
Total Long-Term Debt	0	0	1.9
Fitchburg Gas and Electric Light Company | 6.79% Senior Notes, Due October 15, 2025
Debt Instrument [Line Items]
Total Long-Term Debt	6	6	10
Fitchburg Gas and Electric Light Company | 3.52% Senior Notes, Due November 1, 2027
Debt Instrument [Line Items]
Total Long-Term Debt	10	10	10
Fitchburg Gas and Electric Light Company | 7.37% Notes, Due January 15, 2029
Debt Instrument [Line Items]
Total Long-Term Debt	8.4	9.6	9.6
Fitchburg Gas and Electric Light Company | 5.90% Notes, Due December 15, 2030
Debt Instrument [Line Items]
Total Long-Term Debt	15	15	15
Fitchburg Gas and Electric Light Company | 7.98% Notes, Due June 1, 2031
Debt Instrument [Line Items]
Total Long-Term Debt	14	14	14
Fitchburg Gas and Electric Light Company | 4.32% Senior Notes, Due November 1, 2047
Debt Instrument [Line Items]
Total Long-Term Debt	15	15	15
Fitchburg Gas and Electric Light Company | 3.78% Senior Notes, Due September 15, 2040
Debt Instrument [Line Items]
Total Long-Term Debt	27.5	27.5	27.5
Northern Utilities Inc | 3.52% Senior Notes, Due November 1, 2027
Debt Instrument [Line Items]
Total Long-Term Debt	20	20	20
Northern Utilities Inc | 4.32% Senior Notes, Due November 1, 2047
Debt Instrument [Line Items]
Total Long-Term Debt	30	30	30
Northern Utilities Inc | 7.72% Senior Notes, Due December 3, 2038
Debt Instrument [Line Items]
Total Long-Term Debt	50	50	50
Northern Utilities Inc | 4.42% Senior Notes, Due October 15, 2044
Debt Instrument [Line Items]
Total Long-Term Debt	50	50	50
Northern Utilities Inc | 4.04% Senior Notes, Due September 12, 2049
Debt Instrument [Line Items]
Total Long-Term Debt	40	40	40
Northern Utilities Inc | 3.78% Senior Notes, Due September 15, 2040
Debt Instrument [Line Items]
Total Long-Term Debt	40	40	40
Granite State Gas Transmission Inc | 3.72% Senior Notes, Due November 1, 2027
Debt Instrument [Line Items]
Total Long-Term Debt	15	15	15
Unitil Realty Corp [Member] | 2.64% Senior Secured Notes, Due December 18, 2030
Debt Instrument [Line Items]
Total Long-Term Debt	$ 4.4	$ 4.5	$ 4.7

