Benefit Plans Level 3 Rollforward - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Actual return on plan assets:
Defined Benefit Plan, Plan Assets, Foreign Currency Translation Gain (Loss)	$ 80,307	$ 15,548
Defined Benefit Plan, Plan Assets, Amount	1,093,784	964,774	$ 862,951
Real Asset Mutual Funds, Commodities
Actual return on plan assets:
Defined Benefit Plan, Plan Assets, Amount	53,088	47,697
Real Asset Mutual Funds, Commodities | Fair Value, Inputs, Level 3 [Member]
Actual return on plan assets:
Defined Benefit Plan, Plan Assets, Amount	0	0
Fixed Income Mutual Funds, Insurance Contracts
Actual return on plan assets:
Defined Benefit Plan, Plan Assets, Amount	44,848	38,945
Fixed Income Mutual Funds, Insurance Contracts | Fair Value, Inputs, Level 3 [Member]
Actual return on plan assets:
Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Actual Return (Loss) on Plan Assets Still Held	22	14
Defined Benefit Plan Sales, Total		(54)
Defined Benefit Plan, Purchases, Total	99	83
Defined Benefit Plan, Plan Assets, Foreign Currency Translation Gain (Loss)	186	(18)
Defined Benefit Plan, Plan Assets, Amount	$ 1,793	$ 1,486	$ 1,461