Unitil (UTL) 10-Q 25 Apr 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	Apr. 22, 2019
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Trading Symbol	UTL
Entity Registrant Name	UNITIL CORP
Entity Central Index Key	0000755001
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		14,916,405

CONSOLIDATED STATEMENTS OF EARN

CONSOLIDATED STATEMENTS OF EARNINGS - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating Revenues
Total Operating Revenues	$ 152.1	$ 145.8
Operating Expenses
Operation and Maintenance	18.5	17.3
Depreciation and Amortization	13.8	12.3
Taxes Other than Income Taxes	6.4	5.8
Total Operating Expenses	123.3	117.7
Operating Income	28.8	28.1
Interest Expense, Net	6.2	6
Other (Income) Expense, Net	(12.1)	1.7
Income Before Income Taxes	34.7	20.4
Provision For Income Taxes	8.2	4.8
Net Income	$ 26.5	$ 15.6
Net Income Per Common Share (Basic and Diluted)	$ 1.78	$ 1.06
Weighted Average Common Shares Outstanding - (Basic and Diluted)	14.9	14.8
Gas
Operating Revenues
Total Operating Revenues	$ 86.4	$ 87
Operating Expenses
Operating Expenses	42.9	47.1
Electric
Operating Revenues
Total Operating Revenues	64.8	57.5
Operating Expenses
Operating Expenses	41.7	35.2
Other
Operating Revenues
Total Operating Revenues	$ 0.9	$ 1.3

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Current Assets:
Cash and Cash Equivalents	$ 4.3	$ 7.8	$ 9.5
Accounts Receivable, Net	73.9	66.8	74.4
Accrued Revenue	40.2	54.7	45.1
Exchange Gas Receivable	0.4	8.1	0.2
Gas Inventory	0.5	0.8	0.4
Materials and Supplies	7.8	7	7.8
Prepayments and Other	6.8	7	7.1
Total Current Assets	133.9	152.2	144.5
Utility Plant:
Gas	778.6	760.6	706.7
Electric	511.3	500.1	478.8
Common	61.1	83.1	69.1
Construction Work in Progress	26.1	25.5	32.1
Total Utility Plant	1,377.1	1,369.3	1,286.7
Less: Accumulated Depreciation	339.3	332.5	314.3
Net Utility Plant	1,037.8	1,036.8	972.4
Other Noncurrent Assets:
Regulatory Assets	97.9	99	111.2
Operating Lease Right of Use Assets	3.9
Other Assets	16.7	10.3	16.2
Total Other Noncurrent Assets	118.5	109.3	127.4
TOTAL ASSETS	1,290.2	1,298.3	1,244.3
Current Liabilities:
Accounts Payable	33	42.6	30.1
Short-Term Debt	65.8	82.8	45.3
Long-Term Debt, Current Portion	19.5	18.4	29.8
Regulatory Liabilities	15	11.5	10.9
Energy Supply Obligations	4.6	13.4	7.8
Interest Payable	7	4.3	6.9
Other Current Liabilities	19.9	19.5	15.5
Total Current Liabilities	164.8	192.5	146.3
Noncurrent Liabilities:
Retirement Benefit Obligations	122.9	121.5	151.6
Deferred Income Taxes, Net	103.8	97.8	87
Cost of Removal Obligations	93.7	90.7	86.6
Regulatory Liabilities	47.4	47	49.1
Other Noncurrent Liabilities	10.7	10.1	12.1
Total Noncurrent Liabilities	378.5	367.1	386.4
Capitalization:
Long-Term Debt, Less Current Portion	373	387.4	363
Stockholders' Equity:
Common Equity (Authorized: 25,000,000 and Outstanding:14,916,044, 14,860,123 and 14,876,955 Shares)	280.7	279.1	277.4
Retained Earnings	93	72	71
Total Common Stock Equity	373.7	351.1	348.4
Preferred Stock	0.2	0.2	0.2
Total Stockholders' Equity	373.9	351.3	348.6
Total Capitalization	746.9	738.7	711.6
Commitments and Contingencies (Notes 6 & 7)
TOTAL LIABILITIES AND CAPITALIZATION	$ 1,290.2	$ 1,298.3	$ 1,244.3

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - shares	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Common Stock Authorized	25,000,000	25,000,000	25,000,000
Common Equity Outstanding	14,916,044	14,876,955	14,860,123

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating Activities:
Net Income	$ 26.5	$ 15.6
Adjustments to Reconcile Net Income to Cash Provided by Operating Activities:
Depreciation and Amortization	13.8	12.3
Deferred Tax Provision	8.2	4.7
Gain on Divestiture, Net (See Note 1)	(13.4)
Changes in Working Capital Items:
Accounts Receivable	(7.1)	(7)
Accrued Revenue	14.5	8.2
Exchange Gas Receivable	7.7	5.6
Regulatory Liabilities	3.5	1.7
Accounts Payable	(9.6)	(11.4)
Other Changes in Working Capital Items	0.3	3.6
Deferred Regulatory and Other Charges	(6.9)	(7.9)
Other, Net	0.3	3
Cash Provided by Operating Activities	37.8	28.4
Investing Activities:
Property, Plant and Equipment Additions	(10.9)	(10.1)
Proceeds from Divestiture, Net (See Note 1)	13.4
Cash Provided by (Used in) Investing Activities	2.5	(10.1)
Financing Activities:
(Repayment of) Proceeds from Short-Term Debt, Net	(17)	7
Repayment of Long-Term Debt	(13.4)	(13.4)
Decrease in Capital Lease Obligations	(0.9)	(0.8)
Net Decrease in Exchange Gas Financing	(7.3)	(5.4)
Dividends Paid	(5.5)	(5.4)
Proceeds from Issuance of Common Stock	0.3	0.3
Cash (Used in) Financing Activities	(43.8)	(17.7)
Net (Decrease) Increase in Cash and Cash Equivalents	(3.5)	0.6
Cash and Cash Equivalents at Beginning of Period	7.8	8.9
Cash and Cash Equivalents at End of Period	4.3	9.5
Supplemental Cash Flow Information:
Interest Paid	3.6	3.6
Income Taxes Paid		0.2
Payments on Capital Leases	0.8	0.8
Non-cash Investing Activity:
Capital Expenditures Included in Accounts Payable	0.7	$ 0.5
Right-of-Use Assets Obtained in Exchange for Lease Obligations	$ 3.9

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, 2017	$ 336.6	$ 275.8	$ 60.8
Net Income	15.6		15.6
Dividends on Common Shares	(5.4)		(5.4)
Stock Compensation Plans	1.3	1.3
Issuance of Common Shares	0.3	0.3
Ending Balance at Mar. 31, 2018	348.4	277.4	71
Beginning Balance at Dec. 31, 2018	351.1	279.1	72
Net Income	26.5		26.5
Dividends on Common Shares	(5.5)		(5.5)
Stock Compensation Plans	1.3	1.3
Issuance of Common Shares	0.3	0.3
Ending Balance at Mar. 31, 2019	$ 373.7	$ 280.7	$ 93

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN COMMON STOCK EQUITY (Parenthetical) - shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Common stock, shares issued	5,939	7,812

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2019
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	NOTE 1 – SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Nature of Operations non-regulated The Company’s earnings are seasonal and are typically higher in the first and fourth quarters when customers use natural gas for heating purposes. Unitil’s principal business is the local distribution of electricity in the southeastern seacoast and state capital regions of New Hampshire and the greater Fitchburg area of north central Massachusetts, and the local distribution of natural gas in southeastern New Hampshire, portions of southern and central Maine and in the greater Fitchburg area of north central Massachusetts. Unitil has three distribution utility subsidiaries, 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 a natural gas transportation pipeline, 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 natural gas pipelines and access to domestic natural gas supplies in the south and Canadian natural gas supplies in the north. Granite State derives its revenues principally from the 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, Unitil Power ceased being the wholesale supplier of Unitil Energy on May 1, 2003 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. 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 Divestiture of Non-Regulated non-regulated after-tax pre-tax Utility Revenue Recognition – Billed and unbilled 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 calculated each month based on estimated customer usage by class and applicable customer rates 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 ASU 2014-09. 980-605-25-3, 2014-09 In the following tables, revenue is classified by the types of goods/services rendered and market/customer type. Three Months Ended March 31, 2019 Gas and Electric Operating Revenues ($ millions): Gas Electric Total Billed and Unbilled Revenue: Residential $ 38.7 $ 35.7 $ 74.4 C&I 54.0 24.7 78.7 Other 6.5 2.3 8.8 Total Billed and Unbilled Revenue 99.2 62.7 161.9 Rate Adjustment Mechanism Revenue (12.8 ) 2.1 (10.7 ) Total Gas and Electric Operating Revenues $ 86.4 $ 64.8 $ 151.2 Three Months Ended March 31, 2018 Gas and Electric Operating Revenues ($ millions): Gas Electric Total Billed and Unbilled Revenue: Residential $ 35.8 $ 34.4 $ 70.2 C&I 50.6 24.1 74.7 Other 5.0 3.1 8.1 Total Billed and Unbilled Revenue 91.4 61.6 153.0 Rate Adjustment Mechanism Revenue (4.4 ) (4.1 ) (8.5 ) Total Gas and Electric Operating Revenues $ 87.0 $ 57.5 $ 144.5 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 natural 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 MDPU. Other Operating Revenue – Non-regulated non-regulated Income Taxes – The Company classifies penalty and interest expense related to income tax liabilities as income tax expense and interest expense, respectively, in the Consolidated Statements of Earnings. Provisions for income taxes are calculated in each of the jurisdictions 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 current and 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 – written-off shut-off. The Allowance for Doubtful Accounts as of March 31, 2019, March 31, 2018 and December 31, 2018, which are included in Accounts Receivable, Net on the accompanying unaudited consolidated balance sheets, was as follows: ($ millions) March 31, December 31, 2019 2018 2018 Allowance for Doubtful Accounts $ 1.7 $ 1.6 $ 1.3 Accrued Revenue – March 31, December 31, Accrued Revenue ($ millions) 2019 2018 2018 Regulatory Assets – Current $ 29.4 $ 34.6 $ 41.3 Unbilled Revenues 10.8 10.5 13.4 Total Accrued Revenue $ 40.2 $ 45.1 $ 54.7 Exchange Gas Receivable – March 31, December 31, Exchange Gas Receivable ($ millions) 2019 2018 2018 Northern Utilities $ 0.2 $ — $ 7.5 Fitchburg 0.2 0.2 0.6 Total Exchange Gas Receivable $ 0.4 $ 0.2 $ 8.1 Gas Inventory March 31, December 31, Gas Inventory ($ millions) 2019 2018 2018 Natural Gas $ — $ — $ 0.3 Propane 0.4 0.3 0.4 Liquefied Natural Gas & Other 0.1 0.1 0.1 Total Gas Inventory $ 0.5 $ 0.4 $ 0.8 Utility Plant – Leases – No. 2016-02, . Regulatory Accounting – March 31, December 31, Regulatory Assets consist of the following ($ millions) 2019 2018 2018 Retirement Benefits $ 72.4 $ 85.4 $ 72.0 Energy Supply & Other Rate Adjustment Mechanisms 25.1 31.9 38.4 Deferred Storm Charges 5.9 8.0 6.3 Environmental 7.6 9.0 7.9 Income Taxes 4.7 6.3 5.7 Other Deferred Charges 11.6 5.2 10.0 Total Regulatory Assets 127.3 145.8 140.3 Less: Current Portion of Regulatory Assets (1) 29.4 34.6 41.3 Regulatory Assets – noncurrent $ 97.9 $ 111.2 $ 99.0 Reflects amounts included in Accrued Revenue, discussed above, on the Company’s Consolidated Balance Sheets. March 31, December 31, Regulatory Liabilities consist of the following ($ millions) 2019 2018 2018 Income Taxes (Note 8) $ 48.2 $ 49.1 $ 47.0 Energy Supply & Other Rate Adjustment Mechanisms 13.6 10.3 11.5 Gas Pipeline Refund (Note 6) — 0.6 — Other 0.6 — — Total Regulatory Liabilities 62.4 60.0 58.5 Less: Current Portion of Regulatory Liabilities 15.0 10.9 11.5 Regulatory Liabilities – noncurrent $ 47.4 $ 49.1 $ 47.0 Generally, the Company receives a return on investment on its regulated assets for which a cash outflow has been made. Included in Regulatory Assets as of March 31, 2019 are $5.9 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 impact 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 – Investments in Marketable Securities At March 31, 2019, March 31, 2018 and December 31, 2018, the fair value of the Company’s investments in these trading securities, which are recorded on the Consolidated Balance Sheets in Other Assets, were $5.1 million, $5.1 and $4.8 million, respectively, as shown in the table below. These investments are valued based on quoted prices from active markets and are categorized in Level 1 as they are actively traded and no valuation adjustments have been applied. Changes in the fair value of these investments are recorded in Other Expense, Net. March 31, December 31, Fair Value of Marketable Securities ($ millions) 2019 2018 2018 Equity Funds $ — $ 1.9 $ — Fixed Income Funds — 1.6 — Money Market Funds 5.1 1.6 4.8 Total Marketable Securities $ 5.1 $ 5.1 $ 4.8 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, 2019, March 31, 2018 and December 31, 2018, 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 $0.1 million, $0 and $0, respectively, as shown in the table below. These investments are valued based on quoted prices from active markets and are categorized in Level 1 as they are actively traded and no valuation adjustments have been applied. Changes in the fair value of these investments are recorded in Other Expense, Net. March 31, December 31, Fair Value of Marketable Securities ($ millions) 2019 2018 2018 Equity Funds $ — $ — $ — Money Market Funds 0.1 — — Total Marketable Securities $ 0.1 $ — $ — Energy Supply Obligations – March 31, December 31, Energy Supply Obligations ($ millions) 2019 2018 2018 Current: Exchange Gas Obligation $ 0.2 $ — $ 7.5 Renewable Energy Portfolio Standards 4.1 7.5 5.6 Power Supply Contract Divestitures 0.3 0.3 0.3 Total Energy Supply Obligations – Current 4.6 7.8 13.4 Long-Term: Power Supply Contract Divestitures 0.5 0.8 0.6 Total Energy Supply Obligations $ 5.1 $ 8.6 $ 14.0 Exchange Gas Obligation Renewable Energy Portfolio Standards Fitchburg has entered into long-term renewable contracts for the purchase of clean energy and/or renewable energy certificates (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 four of these contracts have been constructed and are now operating. Since 2017, the Company has participated in two major statewide procurements which resulted in contracts for imported hydroelectric power and associated transmission and for offshore wind generation. The contracts were filed with MDPU in 2018 and approvals remain pending. Additional long-term clean energy contracts are expected in compliance with the Energy Diversity Act and An Act to Promote a Clean Energy Future (2018). 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 – Recently Issued Pronouncements – No. 2016-02, Other than the pronouncement discussed above, there are no recently issued pronouncements that the Company has not already adopted or that have a material impact on the Company. Subsequent Events –

