Debt (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Debt [Abstract]
Line of credit facility, unused borrowing capacity	$ 10.0	$ 10.0
Short-term and long-term investments	$ 18.6
Effective interest rate	1.90%
Basis spread on variable rate (in hundredths)	1.65%	1.65%
Description of variable rate basis	30-day LIBOR