XML 71 R56.htm IDEA: XBRL DOCUMENT v3.19.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Advertising (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Accounting Policies [Abstract]      
Advertising expense $ 418 $ 631 $ 763