Summary Of Operations And Significant Accounting Policies (Summary Of Intangible Assets) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 25,565	$ 25,515
Accumulated Amortization	10,252	9,834
Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	18,533	18,533
Weighted Average Amortization Period	3 years 9 months 18 days	3 years 9 months 18 days
Accumulated Amortization	6,099	5,904
Customer Relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,061	5,061
Weighted Average Amortization Period	3 years 6 months	3 years 6 months
Accumulated Amortization	2,650	2,485
Trade-Name [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	725	725
Weighted Average Amortization Period	2 years 8 months 12 days	2 years 8 months 12 days
Accumulated Amortization	668	644
Non-compete Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	486	486
Weighted Average Amortization Period	1 year 2 months 12 days	1 year 2 months 12 days
Accumulated Amortization	440	421
Patents
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	475	475
Weighted Average Amortization Period	11 years	11 years
Accumulated Amortization	156	145
Other
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	285	235
Weighted Average Amortization Period	3 years	3 years
Accumulated Amortization	$ 239	$ 235