Annual report pursuant to Section 13 and 15(d)

Equity-Based Compensation - Additional Information (Detail)

v3.8.0.1
Equity-Based Compensation - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
1 Months Ended 12 Months Ended
May 31, 2016
Aug. 31, 2015
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Nov. 02, 2012
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Equity program, description     The Deferred Equity Unit represents the unsecured right to receive one unit of SLP or the equivalent cash value of up to 50% (or such other percentage as may be determined by the Company’s Executive Committee) of SLP’s units issuable upon the vesting of any such Deferred Equity Units and the remaining 50% in units upon the vesting of any such Deferred Equity Units.        
Performance Unit, description     The Performance Unit represents the unsecured right to receive one unit of SLP for every two units of SLP issuable upon the vesting of any such Deferred Equity Units.        
Compensation expense     $ 3,248 $ 3,228      
Cash distributions on awards     0 0 $ 0    
Unrecognized compensation expense related to unvested awards     $ 0 $ 0      
Estimated percentage of awards to be forfeited     10.00%        
Estimated service period     4 years        
2012 Equity Incentive Plan              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Shares reserved for issuance     690,077 690,077      
Shares reserved for issuance, authorized             1,687,500
Restricted stock units granted description     Twenty-five percent of the RSUs granted vest and settle on each of the first, second, third and fourth anniversaries of the grant date.        
Restricted stock units granted 3,791 966,510          
Fair Value per unit $ 13.19 $ 13.23          
2012 Equity Incentive Plan | Employee              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Restricted stock units granted description     Twenty-five percent of the RSUs granted vest and settle on each of the first, second, third and fourth anniversaries of the grant date.        
Restricted stock units granted 7,582            
Fair Value per unit $ 13.19            
2012 Equity Incentive Plan | Board of Directors              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Restricted stock units granted description     One hundred percent of the RSUs granted vest and settle on the first anniversary of the grant date.        
Restricted stock units granted 3,000            
Fair Value per unit $ 13.19            
2012 Equity Incentive Plan | First Anniversary              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Restricted stock, vesting percentage 25.00% 25.00%          
2012 Equity Incentive Plan | First Anniversary | Employee              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Restricted stock, vesting percentage 25.00%            
2012 Equity Incentive Plan | First Anniversary | Board of Directors              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Restricted stock, vesting percentage 100.00%            
2012 Equity Incentive Plan | Second Anniversary              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Restricted stock, vesting percentage 25.00% 25.00%          
2012 Equity Incentive Plan | Second Anniversary | Employee              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Restricted stock, vesting percentage 25.00%            
2012 Equity Incentive Plan | Third Anniversary              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Restricted stock, vesting percentage 25.00% 25.00%          
2012 Equity Incentive Plan | Third Anniversary | Employee              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Restricted stock, vesting percentage 25.00%            
2012 Equity Incentive Plan | Fourth Anniversary              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Restricted stock, vesting percentage 25.00% 25.00%          
2012 Equity Incentive Plan | Fourth Anniversary | Employee              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Restricted stock, vesting percentage 25.00%            
Deferred Compensation Share Based Payments              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Compensation expense     $ 0 $ 14 248    
Vested awards settled in cash     0 0 $ 0    
Performance Units              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Compensation expense     0 (32)      
Fair Value per unit         $ 3.75 $ 3.75  
Performance Units | Deferred Compensation Share Based Payments              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Compensation expense     0 1 $ 81    
Restricted Stock Units              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Compensation expense     3,248 3,247      
Unrecognized compensation expense related to unvested awards     $ 5,140 $ 5,169      
Restricted stock units granted       14,373      
Recognition period of unrecognized compensation expense related to unvested awards     2 years 1 month 2 days 2 years 4 months 24 days