Goodwill and Intangible Assets - Amortization (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Goodwill and Intangible Assets      
Aggregate amortization expense $ 9,389 $ 13,499 $ 18,867
Amortization of leasehold interests 1,252 794  
Estimated annual intangible asset amortization expense      
2017 9,638    
2018 9,060    
2019 9,035    
2020 8,897    
2021 8,897    
Thereafter 19,486    
Net intangible assets $ 65,013 $ 75,694