XML 52 R39.htm IDEA: XBRL DOCUMENT v3.20.2
SHORT-TERM INVESTMENTS: (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2020
Jun. 30, 2019
Jun. 30, 2020
Jun. 30, 2019
Dec. 31, 2019
Short-term investment:          
Trading securities $ 30.1   $ 30.1   $ 80.0
Weighted average interest rate (as a percent)     0.10%   2.00%
Available-for-sale 0.6   $ 0.6   $ 0.7
Weighted average interest rate (as a percent)     0.70%   0.70%
Total 30.7   $ 30.7   $ 80.7
Trading:          
Interest earned     0.4 $ 0.1  
Available-for-sale:          
Interest earned 4.3 $ 4.4 12.2 8.1  
Investment redeemed     0.1    
Maximum          
Available-for-sale:          
Interest earned $ 0.1 $ 0.1 $ 0.1 $ 0.1