Discontinued Operations (Narratives) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended	0 Months Ended	3 Months Ended		6 Months Ended		0 Months Ended	3 Months Ended		6 Months Ended		0 Months Ended	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended			0 Months Ended	6 Months Ended
	Jun. 30, 2013 Retail Segment Strip Shopping Centers [Member] Properties	Jan. 06, 2012 West Mart Center 350 [Member]	Jun. 30, 2013 West Mart Center 350 [Member]	Jun. 30, 2012 West Mart Center 350 [Member]	Jun. 30, 2013 West Mart Center 350 [Member]	Jun. 30, 2012 West Mart Center 350 [Member]	Apr. 15, 2013 Plant [Member]	Jun. 30, 2013 Plant [Member]	Jun. 30, 2012 Plant [Member]	Jun. 30, 2013 Plant [Member]	Jun. 30, 2012 Plant [Member]	Jan. 24, 2013 Green Acres Mall [Member]	Jun. 30, 2013 Green Acres Mall [Member]	Jun. 30, 2012 Green Acres Mall [Member]	Jun. 30, 2013 Green Acres Mall [Member]	Jun. 30, 2012 Green Acres Mall [Member]	Jun. 30, 2013 Gallery At Market Street [Member]	Jun. 30, 2012 Gallery At Market Street [Member]	Jun. 30, 2013 Gallery At Market Street [Member]	Jun. 30, 2012 Gallery At Market Street [Member]	Jun. 30, 2013 Other Real Estate [Member]	Jun. 30, 2012 Other Real Estate [Member]	Jun. 30, 2013 Other Real Estate [Member]	Jun. 30, 2012 Other Real Estate [Member]	Jun. 30, 2012 Retail Properties Segment [Member] Retail Segment Strip Shopping Centers [Member] Properties	Apr. 15, 2013 Retail Properties Segment [Member] Gallery At Market Street [Member] Subsequent Event [Member]	Jun. 30, 2013 Retail And Other Segment Properties [Member] Properties
Disposal Group Including Discontinued Operation Additional Disclosures [Abstract]
Gross proceeds from the sale of real estate							$ 203,000					$ 500,000														$ 60,000
Gain Loss On Disposal Of Discontinued Operations		54,911	0	0	0	54,911	32,169	32,169	0	32,169	0	202,275	0	0	202,275	0	33,058	0	33,058	0	438	16,896	492	17,802	17,802	33,058	492
Net proceeds from the sale of real estate							98,000					185,000														58,000
Cash proceeds from the sale of real estate		$ 228,000																							$ 136,000		$ 40,200
Number Of Real Estate Properties Sold	9																								11		10