v2.4.0.6
Income Taxes (Details) (USD $)
3 Months Ended 12 Months Ended
Dec. 31, 2011
Sep. 30, 2011
Jun. 30, 2011
Mar. 31, 2011
Dec. 31, 2010
Sep. 30, 2010
Jun. 30, 2010
Mar. 31, 2010
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Tax treatment of distributions:                      
Ordinary income (in dollars per share)                 $ 2.28131 $ 1.99928 $ 1.8356
Long-term capital gain (in dollars per share)                 $ 0.01869 $ 0.07644 $ 0.1510
Unrecaptured Section 1250 gain (in dollars per share)                 $ 0.00 $ 0.06428 $ 0.0634
Distribution reported for 1099-DIV purposes (in dollars per share)                 $ 2.30000 $ 2.14000 $ 2.0500
Distributions declared per common share outstanding (in dollars per share) $ 0.5750 $ 0.4486 $ 0.7014 $ 0.575 $ 0.535 $ 0.535 $ 0.535 $ 0.535 $ 2.30000 $ 2.14000 $ 2.0500
REIT distribution requirement (as a percent)                 90.00%    
Provision (benefit) for income taxes                      
Current                 $ (4,080,000) $ 2,459,000 $ 2,166,000
Deferred                 (27,057,000) 2,742,000 (3,885,000)
Income tax expense (benefit)                 (31,137,000) 5,201,000 (1,719,000)
Income tax expense related to the noncontrolling interest share of net income                 0 2,300,000 1,700,000
Canadian income tax benefit included in consolidated benefit for income taxes                 $ (500,000) $ 300,000 $ 2,000,000