Investments (Tables)
 3 Months Ended
Mar. 31, 2015
Investments, Debt and Equity Securities [Abstract]  
Investments
The Company’s investments, excluding cash surrender value of insurance contracts of $72.7 and $73.8 as of March 31, 2015 and December 31, 2014, respectively, consisted of the following:
 
 
Cost Basis
 
Unrealized Gain
 
Fair Value
As of March 31, 2015
 
 
 
 
 
 
Short-term investments
 
 
 
 
 
 
Certificates of deposit
 
$
114.4

 
$
—

 
$
114.4

Long-term investments
 
 
 
 
 
 
Assets held in a rabbi trust
 
$
9.1

 
$
0.7

 
$
9.8

 
 
 
 
 
 
 
As of December 31, 2014
 
 
 
 
 
 
Short-term investments
 
 
 
 
 
 
Certificates of deposit
 
$
136.7

 
$
—

 
$
136.7

Long-term investments
 
 
 
 
 
 
Assets held in a rabbi trust
 
$
9.3

 
$
0.5

 
$
9.8