v3.8.0.1
Intangible assets - Carrying Amount (Details) - USD ($)
$ in Thousands
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Intangible assets      
Historical Cost $ 28,905 $ 31,815  
Accumulated Amortization (18,642) (18,032)  
Net 10,263 13,783 $ 16,055
Venue contracts      
Intangible assets      
Historical Cost 22,061 23,601  
Accumulated Amortization (13,835) (13,276)  
Net 8,226 10,325  
Non-compete agreements      
Intangible assets      
Historical Cost 3,590 3,590  
Accumulated Amortization (2,992) (2,274)  
Net 598 1,316  
Technology      
Intangible assets      
Historical Cost 2,410 3,520  
Accumulated Amortization (1,265) (1,742)  
Net 1,145 1,778  
Advertiser relationships      
Intangible assets      
Historical Cost   70  
Accumulated Amortization   (62)  
Net   8  
Patents, trademarks and other      
Intangible assets      
Historical Cost 844 1,034  
Accumulated Amortization (550) (678)  
Net $ 294 $ 356