Details on Long Term Debt (Pare

Details on Long Term Debt (Parenthetical) (Detail)	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Debt Instrument [Line Items]
Stated interest rate	6.33%	6.33%	6.33%
Debt instrument due date	May 1, 2022	May 1, 2022	May 1, 2022
3.70% Senior Notes, Due August 1, 2026
Debt Instrument [Line Items]
Stated interest rate	3.70%	3.70%	3.70%
Debt instrument due date	Aug. 1, 2026	Aug. 1, 2026	Aug. 1, 2026
3.43% Senior Notes, Due December 18, 2029
Debt Instrument [Line Items]
Stated interest rate	3.43%	3.43%	3.43%
Debt instrument due date	Dec. 18, 2029	Dec. 18, 2029	Dec. 18, 2029
First Mortgage Bonds 8.49% Senior Secured Notes, Due October 14, 2024
Debt Instrument [Line Items]
Stated interest rate	8.49%	8.49%	8.49%
Debt instrument due date	Oct. 14, 2024	Oct. 14, 2024	Oct. 14, 2024
First Mortgage Bonds 6.96% Senior Secured Notes, Due September 1, 2028
Debt Instrument [Line Items]
Stated interest rate	6.96%	6.96%	6.96%
Debt instrument due date	Sep. 1, 2028	Sep. 1, 2028	Sep. 1, 2028
First Mortgage Bonds 8.00% Senior Secured Notes, Due May 1, 2031
Debt Instrument [Line Items]
Stated interest rate	8.00%	8.00%	8.00%
Debt instrument due date	May 1, 2031	May 1, 2031	May 1, 2031
First Mortgage Bonds 6.32% Senior Secured Notes, Due September 15, 2036
Debt Instrument [Line Items]
Stated interest rate	6.32%	6.32%	6.32%
Debt instrument due date	Sep. 15, 2036	Sep. 15, 2036	Sep. 15, 2036
3.58% Senior Secured Notes, Due September 15, 2040
Debt Instrument [Line Items]
Stated interest rate	3.58%	3.58%	3.58%
Debt instrument due date	Sep. 15, 2040	Sep. 15, 2040	Sep. 15, 2040
First Mortgage Bonds 4.18% Senior Secured Notes Due November 30, 2048
Debt Instrument [Line Items]
Stated interest rate	4.18%	4.18%	4.18%
Debt instrument due date	Nov. 30, 2048	Nov. 30, 2048	Nov. 30, 2048
6.75% Senior Notes, Due November 30, 2023
Debt Instrument [Line Items]
Stated interest rate	6.75%	6.75%	6.75%
Debt instrument due date	Nov. 30, 2023	Nov. 30, 2023	Nov. 30, 2023
6.79% Senior Notes, Due October 15, 2025
Debt Instrument [Line Items]
Stated interest rate	6.79%	6.79%	6.79%
Debt instrument due date	Oct. 15, 2025	Oct. 15, 2025	Oct. 15, 2025
3.52% Senior Notes, Due November 1, 2027
Debt Instrument [Line Items]
Stated interest rate	3.52%	3.52%	3.52%
Debt instrument due date	Nov. 1, 2027	Nov. 1, 2027	Nov. 1, 2027
7.37% Notes, Due January 15, 2029
Debt Instrument [Line Items]
Stated interest rate	7.37%	7.37%	7.37%
Debt instrument due date	Jan. 15, 2029	Jan. 15, 2029	Jan. 15, 2029
5.90% Notes, Due December 15, 2030
Debt Instrument [Line Items]
Stated interest rate	5.90%	5.90%	5.90%
Debt instrument due date	Dec. 15, 2030	Dec. 15, 2030	Dec. 15, 2030
7.98% Notes, Due June 1, 2031
Debt Instrument [Line Items]
Stated interest rate	7.98%	7.98%	7.98%
Debt instrument due date	Jun. 1, 2031	Jun. 1, 2031	Jun. 1, 2031
3.78% Senior Notes, Due September 15, 2040
Debt Instrument [Line Items]
Stated interest rate	3.78%	3.78%	3.78%
Debt instrument due date	Sep. 15, 2040	Sep. 15, 2040	Sep. 15, 2040
4.32% Senior Notes, Due November 1, 2047
Debt Instrument [Line Items]
Stated interest rate	4.32%	4.32%	4.32%
Debt instrument due date	Nov. 1, 2047	Nov. 1, 2047	Nov. 1, 2047
7.72% Senior Notes, Due December 3, 2038
Debt Instrument [Line Items]
Stated interest rate	7.72%	7.72%	7.72%
Debt instrument due date	Dec. 3, 2038	Dec. 3, 2038	Dec. 3, 2038
4.42% Senior Notes, Due October 15, 2044
Debt Instrument [Line Items]
Stated interest rate	4.42%	4.42%	4.42%
Debt instrument due date	Oct. 15, 2044	Oct. 15, 2044	Oct. 15, 2044
4.04% Senior Notes, Due September 12, 2049
Debt Instrument [Line Items]
Stated interest rate	4.04%	4.04%	4.04%
Debt instrument due date	Sep. 12, 2049	Sep. 12, 2049	Sep. 12, 2049
3.72% Senior Notes, Due November 1, 2027
Debt Instrument [Line Items]
Stated interest rate	3.72%	3.72%	3.72%
Debt instrument due date	Nov. 1, 2027	Nov. 1, 2027	Nov. 1, 2027
2.64% Senior Secured Notes, Due December 18, 2030
Debt Instrument [Line Items]
Stated interest rate	2.64%	2.64%	2.64%
Debt instrument due date	Dec. 18, 2030	Dec. 18, 2030	Dec. 18, 2030

