Annual report pursuant to Section 13 and 15(d)

Revenue - Accounts Receivable, Net (Details)

v3.19.1
Revenue - Accounts Receivable, Net (Details) - USD ($)
$ in Thousands
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Revenue from Contract with Customer [Abstract]        
Accounts receivable, gross $ 103,301 $ 122,225    
Less: Allowance for doubtful accounts (5,678) (8,680) $ (10,091) $ (8,640)
Accounts receivable, net $ 97,623 $ 113,545