DIVIDENDS DECLARED PER SHARE

DIVIDENDS DECLARED PER SHARE	3 Months Ended
	Mar. 31, 2019
DIVIDENDS DECLARED PER SHARE	NOTE 2 – DIVIDENDS DECLARED PER SHARE Declaration Date Date Shareholder of Record Date Dividend Amount 04/24/19 05/29/19 05/15/19 $ 0.370 01/30/19 02/28/19 02/14/19 $ 0.370 10/24/18 11/29/18 11/15/18 $0.365 07/25/18 08/29/18 08/15/18 $0.365 04/25/18 05/29/18 05/15/18 $ 0.365 01/30/18 02/28/18 02/14/18 $ 0.365

SEGMENT INFORMATION

SEGMENT INFORMATION	3 Months Ended
	Mar. 31, 2019
SEGMENT INFORMATION	NOTE 3 – SEGMENT INFORMATION The following table provides significant segment financial data for the three months ended March 31, 2019 and March 31, 2018: Gas Electric Non- Regulated Other Total Three Months Ended March 31, 2019 ($ millions) Revenues: Billed and Unbilled Revenue $ 99.2 $ 62.7 $ — $ — $ 161.9 Rate Adjustment Mechanism Revenue (12.8 ) 2.1 — — (10.7 ) Other Operating Revenue – Non-Regulated — — 0.9 — 0.9 Total Operating Revenues $ 86.4 $ 64.8 $ 0.9 $ — $ 152.1 Segment Profit (Loss) 13.7 1.9 10.1 0.8 26.5 Identifiable Segment Assets 771.6 502.3 0.1 16.2 1,290.2 Capital Expenditures 3.3 6.6 — 1.0 10.9 Three Months Ended March 31, 2018 ($ millions) Revenues: Billed and Unbilled Revenue $ 91.4 $ 61.6 $ — $ — $ 153.0 Rate Adjustment Mechanism Revenue (4.4 ) (4.1 ) — — (8.5 ) Other Operating Revenue – Non-Regulated — — 1.3 — 1.3 Total Operating Revenues $ 87.0 $ 57.5 $ 1.3 $ — $ 145.8 Segment Profit (Loss) 12.6 3.0 0.4 (0.4 ) 15.6 Identifiable Segment Assets 712.6 481.8 7.1 42.8 1,244.3 Capital Expenditures 3.6 6.0 — 0.5 10.1

DEBT AND FINANCING ARRANGEMENTS

DEBT AND FINANCING ARRANGEMENTS	3 Months Ended
	Mar. 31, 2019
DEBT AND FINANCING ARRANGEMENTS	NOTE 4 – DEBT AND FINANCING ARRANGEMENTS Details on long-term debt at March 31, 2019, March 31, 2018 and December 31, 2018 are shown below: ($ millions) March 31, December 31, 2019 2018 2018 Unitil Corporation: 6.33% Senior Notes, Due May 1, 2022 $ 20.0 $ 20.0 $ 20.0 3.70% Senior Notes, Due August 1, 2026 30.0 30.0 30.0 Unitil Energy First Mortgage Bonds: 5.24% Senior Secured Notes, Due March 2, 2020 5.0 10.0 10.0 8.49% Senior Secured Notes, Due October 14, 2024 6.0 7.5 6.0 6.96% Senior Secured Notes, Due September 1, 2028 20.0 20.0 20.0 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 4.18% Senior Secured Notes, Due November 30, 2048 30.0 — 30.0 Fitchburg: 6.75% Senior Notes, Due November 30, 2023 5.7 7.6 5.7 6.79% Senior Notes, Due October 15, 2025 10.0 10.0 10.0 3.52% Senior Notes, Due November 1, 2027 10.0 10.0 10.0 7.37% Senior Notes, Due January 15, 2029 12.0 12.0 12.0 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 4.32% Senior Notes, Due November 1, 2047 15.0 15.0 15.0 Northern Utilities: 6.95% Senior Notes, Due December 3, 2018 — 10.0 — 5.29% Senior Notes, Due March 2, 2020 8.2 16.6 16.6 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 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 Granite State: 7.15% Senior Notes, Due December 15, 2018 — 3.3 — 3.72% Senior Notes, Due November 1, 2027 15.0 15.0 15.0 Total Long-Term Debt 395.9 396.0 409.3 Less: Unamortized Debt Issuance Costs 3.4 3.2 3.5 Total Long-Term Debt, net of Unamortized Debt Issuance Costs 392.5 392.8 405.8 Less: Current Portion 19.5 29.8 18.4 Total Long-term Debt, Less Current Portion $ 373.0 $ 363.0 $ 387.4 Currently, the Company believes that there is no active market in the Company’s debt securities, which have all been sold through private placements. If there were an active market for the Company’s debt securities, the fair value of the Company’s long-term debt would be estimated based on the quoted market prices for the same or similar issues, or on the current rates offered to the Company for debt of the same remaining maturities. The fair value of the Company’s long-term debt is estimated using Level 2 inputs (valuations based on quoted prices available in active markets for similar assets or liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, inputs other than quoted prices that are directly observable, and inputs derived principally from market data.) In estimating the fair value of the Company’s long-term debt, the assumed market yield reflects the Moody’s Baa Utility Bond Average Yield. Costs, including prepayment costs, associated with the early settlement of long-term debt are not taken into consideration in determining fair value. ($ millions) March 31, December 31, 2019 2018 2018 Estimated Fair Value of Long-Term Debt $ 418.0 $ 428.0 $ 422.0 Credit Arrangements 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 extends to July 25, 2023, subject to two one-year one-month The Company utilizes the Credit Facility for cash management purposes related to its short-term operating activities. Total gross borrowings were $75.7 million for the three months ended March 31, 2019. Total gross repayments were $92.7 million for the three months ended March 31, 2019. The following table details the borrowing limits, amounts outstanding and amounts available under the Credit Facility as of March 31, 2019, March 31, 2018 and December 31, 2018: Revolving Credit Facility ($ millions) March 31, December 31, 2019 2018 2018 Limit $ 120.0 $ 120.0 $ 120.0 Short-Term Borrowings Outstanding $ 65.8 $ 45.3 $ 82.8 Available $ 54.2 $ 74.7 $ 37.2 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 shall 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, 2019, March 31, 2018 and December 31, 2018, the Company was in compliance with the covenants contained in the Credit Facility in effect on that date. (See also “Credit Arrangements” in Note 4.) The Company believes the future operating cash flows of the Company, along with its existing borrowing availability and access to financial markets for the issuance of new long-term debt, will be sufficient to meet any working capital and future operating requirements, and capital investment forecast opportunities. The weighted average interest rates on all short-term borrowings and intercompany money pool transactions were 3.7% and 2.9% for the three months ended March 31, 2019 and March 31, 2018, respectively. The weighted average interest rate on all short-term borrowings for the twelve months ended December 31, 2018 was 3.3%. As discussed previously, the Company divested of its non-regulated On November 30, 2018 Unitil Energy issued $30 million of First Mortgage Bonds due November 30, 2048 at 4.18%. Unitil Energy used the net proceeds from this offering to repay short-term debt and for general corporate purposes. Approximately $0.5 million of costs associated with these issuances have been netted against long-term debt for presentation purposes on the Consolidated Balance Sheets. In April 2014, Unitil Service Corp. entered into a financing arrangement, structured as a capital lease obligation, for various information systems and technology equipment. Final funding under this capital lease occurred on October 30, 2015, resulting in total funding of $13.4 million. The capital lease matures on September 30, 2020. As of March 31, 2019, there are $2.8 million of current and $1.6 million of noncurrent obligations under this capital lease on the Company’s Consolidated Balance Sheets. Unitil Corporation and its utility subsidiaries, Fitchburg, Unitil Energy, Northern Utilities, and Granite State are currently rated “BBB+” by Standard & Poor’s Ratings Services. Unitil Corporation and Granite State are currently 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 natural gas pipeline and storage assets, resells the natural gas storage inventory to an asset manager and subsequently repurchases the inventory over the course of the natural gas heating season at the same price at which it sold the natural gas inventory to the asset manager. There was $2.2 million, $1.0 million and $8.4 million of natural gas storage inventory at March 31, 2019, March 31, 2018 and December 31, 2018, respectively, related to these asset management agreements. The amount of natural gas inventory released in March 2019 and payable in April 2019 is $2.1 million and is recorded in Accounts Payable at March 31, 2019. The amount of natural gas inventory released in March 2018 and payable in April 2018 was $1.0 million and was recorded in Accounts Payable at March 31, 2018. The amount of natural gas inventory released in December 2018 and payable in January 2019 was $0.9 million and was recorded in Accounts Payable at December 31, 2018. Guarantees The Company provides limited guarantees on certain energy and natural 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, 2019, there were approximately $4.3 million of guarantees outstanding. Leases Unitil’s subsidiaries and also lease some of their 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, 2019 and 2018 amounted to $0.4 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) 2019 2018 2018 Operating Lease Obligations: Other Current Liabilities (current portion) $ 1.1 $ — $ — Other Noncurrent Liabilities (long-term portion) 2.8 — — Total Operating Lease Obligations $ 3.9 $ — $ — Capital Lease Obligations: Other Current Liabilities (current portion) $ 3.0 $ 3.1 $ 3.1 Other Noncurrent Liabilities (long-term portion) 1.9 4.9 2.7 Total Capital Lease Obligations $ 4.9 $ 8.0 $ 5.8 Total Lease Obligations $ 8.8 $ 8.0 $ 5.8 Cash paid for amounts included in the measurement of operating lease obligations for the three months ended March 31, 2019 was $0.4 million and was included in Cash Provided by Operating Activities on the Consolidated Statements of Cash Flows. Assets under capital leases amounted to approximately $14.9 million, $15.0 million and $15.0 million as of March 31, 2019, March 31, 2018 and December 31, 2018, respectively, less accumulated amortization of $1.8 million, $1.1 million and $1.7 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, 2019. The payments for capital leases consist of $3.0 million of current capital lease obligations, which are included in Other Current Liabilities and $1.9 million of noncurrent capital lease obligations, which are included in Other Noncurrent Liabilities, on the Company’s Consolidated Balance Sheets as of March 31, 2019. $2.8 million of the current capital lease obligations and $1.6 million of the noncurrent capital lease obligations reflect amounts under a financing arrangement entered into in April 2014 for various information systems and technology equipment. The financing arrangement is structured as a capital lease obligation. The payments for operating leases consist of $1.1 million of current operating lease obligations, which are included in Other Current Liabilities and $2.8 million of noncurrent operating lease obligations, which are included in Other Noncurrent Liabilities, on the Company’s Consolidated Balance Sheets as of March 31, 2019. Lease Payments ($000’s) Operating Capital Year Ending December 31, Leases Leases Rest of 2019 $ 967 $ 2,369 2020 1,141 2,576 2021 972 96 2022 691 33 2023 391 15 2024-2028 119 — Total Payments 4,281 5,089 Less: Interest 426 122 Amount of Lease Obligations Recorded on Consolidated Balance Sheets $ 3,855 $ 4,967 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, 2019, the weighted average remaining lease term is 3.9 years and the weighted average operating discount rate used to determine the operating lease obligations was 5.3%. Disclosures Related to Periods Prior to the Adoption of ASU NO. 2016-02 The payment amounts in the following table, which are as of December 31, 2018, would not differ substantially from the payment amounts as of March 31, 2018. Lease Payments ($000’s) Operating Capital Year Ending December 31, Leases Leases 2019 $ 1,372 $ 3,069 2020 1,138 2,535 2021 969 93 2022 689 32 2023 390 14 2024-2028 120 — Total Payments $ 4,678 $ 5,743