Estimated Fair Value of Long Te

Estimated Fair Value of Long Term Debt (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Estimated Fair Value of Long-Term Debt	$ 524.8	$ 584.9	$ 581

Debt and Financing Arrangemen_3

Debt and Financing Arrangements - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended
	Jul. 25, 2018	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Line of Credit Facility [Line Items]
Weighted average interest rate on short term borrowings		1.40%	1.30%	1.20%
Capital lease obligation, current		$ 100,000
Capital lease obligation, noncurrent		200,000
Accounts Payable		39,000,000	$ 28,700,000	$ 52,400,000
Total rental expense under operating leases		500,000	500,000
Net Utility Plant		1,259,900,000	1,192,300,000	1,257,200,000
Guarantee outstanding		700,000
Operating lease obligations		500,000	$ 500,000
Other current operating lease obligation		1,600,000
Other noncurrent operating lease obligation		$ 3,200,000
Operating lease, weighted average remaining lease term		3 years 6 months	3 years 9 months 18 days
Operating lease, weighted average discount rate percentage		3.70%	4.20%
Guarantee Term Period		1 year
Assets under Capital Leases [Member]
Line of Credit Facility [Line Items]
Net Utility Plant		$ 600,000	$ 900,000	700,000
Net Utility Plant, accumulated amortization		$ 300,000	400,000	300,000
Northern Utilities Inc
Line of Credit Facility [Line Items]
Total funded indebtedness as percentage of capitalization		65.00%
Natural gas storage inventory		$ 2,000,000	1,500,000	8,300,000
Accounts Payable		1,500,000	500,000	1,600,000
Revolving Credit Facility
Line of Credit Facility [Line Items]
Revolving credit facility		120,000,000	$ 120,000,000	$ 120,000,000
Proceeds from lines of credit		96,800,000
Repayments of lines of credit		$ 96,900,000
Credit Facility | Second Amended Credit Facility
Line of Credit Facility [Line Items]
Revolving credit facility	$ 120,000,000
Sublimit for the issuance of standby letters of credit	$ 25,000,000
Credit Facility | Second Amended Credit Facility | London Interbank Offered Rate
Line of Credit Facility [Line Items]
Credit facility, daily fluctuating rate of interest	1.125%

Borrowing Limits Amounts Outsta

Borrowing Limits Amounts Outstanding and Amounts Available under Revolving Credit Facility (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Debt Instrument [Line Items]
Short-Term Borrowings Outstanding	$ 64	$ 64.1	$ 37.3
Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit facility, limit	120	120	120
Short-Term Borrowings Outstanding	64	64.1	37.3
Available revolving credit facility	$ 56	$ 55.9	$ 82.7

Debt and Financing Arrangemen_4

Debt and Financing Arrangements - Classification of the Company Lease Obligations (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Operating Lease Obligations:
Other Current Liabilities (current portion)	$ 1,600
Other Noncurrent Liabilities (long-term portion)	3,200
Capital Lease Obligations:
Other Current Liabilities (current portion)	100
Other Noncurrent Liabilities (long-term portion)	200
Lease Obligations [Member]
Operating Lease Obligations:
Other Current Liabilities (current portion)	1,600	$ 1,600	$ 1,600
Other Noncurrent Liabilities (long-term portion)	3,200	3,100	3,800
Total Operating Lease Obligations	4,801	4,700	5,400
Capital Lease Obligations:
Other Current Liabilities (current portion)	100	100	200
Other Noncurrent Liabilities (long-term portion)	200	200	300
Total Capital Lease Obligations	300	300	500
Total Lease Obligations	$ 5,100	$ 5,000	$ 5,900

Future Operating Lease Payment

Future Operating Lease Payment Obligations and Future Minimum Lease Payments under Capital Leases (Detail) - Lease Obligations [Member] - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Operating leases
Rest of 2022	$ 1,340
2023	1,515
2024	1,186
2025	620
2026	316
2027-2031	121
Total Payments	5,098
Less: Interest	297
Amount of Lease Obligations Recorded on Consolidated Balance Sheets	4,801	$ 4,700	$ 5,400
Capital lease
Rest of 2022	111
2023	107
2024	52
2025	19
2026	0
2027-2031	0
Total Payments	289
Less: Interest	10
Amount of Lease Obligations Recorded on Consolidated Balance Sheets	$ 279

