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, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Class of Stock [Line Items]
Net income attributable to common stockholders	$ 93,764	$ 118,088	$ 263,052	$ 283,724
Earnings and dividends allocated to participating securities	(191)	(248)	(595)	(616)
Earnings for basic computations	93,573	117,840	262,457	283,108
Earnings and dividends allocated to participating securities	191	0	595	0
Income allocated to noncontrolling interest - Preferred Operating Partnership (Series A Units) and Operating Partnership	5,163	7,776	15,448	17,926
Fixed component of income allocated to noncontrolling interest - Preferred Operating Partnership (Series A Units)	(572)	(1,271)	(2,547)	(3,814)
Net income for diluted computations	$ 98,355	$ 124,345	$ 275,953	$ 297,220
Weighted average common shares outstanding:
Average number of common shares outstanding - basic (in shares)	125,717,517	125,752,291	125,665,787	125,244,761
OP Units (in shares)	5,590,231	5,534,350	5,586,908	5,557,723
Unvested restricted stock awards included for treasure stock method	280,484	0	288,831	0
Shares related to exchangeable senior notes and dilutive stock options (in shares)	580,761	786,916	591,616	798,727
Average number of common shares outstanding - diluted (in shares)	133,044,473	133,763,472	133,008,622	132,476,691
Earnings per common share
Basic (in dollars per share)	$ 0.74	$ 0.94	$ 2.09	$ 2.26
Diluted (in dollars per share)	$ 0.74	$ 0.93	$ 2.07	$ 2.24
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)	0	814,435	0	0