XML 117 R97.htm IDEA: XBRL DOCUMENT v3.8.0.1
LONG-TERM DEBT - 7.875 Percent Convertible Notes (Details) - Convertible Notes
1 Months Ended 12 Months Ended
Apr. 15, 2016
Mar. 01, 2016
USD ($)
Dec. 31, 2012
USD ($)
$ / shares
$ / note
shares
Sep. 30, 2017
USD ($)
trading_day
d
$ / shares
shares
Sep. 22, 2017
USD ($)
Sep. 30, 2016
USD ($)
Sep. 30, 2015
USD ($)
Jun. 11, 2015
USD ($)
7.875% convertible notes due 2026                
Debt Instrument [Line Items]                
Stated interest rate       7.875%        
Debt instrument, face amount     $ 250,000,000          
Initial principal amount per note (in dollars per note) | $ / note     900          
Face principal amount per note     $ 1,000          
Effective interest rates on convertible notes     10.90%          
Proceeds from convertible debt     $ 220,000,000          
Equivalent shares of common stock per 1000 principal amount of convertible notes (in shares) | shares     83.3333          
Conversion price (in dollars per share) | $ / shares     $ 12.00 $ 12.00        
Threshold trading days | trading_day       20        
Threshold consecutive trading days | trading_day       30        
Threshold percentage of stock price trigger       120.00%        
Redemption price       100.00%        
Maximum number of common stock convertible notes are convertible into (in shares) | shares       2,000,000        
Repurchased principal amount of debt             $ 110,000,000 $ 110,000,000
Debt       $ 22,000,000 $ 140,000,000 $ 129,000,000    
Debt outstanding, gross       $ 23,000,000        
7.875% convertible notes due 2026 | Triggering Event One                
Debt Instrument [Line Items]                
Threshold trading days | trading_day       20        
Threshold consecutive trading days | trading_day       30        
Threshold percentage of stock price trigger       120.00%        
7.875% convertible notes due 2026 | Triggering Event Two                
Debt Instrument [Line Items]                
Threshold trading days | d       5        
Threshold consecutive trading days | trading_day       5        
Threshold percentage of stock price trigger       97.00%        
4.625% convertible notes due 2026                
Debt Instrument [Line Items]                
Stated interest rate 462.50%         4.625%    
Redemption price 100.00% 100.00%            
Repurchased principal amount of debt   $ 55,000,000 $ 245,000,000     $ 55,000,000    
Debt     300,000,000          
Convertible note repurchase price     $ 236,000,000