Goodwill and Other Intangible Assets (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Goodwill and Other Intangible Assets
Intangible assets, net	$ 93,501,000	$ 120,959,000
Intangible Assets, by category
Gross Carrying Amount	250,597,000	249,777,000
Accumulated Amortization	157,096,000	128,818,000
Amortization expense for intangible assets	31,500,000	33,000,000	26,400,000
Estimated amortization expense for next 5 years
2012	17,500,000
2013	15,750,000
2014	13,500,000
2015	8,750,000
2016	7,500,000
Customer related
Intangible Assets, by category
Gross Carrying Amount	183,576,000	184,864,000
Accumulated Amortization	119,708,000	98,104,000
Non-compete agreements
Intangible Assets, by category
Gross Carrying Amount	1,353,000	1,386,000
Accumulated Amortization	1,301,000	1,317,000
Patents
Intangible Assets, by category
Gross Carrying Amount	6,884,000	6,976,000
Accumulated Amortization	5,145,000	4,868,000
Technology related
Intangible Assets, by category
Gross Carrying Amount	29,497,000	29,821,000
Accumulated Amortization	14,614,000	11,863,000
Trade names
Intangible Assets, by category
Gross Carrying Amount	18,538,000	18,635,000
Accumulated Amortization	8,379,000	5,188,000
Other
Intangible Assets, by category
Gross Carrying Amount	10,749,000	8,095,000
Accumulated Amortization	$ 7,949,000	$ 7,478,000