EARNINGS PER COMMON SHARE (Details 3) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Computation of earnings per share
Net income attributable to common stockholders	$ 37,340	$ 31,425
Earnings and dividends allocated to participating securities	(117)	(120)
Earnings for basic computations	37,223	31,305
Earnings and dividends allocated to participating securities		120
Add: Income allocated to noncontrolling interest - Preferred Operating Partnership (Series A Units) and Operating Partnership	3,128	2,494
Subtract: Fixed component of income allocated to noncontrolling interest - Preferred Operating Partnership (Series A Units)	(1,438)	(1,438)
Net income for diluted computations	$ 38,913	$ 32,481
Weighted average common shares outstanding:
Average number of common shares outstanding - basic	115,438,325	110,314,668
Series A Units (in shares)	989,980	989,980
Common OP Units (in shares)	4,334,118	2,755,650
Unvested restricted stock awards included for treasury stock method (in shares)		495,256
Dilutive stock options (in shares)	300,422	411,533
Average number of common shares outstanding - diluted	121,062,845	114,967,087
Earnings per common share
Basic (in dollars per share)	$ 0.32	$ 0.28
Diluted (in dollars per share)	$ 0.32	$ 0.28