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Equity - Additional Information (Detail)
3 Months Ended 12 Months Ended
Jan. 04, 2018
Tranche
shares
Mar. 03, 2017
USD ($)
Feb. 26, 2016
shares
May 06, 2015
shares
Mar. 31, 2018
USD ($)
shares
Dec. 31, 2017
shares
Stockholders Equity Note Disclosure [Line Items]            
Unrecognized compensation expense | $         $ 3,900,000  
Aggregate offering price of shares of common stock that the Company may issue and sell | $   $ 100,000,000        
2015 Equity Incentive Plan [Member]            
Stockholders Equity Note Disclosure [Line Items]            
Compensation expense recognized | $         900,000  
ATM Program            
Stockholders Equity Note Disclosure [Line Items]            
Gross sale of common stock available for grant | $         $ 52,700,000  
Long Term Incentive Plan [Member]            
Stockholders Equity Note Disclosure [Line Items]            
LTIP units of limited partnership interest, granted         173,381  
Aggregate LTIP units earned, during the period           2,079,297
Aggregate performance-based units granted 173,381          
Number of tranches | Tranche 3          
Percentage of awards based on absolute shareholder return performance 75.00%          
Percentage of awards based on relative shareholder return performance 25.00%          
Percentage of awards vesting when earned following completion of applicable performance period 50.00%          
Percentage of awards earned subject to additional year of vesting 50.00%          
Additional vesting year of awards 1 year          
Long Term Incentive Plan [Member] | 2015 Equity Incentive Plan [Member]            
Stockholders Equity Note Disclosure [Line Items]            
LTIP units of limited partnership interest, granted     40,000 891,000    
Tranche One [Member] | Long Term Incentive Plan [Member]            
Stockholders Equity Note Disclosure [Line Items]            
Percentage of shares vest under long term incentive plan           50.00%
Aggregate performance-based units granted 32,448          
Tranche Two [Member] | Long Term Incentive Plan [Member]            
Stockholders Equity Note Disclosure [Line Items]            
Percentage of shares vest under long term incentive plan           50.00%
Aggregate performance-based units granted 55,463          
Tranche Three [Member] | Long Term Incentive Plan [Member]            
Stockholders Equity Note Disclosure [Line Items]            
Aggregate performance-based units granted 85,470