SHARE-BASED COMPENSATION - Share-based Compensation Expense (Details) - General and Administrative Expense - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total Share-based compensation expense	$ 3,248	$ 3,664
Restricted share expense
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total Share-based compensation expense	260	751
Stock option expense
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total Share-based compensation expense	868	1,071
LTIP expense(1)
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total Share-based compensation expense	1,183	1,208
Performance-based LTI expense(2)
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total Share-based compensation expense	915	564
Deferred share unit (“DSU”) expense
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total Share-based compensation expense	$ 22	$ 70