Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011
Earnings Per Share [Abstract]
Net increase (decrease) in shareholders' equity resulting from operations	$ 10,768		$ (1,321)		$ 42,823		$ 9,786
Net increase (decrease) in shareholders' equity resulting from operations - common shares	10,518		(1,291)		41,830		9,563
Net increase (decrease) in shareholders' equity resulting from operations - LTIPs	250		(30)		993		223
Dividends Paid, Common Shares	(11,513)		(6,603)		(18,092)		(28,225)
Dividends Paid, LTIPs	(274)		(154)		(430)		(658)
Total dividends paid to common share and LTIP holders	(11,787)	[1]	(6,757)	[1]	(18,522)	[1]	(28,883)	[1]
Undistributed earnings, Common Shares	(995)		(7,894)		23,738		(18,662)
Undistributed earnings, LTIPs	(24)		(184)		563		(435)
Total undistributed earnings attributable to common share and LTIP holders	$ (1,019)		$ (8,078)		$ 24,301		$ (19,097)
Weighted average common shares outstanding	16,447,651		16,506,453		16,447,651		16,503,940
Weighted average participating LTIPs	390,500		385,000		390,500		385,000
Basic earnings per common share, Distributed	$ 0.70		$ 0.40		$ 1.10		$ 1.71
Basic earnings per common share, Undistributed	$ (0.06)		$ (0.48)		$ 1.44		$ (1.13)
Basic earnings per common share	$ 0.64		$ (0.08)		$ 2.54		$ 0.58
Diluted earnings per common share, Distributed	$ 0.70		$ 0.40		$ 1.10		$ 1.71
Diluted earnings per common share, Undistributed	$ (0.06)		$ (0.48)		$ 1.44		$ (1.13)
Diluted earnings per common share	$ 0.64		$ (0.08)		$ 2.54		$ 0.58

[1] For the three month periods ending June 30, 2012 and 2011, dividends totaling $0.70 and $0.40, respectively, per common share and LT IP unit outstanding were declared and paid. For the six month periods ending June 30, 2012 and 2011, dividends totaling $1.10 and $1.71, respectively, per common share and LT IP unit outstanding were declared and paid.