Segment Information (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Financial data of reportable segments
Total Assets	$ 8,795,391,000		$ 8,814,940,000
Revenues	237,082,000	249,537,000
Operating Expenses	160,643,000	171,103,000
Depreciation and amortization	61,814,000	55,009,000
Interest and other income	9,704,000	11,503,000
Interest expense	52,576,000	62,452,000
Capital expenditures	74,989,000	90,753,000
Commercial Group [Member]
Financial data of reportable segments
Total Assets	4,211,742,000		4,210,714,000
Revenues	128,545,000	130,085,000
Operating Expenses	73,090,000	81,548,000
Depreciation and amortization	32,851,000	30,259,000
Interest and other income	2,633,000	1,784,000
Interest expense	30,322,000	34,566,000
Capital expenditures	28,882,000	30,997,000
Residential Group [Member]
Financial data of reportable segments
Total Assets	3,298,255,000		3,172,188,000
Revenues	69,660,000	65,669,000
Operating Expenses	43,239,000	45,669,000
Depreciation and amortization	19,376,000	15,396,000
Interest and other income	2,996,000	6,445,000
Interest expense	4,465,000	9,185,000
Capital expenditures	43,440,000	53,803,000
Arena [Member]
Financial data of reportable segments
Total Assets	963,029,000		955,570,000
Revenues	28,820,000	35,357,000
Operating Expenses	19,958,000	23,476,000
Depreciation and amortization	8,790,000	8,532,000
Interest and other income	0	0
Interest expense	10,108,000	9,557,000
Capital expenditures	2,652,000	5,937,000
Land Development Group [Member]
Financial data of reportable segments
Total Assets	259,399,000		250,833,000
Revenues	10,057,000	18,426,000
Operating Expenses	4,641,000	8,849,000
Depreciation and amortization	89,000	86,000
Interest and other income	4,040,000	3,245,000
Interest expense	(465,000)	(138,000)
Capital expenditures	15,000	16,000
Corporate Activities [Member]
Financial data of reportable segments
Total Assets	62,966,000		225,635,000
Revenues	0	0
Operating Expenses	19,715,000	11,561,000
Depreciation and amortization	708,000	736,000
Interest and other income	35,000	29,000
Interest expense	8,146,000	9,282,000
Capital expenditures	$ 0	$ 0