Common Stock And Preferred St_3

Common Stock And Preferred Stock - Additional Information (Detail) - USD ($)	Jan. 25, 2022	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Class of Stock [Line Items]
Common stock, shares outstanding		16,020,047	15,041,629	15,977,766
Common stock, shares issued		5,511	6,179
Proceeds from Issuance of Common Stock		$ 300,000	$ 300,000
Restricted Stock Units Granted		$ 47.44	$ 49.44
Share based compensation expense		$ 1,700,000	$ 900,000
Percentage of fully-vested restricted stock units that directors will receive in common shares when settled		70.00%
Fair value of liabilities associated with fully vested RSUs that will be settled in cash		$ 1,100,000	900,000	$ 1,000,000
Percentage of fully-vested restricted stock units that directors will receive in cash when settled		30.00%
Preferred Stock		$ 200,000	200,000	$ 200,000
Maximum
Class of Stock [Line Items]
Dividend declared		$ 100,000	$ 100,000
Restricted Stock
Class of Stock [Line Items]
Restricted stock vesting period		4 years
Restricted stock non-vested		73,178	62,566
Unrecognized share based compensation		$ 1,100,000
Share compensation recognition period		3 years 2 months 12 days
Restricted Stock Units Granted	36,770
Aggregate Market Value	$ 1,700,000
Forfeitures under the stock plan		0
Cancellations under the stock plan		0
Restricted Stock | Maximum
Class of Stock [Line Items]
Restricted stock available for awards		677,500
Restricted stock that may be awarded in any one calendar year to any one participant		20,000
Restricted Stock | Vesting Annually
Class of Stock [Line Items]
Restricted stock vesting percentage annually		25.00%
Restricted Stock Units (RSUs)
Class of Stock [Line Items]
Restricted Stock Units Granted		0
Restricted stock units outstanding			43,584
Weighted-Average Stock Price			$ 41.34
Series 6 | Unitil Energy Systems Inc
Class of Stock [Line Items]
Preferred stock, outstanding		1,861	1,887	1,861
Preferred Stock		$ 200,000	$ 200,000	$ 200,000
Dividend rate		6.00%	6.00%	6.00%
Dividend and Distribution Reinvestment and Share Purchase Plan
Class of Stock [Line Items]
Proceeds from Issuance of Common Stock		$ 268,600
Dividend and Distribution Reinvestment and Share Purchase Plan | Average
Class of Stock [Line Items]
Common stock price per share		$ 48.75
Dividend and Distribution Reinvestment and Share Purchase Plan | Common Stock
Class of Stock [Line Items]
Common stock, shares issued		5,511

Restricted Stock Units Issued (

Restricted Stock Units Issued (Detail) - Restricted Stock Units (RSUs)	3 Months Ended
	Mar. 31, 2022$ / sharesshares
Restricted Stock Units
Beginning Restricted Stock Units | shares	49,182
Restricted Stock Units Granted | shares	0
Dividend Equivalents Earned | shares	377
Restricted Stock Units Settled | shares	0
Ending Restricted Stock Units | shares	49,559
Weighted-Average Stock Price
Beginning Restricted Stock Units | $ / shares	$ 41.67
Restricted Stock Units Granted | $ / shares	0
Dividend Equivalents Earned | $ / shares	50.90
Restricted Stock Units Settled | $ / shares	0
Ending Restricted Stock Units | $ / shares	$ 41.74

Regulatory Matters - Additional

Regulatory Matters - Additional Information (Detail)

Jan. 31, 2022USD ($)

Oct. 01, 2021USD ($)

Aug. 24, 2021USD ($)

Aug. 02, 2021USD ($)

May 27, 2021USD ($)

May 01, 2021USD ($)

Apr. 02, 2021USD ($)

Mar. 01, 2021USD ($)

Nov. 30, 2020USD ($)

Mar. 26, 2020USD ($)

Feb. 28, 2020USD ($)