COMMON STOCK AND PREFERRED STOC

COMMON STOCK AND PREFERRED STOCK	3 Months Ended
	Mar. 31, 2019
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 14,860,123, 14,876,955 and 14,916,044 shares of common stock outstanding at March 31, 2018, December 31, 2018 and March 31, 2019, respectively. Dividend Reinvestment and Stock Purchase Plan – Stock Plan – 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 29, 2019, 33,150 Restricted Shares were issued in conjunction with the Stock Plan with an aggregate market value at the date of issuance of approximately $1.6 million. There were 60,496 and 90,882 non-vested Restricted Stock Units Restricted Stock Units 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, 2019 in conjunction with the Stock Plan are presented in the following table: Restricted Stock Units (Equity Portion) Units Weighted Average Stock Price Restricted Stock Units as of December 31, 2018 61,789 $ 38.25 Restricted Stock Units Granted — — Dividend Equivalents Earned 417 $ 54.91 Restricted Stock Units Settled — — Restricted Stock Units as of March 31, 2019 62,206 $ 38.36 There were 52,677 Restricted Stock Units outstanding as of March 31, 2018 with a weighted average stock price of $36.27. Included in Other Noncurrent Liabilities on the Company’s Consolidated Balance Sheets as of March 31, 2019, March 31, 2018 and December 31, 2018 is $1.4 million, $1.0 million and $1.3 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 was $0.2 million, or 1,893 shares, of Unitil Energy’s 6.00% Series Preferred Stock outstanding as of March 31, 2019, March 31, 2018 and December 31, 2018. There were less than $0.1 million of total dividends declared on Preferred Stock in each of the three month periods ended March 31, 2019 and March 31, 2018, respectively.

REGULATORY MATTERS

REGULATORY MATTERS	3 Months Ended
	Mar. 31, 2019
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 percent, 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 has opened a rulemaking proceeding on this matter which has been addressed in a rate settlement filing by Granite State. More recently, on November 15, 2018, the FERC issued a Notice of Proposed Rulemaking and a Policy Statement to address the TCJA’s effects on the Accumulated Deferred Income Taxes (ADIT) on transmission rates. Under the proposed rules all public utilities with transmission formula rates, including Fitchburg, would be required to: (1) include mechanisms to deduct any excess ADIT from or add any deficient ADIT to their rate bases; (2) include mechanisms in those rates that would raise or lower their income tax allowances by any amortized excess or deficient ADIT; and (3) incorporate a new permanent worksheet into their rates that will annually track information related to excess or deficient ADIT. The Company believes that these matters are substantially resolved and will not have a material impact on its financial position, operating results, or cash flows. Rate Case Activity Unitil Energy – Base Rates – one-year Fitchburg – Base Rates – Electric – Fitchburg – Base Rates – Gas – Fitchburg – Gas System Enhancement Program – year-to-year Northern Utilities – Base Rates – Maine – Northern Utilities – Targeted Infrastructure Replacement Adjustment (TIRA) – Maine – Northern Utilities – Base Rates – New Hampshire – Granite State – Base Rates – Other Matters Fitchburg – Independent Statewide Examination of the Safety of the Commonwealth’s Gas Distribution System – on-going. Reconciliation Filings – Fitchburg – Massachusetts 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 hydroelectric generation were filed in July 2018 for approval by the MDPU. The Section 83D matter remains pending with the EDCs awaiting an approval. The EDCs issued the RFP pursuant to Section 83C for Long-Term Contracts for Offshore Wind Energy Generation in June 2017. Final selection of projects was made 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 400MW of offshore wind energy generation with 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 wholesale market and to credit or charge the difference between the contract costs and the ISO-NE market costs to customers. The MDPU also determined that the EDCs’ request for remuneration equal to 2.75 percent is reasonable and in the public interest. Also, the MDPU approved the EDCs’ proposal to amend their respective tariffs to include the recovery of costs associated with the contracts. The Company believes that the power purchase obligations under these long-term contracts will have a material impact on the contractual obligations and regulatory assets of Fitchburg. Northern Utilities Gas Supply Cost Investigation – FERC Transmission Formula Rate Proceedings – ISO-New Also pending at FERC is a Section 206 proceeding concerning the justness and reasonableness of ISO-New Legal Proceedings The Company is involved in legal and administrative proceedings and claims of various types, 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 impact on its financial position, operating results or cash flows.

ENVIRONMENTAL MATTERS

ENVIRONMENTAL MATTERS	3 Months Ended
	Mar. 31, 2019
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, 2019, 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 the Company’s 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 to address environmental concerns with these sites. Northern Utilities or others have substantially completed remediation of all sites, though on site monitoring continues and it is possible that future activities may be required. 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 below 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 – The Environmental Obligations table below shows the amounts accrued for Fitchburg related to estimated and periodic, regulatory review costs for the completed permanent remediation of the Sawyer Passway site. A corresponding Regulatory Asset was recorded to reflect that the recovery of these environmental remediation costs is probable through the regulatory process. The amounts recorded do not assume any amounts are recoverable from insurance companies or other third parties. 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. The following table sets forth a summary of changes in the Company’s liability for Environmental Obligations for the three months ended March 31, 2019 and 2018. Environmental Obligations ($ millions) Fitchburg Northern Total Three months ended March 31, 2019 2018 2019 2018 2019 2018 Total Balance at Beginning of Period $ — $ 0.1 $ 2.0 $ 2.0 $ 2.0 $ 2.1 Additions — 0.1 0.1 0.1 0.1 0.2 Less: Payments / Reductions — 0.1 0.1 0.1 0.1 0.2 Total Balance at End of Period — 0.1 2.0 2.0 2.0 2.1 Less: Current Portion — 0.1 0.6 0.5 0.6 0.6 Noncurrent Balance at End of Period $ — $ — $ 1.4 $ 1.5 $ 1.4 $ 1.5

INCOME TAXES

INCOME TAXES	3 Months Ended
	Mar. 31, 2019
INCOME TAXES	NOTE 8: INCOME TAXES 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 GAAP Accounting Standard 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. The Company recorded a net Regulatory Liability in the amount of $48.9 million at December 31, 2017 as a result of the ADIT revaluation. The MDPU issued a multi-utility Order D.P.U. 18-15-E non-plant D.P.U.18-15-E On November 15, 2018 the FERC issued two pronouncements regarding the accounting for income taxes due to the TCJA; 1) Notice of Proposed Rulemaking Docket No. RM 19-5-000 19-2-000 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, the recent FERC guidance noted above and IRS normalization rules; the benefit of these 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 to be between fifteen and twenty years. Subject to regulatory approval, the Company expects to flow back to customers a net $47.1 million of protected excess ADIT created as a result of the lowering of the statutory tax rate by the TCJA over periods estimated to be fifteen to twenty years. In addition to the protected excess $47.1 million ADIT amounts the Company expects to flow through to customers in utility rates, as noted above, there is approximately $1.8 million of excess ADIT created through reconciling mechanisms at December 31, 2017, related to the implementation of the new federal tax rate of the TCJA, which had not been previously collected from customers through utility rates. The Company will reconcile these excess ADIT amounts through the specific reconciliation mechanisms in the next filing of each of those individual reconciling mechanisms which will be subject to the review of state regulators. In addition to the $48.9 million of net excess ADIT noted above; there is $5.8 million of excess ADIT at December 31, 2017, created by the recognition of Net Operating Loss Carryforward assets (NOLC), discussed below, and related to the implementation of the new federal tax rate of the TCJA, which had not been previously included in utility rates. The Company is recognizing the benefit of this excess ADIT in accordance with the regulatory treatment of excess ADIT for each of jurisdiction. In 2018 the Company recognized $2.4 million of this tax benefit provision due to the turning of book/tax temporary differences associated with this excess ADIT. The Company expects to recognize the remaining $3.4 million of this excess ADIT in future periods, which is currently expected to be in 2019 and 2020, in accordance with regulatory guidance as discussed above. The Company has not yet received regulatory orders in all of its jurisdictions regarding the flow-back of excess deferred taxes. The Company’s regulators are expected to issue additional ratemaking guidance in future periods that will determine the final disposition of the re-measurement Under the Company’s Tax Sharing Agreement (the “Agreement”) which was approved upon the formation of Unitil as a PUHC; 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 filed its tax returns for the year ended December 31, 2017 with the Internal Revenue Service in September 2018 and generated additional federal NOLC assets of $3.7 million principally due to pension cost deductions, tax repair deductions, tax depreciation and research and development deductions. For the year ended December 31, 2018, the Company calculated federal current tax of $7.7 million and offset it with a decrease to the federal NOLC of $7.7 million, resulting in no federal current taxes payable for the period. As of December 31, 2018, the Company had recorded cumulative federal and state NOLC assets of $10.8 million to offset against taxes payable in future periods. If unused, the Company’s NOLC carryforward assets will begin to expire in 2029. In addition, at December 31, 2017, the Company had $3.5 million of cumulative alternative minimum tax credits, general business tax credit and other state tax credit carryforwards to offset future income taxes payable. In assessing the near-term use of NOLCs and tax credits, the Company evaluates the expected level of future taxable income, available tax planning strategies, reversals of existing taxable temporary differences and taxable income available in carryback years. Based on all available evidence, both positive and negative, and the weight of that evidence to the extent such evidence can be objectively verified, the Company expects to utilize all of its NOLCs by December 31, 2019 prior to their expiration in 2029. In March 2018, Unitil Corporation received notice that its Federal Income Tax return filings for the years ended December 31, 2015 and December 31, 2016 are under examination by the IRS. Currently, the Company believes that the ultimate resolution of this examination will not have a material impact on the Company’s financial statements. The Company remains subject to examination by New Hampshire tax authorities for the tax periods ended December 31, 2015; December 31, 2016; and December 31, 2017. Income tax filings for the year ended December 31, 2017 have been filed with the New Hampshire Department of Revenue Administration. The State of Maine has concluded its review of the Company’s tax returns for December 31, 2014, December 31, 2015, and December 31, 2016 which resulted in a small additional refund to the Company. The Company evaluated its tax positions at March 31, 2019 in accordance with the FASB Codification, and has concluded that no adjustment for recognition, de-recognition, The Company bills its customers for sales tax in Massachusetts and Maine. These taxes are remitted to the appropriate departments of revenue in each state and are excluded from revenues on the Company’s unaudited Consolidated Statements of Earnings.

