Investments and Fair Value Disclosures (Details Textual) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011
Investments and Fair Value Disclosures (Textual) [Abstract]
Short-term Investment Maturity period description	Investments with original maturities greater than three months that mature less than one year from the consolidated balance sheet date are classified as short-term investments
Maturity period of long term investments	Greater than one year
Short term investment maturity term minimum	3 months
Short term investment maturity term maximum	1 year
Cash equivalents and certificates of deposit not included in operating cash	$ 31.1	$ 23.9