Earnings Per Common Share - Schedule of Computation (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Class of Stock [Line Items]
Net income attributable to common stockholders	$ 104,828	$ 95,153	$ 199,598	$ 183,409
Earnings and dividends allocated to participating securities	(176)	(193)	(343)	(371)
Earnings for basic computations	104,652	94,960	199,255	183,038
Earnings and dividends allocated to participating securities	176	0	0	371
Income allocated to noncontrolling interest - Preferred Operating Partnership Units and Operating Partnership Units	6,010	5,271	11,439	10,211
Fixed component of income allocated to noncontrolling interest - Preferred Operating Partnership (Series A Units)	(572)	(572)	(1,144)	(1,144)
Net income for diluted computations	$ 110,266	$ 99,659	$ 209,550	$ 192,476
Weighted average common shares outstanding:
Average number of common shares outstanding - basic (in shares)	127,585,436	125,874,130	127,349,299	125,823,581
OP Units (in shares)	6,085,976	5,651,878	6,023,822	5,657,592
Unvested restricted stock awards included for treasury stock method (in shares)	218,686	0	0	256,733
Shares related to exchangeable senior notes and dilutive stock options (in shares)	889,183	371,284	917,855	379,348
Average number of common shares outstanding - diluted (in shares)	135,654,761	132,772,772	135,166,456	132,992,734
Earnings per common share
Basic (in dollars per share)	$ 0.82	$ 0.75	$ 1.56	$ 1.45
Diluted (in dollars per share)	$ 0.81	$ 0.75	$ 1.55	$ 1.45
Series A Units
Weighted average common shares outstanding:
Preferred series units (in shares)	875,480	875,480	875,480	875,480