Quarterly report pursuant to Section 13 or 15(d)

Organization and Basis of Presentation - Results had former accounting policies been utilized (Details)

v3.19.2
Organization and Basis of Presentation - Results had former accounting policies been utilized (Details) - USD ($)
$ in Thousands
Jun. 30, 2019
Oct. 01, 2018
Sep. 30, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Accounts receivable — unbilled $ 94,102 $ 66,950 $ 31,536
Deferred income taxes 617 209 6,834
Deferred revenue 40,951 39,415 51,182
Deferred income taxes 44,769 33,451 26,377
Accumulated other comprehensive loss (41,110)   (36,953)
Retained earnings 752,370 666,210 $ 633,281
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09      
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Accounts receivable — unbilled 37,761 35,414  
Deferred income taxes (6,582) (6,625)  
Deferred revenue (12,081) (11,767)  
Deferred income taxes 7,574 7,074  
Accumulated other comprehensive loss (998)    
Retained earnings 35,483 $ 32,929  
Calculated under Revenue Guidance in Effect before Topic 606 | Accounting Standards Update 2014-09      
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Accounts receivable — unbilled 56,341    
Deferred income taxes 7,199    
Deferred revenue 53,032    
Deferred income taxes 37,195    
Accumulated other comprehensive loss (40,112)    
Retained earnings $ 716,887