;"Useful life as of Dec. 31, 2018";"Useful life as of Dec. 31, 2017" ;; "Acquired software / licences";"3-7 years";"3-7 years" "Software created internally";"3-5 years";"3-5 years" "Acquired trademark rights";-;- "Client relations / contract inventories";"10-25 years";"10-25 years" "Goodwill / brand names";undefinable;undefinable ;;