Company Earnings Per Share - Schedule of Computation of Basic and Diluted Net Income Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share [Abstract]
Net income	$ 19,651	$ 47,991	$ 39,636	$ 62,244
Noncontrolling interests - consolidated real estate entities	0	(154)	0	(138)
Noncontrolling interests - Operating Partnership	(41)	(118)	(83)	(151)
Distributions to preferred unitholders	(922)	(922)	(1,844)	(1,844)
Unvested restricted stock (allocation of earnings)	(46)	(110)	(86)	(132)
Net income available to common shareholders, adjusted	$ 18,642	$ 46,687	$ 37,623	$ 59,979
Weighted average shares outstanding - basic	54,455	54,223	54,452	54,199
Dilutive shares from stock options	14	112	15	115
Weighted average shares outstanding - diluted	54,469	54,335	54,467	54,314
Basic	$ 0.34	$ 0.86	$ 0.69	$ 1.11
Diluted	$ 0.34	$ 0.86	$ 0.69	$ 1.10