STOCK-BASED COMPENSATION (Details 5)	12 Months Ended
	Dec. 31, 2017 $ / shares shares
Unvested Performance Shares [Rollforward]
Unvested, beginning of period (in shares) | shares	301,529
Granted (in shares) | shares	154,550
Vested (in shares) | shares	(166,262)
Canceled (in shares) | shares	(87,800)
Unvested, end of period (in shares) | shares	202,017
Weighted average fair value per share, beginning of period (in dollars per share) | $ / shares	$ 25.84
Weighted average fair value per share, granted (in dollars per share) | $ / shares	30.05
Weighted average fair value per share, vested (in dollars per share) | $ / shares	35.62
Weighted average fair value per share, canceled (in dollars per share) | $ / shares	26.02
Weighted average fair value per share, end of period (in dollars per share) | $ / shares	$ 35.62
To Settle in Cash
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares outstanding at beginning of period, performance shares (in shares) | shares	542,828
Granted, performance shares (in shares) | shares	154,550
Paid/Issued, performance shares (in shares) | shares	(41,514)
Performance shares converted to cash | shares	82,625
Canceled, performance shares (in shares) | shares	(87,800)
Shares outstanding at end of period, performance shares (in shares) | shares	650,689
Total vested at end of period, performance shares (in shares) | shares	448,672
Weighted average fair value, outstanding at beginning of period, performance shares (in dollars per share) | $ / shares	$ 25.84
Weighted average fair value, granted, performance shares (in dollars per share) | $ / shares	30.05
Weighted average fair value, paid/issued, performance shares (in dollars per share) | $ / shares	25.84
Weighted average fair value, converted from shares to cash, performance shares (in dollars per shares) | $ / shares	17.47
Weighted average fair value, canceled, performance shares (in dollars per share) | $ / shares	26.02
Weighted average fair value, outstanding at end of period, performance shares (in dollars per share) | $ / shares	35.62
Weighted average fair value, total vested at end of period, performance shares (in dollars per share) | $ / shares	$ 35.62
To Settle in Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares outstanding at beginning of period, performance shares (in shares) | shares	536,575
Granted, performance shares (in shares) | shares	154,550
Paid/Issued, performance shares (in shares) | shares	(40,500)
Performance shares converted to cash | shares	(82,625)
Canceled, performance shares (in shares) | shares	(87,800)
Shares outstanding at end of period, performance shares (in shares) | shares	480,200
Total vested at end of period, performance shares (in shares) | shares	278,183
Weighted average fair value, outstanding at beginning of period, performance shares (in dollars per share) | $ / shares	$ 16.18
Weighted average fair value, granted, performance shares (in dollars per share) | $ / shares	30.02
Weighted average fair value, paid/issued, performance shares (in dollars per share) | $ / shares	25.57
Weighted average fair value, converted from shares to cash, performance shares (in dollars per shares) | $ / shares	17.47
Weighted average fair value, canceled, performance shares (in dollars per share) | $ / shares	15.16
Weighted average fair value, outstanding at end of period, performance shares (in dollars per share) | $ / shares	19.81
Weighted average fair value, total vested at end of period, performance shares (in dollars per share) | $ / shares	$ 18.21