Pension Plans And Other Postretirement Benefits (Tables)	9 Months Ended
	Sep. 30, 2021
Pension Plans And Other Postretirement Benefits [Abstract]
Components Of Net Periodic Benefit Costs	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