CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - 9 months ended Sep. 30, 2015 - USD ($) $ in Thousands	Total	Total Shareholders’ Equity	Common Shares	Additional Paid-In Capital	Accumulated Other Comprehensive (Loss) Income	Retained Earnings	Noncontrolling Interests
Balance (in Shares) at Dec. 31, 2014	68,109,287		68,109,000
Balance at Dec. 31, 2014	$ 1,435,957	$ 1,055,541	$ 68	$ 1,027,861	$ (4,005)	$ 31,617	$ 380,416
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of OP Units to Common Shares by limited partners of the Operating Partnership (in Shares)			67,000
Conversion of OP Units to Common Shares by limited partners of the Operating Partnership	0	1,655		1,655			(1,655)
Issuance of Common Shares, net of issuance costs (in Shares)			809,000
Issuance of Common Shares, net of issuance costs	26,933	26,933	$ 1	26,932
Dividends declared ($0.72 per Common Share)	(53,112)	(49,570)				(49,570)	(3,542)
Employee and trustee stock compensation, net (in Shares)			36,000
Employee and trustee stock compensation, net	5,937	801		801			5,136
Acquisition of noncontrolling interests	(662)	(662)		(662)
Noncontrolling interest distributions	(74,656)						(74,656)
Noncontrolling interest contributions	34,895						34,895
Balance before adjustment towards comprehensive income (in Shares)			69,021,000
Balance before adjustment towards comprehensive income	1,375,292	1,034,698	$ 69	1,056,587	(4,005)	(17,953)	340,594
Comprehensive (loss) income:
Net income	142,099	56,818				56,818	85,281
Unrealized loss on valuation of swap agreements	(7,328)	(6,032)			(6,032)		(1,296)
Reclassification of realized interest on swap agreements	4,478	2,691			2,691		1,787
Comprehensive income	$ 139,249	53,477			(3,341)	56,818	85,772
Balance (in Shares) at Sep. 30, 2015	69,020,777		69,021,000
Balance at Sep. 30, 2015	$ 1,514,541	$ 1,088,175	$ 69	$ 1,056,587	$ (7,346)	$ 38,865	$ 426,366