Mar. 31, 2020USD ($)

Mar. 31, 2022USD ($)

Mar. 31, 2021

Dec. 31, 2020

Dec. 31, 2017

Jun. 30, 2027MW

Dec. 31, 2022MW

Mar. 10, 2021MW

Nov. 05, 2020

May 31, 2019MW

Aug. 09, 2018MW

Jul. 31, 2018MWBcf

Jun. 30, 2017MW

Regulatory Assets [Line Items]

Corporate income tax rate

21.00%

21.00%

Approved annual increase in rates

$ 3,600,000

$ 4,600,000

$ 3,700,000

Increase in annual base rate

3.60%

Requested annual increase in rates

$ 1,500,000

Tax Year 2018

Regulatory Assets [Line Items]

Corporate income tax rate

21.00%

21.00%

21.00%

Other Restructuring

Regulatory Assets [Line Items]

Cost recovery period, years

2 years

Offshore Wind Energy

Regulatory Assets [Line Items]

Power generation facility | MW

1,600

Northern Utilities Inc

Regulatory Assets [Line Items]

Approved annual increase in rates

$ 4,500,000

$ 12,000,000

Increase in annual base rate

4.40%

Northern Utilities Inc | ME

Regulatory Assets [Line Items]

Percentage of approved return on equity

9.48%

Percentage of approved return on equity, reflecting on equity

50.00%

Percentage of approved return on equity, reflecting on debt

50.00%

Northern Utilities Inc | New Hampshire

Regulatory Assets [Line Items]

Approved annual increase in rates

$ 2,600,000

Requested annual increase in rates

$ 7,800,000

Requested annual increase in rates Percent

8.10%

Fitchburg Gas and Electric Light Company

Regulatory Assets [Line Items]

Percentage of approved return on equity

9.70%

Percentage of approved return on equity, reflecting on equity

52.45%

Percentage of approved return on equity, reflecting on debt

47.55%

Revenue impact threshold

$ 100,000

Fitchburg Gas and Electric Light Company | Offshore Wind Energy

Regulatory Assets [Line Items]

Power generation facility | Bcf

400

Remuneration Percentage

2.75%

2.75%

2.75%

Fitchburg Gas and Electric Light Company | Offshore Wind Energy | First Solicitation [Member]

Regulatory Assets [Line Items]

Power generation facility | MW

1,600

Fitchburg Gas and Electric Light Company | Offshore Wind Energy | Second Solicitation [Member]

Regulatory Assets [Line Items]

Power generation facility | MW

1,600

1,600

800

Fitchburg Gas and Electric Light Company | Offshore Wind Energy | Second Rate Step Adjustments

Regulatory Assets [Line Items]

Power generation facility | MW

800

Fitchburg Gas and Electric Light Company | Qualified Clean Energy

Regulatory Assets [Line Items]

Power generation capacity | MW

9,554,940

Fitchburg Gas and Electric Light Company | Minimum [Member] | Offshore Wind Energy

Regulatory Assets [Line Items]

Power generation facility | MW

400

Fitchburg Gas and Electric Light Company | Scenario Forecast

Regulatory Assets [Line Items]

Power generation capacity | MW

9,450,000

Fitchburg Gas Company

Regulatory Assets [Line Items]

Percentage of approved return on equity

9.70%

Percentage of approved return on equity, reflecting on equity

52.45%

Percentage of approved return on equity, reflecting on debt

47.55%

Regulatory assets approved increase in revenue due to be recovered

$ 2,200,000

Approved annual increase in rates

$ 1,100,000

$ 900,000

Approved annual increase in rates

$ 900,000

Apporved annual decrease in rates

200,000

Revenue impact threshold

$ 40,000

Granite State

Regulatory Assets [Line Items]

Increase (decrease) in annual revenue

$ 100,000

$ 1,300,000

Spending cap

$ 14,600,000

Environmental Matters - Additio

Environmental Matters - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2022USD ($)
Environmental Restoration Costs
Site Contingency [Line Items]
Estimated Costs Accrued For Remediation	$ 0.8
Maine | Environmental Restoration Costs
Site Contingency [Line Items]
Amortization period for environmental costs	5 years
New Hampshire
Site Contingency [Line Items]
Amortization period for environmental costs	7 years

