SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Schedule of Changes in Restricted Common Shares) (Details)	3 Months Ended
	Mar. 31, 2019 $ / shares shares
Performance Shares [Member]
Number of Shares
Balance at Beginning | shares	42,998
Granted | shares	47,770
Balance at end | shares	90,768
Weighted Average Grant Date Fair Value
Balance at Beginning | $ / shares	$ 35.33
Granted | $ / shares	26.34
Balance at end | $ / shares	$ 30.60
Restricted stock [Member]
Number of Shares
Balance at Beginning | shares	366,541
Granted | shares	194,742
Vested | shares	(138,399)
Balance at end | shares	422,884
Weighted Average Grant Date Fair Value
Balance at Beginning | $ / shares	$ 30.64
Granted | $ / shares	26.38
Vested | $ / shares	27.39
Balance at end | $ / shares	$ 29.75