RETIREMENT BENEFIT OBLIGATIONS

RETIREMENT BENEFIT OBLIGATIONS	3 Months Ended
	Mar. 31, 2019
RETIREMENT BENEFIT OBLIGATIONS	NOTE 9: RETIREMENT BENEFIT OBLIGATIONS The Company co-sponsors 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 2019 2018 Discount Rate 4.25 % 3.60 % Rate of Compensation Increase 3.00 % 3.00 % Expected Long-term rate of return on plan assets 7.75 % 7.75 % Health Care Cost Trend Rate Assumed for Next Year 7.00 % 7.50 % Ultimate Health Care Cost Trend Rate 4.50 % 4.50 % Year that Ultimate Health Care Cost Trend Rate is reached 2024 2024 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, 2019 2018 2019 2018 2019 2018 Service Cost $ 776 $ 848 $ 576 $ 733 $ 60 $ 122 Interest Cost 1,621 1,469 856 851 139 101 Expected Return on Plan Assets (2,119 ) (1,946 ) (411 ) (409 ) — — Prior Service Cost Amortization 80 81 303 327 3 47 Actuarial Loss Amortization 1,081 1,447 57 346 158 122 Sub-total 1,439 1,899 1,381 1,848 360 392 Amounts Capitalized and Deferred (412 ) (720 ) (474 ) (742 ) (103 ) (113 ) Net Periodic Benefit Cost Recognized $ 1,027 $ 1,179 $ 907 $ 1,106 $ 257 $ 279 Employer Contributions As of March 31, 2019, the Company had made $1.3 million and $0.4 million of contributions to its Pension Plan and PBOP Plan, respectively, in 2019. The Company, along with its subsidiaries, expects to continue to make contributions to its Pension and PBOP Plans in 2019 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, 2019, the Company had made $0.1 million of benefit payments under the SERP Plan in 2019. The Company presently anticipates making an additional $0.5 million of benefit payments under the SERP Plan in 2019.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2019
Nature of Operations	Nature of Operations non-regulated The Company’s earnings are seasonal and are typically higher in the first and fourth quarters when customers use natural gas for heating purposes. Unitil’s principal business is the local distribution of electricity in the southeastern seacoast and state capital regions of New Hampshire and the greater Fitchburg area of north central Massachusetts, and the local distribution of natural gas in southeastern New Hampshire, portions of southern and central Maine and in the greater Fitchburg area of north central Massachusetts. Unitil has three distribution utility subsidiaries, 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 a natural gas transportation pipeline, 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 natural gas pipelines and access to domestic natural gas supplies in the south and Canadian natural gas supplies in the north. Granite State derives its revenues principally from the 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, Unitil Power ceased being the wholesale supplier of Unitil Energy on May 1, 2003 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. 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
Divestiture of Non-Regulated Business Subsidiary	Divestiture of Non-Regulated non-regulated after-tax pre-tax
Utility Revenue Recognition	Utility Revenue Recognition – Billed and unbilled 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 calculated each month based on estimated customer usage by class and applicable customer rates 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 ASU 2014-09. 980-605-25-3, 2014-09 In the following tables, revenue is classified by the types of goods/services rendered and market/customer type. Three Months Ended March 31, 2019 Gas and Electric Operating Revenues ($ millions): Gas Electric Total Billed and Unbilled Revenue: Residential $ 38.7 $ 35.7 $ 74.4 C&I 54.0 24.7 78.7 Other 6.5 2.3 8.8 Total Billed and Unbilled Revenue 99.2 62.7 161.9 Rate Adjustment Mechanism Revenue (12.8 ) 2.1 (10.7 ) Total Gas and Electric Operating Revenues $ 86.4 $ 64.8 $ 151.2 Three Months Ended March 31, 2018 Gas and Electric Operating Revenues ($ millions): Gas Electric Total Billed and Unbilled Revenue: Residential $ 35.8 $ 34.4 $ 70.2 C&I 50.6 24.1 74.7 Other 5.0 3.1 8.1 Total Billed and Unbilled Revenue 91.4 61.6 153.0 Rate Adjustment Mechanism Revenue (4.4 ) (4.1 ) (8.5 ) Total Gas and Electric Operating Revenues $ 87.0 $ 57.5 $ 144.5 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 natural 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 MDPU.
Other Operating Revenue - Non-regulated	Other Operating Revenue – Non-regulated non-regulated
Income Taxes	Income Taxes – The Company classifies penalty and interest expense related to income tax liabilities as income tax expense and interest expense, respectively, in the Consolidated Statements of Earnings. Provisions for income taxes are calculated in each of the jurisdictions 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 current and 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 – written-off shut-off. The Allowance for Doubtful Accounts as of March 31, 2019, March 31, 2018 and December 31, 2018, which are included in Accounts Receivable, Net on the accompanying unaudited consolidated balance sheets, was as follows: ($ millions) March 31, December 31, 2019 2018 2018 Allowance for Doubtful Accounts $ 1.7 $ 1.6 $ 1.3
Accrued Revenue	Accrued Revenue – March 31, December 31, Accrued Revenue ($ millions) 2019 2018 2018 Regulatory Assets – Current $ 29.4 $ 34.6 $ 41.3 Unbilled Revenues 10.8 10.5 13.4 Total Accrued Revenue $ 40.2 $ 45.1 $ 54.7
Exchange Gas Receivable	Exchange Gas Receivable – March 31, December 31, Exchange Gas Receivable ($ millions) 2019 2018 2018 Northern Utilities $ 0.2 $ — $ 7.5 Fitchburg 0.2 0.2 0.6 Total Exchange Gas Receivable $ 0.4 $ 0.2 $ 8.1
Gas Inventory	Gas Inventory March 31, December 31, Gas Inventory ($ millions) 2019 2018 2018 Natural Gas $ — $ — $ 0.3 Propane 0.4 0.3 0.4 Liquefied Natural Gas & Other 0.1 0.1 0.1 Total Gas Inventory $ 0.5 $ 0.4 $ 0.8
Utility Plant	Utility Plant –
Leases	Leases – No. 2016-02, .
Regulatory Accounting	Regulatory Accounting – March 31, December 31, Regulatory Assets consist of the following ($ millions) 2019 2018 2018 Retirement Benefits $ 72.4 $ 85.4 $ 72.0 Energy Supply & Other Rate Adjustment Mechanisms 25.1 31.9 38.4 Deferred Storm Charges 5.9 8.0 6.3 Environmental 7.6 9.0 7.9 Income Taxes 4.7 6.3 5.7 Other Deferred Charges 11.6 5.2 10.0 Total Regulatory Assets 127.3 145.8 140.3 Less: Current Portion of Regulatory Assets (1) 29.4 34.6 41.3 Regulatory Assets – noncurrent $ 97.9 $ 111.2 $ 99.0 Reflects amounts included in Accrued Revenue, discussed above, on the Company’s Consolidated Balance Sheets. March 31, December 31, Regulatory Liabilities consist of the following ($ millions) 2019 2018 2018 Income Taxes (Note 8) $ 48.2 $ 49.1 $ 47.0 Energy Supply & Other Rate Adjustment Mechanisms 13.6 10.3 11.5 Gas Pipeline Refund (Note 6) — 0.6 — Other 0.6 — — Total Regulatory Liabilities 62.4 60.0 58.5 Less: Current Portion of Regulatory Liabilities 15.0 10.9 11.5 Regulatory Liabilities – noncurrent $ 47.4 $ 49.1 $ 47.0 Generally, the Company receives a return on investment on its regulated assets for which a cash outflow has been made. Included in Regulatory Assets as of March 31, 2019 are $5.9 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 impact 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 –
Investments in Marketable Securities	Investments in Marketable Securities At March 31, 2019, March 31, 2018 and December 31, 2018, the fair value of the Company’s investments in these trading securities, which are recorded on the Consolidated Balance Sheets in Other Assets, were $5.1 million, $5.1 and $4.8 million, respectively, as shown in the table below. These investments are valued based on quoted prices from active markets and are categorized in Level 1 as they are actively traded and no valuation adjustments have been applied. Changes in the fair value of these investments are recorded in Other Expense, Net. March 31, December 31, Fair Value of Marketable Securities ($ millions) 2019 2018 2018 Equity Funds $ — $ 1.9 $ — Fixed Income Funds — 1.6 — Money Market Funds 5.1 1.6 4.8 Total Marketable Securities $ 5.1 $ 5.1 $ 4.8 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, 2019, March 31, 2018 and December 31, 2018, 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 $0.1 million, $0 and $0, respectively, as shown in the table below. These investments are valued based on quoted prices from active markets and are categorized in Level 1 as they are actively traded and no valuation adjustments have been applied. Changes in the fair value of these investments are recorded in Other Expense, Net. March 31, December 31, Fair Value of Marketable Securities ($ millions) 2019 2018 2018 Equity Funds $ — $ — $ — Money Market Funds 0.1 — — Total Marketable Securities $ 0.1 $ — $ —
Energy Supply Obligations	Energy Supply Obligations – March 31, December 31, Energy Supply Obligations ($ millions) 2019 2018 2018 Current: Exchange Gas Obligation $ 0.2 $ — $ 7.5 Renewable Energy Portfolio Standards 4.1 7.5 5.6 Power Supply Contract Divestitures 0.3 0.3 0.3 Total Energy Supply Obligations – Current 4.6 7.8 13.4 Long-Term: Power Supply Contract Divestitures 0.5 0.8 0.6 Total Energy Supply Obligations $ 5.1 $ 8.6 $ 14.0 Exchange Gas Obligation Renewable Energy Portfolio Standards Fitchburg has entered into long-term renewable contracts for the purchase of clean energy and/or renewable energy certificates (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 four of these contracts have been constructed and are now operating. Since 2017, the Company has participated in two major statewide procurements which resulted in contracts for imported hydroelectric power and associated transmission and for offshore wind generation. The contracts were filed with MDPU in 2018 and approvals remain pending. Additional long-term clean energy contracts are expected in compliance with the Energy Diversity Act and An Act to Promote a Clean Energy Future (2018). 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 –
Recently Issued Pronouncements	Recently Issued Pronouncements – No. 2016-02, Other than the pronouncement discussed above, there are no recently issued pronouncements that the Company has not already adopted or that have a material impact on the Company.
Subsequent Events	Subsequent Events –

