Annual report pursuant to Section 13 and 15(d)

Properties, Net (Details)

v3.8.0.1
Properties, Net (Details) - USD ($)
$ in Thousands
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Properties        
Gross $ 3,980,813 $ 3,874,715 $ 4,158,616 $ 4,014,336
Operating properties, net 2,737,611 2,671,831    
Operating properties, net [Member]        
Properties        
Less: accumulated depreciation (786,193) (706,385)    
Operating properties, net 2,737,611 2,671,831    
Operating properties, net [Member] | Land [Member]        
Properties        
Gross 455,680 433,311    
Operating properties, net [Member] | Buildings and improvements [Member]        
Properties        
Gross $ 3,068,124 $ 2,944,905