SHARE-BASED PAYMENT - Compensation Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Compensation costs
Share-based compensation	$ 18,477	$ 14,084	$ 9,994
Excess tax benefit (shortfall) recognized	631	1,410	(38)
Restricted shares
Compensation costs
Share-based compensation	10,272	8,214	7,105
Stock options
Compensation costs
Share-based compensation	1,768	1,957	1,878
2014 PSP | RSUs
Compensation costs
Share-based compensation	3,625	$ 3,913	$ 1,011
2016 PSP | RSUs
Compensation costs
Share-based compensation	$ 2,812