Accrued Restructuring Costs (Narrative) (Details) (USD $)	9 Months Ended	12 Months Ended		9 Months Ended	12 Months Ended	3 Months Ended			9 Months Ended	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2010 Personnel [Member]	Dec. 31, 2010 Personnel [Member]	Sep. 30, 2011 Facilities [Member]	Mar. 31, 2011 Facilities [Member]	Dec. 31, 2010 Facilities [Member]	Dec. 31, 2010 Facilities [Member]	Dec. 31, 2011 Facilities [Member]
Restructuring Cost And Reserve [Line Items]
Severance and related benefit costs			$ 6,500,000
Number of positions eliminated as a result of restructuring activities					50
Restructuring costs	8,064,000	(62,000)	8,064,000	6,501,000				1,600,000	1,563,000	(62,000)
Lease expiration date										2013
Exit costs						$ 200,000	$ 100,000