Annual report pursuant to Section 13 and 15(d)

Real Estate Investments And Accumulated Depreciation (Schedule Of Changes In Rental Properties And Accumulated Depreciation) (Details)

v2.4.0.8
Real Estate Investments And Accumulated Depreciation (Schedule Of Changes In Rental Properties And Accumulated Depreciation) (Details) (USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Real Estate Investments And Accumulated Depreciation [Abstract]      
Rental Properties, Balance at beginning of year $ 5,379,436 $ 5,279,770 $ 5,216,720
Rental Properties, Additions 317,994 296,079 91,716
Rental Properties, Rental property held for sale (107,205) (84,716)  
Rental Properties, Properties sold (256,335) (34,563)  
Rental Properties, Impairment charge on rental property (149,030) (20,573)  
Rental Properties, Retirements/disposals (54,927) (56,561) (28,666)
Rental Properties, Balance at end of year 5,129,933 5,379,436 5,279,770
Accumulated Depreciation, Balance at beginning of year 1,478,214 1,409,163 1,278,985
Accumulated Depreciation, Depreciation expense 155,846 157,175 158,559
Accumulated Depreciation, Rental property held for sale (35,594) (23,852)  
Accumulated Depreciation, Properties sold (104,196) (10,026)  
Accumulated Depreciation, Impairment charge on rental property (38,353) 2,058  
Accumulated Depreciation, Retirements/disposals (54,929) (56,304) (28,381)
Accumulated Depreciation, Balance at end of year $ 1,400,988 [1] $ 1,478,214 $ 1,409,163
[1] Depreciation of buildings and improvements are calculated over lives ranging from the life of the lease to 40 years.