Stockholder's Equity - Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Loss (Detail) - USD ($) shares in Millions		3 Months Ended			12 Months Ended
		Mar. 31, 2022	Sep. 30, 2021	Mar. 31, 2021	Dec. 31, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		$ 1,303,000		$ (2,865,000)	$ (2,865,000)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		2,498,000		2,372,000
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(1,951,000)		(2,145,000)
Net current-period other comprehensive income (loss)		547,000		227,000
Ending balance		$ 1,850,000		(2,638,000)	$ 1,303,000
Stock Issued During Period, Shares, Dividend Reinvestment Plan		0.1			0.1
Stock Issued During Period, Value, Dividend Reinvestment Plan		$ 137.45			$ 125.71
Proceeds from Issuance of Common Stock, Dividend Reinvestment Plan		$ 3,200,000			$ 15,200,000
Stock Issued During Period, Shares, Dividend Reinvestment Plan		0.1			0.1
Stock Issued During Period, Value, Dividend Reinvestment Plan		$ 137.45			$ 125.71
Proceeds from Issuance of Common Stock, Dividend Reinvestment Plan		3,200,000			15,200,000
Maximum [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Proceeds from Stock Plans			$ 75,000,000
Proceeds from Stock Plans			$ 75,000,000
UnrealizedGainsLossesFromDefinedBenefitPensionAndPostretirementPlanItems [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(3,268,000)		(5,146,000)	(5,146,000)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		18,000		63,000
Net current-period other comprehensive income (loss)		18,000		63,000
Ending balance		(3,250,000)		(5,083,000)	(3,268,000)
Accumulated (Gain) Loss from Commodity Contracts Cash Flows Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		4,571,000		2,309,000	2,309,000
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		2,498,000		2,371,000
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(1,969,000)		(2,205,000)
Net current-period other comprehensive income (loss)		529,000		166,000
Ending balance		5,100,000		2,475,000	4,571,000
Accumulated (Gain) Loss from Interest Rate Swap Cash Flows Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	[1]	0		(28,000)	(28,000)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	[1]	0		1,000
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[1]	0		(3,000)
Net current-period other comprehensive income (loss)	[1]	0		(2,000)
Ending balance	[1]	$ 0		$ (30,000)	$ 0

[1] 1) All of our interest rate swaps expired at December 31, 2021.