XML 55 R45.htm IDEA: XBRL DOCUMENT v3.19.2
STOCK-BASED COMPENSATION - Fair value (Details) - USD ($)
6 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Restricted Stock    
Stock-based compensation    
Fair value, shares vested $ 3,818,000 $ 4,289,000