Supplemental Financial Statement Information (Balance Sheet Information) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other assets:
Long-term investments	$ 364,212	$ 238,882
Company owned life insurance policies	0	50,081
Other (net of allowance of $16,445 in 2020)	127,302	111,493
Other assets	16,445	0	$ 0
Total	491,514	400,456
Accounts payable and accrued liabilities:
Accounts payable	295,173	282,125
Customer deposits	165,774	115,889
Employee related liabilities	232,236	219,995
Other	187,433	175,681
Total	880,616	793,690
Other noncurrent liabilities:
Pension liabilities	235,439	214,742
Postretirement medical benefits	153,838	147,972
Other	47,738	37,804
Total	$ 437,015	$ 400,518

Sum of the carrying values as of the balance sheet date of obligations incurred through that date and due within one year (or the operating cycle, if longer), including liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received, taxes, interest, rent and utilities, accrued salaries and bonuses, payroll taxes and fringe benefits.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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