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)

v3.6.0.2
Real Estate Investments And Accumulated Depreciation (Schedule Of Changes In Rental Properties And Accumulated Depreciation) (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Real Estate Investments And Accumulated Depreciation [Abstract]      
Rental Properties, Balance at beginning of year $ 4,807,718 $ 4,958,179 $ 5,129,933
Rental Properties, Additions 819,535 219,227 193,005
Rental Properties, Rental property held for sale (79,200)    
Rental Properties, Properties sold (695,837) (82,015) (331,181)
Rental Properties, Impairment charge   (255,849)  
Rental Properties, Retirements/disposals (47,349) (31,824) (33,578)
Rental Properties, Balance at end of year 4,804,867 [1] 4,807,718 4,958,179
Accumulated Depreciation, Balance at beginning of year 1,464,482 1,414,305 1,400,988
Accumulated Depreciation, Depreciation expense 151,569 147,447 143,278
Accumulated Depreciation, Rental property held for sale (31,792)    
Accumulated Depreciation, Properties sold (204,837) (7,517) (96,383)
Accumulated Depreciation, Impairment charge   (57,929)  
Accumulated Depreciation, Retirements/disposals (47,349) (31,824) (33,578)
Accumulated Depreciation, Balance at end of year $ 1,332,073 [2] $ 1,464,482 $ 1,414,305
[1] Properties identified as held for sale at December 31, 2016 are excluded.
[2] Depreciation of buildings and improvements are calculated over lives ranging from the life of the lease to 40 years.