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Common Stock and Other Equity Related Transactions - Common Stock, OP Units, and Distributions (Details) - $ / shares
 12 Months Ended
Jan. 11, 2019
Oct. 12, 2018
Jul. 13, 2018
Apr. 13, 2018
Jan. 12, 2018
Oct. 13, 2017
Jul. 14, 2017
Apr. 14, 2017
Jan. 13, 2017
Oct. 14, 2016
Jul. 08, 2016
Apr. 08, 2016
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Class of Stock [Line Items]                              
Units of partnership interest (in shares)                         5,745,966 5,834,100 7,170,000
Common Stock Outstanding [Roll Forward]                              
Shares outstanding at January 1, (shares)                         88,585,160 85,529,386 84,253,065
Common stock issued through the At-The-Market Offering Program (in shares)                         861,141 1,380,017 683,548
Common stock issued through conversion of OP Units (in shares)                         88,134 1,335,900 37,678
Common stock issued through exercise of options (in shares)                         202,800 220,000 440,000
Common stock issued through restricted stock grants (in shares)                           130,426 133,717
Common stock forfeitures (in shares)                         0 (990) 0
Common stock issued through ESPP and Dividend Reinvestment Plan (in shares)                         22,572 25,101 17,373
Common stock repurchased and retired (in shares)                         (31,294) (34,680) (35,995)
Shares outstanding at December 31, (shares)                         89,921,018 88,585,160 85,529,386
Share based payment award repurchased shares for taxes (usd per share)                         $ 96.23 $ 89.02 $ 72.22
Percentage of ownership interests (in percentage)                         94.00% 93.80% 92.30%
Ownership percentage by noncontrolling owners (in percentage)                         6.00% 6.20% 7.70%
Disclosure Regular Quarterly Distributions Declared And Paid To Common Stockholders And Common O P Unit Non Controlling Interests [Abstract]                              
Distribution Amount Per Share (usd per share)   $ 0.55 $ 0.55 $ 0.55 $ 0.4875 $ 0.4875 $ 0.4875 $ 0.4875 $ 0.4250 $ 0.4250 $ 0.4250 $ 0.4250 $ 0.487    
Subsequent Event                              
Disclosure Regular Quarterly Distributions Declared And Paid To Common Stockholders And Common O P Unit Non Controlling Interests [Abstract]                              
Distribution Amount Per Share (usd per share) $ 0.55