CONSOLIDATED AND COMBINED STATEMENT OF CHANGES IN EQUITY (DEFICIT) - USD ($)
$ in Thousands
Total
Common Shares [Member]
Additional Paid-in Capital [Member]
Retained Earnings [Member]
Accumulated Other Comprehensive Loss [Member]
Noncontrolling Interests [Member]
Class A And B Units [Member]
Class A And B Units [Member]
Noncontrolling Interests [Member]
LTIP units [Member]
LTIP units [Member]
Noncontrolling Interests [Member]
Balances (NSA Predecessor [Member]) at Dec. 31, 2012 $ (12,151)                  
Increase (Decrease) in Stockholders' Equity [Roll Forward]                    
Other comprehensive loss | NSA Predecessor [Member] 0                  
Net income (loss) | NSA Predecessor [Member] (1,253)                  
Balances (in shares) at Mar. 31, 2013   0                
Balances (NSA Predecessor [Member]) at Mar. 31, 2013 (13,404)                  
Balances at Mar. 31, 2013 0 $ 0 $ 0 $ 0 $ 0 $ 0        
Increase (Decrease) in Stockholders' Equity [Roll Forward]                    
OP equity issuances for properties contributed by NSA Predecessor in reorganization of entities under common control (23,775)         (23,775)        
NSA Predecessor distributions and other (1,641)         (1,641)        
Issuance of OP units for cash, net of offering expenses 5,916         5,916        
OP equity issuances in business combinations             $ 83,568 $ 83,568 $ 2,918 $ 2,918
Equity-based compensation expense 1,104         1,104        
Receivables from partners for OP equity issued in business combinations (220)         (220)        
Issuance of common shares, net of offering costs (in shares)   1,000                
Distributions to limited partners of OP (2,192)         (2,192)        
Other comprehensive loss 0                  
Net income (loss) (10,481)         (10,481)        
Balances (in shares) at Dec. 31, 2013   1,000                
Balances at Dec. 31, 2013 55,197 $ 0 0 0 0 55,197        
Increase (Decrease) in Stockholders' Equity [Roll Forward]                    
OP equity issuances in business combinations 41,297         41,297 142,223 142,223 3,652 3,652
Equity-based compensation expense 1,468         1,468        
Noncontrolling Interest, Increase Due To Issuance Of Shares For Services 2,101         2,101        
Receivables from partners for OP equity issued in business combinations (5,206)         (5,206)        
Issuance of OP units 6,294         6,294        
Issuance of subordinated performance units for related party acquisition expenses 3,542         3,542        
Reduction in Receivables from Partners of OP 194         194        
Distributions to limited partners of OP (19,436)         (19,436)        
Other comprehensive loss (865)         (865)        
Net income (loss) $ (16,357)         (16,357)        
Balances (in shares) at Dec. 31, 2014 1,000 1,000                
Balances at Dec. 31, 2014 $ 214,104 $ 0 0 0 0 214,104        
Increase (Decrease) in Stockholders' Equity [Roll Forward]                    
OP equity issuances in business combinations 21,137         21,137 $ 42,113 $ 42,113 $ 1,402 $ 1,402
Noncontrolling Interest, Increase Due To Issuance Of Shares For Services 1,020         1,020        
Issuance of OP units 1,416         1,416        
Redemption of common shares (in shares)   (1,000)                
Redemption of common shares, value 0                  
Issuance of common shares, net of offering costs (in shares)   23,000,000                
Issuance of common shares, net of offering costs 270,945 $ 230 270,715              
Issuance of common shares, share based compensation plans (in shares)   4,751                
Effect of changes in ownership for consolidated entities 0   (34,376)     34,376        
Equity-based compensation expense 3,027   74     2,953        
Issuance of restricted common shares (in shares)   17,210                
Vesting and forfeitures of restricted common shares (in shares)   (6,210)                
Vesting and forfeitures of restricted common shares (21)   (21)              
Reduction in Receivables from Partners of OP 1,589         1,589        
Common share dividends (12,429)     (12,429)            
Distributions to limited partners of OP (33,200)         (33,200)        
Other comprehensive loss 148         148        
Net income (loss) $ 4,796     12,440   (7,644)        
Balances (in shares) at Dec. 31, 2015 23,015,751 23,015,751                
Balances at Dec. 31, 2015 $ 516,047 $ 230 $ 236,392 $ 11 $ 0 $ 279,414