CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - 3 months ended Mar. 31, 2016 - 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, 2015	70,258,415		70,258,000
Balance at Dec. 31, 2015	$ 1,521,354	$ 1,100,488	$ 70	$ 1,092,239	$ (4,463)	$ 12,642	$ 420,866
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of OP Units to Common Shares by limited partners of the Operating Partnership (in Shares)			249,000
Conversion of OP Units to Common Shares by limited partners of the Operating Partnership	0	5,680	$ 1	5,679			(5,680)
Issuance of Common Shares, net of issuance costs (in Shares)			1,050,000
Issuance of Common Shares, net of issuance costs	35,220	35,220	$ 1	35,219
Issuance of OP Units to Acquire Real Estate	29,336						29,336
Dividends declared ($0.25 per Common Share)	(19,345)	(17,872)				(17,872)	(1,473)
Employee and trustee stock compensation, net (in Shares)			9,000
Employee and trustee stock compensation, net	4,019	208		208			3,811
Acquisition of noncontrolling interests	(18,379)	7,569		7,569			(25,948)
Noncontrolling interest distributions	(36,174)						(36,174)
Noncontrolling interest contributions	46,343						46,343
Balance before adjustment towards comprehensive income (in Shares)			71,566,000
Balance before adjustment towards comprehensive income	1,562,374	1,131,293	$ 72	1,140,914	(4,463)	(5,230)	431,081
Comprehensive income(loss):
Net income	73,875	28,925				28,925	44,950
Unrealized loss on valuation of swap agreements	(8,819)	(7,905)			(7,905)		(914)
Reclassification of realized interest on swap agreements	1,046	901			901		145
Comprehensive income	$ 66,102	21,921			(7,004)	28,925	44,181
Balance (in Shares) at Mar. 31, 2016	71,566,457		71,566,000
Balance at Mar. 31, 2016	$ 1,628,476	$ 1,153,214	$ 72	$ 1,140,914	$ (11,467)	$ 23,695	$ 475,262