Quarterly report pursuant to Section 13 or 15(d)

Debt (Details)

v3.8.0.1
Debt (Details)
1 Months Ended 9 Months Ended
Jun. 30, 2020
USD ($)
Jun. 30, 2018
USD ($)
Jun. 30, 2017
USD ($)
May 23, 2017
USD ($)
$ / shares
shares
Apr. 03, 2017
USD ($)
Feb. 29, 2016
USD ($)
Sep. 30, 2017
USD ($)
tradingdays
consecutivetradingdays
shares
Sep. 30, 2016
USD ($)
Sep. 30, 2014
USD ($)
Sep. 30, 2019
Dec. 31, 2017
May 31, 2017
USD ($)
Feb. 28, 2017
USD ($)
Dec. 31, 2016
USD ($)
Line of Credit Facility [Line Items]                            
Ratio of indebtedness         3.50                  
Covenant, interest coverage ratio                 3.00          
Revolving line of credit facility, available borrowing capacity             $ 400,000,000              
Proceeds from borrowings on convertible notes             345,000,000 $ 0            
Convertible notes, net             278,392,000             $ 0
Common stock warrants (in shares) | shares       8,200,000                    
Purchases of convertible note hedges       $ 62,500,000     62,549,000              
Proceeds from issuance of warrants       $ 31,500,000     $ 31,499,000 $ 0            
Warrants strike price (in dollars per share) | $ / shares       $ 57.58                    
Number of warrants exercised (in shares) | shares             0              
Maximum                            
Line of Credit Facility [Line Items]                            
Common stock warrants (in shares) | shares       8,200,000                    
Revolving Credit Facility                            
Line of Credit Facility [Line Items]                            
Line of credit facility, maximum borrowing capacity                 $ 200,000,000          
Line of credit facility, additional borrowing capacity                 $ 150,000,000          
Ratio of indebtedness                 3.25          
Revolving line of credit facility, available borrowing capacity             $ 200,000,000              
Unamortized debt issuance costs             (600,000)             (800,000)
Revolving Credit Facility | LIBOR                            
Line of Credit Facility [Line Items]                            
Basis spread on interest rate                 1.00%          
Revolving Credit Facility | LIBOR | Minimum                            
Line of Credit Facility [Line Items]                            
Basis spread on interest rate         1.25% 1.25%     1.25%          
Revolving Credit Facility | LIBOR | Maximum                            
Line of Credit Facility [Line Items]                            
Basis spread on interest rate         2.25% 2.00%     1.75%          
Revolving Credit Facility | Federal Funds Rate                            
Line of Credit Facility [Line Items]                            
Basis spread on interest rate                 0.50%          
Revolving Credit Facility | Base Rate | Minimum                            
Line of Credit Facility [Line Items]                            
Basis spread on interest rate         0.25% 0.25%     0.25%          
Revolving Credit Facility | Base Rate | Maximum                            
Line of Credit Facility [Line Items]                            
Basis spread on interest rate         1.25% 1.00%     0.75%          
Letters of credit                            
Line of Credit Facility [Line Items]                            
Sub limit for issuance of letters of credit                 $ 10,000,000          
Swingline Loan                            
Line of Credit Facility [Line Items]                            
Sub limit for issuance of letters of credit                 $ 20,000,000          
Line of Credit | Revolving Credit Facility                            
Line of Credit Facility [Line Items]                            
Revolving line of credit outstanding borrowings             0             0
Term Loan                            
Line of Credit Facility [Line Items]                            
Revolving line of credit outstanding principle             121,100,000             122,600,000
Convertible Senior Notes                            
Line of Credit Facility [Line Items]                            
Proceeds from borrowings on convertible notes       $ 304,200,000                    
Amendment                            
Line of Credit Facility [Line Items]                            
Line of credit facility, additional borrowing capacity                         $ 200,000,000  
Periodic principle payment, percentage     0.625%                      
Periodic payment     $ 800,000                      
Debt issuance costs                         $ 1,300,000  
Revolving line of credit facility, available borrowing capacity             200,000,000              
Amendment | Line of Credit                            
Line of Credit Facility [Line Items]                            
Line of credit facility, maximum borrowing capacity           $ 125,000,000                
Debt issuance costs           $ 700,000                
Amendment | Line of Credit | Base Rate                            
Line of Credit Facility [Line Items]                            
Ratio of indebtedness         4                  
Amendment | Term Loan                            
Line of Credit Facility [Line Items]                            
Unamortized debt issuance costs             (1,800,000)             $ (500,000)
Convertible Senior Notes Due November 2022 | Convertible Senior Notes                            
Line of Credit Facility [Line Items]                            
Debt issuance costs                       $ 9,800,000    
Principal amount       $ 345,000,000     $ 345,000,000              
Interest rate stated percentage       1.50%                    
Conversion rate, convertible notes             0.02384              
Conversion price | $ / shares       $ 41.95                    
Threshold trading days | tradingdays             20              
Threshold consecutive trading days | consecutivetradingdays             30              
Measurement period threshold trading days | tradingdays             5              
Measurement period threshold consecutive trading days | consecutivetradingdays             5              
Redemption price (percentage)             100.00%              
Convertible notes, net             $ 278,392,000         282,500,000    
Carrying amount of convertible debt equity component             $ 61,390,000         $ 62,500,000    
Convertible Senior Notes Due November 2022 | Convertible Senior Notes | Minimum                            
Line of Credit Facility [Line Items]                            
Threshold percentage of stock price trigger             130.00%              
Ratio of trading price per $1000 principle amount             98.00%              
Percentage of debt held by individual owner             25.00%              
Over-Allotment Option | Convertible Senior Notes                            
Line of Credit Facility [Line Items]                            
Principal amount       $ 45,000,000                    
Fourth Amendment                            
Line of Credit Facility [Line Items]                            
Ratio of indebtedness         3.75                  
Debt covenant, acquisition completion period         1 year                  
Fourth Amendment | Minimum                            
Line of Credit Facility [Line Items]                            
Unsecured debt issuance         $ 225,000,000                  
Fourth Amendment | Line of Credit | Base Rate                            
Line of Credit Facility [Line Items]                            
Ratio of indebtedness         5.0                  
Fourth Amendment | Convertible Debt                            
Line of Credit Facility [Line Items]                            
Principal amount         $ 150,000,000                  
Debt covenant, acquisition floor for one time leverage extension         $ 50,000,000                  
Scenario, Forecast | Amendment                            
Line of Credit Facility [Line Items]                            
Periodic principle payment, percentage 2.50% 1.25%                        
Periodic payment $ 3,100,000 $ 1,500,000                        
Scenario, Forecast | Fourth Amendment | Line of Credit | Base Rate                            
Line of Credit Facility [Line Items]                            
Ratio of indebtedness                   4 5