EMPLOYEE BENEFITS & SHARE-BASED COMPENSATION PLANS - Shares held by ESOP (Details) - shares
Mar. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Shares held by the ESOP include the following:      
Allocated 95,240 71,430 47,620
Committed to be allocated 5,952 23,810 23,810
Unallocated 255,960 261,912 285,722
Total 357,152 357,152 357,152