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	3 Months Ended
	Mar. 31, 2019
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, 2019 Gas and Electric Operating Revenues ($ millions): Gas Electric Total Billed and Unbilled Revenue: Residential $ 38.7 $ 35.7 $ 74.4 C&I 54.0 24.7 78.7 Other 6.5 2.3 8.8 Total Billed and Unbilled Revenue 99.2 62.7 161.9 Rate Adjustment Mechanism Revenue (12.8 ) 2.1 (10.7 ) Total Gas and Electric Operating Revenues $ 86.4 $ 64.8 $ 151.2 Three Months Ended March 31, 2018 Gas and Electric Operating Revenues ($ millions): Gas Electric Total Billed and Unbilled Revenue: Residential $ 35.8 $ 34.4 $ 70.2 C&I 50.6 24.1 74.7 Other 5.0 3.1 8.1 Total Billed and Unbilled Revenue 91.4 61.6 153.0 Rate Adjustment Mechanism Revenue (4.4 ) (4.1 ) (8.5 ) Total Gas and Electric Operating Revenues $ 87.0 $ 57.5 $ 144.5
Allowance for Doubtful Accounts Included in Accounts Receivable Net	The Allowance for Doubtful Accounts as of March 31, 2019, March 31, 2018 and December 31, 2018, which are included in Accounts Receivable, Net on the accompanying unaudited consolidated balance sheets, was as follows: ($ millions) March 31, December 31, 2019 2018 2018 Allowance for Doubtful Accounts $ 1.7 $ 1.6 $ 1.3
Components of Accrued Revenue	The following table shows the components of Accrued Revenue as of March 31, 2019, March 31, 2018 and December 31, 2018. March 31, December 31, Accrued Revenue ($ millions) 2019 2018 2018 Regulatory Assets – Current $ 29.4 $ 34.6 $ 41.3 Unbilled Revenues 10.8 10.5 13.4 Total Accrued Revenue $ 40.2 $ 45.1 $ 54.7
Components of Exchange Gas Receivable	The following table shows the components of Exchange Gas Receivable as of March 31, 2019, March 31, 2018 and December 31, 2018. March 31, December 31, Exchange Gas Receivable ($ millions) 2019 2018 2018 Northern Utilities $ 0.2 $ — $ 7.5 Fitchburg 0.2 0.2 0.6 Total Exchange Gas Receivable $ 0.4 $ 0.2 $ 8.1
Components of Gas Inventory	The following table shows the components of Gas Inventory as of March 31, 2019, March 31, 2018 and December 31, 2018. March 31, December 31, Gas Inventory ($ millions) 2019 2018 2018 Natural Gas $ — $ — $ 0.3 Propane 0.4 0.3 0.4 Liquefied Natural Gas & Other 0.1 0.1 0.1 Total Gas Inventory $ 0.5 $ 0.4 $ 0.8
Regulatory Assets	March 31, December 31, Regulatory Assets consist of the following ($ millions) 2019 2018 2018 Retirement Benefits $ 72.4 $ 85.4 $ 72.0 Energy Supply & Other Rate Adjustment Mechanisms 25.1 31.9 38.4 Deferred Storm Charges 5.9 8.0 6.3 Environmental 7.6 9.0 7.9 Income Taxes 4.7 6.3 5.7 Other Deferred Charges 11.6 5.2 10.0 Total Regulatory Assets 127.3 145.8 140.3 Less: Current Portion of Regulatory Assets (1) 29.4 34.6 41.3 Regulatory Assets – noncurrent $ 97.9 $ 111.2 $ 99.0 Reflects amounts included in Accrued Revenue, discussed above, on the Company’s Consolidated Balance Sheets.
Regulatory Liabilities	March 31, December 31, Regulatory Liabilities consist of the following ($ millions) 2019 2018 2018 Income Taxes (Note 8) $ 48.2 $ 49.1 $ 47.0 Energy Supply & Other Rate Adjustment Mechanisms 13.6 10.3 11.5 Gas Pipeline Refund (Note 6) — 0.6 — Other 0.6 — — Total Regulatory Liabilities 62.4 60.0 58.5 Less: Current Portion of Regulatory Liabilities 15.0 10.9 11.5 Regulatory Liabilities – noncurrent $ 47.4 $ 49.1 $ 47.0
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) 2019 2018 2018 Equity Funds $ — $ 1.9 $ — Fixed Income Funds — 1.6 — Money Market Funds 5.1 1.6 4.8 Total Marketable Securities $ 5.1 $ 5.1 $ 4.8
Components of Energy Supply Obligations	The following discussion and table summarize the nature and amounts of the items recorded as Energy Supply Obligations (current portion) and Other Noncurrent Liabilities (noncurrent portion) on the Company’s Consolidated Balance Sheets. March 31, December 31, Energy Supply Obligations ($ millions) 2019 2018 2018 Current: Exchange Gas Obligation $ 0.2 $ — $ 7.5 Renewable Energy Portfolio Standards 4.1 7.5 5.6 Power Supply Contract Divestitures 0.3 0.3 0.3 Total Energy Supply Obligations – Current 4.6 7.8 13.4 Long-Term: Power Supply Contract Divestitures 0.5 0.8 0.6 Total Energy Supply Obligations $ 5.1 $ 8.6 $ 14.0
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) 2019 2018 2018 Equity Funds $ — $ — $ — Money Market Funds 0.1 — — Total Marketable Securities $ 0.1 $ — $ —

DIVIDENDS DECLARED PER SHARE (T

DIVIDENDS DECLARED PER SHARE (Tables)	3 Months Ended
	Mar. 31, 2019
Schedule of Dividends Declared	Declaration Date Date Shareholder of Record Date Dividend Amount 04/24/19 05/29/19 05/15/19 $ 0.370 01/30/19 02/28/19 02/14/19 $ 0.370 10/24/18 11/29/18 11/15/18 $0.365 07/25/18 08/29/18 08/15/18 $0.365 04/25/18 05/29/18 05/15/18 $ 0.365 01/30/18 02/28/18 02/14/18 $ 0.365

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2019
Significant Segment Financial Data	The following table provides significant segment financial data for the three months ended March 31, 2019 and March 31, 2018: Gas Electric Non- Regulated Other Total Three Months Ended March 31, 2019 ($ millions) Revenues: Billed and Unbilled Revenue $ 99.2 $ 62.7 $ — $ — $ 161.9 Rate Adjustment Mechanism Revenue (12.8 ) 2.1 — — (10.7 ) Other Operating Revenue – Non-Regulated — — 0.9 — 0.9 Total Operating Revenues $ 86.4 $ 64.8 $ 0.9 $ — $ 152.1 Segment Profit (Loss) 13.7 1.9 10.1 0.8 26.5 Identifiable Segment Assets 771.6 502.3 0.1 16.2 1,290.2 Capital Expenditures 3.3 6.6 — 1.0 10.9 Three Months Ended March 31, 2018 ($ millions) Revenues: Billed and Unbilled Revenue $ 91.4 $ 61.6 $ — $ — $ 153.0 Rate Adjustment Mechanism Revenue (4.4 ) (4.1 ) — — (8.5 ) Other Operating Revenue – Non-Regulated — — 1.3 — 1.3 Total Operating Revenues $ 87.0 $ 57.5 $ 1.3 $ — $ 145.8 Segment Profit (Loss) 12.6 3.0 0.4 (0.4 ) 15.6 Identifiable Segment Assets 712.6 481.8 7.1 42.8 1,244.3 Capital Expenditures 3.6 6.0 — 0.5 10.1

DEBT AND FINANCING ARRANGEMEN_2

DEBT AND FINANCING ARRANGEMENTS (Tables)	3 Months Ended
	Mar. 31, 2019
Details on Long Term Debt	Details on long-term debt at March 31, 2019, March 31, 2018 and December 31, 2018 are shown below: ($ millions) March 31, December 31, 2019 2018 2018 Unitil Corporation: 6.33% Senior Notes, Due May 1, 2022 $ 20.0 $ 20.0 $ 20.0 3.70% Senior Notes, Due August 1, 2026 30.0 30.0 30.0 Unitil Energy First Mortgage Bonds: 5.24% Senior Secured Notes, Due March 2, 2020 5.0 10.0 10.0 8.49% Senior Secured Notes, Due October 14, 2024 6.0 7.5 6.0 6.96% Senior Secured Notes, Due September 1, 2028 20.0 20.0 20.0 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 4.18% Senior Secured Notes, Due November 30, 2048 30.0 — 30.0 Fitchburg: 6.75% Senior Notes, Due November 30, 2023 5.7 7.6 5.7 6.79% Senior Notes, Due October 15, 2025 10.0 10.0 10.0 3.52% Senior Notes, Due November 1, 2027 10.0 10.0 10.0 7.37% Senior Notes, Due January 15, 2029 12.0 12.0 12.0 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 4.32% Senior Notes, Due November 1, 2047 15.0 15.0 15.0 Northern Utilities: 6.95% Senior Notes, Due December 3, 2018 — 10.0 — 5.29% Senior Notes, Due March 2, 2020 8.2 16.6 16.6 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 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 Granite State: 7.15% Senior Notes, Due December 15, 2018 — 3.3 — 3.72% Senior Notes, Due November 1, 2027 15.0 15.0 15.0 Total Long-Term Debt 395.9 396.0 409.3 Less: Unamortized Debt Issuance Costs 3.4 3.2 3.5 Total Long-Term Debt, net of Unamortized Debt Issuance Costs 392.5 392.8 405.8 Less: Current Portion 19.5 29.8 18.4 Total Long-term Debt, Less Current Portion $ 373.0 $ 363.0 $ 387.4
Fair Value of Long Term Debt	($ millions) March 31, December 31, 2019 2018 2018 Estimated Fair Value of Long-Term Debt $ 418.0 $ 428.0 $ 422.0
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, 2019, March 31, 2018 and December 31, 2018: Revolving Credit Facility ($ millions) March 31, December 31, 2019 2018 2018 Limit $ 120.0 $ 120.0 $ 120.0 Short-Term Borrowings Outstanding $ 65.8 $ 45.3 $ 82.8 Available $ 54.2 $ 74.7 $ 37.2
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) 2019 2018 2018 Operating Lease Obligations: Other Current Liabilities (current portion) $ 1.1 $ — $ — Other Noncurrent Liabilities (long-term portion) 2.8 — — Total Operating Lease Obligations $ 3.9 $ — $ — Capital Lease Obligations: Other Current Liabilities (current portion) $ 3.0 $ 3.1 $ 3.1 Other Noncurrent Liabilities (long-term portion) 1.9 4.9 2.7 Total Capital Lease Obligations $ 4.9 $ 8.0 $ 5.8 Total Lease Obligations $ 8.8 $ 8.0 $ 5.8
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, 2019. The payments for capital leases consist of $3.0 million of current capital lease obligations, which are included in Other Current Liabilities and $1.9 million of noncurrent capital lease obligations, which are included in Other Noncurrent Liabilities, on the Company’s Consolidated Balance Sheets as of March 31, 2019. $2.8 million of the current capital lease obligations and $1.6 million of the noncurrent capital lease obligations reflect amounts under a financing arrangement entered into in April 2014 for various information systems and technology equipment. The financing arrangement is structured as a capital lease obligation. The payments for operating leases consist of $1.1 million of current operating lease obligations, which are included in Other Current Liabilities and $2.8 million of noncurrent operating lease obligations, which are included in Other Noncurrent Liabilities, on the Company’s Consolidated Balance Sheets as of March 31, 2019. Lease Payments ($000’s) Operating Capital Year Ending December 31, Leases Leases Rest of 2019 $ 967 $ 2,369 2020 1,141 2,576 2021 972 96 2022 691 33 2023 391 15 2024-2028 119 — Total Payments 4,281 5,089 Less: Interest 426 122 Amount of Lease Obligations Recorded on Consolidated Balance Sheets $ 3,855 $ 4,967 The payment amounts in the following table, which are as of December 31, 2018, would not differ substantially from the payment amounts as of March 31, 2018. Lease Payments ($000’s) Operating Capital Year Ending December 31, Leases Leases 2019 $ 1,372 $ 3,069 2020 1,138 2,535 2021 969 93 2022 689 32 2023 390 14 2024-2028 120 — Total Payments $ 4,678 $ 5,743

