XML 71 R54.htm IDEA: XBRL DOCUMENT v3.20.1
Debt - Narrative (Details) - USD ($)
3 Months Ended 9 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Mar. 31, 2020
Mar. 31, 2019
Jun. 30, 2019
Debt Instrument [Line Items]          
Short-term borrowings $ 170,000,000.0   $ 170,000,000.0   $ 19,700,000
Interest costs 7,200,000 $ 8,400,000 22,100,000 $ 23,500,000  
Interest costs, capitalized 2,300,000 $ 1,300,000 6,500,000 $ 3,200,000  
Credit Agreement          
Debt Instrument [Line Items]          
Maximum borrowing capacity 400,000,000.0   400,000,000.0    
Letters of credit issued 5,900,000   5,900,000    
Short-term borrowings 170,000,000.0   170,000,000.0    
Credit Agreement available for future borrowings $ 224,100,000   $ 224,100,000    
Credit Agreement | LIBOR          
Debt Instrument [Line Items]          
Interest rate margin     1.25%    
Credit Agreement | LIBOR | Minimum          
Debt Instrument [Line Items]          
Interest rate margin     1.00%    
Credit Agreement | LIBOR | Maximum          
Debt Instrument [Line Items]          
Interest rate margin     1.75%    
Credit Agreement | Base Rate          
Debt Instrument [Line Items]          
Interest rate margin     0.25%    
Credit Agreement | Base Rate | Minimum          
Debt Instrument [Line Items]          
Interest rate margin     0.00%    
Credit Agreement | Base Rate | Maximum          
Debt Instrument [Line Items]          
Interest rate margin     0.75%    
Letters of credit          
Debt Instrument [Line Items]          
Commitment fee rate     0.20%    
Letter of credit fees     1.25%    
Required interest coverage ratio     3.50    
Letters of credit | Minimum          
Debt Instrument [Line Items]          
Commitment fee rate     0.125%    
Letter of credit fees     1.00%    
Letters of credit | Maximum          
Debt Instrument [Line Items]          
Commitment fee rate     0.40%    
Letter of credit fees     1.75%    
Required debt to capital ratio (less than) 0.55   0.55    
Revolving Credit Facility | Unsecured Revolving Credit Facility, Credit Agreement          
Debt Instrument [Line Items]          
Borrowing rate 2.49%   2.49%