XML 50 R38.htm IDEA: XBRL DOCUMENT v3.8.0.1
Summary of Significant Accounting Policies - Narrative (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Dec. 31, 2017
Accounting Policies [Abstract]      
Allowance for doubtful accounts $ 1,892   $ 1,949
Unearned revenue 7,184   $ 7,353
Share-based compensation costs $ 3,400 $ 5,800