Pension Plans And Other Postretirement Benefits	9 Months Ended
	Sep. 30, 2021
Pension Plans And Other Postretirement Benefits [Abstract]
Pension Plans And Other Postretirement Benefits	Note 10 – Pension Plans and Other Postretirement Benefits   The Company maintains a qualified defined benefit pension plan (the “Pension Plan”), a nonqualified pension plan, and other postretirement benefit plans for certain of its employees. On March 16, 2020, we completed the Peoples Gas Acquisition and assumed the pension and other postretirement benefit plans for its employees. The operating results of Peoples has been included in our consolidated financial statements since the date of acquisition. On April 1, 2020, the Company merged the pension plans acquired in the Peoples Gas Acquisition into the Company’s legacy Pension Plan. The following tables provide the components of net periodic benefit cost for the Company’s pension and other postretirement benefit plans: Pension Benefits Three Months Ended Nine Months Ended September 30, September 30, 2021 2020 2021 2020Service cost $ 775 $ 992 $ 2,728 $ 2,783Interest cost 3,351 3,642 9,667 10,003Expected return on plan assets (5,733) (5,676) (17,432) (15,573)Amortization of prior service cost 140 148 419 444Amortization of actuarial loss 555 1,992 2,352 5,976Net periodic benefit cost $ (912) $ 1,098 $ (2,266) $ 3,633 Other Postretirement Benefits Three Months Ended Nine Months Ended September 30, September 30, 2021 2020 2021 2020Service cost $ 698 $ 662 $ 2,094 $ 1,614Interest cost 840 989 2,520 2,707Expected return on plan assets (1,039) (1,111) (3,117) (2,969)Amortization of prior service credit (108) (116) (324) (348)Amortization of actuarial loss 55 156 165 468Net periodic benefit cost $ 446 $ 580 $ 1,338 $ 1,472 The net periodic benefit cost is based on estimated values and an extensive use of assumptions about the discount rate, expected return on plan assets, the rate of future compensation increases received by the Company’s employees, mortality, turnover, and medical costs. The Company presents the components of net periodic benefit cost other than service cost in the consolidated statements of operations and comprehensive income on the line item “Other”. The Company made cash contributions of $14,775 to its Pension Plan during the first nine months of 2021, which completed the Company’s expected cash contributions for the year. During the second quarter of 2021, the Company remeasured its Pension Plan’s obligations and assets due to a plan amendment, effective May 1, 2021, that ended benefit accrual for a certain group of participants in the Pension Plan.  The remeasurement resulted in a decrease in pension benefit obligation and regulatory assets totaling $20,732, of which $17,520 is attributable to the increase in the discount rate assumption from 2.57% at December 31, 2020 to 3.08% at May 1, 2021, and $3,212 is due to the curtailment of benefits. All other assumptions used for the remeasurement were consistent with the valuation as of December 31, 2020.