Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016		Jun. 30, 2015
Net increase (decrease) in shareholders' equity resulting from operations
Net Income (Loss) Attributable to Parent		$ 4,985	$ 13,152	$ (18,215)		$ 32,413
Net Income (Loss) Attributable to Participating Non-controlling Interest	[1]	32	82	(115)		202
Net income (loss) attributable to parent and participating non-controlling interest		5,017	13,234	(18,330)		32,615
Net increase (decrease) in shareholders' equity resulting from operations– common shares		4,918	12,985	(17,970)		32,002
Net increase (decrease) in shareholders' equity resulting from operations– LTIP units		67	167	(245)		411
Dividends Paid:
Common shareholders	[2]	(16,413)	(21,742)	(32,954)		(43,486)
LTIP unit holders	[2]	(225)	(279)	(450)		(558)
Non-controlling Interest	[2]	(106)	(138)	(212)		(274)
Total dividends paid to common shareholders, LTIP unit holders, and non-controlling interest	[2]	(16,744)	(22,159)	(33,616)	[3]	(44,318)	[3]
Undistributed (Distributed in excess of) earnings:
Common shareholders		(11,495)	(8,757)	(50,924)		(11,484)
LTIP unit holders		(158)	(112)	(695)		(147)
Non-controlling interest		(74)	(56)	(327)		(72)
Total undistributed (distributed in excess of) earnings attributable to common shareholders, LTIP unit holders, and non-controlling interest		$ (11,727)	$ (8,925)	$ (51,946)		$ (11,703)
Weighted average shares outstanding (basic and diluted):
Weighted average common shares outstanding		32,840,429	33,449,678	32,962,056		33,449,678
Weighted average participating LTIP units		449,938	429,314	449,938		429,314
Weighted average non-controlling interest units		212,000	212,000	212,000		212,000
Basic earnings per common share:
Distributed (in usd per share)		$ 0.50	$ 0.65	$ 1.00		$ 1.30
Undistributed (Distributed in excess of) (in usd per share)		(0.35)	(0.26)	(1.54)		(0.34)
Basic earnings per common share (in usd per share)		0.15	0.39	(0.54)		0.96
Diluted earnings per common share:
Distributed (in usd per share)		0.50	0.65	1.00		1.30
Undistributed (Distributed in excess of) (in usd per share)		(0.35)	(0.26)	(1.54)		(0.34)
Diluted earnings per common share (in usd per share)		$ 0.15	$ 0.39	$ (0.54)		$ 0.96
Net Income (Loss) Attributable to Non-Participating Non-controlling Interest		$ (100)	$ (11)	$ 100		$ 25

[1] For the three month periods ended June 30, 2016 and 2015, excludes net increase in equity resulting from operations of $(0.1) million and $(11) thousand, respectively attributable to joint venture partners, which have non-participating interests as described in Note 9. For the six month periods ended June 30, 2016 and 2015, excludes net increase in equity resulting from operations of $0.1 million and $25 thousand, respectively attributable to joint venture partners, which have non-participating interests as described in Note 9.

[2] The Company pays quarterly dividends in arrears, so a portion of the dividends paid in each calendar year relate to the prior year's earnings.

[3] For the six month periods ended June 30, 2016 and 2015, dividends totaling $1.00 and $1.30, respectively, per common share and convertible unit outstanding, were declared and paid.