Employee and Retiree Benefit Plans - Narrative (Details) $ in Thousands	12 Months Ended			120 Months Ended
	Dec. 31, 2020 USD ($) investment fund	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2020 USD ($) fund
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Increase in pension and other postretirement benefit liabilities	$ 63,000
Future annual rate of increase in cost of health care to measure postretirement benefit obligations	6.20%			6.20%
Ultimate rate of health care cost	4.50%			4.50%
Plan asset, maximum investment in any one issuer	10.00%			10.00%
Equity securities minimum market capitalization	$ 100,000			$ 100,000
Fixed income portfolio, maximum average maturity years	11 years
Number of funds (in funds) | fund	2			2
Weighted average expected return on plan asset	4.70%
Basis used to determine expected return on plan asset, average expected investment expenses	0.60%
Perentage return on plan assets over the last ten years				7.55%
Number of investments in hedge funds and other alternative investments (in investments) | investment	3
Defined benefit plan, percentage of employer's matching contribution	6.00%
Thrift plan expense	$ 6,600	$ 8,400	$ 5,200
Equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Weighted average expected return on plan asset	3.90%
Fixed income securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Weighted average expected return on plan asset	0.80%
Equity funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Domestic plan, investment notice period	10 days
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions to benefit plans	$ 30,178	$ 25,915
Weighted average expected return on plan asset	4.43%	5.05%
Pension Benefits | U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions to benefit plans	$ 30,500
Contributions to benefit plans, next fiscal year	31,300			$ 31,300
Pension Benefits | Foreign Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions to benefit plans, next fiscal year	5,300			5,300
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions to benefit plans	$ 1,770	$ 2,333
Weighted average expected return on plan asset	0.00%	0.00%
Other Postretirement Benefits | U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions to benefit plans	$ 1,800
Contributions to benefit plans, next fiscal year	$ 5,300			$ 5,300
Second investment
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Domestic plan, investment notice period	90 days
Third investment
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Domestic plan, investment notice period	95 days
Domestic plan, investment lock up period	2 years