Schedule III - Reconciliation (Details)
$ in Thousands
 3 Months Ended 9 Months Ended 12 Months Ended
Apr. 01, 2013
USD ($)
property
Mar. 31, 2013
USD ($)
property
Dec. 31, 2013
USD ($)
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Self Storage properties:          
Balance at beginning of period $ 178,099   $ 178,099 $ 838,941 $ 370,698
Acquisitions and improvements     192,599 308,323 470,060
Write-off of fully depreciated assets and other     0 (63) 0
Dispositions     0 0 (1,817)
NSA Predecessor properties not contributed to NSA     0 0 0
Balance at end of period   $ 178,099 370,698 1,147,201 838,941
Accumulated depreciation:          
Balance at beginning of period 18,590   18,590 39,614 24,379
Depreciation expense     5,789 28,549 15,508
Write-off of fully depreciated assets and other     0 (63) 0
Dispositions     0 0 (273)
NSA Predecessor properties not contributed to NSA     0 0 0
Balance at end of period   18,590 24,379 $ 68,100 $ 39,614
NSA Predecessor [Member]          
Self Storage properties:          
Balance at beginning of period 178,099 190,987 178,099    
Acquisitions and improvements   205      
Write-off of fully depreciated assets and other   0      
Dispositions   0      
NSA Predecessor properties not contributed to NSA   (13,093)      
Balance at end of period   178,099      
Accumulated depreciation:          
Balance at beginning of period 18,590 18,683 $ 18,590    
Depreciation expense   972      
Write-off of fully depreciated assets and other   0      
Dispositions   0      
NSA Predecessor properties not contributed to NSA   (1,065)      
Balance at end of period   $ 18,590      
Net book value not meeting NSA's criteria for contribution $ 179,358        
NSA Predecessor [Member]          
Accumulated depreciation:          
Number of properties not meeting criteria for contribution | property 22 22      
Net book value not meeting NSA's criteria for contribution $ 12,202