Accrued Restructuring Costs (Narrative) (Details) (USD $)	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended
	Mar. 31, 2011	Dec. 31, 2010	Mar. 31, 2012 Facilities [Member]	Dec. 31, 2010 Facilities [Member]
Restructuring Cost And Reserve [Line Items]
Severance and related benefit costs		$ 6,500,000
Restructuring costs	$ 141,000			$ 1,600,000
Lease expiration date			2013