Fair Value Of Assets And Liabilities (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Feb. 28, 2011
Fair Value Of Assets And Liabilities [Abstract]
Contingent consideration	$ 21,595	$ 21,595	$ 1,100	$ 10,900	$ 9,600