|
Real Estate Investments And Accumulated Depreciation (Changes In Rental Properties And Accumulated Depreciation) (Details) (USD $)
In Thousands, unless otherwise specified
|
12 Months Ended |
|
Dec. 31, 2011
|
Dec. 31, 2010
|
Dec. 31, 2009
|
| Real Estate Investments And Accumulated Depreciation [Abstract] |
|
|
|
| Rental Properties, Balance at beginning of year |
$ 5,216,720 |
$ 5,186,208 |
$ 4,963,780 |
| Rental Properties, Additions |
91,716 |
86,455 |
282,122 |
| Rental Properties, Properties sold |
|
(16,052) |
|
| Rental Properties, Impairment charge on rental property |
|
(12,560) |
|
| Rental Properties, Retirements/disposals |
(28,666) |
(27,331) |
(59,694) |
| Rental Properties, Balance at end of year |
5,279,770 |
5,216,720 |
5,186,208 |
| Accumulated Depreciation, Balance at beginning of year |
1,278,985 |
1,153,223 |
1,040,778 |
| Accumulated Depreciation, Depreciation expense |
158,559 |
158,318 |
155,613 |
| Accumulated Depreciation, Properties sold |
|
(2,091) |
|
| Accumulated Depreciation, Impairment charge on rental property |
|
(3,256) |
(1,009) |
| Accumulated Depreciation, Retirements/disposals |
(28,381) |
(27,209) |
(42,159) |
| Accumulated Depreciation, Balance at end of year |
$ 1,409,163 |
$ 1,278,985 |
$ 1,153,223 |