Consolidated Statement of Equity Statement - 9 months ended Sep. 30, 2016 - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Including Portion Attributable to Noncontrolling Interest [Member]	Parent [Member]	Operating Partnership Noncontrolling Interest [Member]	Partially Owned Properties Noncontrolling Interest [Member]	Noncontrolling Interest [Member]
Balance at Dec. 31, 2015	$ 1,076,461	$ 872	$ 1,129,284	$ (109,024)		$ 1,021,132	$ 45,451	$ 9,878	$ 55,329
Net proceeds from sale of common shares	764,292	472	763,820			764,292
Restricted share award grants, net	3,203	1	3,496	(294)		3,203
Purchase of OP Units	(2,999)						(2,999)		(2,999)
Conversion of OP Units		4	8,094			8,098	(8,098)		(8,098)
Dividends/distributions declared	(87,602)			(85,208)		(85,208)	(2,394)		(2,394)
Preferred distributions	(1,421)			(1,421)		(1,421)
Issuance of OP Units in connection with acquisition	2,869		(3,900)			(3,900)	6,869	(100)	6,769
Contributions	50							50	50
Distributions	(450)							(450)	(450)
Change in market value of Redeemable Noncontrolling Interests in Operating Partnership	(422)		(422)			(422)
Reclassification of Noncontrolling Interest - partially owned properties	(8,514)							(8,514)	(8,514)
Buyout of Noncontrolling Interests - partially owned properties	(611)		53			53		(664)	(664)
Change in fair value of interest rate cap agreements	652				$ 652	652
Net income	22,902			21,720		21,720	629	553	1,182
Adjustment for Noncontrolling Interests ownership in Operating Partnership			(6,680)			(6,680)	6,680		6,680
Balance at Sep. 30, 2016	$ 1,768,410	$ 1,349	$ 1,893,745	$ (174,227)	$ 652	$ 1,721,519	$ 46,138	$ 753	$ 46,891