Quarterly report pursuant to Section 13 or 15(d)

Equity-Based Compensation - Additional Information (Detail)

v3.5.0.2
Equity-Based Compensation - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
1 Months Ended 3 Months Ended 9 Months Ended 12 Months Ended
May 31, 2016
Aug. 31, 2015
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
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     $ 842 $ 497 $ 2,417 $ 716      
Unrecognized compensation expense related to unvested awards       0   0 $ 21    
Recognition period of unrecognized compensation expense related to unvested awards         0 years   1 month 17 days    
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 3,791 966,510              
Fair Value per unit $ 13.19 $ 13.23              
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.        
2012 Equity Incentive Plan | Employee                  
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                  
Restricted stock units granted 7,582                
Fair Value per unit $ 13.19                
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.        
2012 Equity Incentive Plan | Board of Directors                  
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                  
Restricted stock units granted 3,000                
Fair Value per unit $ 13.19                
Restricted stock units granted description         One hundred percent of the RSUs granted vest and settle on the first anniversary of the grant date.        
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 12 $ 14 232      
Vested awards settled in cash         0 0      
Performance Units                  
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                  
Compensation expense     0 $ 2 (32) $ 80      
Reversed compensation expense         33        
Fair Value per unit       $ 3.75   $ 3.75 $ 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 $ 2 1 $ 80      
Restricted Stock Units                  
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                  
Compensation expense     842 $ 484 2,436 $ 484      
Unrecognized compensation expense related to unvested awards     $ 9,166   $ 9,166   $ 11,383    
Recognition period of unrecognized compensation expense related to unvested awards         2 years 7 months 24 days   3 years 7 months 6 days    
Restricted stock units granted         14,373        
Fair Value per unit             $ 13.23