CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Shares	Additional Paid In Capital	Cumulative Net Income	Cumulative Other Comprehensive Income (Loss)	Cumulative Common Distributions
Balance at Dec. 31, 2010	$ 757,397	$ 405	$ 776,913	$ 41,336	$ 2	$ (61,259)
Balance (in shares) at Dec. 31, 2010		40,500,800
Increase (Decrease) in Shareholders' Equity
Issuance of shares, net	157,870	65	157,805
Issuance of shares, net (in shares)		6,500,000
Share grants	721	1	720
Share grants (in shares)		50,850
Equity in unrealized gain of an investee	75				75
Net income	45,997			45,997
Distributions to common shareholders	(70,392)					(70,392)
Balance at Dec. 31, 2011	891,668	471	935,438	87,333	77	(131,651)
Balance (in shares) at Dec. 31, 2011		47,051,650
Increase (Decrease) in Shareholders' Equity
Issuance of shares, net	166,718	75	166,643
Issuance of shares, net (in shares)		7,500,000
Share grants	1,902	1	1,901
Share grants (in shares)		92,238
Equity in unrealized gain of an investee	22				22
Net income	49,960			49,960
Distributions to common shareholders	(82,819)					(82,819)
Balance at Dec. 31, 2012	1,027,451	547	1,103,982	137,293	99	(214,470)
Balance (in shares) at Dec. 31, 2012		54,643,888
Increase (Decrease) in Shareholders' Equity
Share grants	1,697		1,697
Share grants (in shares)		78,130
Equity in unrealized gain of an investee	(50)				(50)
Net income	54,620			54,620
Distributions to common shareholders	(94,043)					(94,043)
Balance at Dec. 31, 2013	$ 989,675	$ 547	$ 1,105,679	$ 191,913	$ 49	$ (308,513)
Balance (in shares) at Dec. 31, 2013		54,722,018