Discontinued Operations (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended	6 Months Ended				3 Months Ended	12 Months Ended		3 Months Ended	12 Months Ended		3 Months Ended	12 Months Ended				3 Months Ended	12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012	Jun. 30, 2013 1500 Sunday Drive [Member]	Jun. 30, 2013 Peninsula Business Center I and II [Member]		Jun. 30, 2013 Lake Point and SunTrust Office [Member]	Sep. 30, 2012 Willowbrook Plaza [Member]	Dec. 31, 2012 Willowbrook Plaza [Member]		Sep. 30, 2012 Towne Mall [Member]	Dec. 31, 2012 Towne Mall [Member]		Sep. 30, 2012 Hickory Hollow Mall [Member]	Dec. 31, 2012 Hickory Hollow Mall [Member]		Dec. 31, 2012 Massard Crossing [Member]	Dec. 31, 2012 Settlers Ridge Phase II [Member]	Mar. 31, 2012 Oak Hollow Square [Member]	Dec. 31, 2012 Oak Hollow Square [Member]		Dec. 31, 2012 Westridge Square [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of Long-Lived Assets to be Disposed of										$ 17,743			$ 419			$ 8,047					$ 255
Gain on (loss) discontinued operations	91	(16)	872	895	895	(549)	598	[1]	823		0	[2]		0	[3]		0	[4]	0	867		(1)	[5]	29	[6]
Gross sales price			44,425		67,594	8,300	5,250	[1]	30,875		24,450	[2]		950	[3]		1,000	[4]	7,803	19,144		14,247	[5]
Proceeds from Sale of Real Estate			43,473		66,208	7,862	5,121	[1]	30,490		24,171	[2]		892	[3]		966	[4]	7,432	18,951		13,796	[5]
Revenues of discontinued operations	3	3,754	450	8,367
Assets of Disposal Group, Including Discontinued Operation	$ 42,693		$ 42,693

[1] Classified as held for sale as of December 31, 2012.

[2] Loss on impairment of $17,743 recorded in the third quarter of 2012 to write down the book value of this property to its then estimated fair value.

[3] Loss on impairment of $419 recorded in the third quarter of 2012 to write down the book value of this property to expected sales price.

[4] Loss on impairment of $8,047 recorded in the third quarter of 2012 to write down the book value of this property to expected sales price.

[5] Loss on impairment of $255 recorded in the first quarter of 2012 related to the true-up of certain estimated amounts to actual amounts.

[6] Reflects subsequent true-up for settlement of estimated expenses based on actual amounts.