EQUITY - Changes in common stock (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Beginning common shares outstanding	104,783,179	104,287,128
Common Unit redemptions	50,244	64,126
Performance share and other forfeitures	(167,757)	(1,636)
Shares retained for employee tax withholding requirements	(74,340)	(187,850)
Ending common shares outstanding	105,169,515	104,783,179
Equity Plan
Class of Stock [Line Items]
Grants under the Equity Plan	537,734	583,738
Director stock
Class of Stock [Line Items]
Grants under the Equity Plan	40,455	34,130
Common stock issued for director fees	0	3,543