Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Weighted Average Common Shares
Weighted average Common Shares outstanding																	92,725,112	80,360,422	74,156,849
Non-vested shares																	(1,784,485)	(1,515,582)	(1,436,702)
Weighted average Common Shares - Basic																	90,940,627	78,844,840	72,720,147
Dilutive effect of non-vested shares																		1,144,465
Dilutive effect of employee stock purchase plan																		138,578
Weighted average Common Shares - Diluted																	90,940,627	80,127,883	72,720,147
Net Income (loss)
Income (loss) from continuing operations	$ 9,888	[1]	$ 4,703	[2]	$ (27,701)	[3]	$ 842	[4]	$ (1,467)	[5]	$ 635	[6]	$ 875	[7]	$ 52	[8]	$ (12,268)	$ 95	$ (11,543)
Less: Net income attributable to noncontrolling interests	(72)	[1]	(17)	[2]	33	[3]	19	[4]	(29)	[5]	(21)	[6]	(20)	[7]	0	[8]	(37)	(70)	(30)
Income (loss) from continuing operations attributable to common stockholders																	(12,305)	25	(11,573)
Discontinued operations	2,568	[1]	15,080	[2]	3,463	[3]	(1,860)	[4]	(4,895)	[5]	5,200	[6]	2,053	[7]	3,082	[8]	19,251	5,440	11,359
NET INCOME (LOSS) ATTRIBUTABLE TO COMMON STOCKHOLDERS	$ 12,384	[1]	$ 19,766	[2]	$ (24,205)	[3]	$ (999)	[4]	$ (6,391)	[5]	$ 5,814	[6]	$ 2,908	[7]	$ 3,134	[8]	$ 6,946	$ 5,465	$ (214)
Basic Earnings (Loss) Per Common Share
Income (loss) from continuing operations (in dollars per share)																	$ (0.13)	$ 0.00	$ (0.16)
Discontinued operations (in dollars per share)																	$ 0.21	$ 0.07	$ 0.16
Net income (loss) attributable to common stockholders (in dollars per share)	$ 0.13	[1]	$ 0.21	[2]	$ (0.27)	[3]	$ (0.01)	[4]	$ (0.07)	[5]	$ 0.08	[6]	$ 0.04	[7]	$ 0.04	[8]	$ 0.08	$ 0.07	$ 0.00
Diluted Earnings (Loss) Per Common Share
Income (loss) from continuing operations (in dollars per share)																	$ (0.13)		$ (0.16)
Discontinued operations (in dollars per share)																	$ 0.21	$ 0.07	$ 0.16
Net income (loss) attributable to common stockholders (in dollars per share)	$ 0.13	[1]	$ 0.21	[2]	$ (0.27)	[3]	$ (0.01)	[4]	$ (0.07)	[5]	$ 0.07	[6]	$ 0.04	[7]	$ 0.04	[8]	$ 0.08	$ 0.07	$ 0.00

[1] The increases in net income and amounts per share for the fourth quarter of 2013 are primarily attributable to gains on sales of real estate totaling $2.7 million.

[2] The increases in net income and amounts per share for the third quarter of 2013 are primarily attributable to gains on sales of real estate totaling $20.2 million, partially offset by impairment charges of $6.3 million.

[3] The decreases in net income and amounts per share for the second quarter of 2013 are primarily attributable to losses of extinguishment of debt of $29.9 million, of which $0.3 million is included in discontinued operations. This amount is partially offset by gains on sales of real estate totaling $1.8 million.

[4] The decreases in net income and amounts per share for the first quarter of 2013 are primarily attributable to impairment charges of $3.6 million.

[5] The decreases in net income and amounts per share for the fourth quarter of 2012 are primarily attributable to impairment charges of $7.7 million. This amount is partially offset by gains on sales of real estate totaling $1.2 million.

[6] The increases in net income and amounts per share for the third quarter of 2012 are primarily attributable to gains on sales of real estate totaling $6.3 million, partially offset by impairment charges of $2.9 million.

[7] The decreases in net income and amounts per share for the second quarter of 2012 are primarily attributable to impairment charges of $0.2 million.

[8] The increases in net income and amounts per share for the first quarter of 2012 are primarily attributable to gains on sales of real estate totaling $3.4 million and a lease termination fee totaling $1.5 million which is included in discontinued operations. This amount is partially offset by impairment charges of $4.2 million.