Acquisitions, Goodwill And Other Intangible Assets (Narrative) (Details) - USD ($)	1 Months Ended								3 Months Ended			9 Months Ended		12 Months Ended
	Aug. 31, 2015	Apr. 30, 2015	Jan. 31, 2015	Aug. 31, 2014	Jun. 30, 2014	Apr. 30, 2014	Mar. 31, 2014	Feb. 28, 2014	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	Jul. 31, 2015
Business Acquisition
Long-term purchase commitment, time period						6 years
Pre-tax loss on sale of business assets											$ 2,000,000
Proceeds from sale of aluminum extrusion assets, cash received						$ 300,000
Proceeds from first installment of note receivable												$ 0	$ 750,000
Gain on contract termination									$ 1,600,000
Note Receivable for Sale of Assets
Business Acquisition
Notes receivable						$ 7,200,000.0
Term of note receivable						4 years
Proceeds from first installment of note receivable														$ 1,800,000
Financing receivable						$ 6,400,000			5,100,000			5,100,000
Note Receivable for Contract Termination
Business Acquisition
Notes receivable																$ 2,000,000.0
Financing receivable									$ 1,600,000			$ 1,600,000				$ 1,600,000
Signature Seating
Business Acquisition
Annual sales of acquired entity	$ 16,000,000
Cash consideration	$ 16,000,000
Signature Seating | Customer Relationships
Business Acquisition
Estimated useful life in years	10 years
Spectal Industries
Business Acquisition
Annual sales of acquired entity		$ 25,000,000
Cash consideration		$ 22,335,000
Spectal Industries | Customer Relationships
Business Acquisition
Estimated useful life in years		15 years
EA Technologies
Business Acquisition
Annual sales of acquired entity			$ 17,000,000
Cash consideration			$ 9,248,000							$ 6,600,000
Duncan Systems
Business Acquisition
Annual sales of acquired entity				$ 26,000,000
Cash consideration				$ 18,000,000
Duncan Systems | Customer Relationships
Business Acquisition
Estimated useful life in years				14 years
Power Gear and Kwikee Brands
Business Acquisition
Annual sales of acquired entity					$ 28,000,000
Cash consideration					$ 35,500,000
Power Gear and Kwikee Brands | Patents
Business Acquisition
Estimated useful life in years					8 years
Power Gear and Kwikee Brands | Customer Relationships
Business Acquisition
Estimated useful life in years					14 years
Star Design
Business Acquisition
Annual sales of acquired entity															$ 10,000,000
Cash consideration							$ 12,232,000
Star Design | Customer Relationships
Business Acquisition
Estimated useful life in years							14 years
Innovative Design Solutions
Business Acquisition
Annual sales of acquired entity															19,000,000
Cash consideration								$ 34,175,000
Revenue from acquired entity to company for last annual period															$ 15,000,000
Consideration transferred total, less future payments								$ 35,900,000
Payment term for remaining consideration to be paid								3 years
Innovative Design Solutions | Patents
Business Acquisition
Estimated useful life in years								10 years
Innovative Design Solutions | Customer Relationships
Business Acquisition
Estimated useful life in years								12 years