Summary of Significant Accounting and Reporting Policies (Narrative) (Details)	12 Months Ended
	Dec. 31, 2020 USD ($) plan shares	Dec. 31, 2019 USD ($) shares	Dec. 31, 2018 USD ($) shares
Summary Of Significant Accounting And Reporting Policies [Line Items]
Technology investments	$ 4,000,000.0	$ 9,000,000.0
Decrease in the balance of technology investments	5,000,000.0
Equity Investment losses were considered to be other than temporary	0	0
Allowance for obsolete and slow moving inventories	10,400,000	7,600,000
Depreciation expense	82,400,000	82,300,000	$ 79,700,000
Advertising and promotional costs	2,000,000.0	3,000,000.0	2,500,000
Repair and maintenance of plant and equipment	$ 22,600,000	$ 28,900,000	$ 28,900,000
Weighted average remaining lease term	2 years
Weighted average discount rate	1.20%
Number of shares related to stock plans not included in diluted average common shares outstanding because their effect would be antidilutive | shares	403,071	247,855	698,019
Employee Stock Option
Summary Of Significant Accounting And Reporting Policies [Line Items]
Number of plans | plan	2
Minimum
Summary Of Significant Accounting And Reporting Policies [Line Items]
Remaining lease term	1 year
Maximum
Summary Of Significant Accounting And Reporting Policies [Line Items]
Remaining lease term	5 years
Buildings and improvements | Minimum
Summary Of Significant Accounting And Reporting Policies [Line Items]
Minimum estimated useful life, in years	7 years
Buildings and improvements | Maximum
Summary Of Significant Accounting And Reporting Policies [Line Items]
Minimum estimated useful life, in years	30 years
Machinery and equipment | Minimum
Summary Of Significant Accounting And Reporting Policies [Line Items]
Minimum estimated useful life, in years	3 years
Machinery and equipment | Maximum
Summary Of Significant Accounting And Reporting Policies [Line Items]
Minimum estimated useful life, in years	10 years