Annual report pursuant to Section 13 and 15(d)

Equity-Based Compensation - Additional Information (Detail)

v3.10.0.1
Equity-Based Compensation - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
1 Months Ended 12 Months Ended
Oct. 31, 2018
May 31, 2016
Aug. 31, 2015
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
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.        
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       584,679 690,077      
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\non-qualified stock options, 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\non-qualified stock options, 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\non-qualified stock options, 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 $ 0 14    
Vested awards settled in cash       0 0 0    
Performance Units                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Fair Value per unit             $ 3.75  
Performance Units | Deferred Compensation Share Based Payments                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Compensation expense       0 0 $ 1    
Non-Qualified Stock Options                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Compensation expense       3,275 3,248      
Restricted stock units\non-qualified stock options, granted description One third of the NQOs will vest and settle on each of the first, second and third anniversaries of the grant date              
Stock options granted in period 105,398              
Fair value assumptions, strike price $ 13.97              
Fair value assumptions, risk free rate 2.94%              
Fair value assumptions, expiration 5 years              
Fair value assumptions, volatility 32.70%              
Compensation expense forfeiture rate 1.00%              
Unrecognized compensation expense related to unvested awards       $ 2,392 $ 5,140      
Recognition period of unrecognized compensation expense related to unvested awards       1 year 6 months 3 days 2 years 1 month 2 days      
Restricted Stock Units                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Compensation expense       $ 3,275 $ 3,248      
Unrecognized compensation expense related to unvested awards       $ 2,392 $ 5,140      
Recognition period of unrecognized compensation expense related to unvested awards       1 year 6 months 3 days 2 years 1 month 2 days      
Deferred Equity Units                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Compensation expense       $ 3,275 $ 3,248