Goodwill and Other Intangible Assets (Goodwill) (Details) $ in Thousands	9 Months Ended
Sep. 30, 2017 USD ($)
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	$ 348,842
Accumulated impairment losses, beginning balance	(58,143)
Goodwill, net, beginning balance	290,699
Foreign currency translation adjustments	(42)
Goodwill, gross, ending balance	348,800
Accumulated impairment losses, ending balance	(58,143)
Goodwill, net, ending balance	290,657
Office Furniture
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	165,643
Accumulated impairment losses, beginning balance	(58,000)
Goodwill, net, beginning balance	107,643
Foreign currency translation adjustments	(42)
Goodwill, gross, ending balance	165,601
Accumulated impairment losses, ending balance	(58,000)
Goodwill, net, ending balance	107,601
Hearth Products
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	183,199
Accumulated impairment losses, beginning balance	(143)
Goodwill, net, beginning balance	183,056
Foreign currency translation adjustments	0
Goodwill, gross, ending balance	183,199
Accumulated impairment losses, ending balance	(143)
Goodwill, net, ending balance	$ 183,056

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

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Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount before accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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