Stockholders' Equity (Schedule Of Activity Under The Stock Purchase Plan) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Stockholders' Equity [Line Items]
Shares Purchased	229,014	173,379	146,692
Employee Stock Purchase Plan [Member]
Stockholders' Equity [Line Items]
Weighted-average purchase price per share	11.03	8.68	8.46