COMMON STOCK AND PREFERRED ST_2

COMMON STOCK AND PREFERRED STOCK (Tables)	3 Months Ended
	Mar. 31, 2019
Restricted Stock Units Issued	The equity portion of Restricted Stock Units activity during the three months ended March 31, 2019 in conjunction with the Stock Plan are presented in the following table: Restricted Stock Units (Equity Portion) Units Weighted Average Stock Price Restricted Stock Units as of December 31, 2018 61,789 $ 38.25 Restricted Stock Units Granted — — Dividend Equivalents Earned 417 $ 54.91 Restricted Stock Units Settled — — Restricted Stock Units as of March 31, 2019 62,206 $ 38.36

ENVIRONMENTAL MATTERS (Tables)

ENVIRONMENTAL MATTERS (Tables)	3 Months Ended
	Mar. 31, 2019
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, 2019 and 2018. Environmental Obligations ($ millions) Fitchburg Northern Total Three months ended March 31, 2019 2018 2019 2018 2019 2018 Total Balance at Beginning of Period $ — $ 0.1 $ 2.0 $ 2.0 $ 2.0 $ 2.1 Additions — 0.1 0.1 0.1 0.1 0.2 Less: Payments / Reductions — 0.1 0.1 0.1 0.1 0.2 Total Balance at End of Period — 0.1 2.0 2.0 2.0 2.1 Less: Current Portion — 0.1 0.6 0.5 0.6 0.6 Noncurrent Balance at End of Period $ — $ — $ 1.4 $ 1.5 $ 1.4 $ 1.5

RETIREMENT BENEFIT OBLIGATIONS

RETIREMENT BENEFIT OBLIGATIONS (Tables)	3 Months Ended
	Mar. 31, 2019
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 2019 2018 Discount Rate 4.25 % 3.60 % Rate of Compensation Increase 3.00 % 3.00 % Expected Long-term rate of return on plan assets 7.75 % 7.75 % Health Care Cost Trend Rate Assumed for Next Year 7.00 % 7.50 % Ultimate Health Care Cost Trend Rate 4.50 % 4.50 % Year that Ultimate Health Care Cost Trend Rate is reached 2024 2024
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, 2019 2018 2019 2018 2019 2018 Service Cost $ 776 $ 848 $ 576 $ 733 $ 60 $ 122 Interest Cost 1,621 1,469 856 851 139 101 Expected Return on Plan Assets (2,119 ) (1,946 ) (411 ) (409 ) — — Prior Service Cost Amortization 80 81 303 327 3 47 Actuarial Loss Amortization 1,081 1,447 57 346 158 122 Sub-total 1,439 1,899 1,381 1,848 360 392 Amounts Capitalized and Deferred (412 ) (720 ) (474 ) (742 ) (103 ) (113 ) Net Periodic Benefit Cost Recognized $ 1,027 $ 1,179 $ 907 $ 1,106 $ 257 $ 279

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)Subsidiarymi	Jan. 01, 2019USD ($)	Dec. 31, 2018USD ($)	Mar. 31, 2018USD ($)
Significant Accounting Policies [Line Items]
Length Of Pipeline | mi	86
Gain on divestiture of business, pretax	$ 13.4
Gain on divestiture of business, net	9.8
Provision for income taxes	3.6
Cost of removal obligation	93.7		$ 90.7	$ 86.6
Recognition of lease assets		$ 4.2
Recognition of lease liabilities		$ 4.2
Regulatory assets	127.3		140.3	145.8
Investments in trading securities	5.1		4.8	5.1
Deferred Compensation Plan [Member]
Significant Accounting Policies [Line Items]
Investments in trading securities	$ 0.1		0	0
Maximum
Significant Accounting Policies [Line Items]
Cash equivalents maturity period	3 months
Lease term	12 months
ISO-NE Obligations
Significant Accounting Policies [Line Items]
Cash Deposits	$ 3		$ 3.5	$ 3.3
Environmental and Rate Case Costs and Other Expenditures | Recovered over the next seven years
Significant Accounting Policies [Line Items]
Regulatory assets	$ 5.9
Utilities
Significant Accounting Policies [Line Items]
Number of Subsidiaries | Subsidiary	3
Unitil Service; Unitil Realty; and Unitil Resources
Significant Accounting Policies [Line Items]
Number of Subsidiaries | Subsidiary	3

Components of Gas and Electric

Components of Gas and Electric Operating Revenue (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	$ 151.2	$ 144.5
Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	161.9	153
Rate Adjustment Mechanism Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	(10.7)	(8.5)
Gas Segment
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	86.4	87
Gas Segment | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	99.2	91.4
Gas Segment | Rate Adjustment Mechanism Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	(12.8)	(4.4)
Electric
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	64.8	57.5
Electric | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	62.7	61.6
Electric | Rate Adjustment Mechanism Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	2.1	(4.1)
Residential | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	74.4	70.2
Residential | Gas Segment | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	38.7	35.8
Residential | Electric | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	35.7	34.4
C&I | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	78.7	74.7
C&I | Gas Segment | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	54	50.6
C&I | Electric | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	24.7	24.1
Other | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	8.8	8.1
Other | Gas Segment | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	6.5	5
Other | Electric | Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	$ 2.3	$ 3.1

Allowance for Doubtful Accounts

Allowance for Doubtful Accounts Included in Accounts Receivable Net (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Valuation Allowance [Line Items]
Allowance for Doubtful Accounts	$ 1.7	$ 1.3	$ 1.6

Components of Accrued Revenue (

Components of Accrued Revenue (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Deferred Revenue Arrangement [Line Items]
Accrued Revenue	$ 40.2	$ 54.7	$ 45.1
Unbilled Revenues
Deferred Revenue Arrangement [Line Items]
Accrued Revenue	10.8	13.4	10.5
Regulatory Assets
Deferred Revenue Arrangement [Line Items]
Accrued Revenue	$ 29.4	$ 41.3	$ 34.6

Components of Exchange Gas Rece

Components of Exchange Gas Receivable (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Receivables [Line Items]
Total Exchange Gas Receivable	$ 0.4	$ 8.1	$ 0.2
Northern Utilities Inc
Receivables [Line Items]
Total Exchange Gas Receivable	0.2	7.5
Fitchburg Gas and Electric Light Company
Receivables [Line Items]
Total Exchange Gas Receivable	$ 0.2	$ 0.6	$ 0.2

Components of Gas Inventory (De

Components of Gas Inventory (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Public Utilities, Inventory [Line Items]
Weighted average cost inventory amount	$ 0.5	$ 0.8	$ 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		0.3
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, 2019	Dec. 31, 2018	Mar. 31, 2018
Regulatory Assets [Line Items]
Regulatory assets		$ 127.3	$ 140.3	$ 145.8
Less: Current Portion of Regulatory Assets	[1]	29.4	41.3	34.6
Regulatory Assets - noncurrent		97.9	99	111.2
Environmental Matters
Regulatory Assets [Line Items]
Regulatory assets		7.6	7.9	9
Other Deferred Charges
Regulatory Assets [Line Items]
Regulatory assets		11.6	10	5.2
Retirement Benefits
Regulatory Assets [Line Items]
Regulatory assets		72.4	72	85.4
Deferred Storm Charges
Regulatory Assets [Line Items]
Regulatory assets		5.9	6.3	8
Income Taxes
Regulatory Assets [Line Items]
Regulatory assets		4.7	5.7	6.3
Energy Supply & Other Rate Adjustment Mechanisms
Regulatory Assets [Line Items]
Regulatory assets		$ 25.1	$ 38.4	$ 31.9
[1]	Reflects amounts included in Accrued Revenue, discussed above, on the Company's Consolidated Balance Sheets.

Regulatory Liabilities (Detail)

Regulatory Liabilities (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Regulatory Liabilities [Line Items]
Regulatory Liabilities	$ 62.4	$ 58.5	$ 60
Less: Current Portion of Regulatory Liabilities	15	11.5	10.9
Regulatory Liabilities-noncurrent	47.4	47	49.1
Other Liabilities
Regulatory Liabilities [Line Items]
Regulatory Liabilities	0.6
Energy Supply & Other Rate Adjustment Mechanisms
Regulatory Liabilities [Line Items]
Regulatory Liabilities	13.6	11.5	10.3
Gas Pipeline Refund
Regulatory Liabilities [Line Items]
Regulatory Liabilities			0.6
Income Tax Related Liabilities
Regulatory Liabilities [Line Items]
Regulatory Liabilities	$ 48.2	$ 47	$ 49.1	$ 48.9

Fair Value of Marketable Securi

Fair Value of Marketable Securities (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities	$ 5.1	$ 4.8	$ 5.1
Deferred Compensation Plan [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities	0.1	0	0
Fair Value, Inputs, Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities	5.1	4.8	5.1
Fair Value, Inputs, Level 1 | Deferred Compensation Plan [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities	0.1
Fair Value, Inputs, Level 1 | Equity Funds
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities			1.9
Fair Value, Inputs, Level 1 | Fixed Income Funds
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities			1.6
Fair Value, Inputs, Level 1 | Money Market Funds
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities	5.1	$ 4.8	$ 1.6
Fair Value, Inputs, Level 1 | Money Market Funds | Deferred Compensation Plan [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities	$ 0.1

Components of Energy Supply Obl

Components of Energy Supply Obligations (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Contractual Obligation [Line Items]
Energy Supply Obligations-Current	$ 4.6	$ 13.4	$ 7.8
Power Supply Contract Divestitures, Noncurrent	0.5	0.6	0.8
Total Energy Supply Obligations	5.1	14	8.6
Exchange Gas Obligation
Contractual Obligation [Line Items]
Energy Supply Obligations-Current	0.2	7.5
Renewable Energy Portfolio Standards
Contractual Obligation [Line Items]
Energy Supply Obligations-Current	4.1	5.6	7.5
Power Supply Contract Divestitures
Contractual Obligation [Line Items]
Energy Supply Obligations-Current	$ 0.3	$ 0.3	$ 0.3

Dividends Declared Per Share (D

Dividends Declared Per Share (Detail)	3 Months Ended
	Mar. 31, 2019$ / shares
Group One
Dividends Payable [Line Items]
Declaration Date	Apr. 24, 2019
Date Paid (Payable)	May 29, 2019
Shareholder of Record Date	May 15, 2019
Dividend Amount	$ 0.370
Group Two
Dividends Payable [Line Items]
Declaration Date	Jan. 30, 2019
Date Paid (Payable)	Feb. 28, 2019
Shareholder of Record Date	Feb. 14, 2019
Dividend Amount	$ 0.370
Group Three
Dividends Payable [Line Items]
Declaration Date	Oct. 24, 2018
Date Paid (Payable)	Nov. 29, 2018
Shareholder of Record Date	Nov. 15, 2018
Dividend Amount	$ 0.365
Group Four
Dividends Payable [Line Items]
Declaration Date	Jul. 25, 2018
Date Paid (Payable)	Aug. 29, 2018
Shareholder of Record Date	Aug. 15, 2018
Dividend Amount	$ 0.365
Group Five
Dividends Payable [Line Items]
Declaration Date	Apr. 25, 2018
Date Paid (Payable)	May 29, 2018
Shareholder of Record Date	May 15, 2018
Dividend Amount	$ 0.365
Group Six
Dividends Payable [Line Items]
Declaration Date	Jan. 30, 2018
Date Paid (Payable)	Feb. 28, 2018
Shareholder of Record Date	Feb. 14, 2018
Dividend Amount	$ 0.365

