Earnings Per Common Share - Schedule of Computation of Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Line Items]
Net income attributable to common stockholders	$ 118,088	$ 71,718	$ 283,724	$ 180,799
Earnings and dividends allocated to participating securities	(248)	(173)	(616)	(432)
Earnings for basic computations	117,840	71,545	283,108	180,367
Earnings and dividends allocated to participating securities	0	173	0	0
Income allocated to noncontrolling interest - Preferred Operating Partnership (Series A Units) and Operating Partnership	7,776	5,151	17,926	13,062
Fixed component of income allocated to noncontrolling interest - Preferred Operating Partnership (Series A Units)	(1,271)	(1,272)	(3,814)	(3,817)
Net income for diluted computations	$ 124,345	$ 75,597	$ 297,220	$ 189,612
Weighted average common shares outstanding:
Average number of common shares outstanding - basic (in shares)	125,752,291	122,644,837	125,244,761	118,564,872
OP Units (in shares)	5,534,350	5,934,539	5,557,723	5,320,130
Unvested restricted stock awards included for treasury stock method (in shares)	0	304,610	0	0
Shares related to exchangeable senior notes and dilutive stock options (in shares)	786,916	638,645	798,727	645,831
Average number of common shares outstanding - diluted (in shares)	133,763,472	130,398,111	132,476,691	125,406,313
Earnings per common share
Basic (in dollars per share)	$ 0.94	$ 0.58	$ 2.26	$ 1.52
Diluted (in dollars per share)	$ 0.93	$ 0.58	$ 2.24	$ 1.51
Series A Units [Member]
Weighted average common shares outstanding:
Preferred Series Units (in shares)	875,480	875,480	875,480	875,480
Series D Units [Member]
Weighted average common shares outstanding:
Preferred Series Units (in shares)	814,435	0	0	0