Nature Of Operations And Significant Accounting Policies (Summary Of Intangible Assets) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period of Finite Lived Assets (in years)	14 years
Gross Asset	$ 291,106	$ 299,889
Accumulated Amortization	165,193	153,662
Finite-Lived Intangible Assets, Net	125,913	146,227	162,636
Intellectual property rights [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period of Finite Lived Assets (in years)	18 years 10 months 24 days
Gross Asset	88,614	89,619
Accumulated Amortization	47,202	46,286
Finite-Lived Intangible Assets, Net	41,412	43,333
Customer relationships and backlog [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period of Finite Lived Assets (in years)	11 years 7 months 6 days
Gross Asset	140,250	146,291
Accumulated Amortization	73,630	66,256
Finite-Lived Intangible Assets, Net	66,620	80,035
Drawings [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period of Finite Lived Assets (in years)	37 years 10 months 24 days
Gross Asset	11,149	11,824
Accumulated Amortization	9,850	10,423
Finite-Lived Intangible Assets, Net	1,299	1,401
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period of Finite Lived Assets (in years)	14 years 1 month 6 days
Gross Asset	51,093	52,155
Accumulated Amortization	34,511	30,697
Finite-Lived Intangible Assets, Net	$ 16,582	$ 21,458