Company's Liability for Environ

Company's Liability for Environmental Obligations (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Environmental Exit Cost [Line Items]
Total Balance at Beginning of Period	$ 2.7	$ 2.1
Additions	0	0.1
Less: Payments / Reductions	0	0.1
Total Balance at End of Period	2.7	2.1
Less: Current Portion	0.5	0.3	$ 0.5
Noncurrent Balance at End of Period	$ 2.2	$ 1.8	$ 2.2

Differences Between Provisions

Differences Between Provisions for Income Taxes and Provisions Calculated at Statutory Federal Tax Rate (Detail)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Income Tax Examination [Line Items]
Statutory Federal Income Tax Rate	21.00%	21.00%
State Income Taxes, net	6.00%	6.00%
Utility Plant Differences	(1.00%)	(1.00%)
Other, net	0.00%
Effective Income Tax Rate	26.00%	26.00%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		12 Months Ended
	Dec. 31, 2020	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2017
Income Taxes [Line Items]
Corporate federal income tax		21.00%	21.00%
Regulatory liability, expected flow back to customers					$ 47.1
Regulatory liability, expected pass back to ratepayers				$ 0.7
Net Operating Loss Carryforwards Utilized For Income Taxes					$ 7.7
Deferred tax assets, operating loss carryforwards, federal				$ 3.6
Percentage of employment retention credit		50.00%
Employment retention duties capacity		100.00%
Consolidated Appropriations Act 2021 [Member]
Income Taxes [Line Items]
Percentage of employment retention credit	70.00%
Employment retention duties capacity	100.00%
Minimum
Income Taxes [Line Items]
Average Rate Assumption Method estimated flow back period		15 years
Maximum
Income Taxes [Line Items]
Average Rate Assumption Method estimated flow back period		20 years
Gas Ratepayers | Massachusetts And Maine [Member]
Income Taxes [Line Items]
Regulatory liability, expected flow back to customers		$ 3.6
Tax Year 2018
Income Taxes [Line Items]
Corporate federal income tax		21.00%			21.00%	21.00%

Key Weighted Average Assumption

Key Weighted Average Assumptions Used in Determining Benefit Plan Costs and Obligations (Detail) - Benefit Plan Costs	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Discount Rate	2.85%	2.50%
Rate of Compensation Increase	3.00%	3.00%
Expected Long-term rate of return on plan assets	7.50%	7.50%
Health Care Cost Trend Rate Assumed for Next Year	6.20%	6.60%
Ultimate Health Care Cost Trend Rate	4.50%	4.50%
Year that Ultimate Health Care Cost Trend Rate is reached	2029	2029

Components of Retirement Plan C

Components of Retirement Plan Costs (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service Cost	$ 791	$ 868
Interest Cost	1,371	1,251
Expected Return on Plan Assets	(2,720)	(2,423)
Prior Service Cost Amortization	89	75
Actuarial Loss Amortization	1,377	2,022
Sub-total	908	1,793
Amounts Capitalized and Deferred	(156)	(713)
Net Periodic Benefit Cost Recognized	752	1,080
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Service Cost	722	758
Interest Cost	799	685
Expected Return on Plan Assets	(854)	(627)
Prior Service Cost Amortization	273	302
Actuarial Loss Amortization	255	262
Sub-total	1,195	1,380
Amounts Capitalized and Deferred	(511)	(662)
Net Periodic Benefit Cost Recognized	684	718
Supplemental Employee Retirement Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Service Cost	68	89
Interest Cost	118	114
Prior Service Cost Amortization	14	14
Actuarial Loss Amortization	199	372
Sub-total	399	589
Amounts Capitalized and Deferred	(118)	(178)
Net Periodic Benefit Cost Recognized	$ 281	$ 411

Retirement Benefit Obligation_2

Retirement Benefit Obligations - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2022USD ($)
Defined Benefit Plan Disclosure [Line Items]
Company's contributions	$ 0
Supplemental Employee Retirement Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Benefit payments under SERP Plan	0.2
Expected additional benefit payments for the remainder of 2020	$ 0.4