XML 83 R60.htm IDEA: XBRL DOCUMENT v3.7.0.1
Investments (Details) - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2017
Dec. 31, 2016
Short-term investments:    
Short-term investments $ 77.7 $ 64.1
Long-term Investments 94.5 94.7
Certificates of deposit    
Short-term investments:    
Investments, Cost Basis 77.7 64.1
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax 0.0 0.0
Assets held in rabbi trusts [Member]    
Short-term investments:    
Long-term Investments 8.0 7.9
Long-term investments:    
Long-term investments, Unrealized Gain 0.9 0.6
Short-term investments | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Certificates of deposit    
Short-term investments:    
Short-term investments 77.7 64.1
Short-term investments | Certificates of deposit | Fair Value, Measurements, Recurring [Member]    
Long-term investments:    
Fair value of assets held under trust 77.7 64.1
Other liabilities | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Assets held in rabbi trusts [Member]    
Long-term investments:    
Fair value of assets held under trust $ 8.9 $ 8.5