Company Earnings Per Share - Schedule of Computation of Basic and Diluted Net Income Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income from continuing operations	$ 156,435	$ 18,632	$ 218,679	$ 65,760
Noncontrolling interests - consolidated real estate entities	(22,416)	(32)	(22,554)	(87)
Noncontrolling interests - Operating Partnership	(313)	(48)	(464)	(167)
Preferred stock dividends	(922)	(922)	(2,766)	(2,766)
Unvested restricted stock (allocation of earnings)	(314)	(39)	(435)	(136)
Income from continuing operations available to common shareholders	132,470	17,592	192,460	62,607
Weighted average shares outstanding - basic	54,301	54,371	54,233	54,424
Dilutive shares from stock options	72	168	103	187
Weighted average shares outstanding - diluted	54,373	54,539	54,336	54,611
Basic	$ 2.44	$ 0.32	$ 3.55	$ 1.15
Diluted	$ 2.44	$ 0.32	$ 3.54	$ 1.15
Continuing Operations [Member]
Noncontrolling interests - Operating Partnership		$ (47)		$ (164)