Intangible Assets (Schedule Of Intangible Assets Subject To Amortization) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2012	Dec. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 128,149	$ 106,355
Finite-Lived Intangible Assets, Accumulated Amortization	(44,417)	(33,281)
Finite-Lived Intangible Assets, Net, Total	83,732	73,074
Weighted Average Useful Life, years	7 years 7 months 6 days	7 years 4 months 24 days
Customer lists [Member]
Finite-Lived Intangible Assets [Line Items]
Customer lists, Gross Carrying Amount	81,940	71,783
Finite-Lived Intangible Assets, Accumulated Amortization	(23,649)	(17,809)
Finite-Lived Intangible Assets, Net, Total	58,291	53,974
Weighted Average Useful Life, years	9 years 4 months 24 days	9 years 7 months 6 days
Intellectual property [Member]
Finite-Lived Intangible Assets [Line Items]
Intellectual property, Gross Carrying Amount	37,569	26,134
Finite-Lived Intangible Assets, Accumulated Amortization	(14,076)	(9,316)
Finite-Lived Intangible Assets, Net, Total	23,493	16,818
Weighted Average Useful Life, years	4 years	2 years 2 months 12 days
Non-compete [Member]
Finite-Lived Intangible Assets [Line Items]
Non-compete, Gross Carrying Amount	1,000	2,007
Finite-Lived Intangible Assets, Accumulated Amortization	(686)	(1,546)
Finite-Lived Intangible Assets, Net, Total	314	461
Weighted Average Useful Life, years	6 months	8 months 12 days
Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Trademarks, Gross Carrying Amount	2,234	2,232
Finite-Lived Intangible Assets, Accumulated Amortization	(600)	(411)
Finite-Lived Intangible Assets, Net, Total	1,634	1,821
Weighted Average Useful Life, years	5 years 1 month 6 days	5 years 7 months 6 days
Fully amortized intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Fully amortized intangibles, Gross Carrying Amount	5,406	4,199
Finite-Lived Intangible Assets, Accumulated Amortization	$ (5,406)	$ (4,199)