Significant Segment Financial D

Significant Segment Financial Data (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other Operating Revenue - Non-Regulated	$ 0.9	$ 1.3
Total Operating Revenues	152.1	145.8
Segment Profit (Loss)	26.5	15.6
Identifiable Segment Assets	1,290.2	1,244.3	$ 1,298.3
Capital Expenditures	10.9	10.1
Billed and Unbilled Revenue
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	161.9	153
Rate Adjustment Mechanism Revenue
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	(10.7)	(8.5)
Gas Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	86.4	87
Segment Profit (Loss)	13.7	12.6
Identifiable Segment Assets	771.6	712.6
Capital Expenditures	3.3	3.6
Gas Segment | Billed and Unbilled Revenue
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	99.2	91.4
Gas Segment | Rate Adjustment Mechanism Revenue
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	(12.8)	(4.4)
Electric
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	64.8	57.5
Segment Profit (Loss)	1.9	3
Identifiable Segment Assets	502.3	481.8
Capital Expenditures	6.6	6
Electric | Billed and Unbilled Revenue
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	62.7	61.6
Electric | Rate Adjustment Mechanism Revenue
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	2.1	(4.1)
All Other Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Segment Profit (Loss)	0.8	(0.4)
Identifiable Segment Assets	16.2	42.8
Capital Expenditures	1	0.5
Unregulated Operation
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other Operating Revenue - Non-Regulated	0.9	1.3
Total Operating Revenues	0.9	1.3
Segment Profit (Loss)	10.1	0.4
Identifiable Segment Assets	$ 0.1	$ 7.1

Details on Long Term Debt (Deta

Details on Long Term Debt (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Debt Instrument [Line Items]
Total Long-Term Debt	$ 395.9	$ 409.3	$ 396
Less: Unamortized Debt Issuance Costs	3.4	3.5	3.2
Long-Term Debt	392.5	405.8	392.8
Less: Current Portion	19.5	18.4	29.8
Total Long-Term Debt, Less Current Portion	373	387.4	363
Long-Term Debt	392.5	405.8	392.8
6.33% Senior Notes, Due May 1, 2022
Debt Instrument [Line Items]
Total Long-Term Debt	20	20	20
3.70% Senior Notes, Due August 1, 2026
Debt Instrument [Line Items]
Total Long-Term Debt	30	30	30
Unitil Energy Systems Inc | First Mortgage Bonds 5.24% Senior Secured Notes, Due March 2, 2020
Debt Instrument [Line Items]
Total Long-Term Debt	5	10	10
Unitil Energy Systems Inc | First Mortgage Bonds 8.49% Senior Secured Notes, Due October 14, 2024
Debt Instrument [Line Items]
Total Long-Term Debt	6	6	7.5
Unitil Energy Systems Inc | First Mortgage Bonds 6.96% Senior Secured Notes, Due September 1, 2028
Debt Instrument [Line Items]
Total Long-Term Debt	20	20	20
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
Fitchburg Gas and Electric Light Company | 6.75% Senior Notes, Due November 30, 2023
Debt Instrument [Line Items]
Total Long-Term Debt	5.7	5.7	7.6
Fitchburg Gas and Electric Light Company | 6.79% Senior Notes, Due October 15, 2025
Debt Instrument [Line Items]
Total Long-Term Debt	10	10	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	12	12	12
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
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 | 6.95% Senior Notes, Due December 3, 2018
Debt Instrument [Line Items]
Total Long-Term Debt			10
Northern Utilities Inc | 5.29% Senior Notes, Due March 2, 2020
Debt Instrument [Line Items]
Total Long-Term Debt	8.2	16.6	16.6
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
Granite State Gas Transmission Inc | 7.15% Senior Notes, Due December 15, 2018
Debt Instrument [Line Items]
Total Long-Term Debt			3.3
Granite State Gas Transmission Inc | 3.72% Senior Notes, Due November 1, 2027
Debt Instrument [Line Items]
Total Long-Term Debt	$ 15	$ 15	$ 15

Details on Long Term Debt (Pare

Details on Long Term Debt (Parenthetical) (Detail)	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
6.33% Senior Notes, Due May 1, 2022
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
First Mortgage Bonds 5.24% Senior Secured Notes, Due March 2, 2020 | Unitil Energy Systems Inc
Debt Instrument [Line Items]
Stated interest rate	5.24%	5.24%	5.24%
Debt instrument due date	Mar. 2, 2020	Mar. 2, 2020	Mar. 2, 2020
First Mortgage Bonds 8.49% Senior Secured Notes, Due October 14, 2024 | Unitil Energy Systems Inc
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 | Unitil Energy Systems Inc
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 | Unitil Energy Systems Inc
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 | Unitil Energy Systems Inc
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
First Mortgage Bonds 4.18% Senior Secured Notes Due November 30, 2048 | Unitil Energy Systems Inc
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 | Fitchburg Gas and Electric Light Company
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 | Fitchburg Gas and Electric Light Company
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 | Fitchburg Gas and Electric Light Company
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
3.52% Senior Notes, Due November 1, 2027 | Northern Utilities Inc
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 | Fitchburg Gas and Electric Light Company
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 | Fitchburg Gas and Electric Light Company
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 | Fitchburg Gas and Electric Light Company
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
4.32% Senior Notes, Due November 1, 2047 | Fitchburg Gas and Electric Light Company
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
4.32% Senior Notes, Due November 1, 2047 | Northern Utilities Inc
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
6.95% Senior Notes, Due December 3, 2018 | Northern Utilities Inc
Debt Instrument [Line Items]
Stated interest rate	6.95%	6.95%	6.95%
Debt instrument due date	Dec. 3, 2018	Dec. 3, 2018	Dec. 3, 2018
5.29% Senior Notes, Due March 2, 2020 | Northern Utilities Inc
Debt Instrument [Line Items]
Stated interest rate	5.29%	5.29%	5.29%
Debt instrument due date	Mar. 2, 2020	Mar. 2, 2020	Mar. 2, 2020
7.72% Senior Notes, Due December 3, 2038 | Northern Utilities Inc
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 | Northern Utilities Inc
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
7.15% Senior Notes, Due December 15, 2018 | Granite State Gas Transmission Inc
Debt Instrument [Line Items]
Stated interest rate	7.15%	7.15%	7.15%
Debt instrument due date	Dec. 15, 2018	Dec. 15, 2018	Dec. 15, 2018
3.72% Senior Notes, Due November 1, 2027 | Granite State Gas Transmission Inc
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

Estimated Fair Value of Long Te

Estimated Fair Value of Long Term Debt (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Estimated Fair Value of Long-Term Debt	$ 418	$ 422	$ 428

Debt and Financing Arrangemen_3

Debt and Financing Arrangements - Additional Information (Detail) - USD ($)	Jul. 25, 2018	Nov. 30, 2018	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Oct. 30, 2015
Line of Credit Facility [Line Items]
Weighted average interest rate on short term borrowings			3.70%	2.90%	3.30%
Gain on divestiture of business, net			$ 9,800,000
Issuance of long-term debt		$ 500,000
Capital lease obligation, total capitalized cost			4,967,000	$ 8,000,000	$ 5,800,000
Capital lease obligation, current			3,000,000	3,100,000	3,100,000
Capital lease obligation, noncurrent			1,900,000	4,900,000	2,700,000
Accounts Payable			33,000,000	30,100,000	42,600,000
Guarantee outstanding			4,300,000
Total rental expense under operating leases			400,000	500,000
Operating lease obligations			400,000
Net Utility Plant			1,037,800,000	972,400,000	1,036,800,000
Current operating lease obligation			1,100,000
Non-current operating lease obligation			$ 2,800,000
Operating lease, weighted average remaining lease term			3 years 10 months 24 days
Operating lease, weighted average discount rate percentage			5.30%
Financing Arrangements
Line of Credit Facility [Line Items]
Capital lease obligation, current			$ 2,800,000
Capital lease obligation, noncurrent			1,600,000
Assets under Capital Leases
Line of Credit Facility [Line Items]
Net Utility Plant			14,900,000	15,000,000	15,000,000
Net Utility Plant, accumulated amortization			$ 1,800,000	1,100,000	1,700,000
Unitil Service Corp.
Line of Credit Facility [Line Items]
Capital lease obligation, total capitalized cost						$ 13,400,000
Capital lease obligation, maturity period			Sep. 30, 2020
Capital lease obligation, current			$ 2,800,000
Capital lease obligation, noncurrent			1,600,000
Northern Utilities Inc
Line of Credit Facility [Line Items]
Natural gas storage inventory			2,200,000	1,000,000	8,400,000
Accounts Payable			2,100,000	1,000,000	900,000
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			75,700,000
Repayments of lines of credit			$ 92,700,000
Credit Facility | Amended Credit Facility [Member]
Line of Credit Facility [Line Items]
Revolving credit facility	$ 120,000,000
Sublimit for the issuance of standby letters of credit	$ 25,000,000
Revolving credit facility termination date	Jul. 25, 2023
Increase in borrowing limit	$ 50,000,000
Credit Facility | Amended Credit Facility [Member] | London Interbank Offered Rate
Line of Credit Facility [Line Items]
Credit facility, daily fluctuating rate of interest	1.125%
Credit Facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Percentage of capitalization			The affirmative and negative covenants under the Credit Facility shall 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, 2018, March 31, 2017 and December 31, 2017, the Company was in compliance with the covenants contained in the Credit Facility in effect on that date.
4.18% First Mortgage Bonds, Due November 30, 2048 | Unitil Energy
Line of Credit Facility [Line Items]
Long-term debt, aggregate principal amount		$ 30,000,000
Long-term debt, stated interest rate		4.18%
Long-term debt, maturity date		Nov. 30, 2048

Borrowing Limits Amounts Outsta

Borrowing Limits Amounts Outstanding and Amounts Available under Revolving Credit Facility (Detail) - USD ($)	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Debt Instrument [Line Items]
Short-Term Borrowings Outstanding	$ 65,800,000	$ 82,800,000	$ 45,300,000
Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit facility, limit	120,000,000	120,000,000	120,000,000
Short-Term Borrowings Outstanding	65,800,000	82,800,000	45,300,000
Available revolving credit facility	$ 54,200,000	$ 37,200,000	$ 74,700,000

Debt and Financing Arrangemen_4

Debt and Financing Arrangements - Classification of the Company Lease Obligations (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Operating Lease Obligations:
Other Current Liabilities (current portion)	$ 1,100
Other Noncurrent Liabilities (long-term portion)	2,800
Total Operating Lease Obligations	3,855
Capital Lease Obligations:
Other Current Liabilities (current portion)	3,000	$ 3,100	$ 3,100
Other Noncurrent Liabilities (long-term portion)	1,900	2,700	4,900
Total Capital Lease Obligations	4,967	5,800	8,000
Total Lease Obligations	$ 8,800	$ 5,800	$ 8,000

Future Operating Lease Payment

Future Operating Lease Payment Obligations and Future Minimum Lease Payments under Capital Leases (Detail) - USD ($)	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Operating leases
Rest of 2019	$ 967,000
2019		$ 1,372,000
2020	1,141,000	1,138,000
2021	972,000	969,000
2022	691,000	689,000
2023	391,000	390,000
2024-2028	119,000	120,000
Total Payments	4,281,000	4,678,000
Less: Interest	426,000
Amount of Lease Obligations Recorded on Consolidated Balance Sheets	3,855,000
Capital lease
Rest of 2019	2,369,000
2019		3,069
2020	2,576,000	2,535
2021	96,000	93
2022	33,000	32
2023	15,000	14
2024-2028	0	0
Total Payments	5,089,000	5,743
Less: Interest	122,000
Amount of Lease Obligations Recorded on Consolidated Balance Sheets	$ 4,967,000	$ 5,800,000	$ 8,000,000

