Annual report pursuant to Section 13 and 15(d)

Significant Accounting Policies (Narrative) (Details)

v3.10.0.1
Significant Accounting Policies (Narrative) (Details) - USD ($)
 3 Months Ended 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Jan. 03, 2019
Jan. 03, 2018
Dec. 31, 2015
Significant Accounting Policies [Line Items]                
Capitalized development and construction salaries and other related costs     $ 2,300,000 $ 2,200,000 $ 2,600,000      
Maximum period after cessation of major construction activity that projects are considered complete     1 year          
Threshold of investment value for discontinuation of equity method accounting $ 0   $ 0          
Amortization of deferred financing costs     5,028,000 4,612,000 4,582,000      
Loss from extinguishment of debt, net     (10,750,000) (421,000) 12,420,000      
Deferred leasing costs     3,463,000 3,146,000 3,270,000      
Goodwill 2,945,000 $ 2,945,000 2,945,000 2,945,000        
Goodwill impairment     0          
Difference between the estimated net basis and net assets of the rental property for federal income tax purposes 410,573,000   410,573,000          
Taxable income     82,106,000 $ 97,037,000 $ 30,208,000      
Deferred tax asset $ 10,100,000   10,100,000          
Income taxes, material adjustment amount     $ 0          
Common stock, shares outstanding 90,320,306 89,914,113 90,320,306 89,914,113     89,914,658  
Common units outstanding 10,174,285 10,438,855 10,174,285 10,438,855 10,488,105   10,438,855 10,516,844
LTIP units outstanding 1,762,170 1,230,877 1,762,170 1,230,877 657,373   1,230,877
Distributions payable, record date Jan. 03, 2019 Jan. 03, 2018            
Distributions payable, approved date Dec. 11, 2018 Dec. 12, 2017            
Common stock dividends and common unit distributions per share $ 0.20 $ 0.20            
Dividends paid per common share     $ 0.80 $ 0.70 $ 0.60      
Dividends paid, percent representing ordinary income     47.00% 100.00%        
Dividends paid, percent representing return of capital to shareholders         100.00%      
Dividends paid, percent representing capital gain     53.00%          
Restricted stock expense     $ 6,894,000 $ 7,447,000 $ 5,646,000      
Distributions payable, pay date Jan. 11, 2019 Jan. 12, 2018            
Increase (decrease) to deferred tax assets     (5,300,000)          
Increase (decrease) to valuation allowance     $ (5,300,000)          
Federal income tax rate     21.00%          
Write off of unamortized deferred financing costs     $ 600,000 400,000 700,000      
Loss from extinguishment of debt, net     $ (10,750,000) $ (421,000) $ (30,540,000)      
Subsequent Event [Member]                
Significant Accounting Policies [Line Items]                
Common stock, shares outstanding           90,320,408    
Common units outstanding           10,174,285    
LTIP units outstanding           1,762,170