XML 79 R58.htm IDEA: XBRL DOCUMENT v3.3.1.900
Investments (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]    
Auction rate securities, amortized cost $ 0.4 $ 0.3
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax 5.4 4.3
Auction rate securities, gross unrealized losses 0.0 0.0
Auction rate securities, fair value 5.8 4.6
Par Value Available For Sale Securities 23.4  
Auction Rate Securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Auction rate securities, amortized cost 0.4 0.3
Available-for-sale Securities, Gross Unrealized Gain 5.4 4.3
Auction rate securities, gross unrealized losses 0.0 0.0
Auction rate securities, fair value $ 5.8 $ 4.6