Common Stock And Preferred St_3

Common Stock And Preferred Stock - Additional Information (Detail) - USD ($)	Jan. 29, 2019	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Class of Stock [Line Items]
Common stock, shares outstanding		14,916,044	14,860,123	14,876,955
Common stock, shares issued		5,939	7,812
Proceeds from Issuance of Common Stock		$ 300,000	$ 300,000
Share based compensation expense		$ 1,700,000	1,800,000
Percentage of fully-vested restricted stock units that directors will receive in common shares when settled		70.00%
Percentage of fully-vested restricted stock units that directors will receive in cash when settled		30.00%
Fair value of liabilities associated with fully vested RSUs that will be settled in cash		$ 1,400,000	1,000,000	$ 1,300,000
Preferred Stock		200,000	200,000	$ 200,000
Maximum
Class of Stock [Line Items]
Dividend declared		100,000	$ 100,000
Dividend and Distribution Reinvestment and Share Purchase Plan
Class of Stock [Line Items]
Proceeds from Issuance of Common Stock		$ 314,700
Dividend and Distribution Reinvestment and Share Purchase Plan | Average
Class of Stock [Line Items]
Common stock price per share		$ 52.98
Dividend and Distribution Reinvestment and Share Purchase Plan | Common Stock
Class of Stock [Line Items]
Common stock, shares issued		5,939
Unitil Energy Systems Inc | Series 6
Class of Stock [Line Items]
Preferred stock, outstanding		1,893	1,893	1,893
Preferred Stock		$ 200,000	$ 200,000	$ 200,000
Dividend rate		6.00%	6.00%	6.00%
Restricted Stock
Class of Stock [Line Items]
Restricted stock vesting period		4 years
Restricted stock non-vested		60,496	90,882
Restricted stock weighted average grant date fair value		$ 46.23	$ 41.93
Unrecognized share based compensation		$ 1,300,000
Share compensation recognition period		3 years
Restricted Stock Units Granted	33,150
Aggregate Market Value	$ 1,600,000
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			52,677
Weighted-Average Stock Price			$ 36.27

Restricted Stock Units Issued (

Restricted Stock Units Issued (Detail) - Restricted Stock Units (RSUs)	3 Months Ended
	Mar. 31, 2019$ / sharesshares
Restricted Stock Units
Beginning Restricted Stock Units | shares	61,789
Restricted Stock Units Granted | shares	0
Dividend Equivalents Earned | shares	417
Restricted Stock Units Settled | shares	0
Ending Restricted Stock Units | shares	62,206
Weighted-Average Stock Price
Beginning Restricted Stock Units | $ / shares	$ 38.25
Restricted Stock Units Granted | $ / shares	0
Dividend Equivalents Earned | $ / shares	54.91
Restricted Stock Units Settled | $ / shares	0
Ending Restricted Stock Units | $ / shares	$ 38.36

Regulatory Matters - Additional

Regulatory Matters - Additional Information (Detail)

May 01, 2019USD ($)

Feb. 28, 2019USD ($)

Oct. 31, 2018USD ($)

May 07, 2018USD ($)

May 02, 2018USD ($)

May 01, 2018USD ($)

Apr. 30, 2018USD ($)

Feb. 28, 2018USD ($)

Jan. 01, 2018USD ($)

Aug. 01, 2017USD ($)

Jun. 30, 2017MW

Apr. 20, 2017USD ($)

Oct. 31, 2018USD ($)

Dec. 31, 2017

Mar. 31, 2019

Jun. 30, 2027MW

Dec. 31, 2022MWh

Apr. 03, 2019USD ($)

Jul. 31, 2018MWhMW

Jul. 23, 2018MW

Regulatory Assets [Line Items]

Annual revenue adjustment

$ 2,300,000

Tax Year 2018

Regulatory Assets [Line Items]

Corporate income tax rate

21.00%

21.00%

Scenario Forecast

Regulatory Assets [Line Items]

Annual revenue adjustment

$ 1,400,000

Unitil Energy Systems Inc | New Hampshire

Regulatory Assets [Line Items]

Permanent rate increase

$ 4,100,000

Increase (decrease) in annual revenue

$ 340,000

$ 300,000

Reduction of federal tax decrease

2,200,000

Reconciliation adjustment of recouped difference between temporary rates and final rates

1,400,000

Unitil Energy Systems Inc | New Hampshire | Second rate Step Adjustments [Member]

Regulatory Assets [Line Items]

Increase (decrease) in annual revenue

$ 3,300,000

Fitchburg Gas and Electric Light Company

Regulatory Assets [Line Items]

Increase (decrease) in annual revenue

$ 800,000

$ 900,000

Annual revenue adjustment

$ 400,000

Amendment effective date

Nov. 1, 2018

Fitchburg Gas and Electric Light Company | Subsequent Event

Regulatory Assets [Line Items]

Recovery amount

$ 400,000

Fitchburg Gas and Electric Light Company | Offshore Wind Energy

Regulatory Assets [Line Items]

Power generation facility | MW

400

400

Remuneration percentage

2.75%

Fitchburg Gas and Electric Light Company | Qualified Clean Energy

Regulatory Assets [Line Items]

Power generation capacity | MWh

9,554,940

Fitchburg Gas and Electric Light Company | Minimum | Offshore Wind Energy

Regulatory Assets [Line Items]

Power generation facility | MW

400

Pro rata percentage share of contracts

1.00%

Fitchburg Gas and Electric Light Company | Scenario Forecast

Regulatory Assets [Line Items]

Power generation capacity | MWh

9,450,000

Fitchburg Gas and Electric Light Company | Scenario Forecast | Offshore Wind Energy

Regulatory Assets [Line Items]

Power generation facility | MW

1,600

Northern Utilities Inc

Regulatory Assets [Line Items]

Increase (decrease) in annual revenue

$ 2,600,000

$ 3,200,000

$ 2,600,000

Increase in annual base rate

2.10%

2.40%

Annual TIRA Adjustment

$ 1,000,000

$ 1,100,000

TIRA initial term

Four years

Northern Utilities Inc | Revenue Offset [Member]

Regulatory Assets [Line Items]

Increase (decrease) in annual revenue

$ (1,700,000)

Northern Utilities Inc | Maine

Regulatory Assets [Line Items]

Increase (decrease) in annual revenue

$ 2,100,000

Percentage of approved return on equity

9.50%

Percentage of approved return on equity, reflecting on equity

50.00%

Percentage of approved return on equity, reflecting on debt

50.00%

TIRA extended term

8 years

Northern Utilities Inc | Maine | Revenue Offset [Member]

Regulatory Assets [Line Items]

Increase (decrease) in annual revenue

$ 2,200,000

Environmental Matters - Additio

Environmental Matters - Additional Information (Detail) - Environmental Restoration Costs	3 Months Ended
	Mar. 31, 2019
Maine
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, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Environmental Exit Cost [Line Items]
Total Balance at Beginning of Period	$ 2	$ 2.1
Additions	0.1	0.2
Less: Payments / Reductions	0.1	0.2
Total Balance at End of Period	2	2.1
Less: Current Portion			$ 0.6	$ 0.6
Noncurrent Balance			1.4	1.5
Total Balance at End of period	2	2.1	2	2.1
Fitchburg Gas and Electric Light Company
Environmental Exit Cost [Line Items]
Total Balance at Beginning of Period		0.1
Additions		0.1
Less: Payments / Reductions		0.1
Total Balance at End of Period		0.1
Less: Current Portion				0.1
Total Balance at End of period		0.1		0.1
Northern Utilities Inc
Environmental Exit Cost [Line Items]
Total Balance at Beginning of Period	2	2
Additions	0.1	0.1
Less: Payments / Reductions	0.1	0.1
Total Balance at End of Period	2	2
Less: Current Portion			0.6	0.5
Noncurrent Balance			1.4	1.5
Total Balance at End of period	$ 2	$ 2	$ 2	$ 2

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2018	Mar. 31, 2018
Income Taxes [Line Items]
Regulatory Liability		$ 62,400,000	$ 58,500,000			$ 60,000,000
Regulatory liability, expected flow back to customers		$ 47,100,000		$ 48,900,000
Tax provision			2,400,000
Net Operating Loss Carryforwards			10,800,000		$ 3,700,000
Calculated federal current tax			7,700,000
Deferred tax assets, operating loss carryforwards, federal			7,700,000
Federal current taxes payable			$ 0
NOL carryforward assets expiration date			2029
Alternative minimum tax credit carryforwards	$ 3,500,000			3,500,000
Reconciling Mechanisms
Income Taxes [Line Items]
Regulatory liability, expected pass back to ratepayers				1,800,000
Net Operating Loss Carryforward Assets
Income Taxes [Line Items]
Regulatory liability, expected pass back to ratepayers			$ 3,400,000	5,800,000
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
Fitchburg Gas and Electric Light Company
Income Taxes [Line Items]
Average Rate Assumption Method estimated flow back period		15 years
Income Tax Related Liabilities
Income Taxes [Line Items]
Regulatory Liability	$ 48,900,000	$ 48,200,000	$ 47,000,000	$ 48,900,000		$ 49,100,000
Electric Ratepayers | Fitchburg Gas and Electric Light Company
Income Taxes [Line Items]
Regulatory liability, expected flow back to customers		10,100,000
Gas Ratepayers | Fitchburg Gas and Electric Light Company
Income Taxes [Line Items]
Regulatory liability, expected flow back to customers		$ 10,400,000
Tax Year 2018
Income Taxes [Line Items]
Corporate federal income tax	21.00%	21.00%
Federal, Maine, Massachusetts, and New Hampshire Tax Authorities
Income Taxes [Line Items]
Tax examination description		The Company remains subject to examination by Federal, Maine, Massachusetts, and New Hampshire tax authorities for the tax periods ended December 31, 2015; December 31, 2016; and December 31, 2017.

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, 2019	Mar. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Discount Rate	4.25%	3.60%
Rate of Compensation Increase	3.00%	3.00%
Expected Long-term rate of return on plan assets	7.75%	7.75%
Health Care Cost Trend Rate Assumed for Next Year	7.00%	7.50%
Ultimate Health Care Cost Trend Rate	4.50%	4.50%
Year that Ultimate Health Care Cost Trend Rate is reached	2024	2024

Components of Retirement Plan C

Components of Retirement Plan Costs (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service Cost	$ 776	$ 848
Interest Cost	1,621	1,469
Expected Return on Plan Assets	(2,119)	(1,946)
Prior Service Cost Amortization	80	81
Actuarial Loss Amortization	1,081	1,447
Sub-total	1,439	1,899
Amounts Capitalized and Deferred	(412)	(720)
Net Periodic Benefit Cost Recognized	1,027	1,179
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Service Cost	576	733
Interest Cost	856	851
Expected Return on Plan Assets	(411)	(409)
Prior Service Cost Amortization	303	327
Actuarial Loss Amortization	57	346
Sub-total	1,381	1,848
Amounts Capitalized and Deferred	(474)	(742)
Net Periodic Benefit Cost Recognized	907	1,106
Supplemental Employee Retirement Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Service Cost	60	122
Interest Cost	139	101
Prior Service Cost Amortization	3	47
Actuarial Loss Amortization	158	122
Sub-total	360	392
Amounts Capitalized and Deferred	(103)	(113)
Net Periodic Benefit Cost Recognized	$ 257	$ 279

Retirement Benefit Obligation_2

Retirement Benefit Obligations - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Contributions to benefit plan	$ 1.3
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Contributions to benefit plan	0.4
Supplemental Employee Retirement Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Benefit payments under SERP Plan	0.1
Expected additional benefit payments for the remainder of 2018	$ 0.5