Summary Of Significant Accounting Policies (Narrative) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Percentage of weighted average cost of inventory		50.00%	47.00%
Impairment of long lived assets held for use		$ 0	$ 14,956,000	$ 0
Goodwill impairment	$ 128,938,000	0	61,142,000	80,337,000
Impairment of finite lived intangible assets		0	59,786,000	0
Accrued warranty		8,682,000	10,154,000
Foreign currency transaction (losses) gains		(804,000)	(12,000)	1,616,000
Research and development expense		$ 2,241,000	3,511,000	$ 3,937,000
Minimum
Finite lived intangible assets useful life		4 years
Minimum | Buildings
Property, plant and equipment useful life		5 years
Minimum | Machinery and Equipment
Property, plant and equipment useful life		2 years
Minimum | Leasehold Improvements
Property, plant and equipment useful life		5 years
Maximum
Finite lived intangible assets useful life		25 years
Maximum | Buildings
Property, plant and equipment useful life		40 years
Maximum | Machinery and Equipment
Property, plant and equipment useful life		10 years
Maximum | Leasehold Improvements
Property, plant and equipment useful life		13 years
Weighted Average
Finite lived intangible assets useful life		15 years
Non-Domestic
Cash and cash equivalents		$ 35,807,000	29,400,000
Bank term deposits		$ 17,000	$ 16,000