Impairment Charges (Narrative) (Details)	3 Months Ended		12 Months Ended
	Sep. 30, 2017 USD ($)	Jun. 30, 2016 USD ($) business	Dec. 31, 2018 USD ($) business	Dec. 31, 2017 USD ($) reporting_unit	Dec. 31, 2016 USD ($)	Dec. 31, 2015
Goodwill [Line Items]
Impairments			$ 5,400,000	$ 4,900,000	$ 4,100,000
Number of reporting units tested for goodwill impairment | reporting_unit				2
Goodwill impairment, including discontinued operations			0	$ 0
Goodwill			$ 833,800,000	822,200,000	791,300,000
Goodwill impairment, including discontinued operations, held-for-sale	$ 1,300,000
Impairment of other long-lived assets	$ 3,300,000
Minimum
Goodwill [Line Items]
Fair values of reporting units in excess of carrying amount (as a percent) (at least)						115.00%
Maximum
Goodwill [Line Items]
Fair values of reporting units in excess of carrying amount (as a percent) (at least)						600.00%
Work Furniture and Aerospace reporting units
Goodwill [Line Items]
Goodwill				$ 157,400,000
Work Furniture and Aerospace reporting units | Minimum
Goodwill [Line Items]
Fair values of reporting units in excess of carrying amount (as a percent) (at least)				75.00%
Drawn Wire Unit
Goodwill [Line Items]
Number of businesses sold | business			1
CVP reporting unit
Goodwill [Line Items]
Goodwill impairment, including discontinued operations		$ 3,700,000
Number of businesses sold | business		1
Number of businesses owned prior to sale | business		2
Number of remaining businesses | business		1
Furniture Products
Goodwill [Line Items]
Impairments			$ 5,100,000	$ 0	0
Goodwill			$ 193,100,000	$ 196,200,000	$ 187,900,000