Investments (Details Textuals) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Investments [Abstract]
Short-term investments, maturity period description			Greater than three months and up to one year	Greater than three months and up to one year
Long-term investments maturity period description			Greater than one year	Greater than one year
Schedule of Available-for-sale Securities [Line Items]
Proceeds from sales and maturities of debt securities	$ 2.7	$ 0.8	$ 7.7	$ 17.7
Available-for-sale securities, realized gains less than	0.1	0.1	0.1	0.1
Purchases of debt securities	1.8	0.2	6.0	9.9
Proceeds from the maturity of time deposits			0	4.8
Held-to-maturity investments	0		0		0
Other-than-temporary impairment losses on investments	$ 0		$ 0	$ 21.5