Restructurings and Lease Terminations (Narrative) (Details) (USD $)	1 Months Ended		12 Months Ended				1 Months Ended						12 Months Ended
	Dec. 31, 2011	Nov. 30, 2008	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2011 One-time Termination Benefits [Member]	Nov. 30, 2008 One-time Termination Benefits [Member]	Dec. 31, 2011 Non-Cash Stock-Based Compensation [Member]	Nov. 30, 2008 Non-Cash Stock-Based Compensation [Member]	Dec. 31, 2011 Leases [Member]	Dec. 31, 2008 Leases [Member]	Dec. 31, 2011 Leases [Member]	Dec. 31, 2009 Leases [Member]	Dec. 31, 2010 Leases [Member]
Restructuring Cost and Reserve [Line Items]
Accrued restructuring liability	$ 3,900,000		$ 3,900,000	$ 300,000	$ 800,000	$ 1,700,000					$ 600,000	$ 300,000	$ 600,000	$ 100,000	$ 0
Number of employees in workforce reduction	70	110
Restructuring charge			$ 4,886,000	$ 0	$ 454,000		$ 4,200,000	$ 2,000,000	$ 400,000	$ (800,000)	$ 700,000	$ 500,000	$ 700,000	$ 0