Goodwill and Other Intangible Assets (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Intangible Assets, by category
Gross Carrying Amount	$ 195,729		$ 195,729		$ 250,338
Accumulated Amortization	141,045		141,045		172,612
Amortization expense for intangible assets	3,629	4,111	11,481	13,518
Estimated amortization expense for next 5 years
2013	14,750		14,750
2014	9,000		9,000
2015	8,000		8,000
2016	7,250		7,250
2017	3,500		3,500
Customer related
Intangible Assets, by category
Gross Carrying Amount	149,421		149,421		183,862
Accumulated Amortization	109,413		109,413		129,904
Non-compete agreements
Intangible Assets, by category
Gross Carrying Amount	1,123		1,123		1,347
Accumulated Amortization	1,013		1,013		1,310
Patents
Intangible Assets, by category
Gross Carrying Amount	6,196		6,196		6,909
Accumulated Amortization	5,186		5,186		5,503
Technology related
Intangible Assets, by category
Gross Carrying Amount	27,354		27,354		29,588
Accumulated Amortization	18,343		18,343		17,551
Trade names
Intangible Assets, by category
Gross Carrying Amount	4,116		4,116		18,685
Accumulated Amortization	2,838		2,838		11,688
Other
Intangible Assets, by category
Gross Carrying Amount	7,519		7,519		9,947
Accumulated Amortization	$ 4,252		$ 4,252		$ 6,656