Consolidated Balance Sheet (Parentheticals) (USD $) Share data in Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Accounts receivable. allowance	$ 3,597,000	$ 2,945,000
Straight-line rent receivable, allowance	7,447,000	7,260,000
Deferred financing costs, accumulated amortization	59,109,000	46,407,000
Deferred leasing and other costs, accumulated amortization	$ 292,334,000	$ 269,000,000
General Partners' Capital Account, Units Issued	252,927	252,195
General Partners' Capital Account, Units Outstanding	252,927	252,195
Preferred Units, Issued	3,176	3,618
Preferred Units, Outstanding	3,176	3,618
Limited Partners' Capital Account, Units Issued	6,945	5,231
Limited Partners' Capital Account, Units Outstanding	6,945	5,231