Restructuring Costs (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Restructuring liability [Roll Forward]
Restructuring and other costs	$ 470,000	$ 865,000	$ 22,024,000
Year 2007 Restructuring Program [Member]
Restructuring liability [Roll Forward]
Balance, beginning of period	1,300,000
Additional provisions (reversals)	700,000
Cash expenditures	(1,200,000)	(400,000)
Balance, end of period	800,000	1,300,000
Year 2007 Restructuring Program [Member] | Contract Termination Costs [Member]
Restructuring liability [Roll Forward]
Balance, beginning of period	1,300,000
Additional provisions (reversals)	(200,000)
Cash expenditures	(300,000)
Balance, end of period	800,000
Reduction in workforce (in number of employees)	250
Year 2007 Restructuring Program [Member] | Other Exit Costs [Member]
Restructuring liability [Roll Forward]
Additional provisions (reversals)	900,000
Cash expenditures	(900,000)
Year 2009 Restructuring Program [Member]
Restructuring liability [Roll Forward]
Balance, beginning of period	2,000,000
Additional provisions (reversals)	(600,000)
Cash expenditures	(1,300,000)	(3,500,000)
Balance, end of period	100,000	2,000,000
Reduction in workforce (in number of employees)	200
Year 2009 Restructuring Program [Member] | Employee Severance and Other Employee Benefits [Member]
Restructuring liability [Roll Forward]
Balance, beginning of period	2,000,000
Additional provisions (reversals)	(600,000)
Cash expenditures	(1,300,000)
Balance, end of period	100,000
Other Restructuring [Member]
Restructuring liability [Roll Forward]
Balance, beginning of period	100,000
Additional provisions (reversals)	400,000
Cash expenditures	0
Balance, end of period	500,000
Other Restructuring [Member] | Employee Severance and Other Employee Benefits [Member]
Restructuring liability [Roll Forward]
Balance, beginning of period	100,000
Additional provisions (reversals)	400,000
Cash expenditures	0
Balance, end of period	$ 500,000