Earnings Per Common Share - Schedule of Computation of Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Earnings Per Share [Abstract]
Net income attributable to common stockholders	$ 83,044	$ 55,339	$ 165,636	$ 109,081
Earnings and dividends allocated to participating securities	(214)	(140)	(380)	(259)
Earnings for basic computations	82,830	55,199	165,256	108,822
Earnings and dividends allocated to participating securities	0	0	380	0
Income allocated to noncontrolling interest - Preferred Operating Partnership (Series A Units) and Operating Partnership	5,398	4,276	10,872	7,911
Fixed component of income allocated to noncontrolling interest - Preferred Operating Partnership (Series A Units)	(1,271)	(1,271)	(2,542)	(2,545)
Net income for diluted computations	$ 86,957	$ 58,204	$ 173,966	$ 114,188
Weighted average common shares outstanding:
Average number of common shares outstanding - basic (in shares)	124,914,467	116,861,678	124,678,293	116,491,710
Series A Units (in shares)	875,480	875,480	875,480	875,480
OP Units (in shares)	5,517,607	5,642,737	5,569,537	5,007,835
Unvested restricted stock awards included for treasury stock method (in shares)	0	0	309,987	0
Shares related to exchangeable senior notes and dilutive stock options (in shares)	718,361	1,095,995	719,222	1,102,216
Average number of common shares outstanding - diluted (in shares)	132,025,915	124,475,890	132,152,519	123,477,241
Earnings per common share
Basic (in dollars per share)	$ 0.66	$ 0.47	$ 1.33	$ 0.93
Diluted (in dollars per share)	$ 0.66	$ 0.47	$ 1.32	$ 0.92