Annual report pursuant to Section 13 and 15(d)

Business and summary of significant accounting policies - New Accounting Policies (Details)

v3.10.0.1
Business and summary of significant accounting policies - New Accounting Policies (Details) - USD ($)
$ in Thousands
Oct. 01, 2018
Sep. 30, 2018
Sep. 30, 2017
Item Effected [Line Items]      
Retained earnings   $ 633,281 $ 492,112
Pro Forma | Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09      
Item Effected [Line Items]      
Retained earnings $ 33,000