Stockholders' Equity (Narrative) (Details) (USD $)	0 Months Ended	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Feb. 25, 2011	Mar. 31, 2011	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011	Dec. 31, 2011 Shares Authorized For Repurchase [Member]	Dec. 31, 2011 Cumulative Number Of Shares Authorized For Repurchase [Member]	Mar. 31, 2011 Cumulative Number Of Shares Authorized For Repurchase [Member]	Aug. 31, 2007 Cumulative Number Of Shares Authorized For Repurchase [Member]	Jun. 30, 2012 Current Program [Member]
Stockholders' Equity [Line Items]
Cash dividends declared			$ 0	$ 0.0	$ 0.0	$ 0.0
Authorized stock repurchase, shares								15,000,000	75,000,000	60,000,000	30,000,000
Stock split conversion ratio	2	2
Remaining shares available for purchase (in shares)												16,800,000
Shares issued from treasury stock in connection with stock-based compensation					1,300,000		975,000