XML 61 R50.htm IDEA: XBRL DOCUMENT v3.8.0.1
Income taxes - Narrative (Details)
$ in Thousands
Sep. 30, 2017
USD ($)
Income Tax Disclosure [Abstract]  
Unrecognized tax benefits $ 150,651
Amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate 97,900
Accrued interest related to the gross unrecognized tax benefits excluded from the unrecognized tax benefits 16,724
Significant decrease in unrecognized tax benefits that is reasonably possible $ 110,000