CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net unrealized gain (loss) from pension and postretirement plans, tax	$ (609)	$ (1,846)	$ (12,677)
Subsidiaries [Member]
Net unrealized gain (loss) from pension and postretirement plans, tax	1,897	539	(9,844)
Amortization of Financing Cash Flow Hedge Contracts to Earnings Tax	$ 102	$ 102	$ 102

Amount, after reclassification adjustment, of tax (expense) benefit for (increase) decrease in accumulated other comprehensive income of defined benefit plan.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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