XML 41 R21.htm IDEA: XBRL DOCUMENT v3.2.0.727
Basis of Presentation of Interim Period Statements - Additional Information (Detail) - USD ($)
 6 Months Ended
Jun. 30, 2015
Jun. 30, 2014
Mar. 31, 2015
Dec. 31, 2014
Mar. 31, 2014
Dec. 31, 2013
Basis Of Presentation Of Interim Period Statements [Line Items]            
Revenue recognition professional employer services contracts term 1 year          
Professional employer service contract cancellation and termination period 30 days          
Allowance for doubtful accounts $ 222,000     $ 291,000    
Balance in trust account 109,500,000     50,100,000    
Estimated future liability for unsettled workers' compensation 229,611,000 $ 122,506,000 $ 222,265,000 215,982,000 $ 120,135,000 $ 112,444,000
Estimate of liability for unpaid safety incentives 18,100,000     $ 14,200,000    
Income taxes Received 1,100,000          
Income taxes paid   $ 1,300,000        
AICE [Member]            
Basis Of Presentation Of Interim Period Statements [Line Items]            
Worker's compensation risk claim excess value 5,000,000          
AICE [Member] | Self-Insured States [Member]            
Basis Of Presentation Of Interim Period Statements [Line Items]            
Excess workers' compensation insurance retention 5,000,000          
AICE [Member] | Maryland [Member]            
Basis Of Presentation Of Interim Period Statements [Line Items]            
Excess workers' compensation insurance retention 1,000,000          
AICE [Member] | Colorado [Member]            
Basis Of Presentation Of Interim Period Statements [Line Items]            
Excess workers' compensation insurance retention 2,000,000          
ACE Group [Member] | Minimum [Member]            
Basis Of Presentation Of Interim Period Statements [Line Items]            
Excess workers' compensation insurance coverage with ACE group 5,000,000          
ACE Group [Member] | Maximum [Member]            
Basis Of Presentation Of Interim Period Statements [Line Items]            
Excess workers' compensation insurance coverage with ACE group 15,000,000          
ACE Group [Member] | Maryland [Member] | Minimum [Member]            
Basis Of Presentation Of Interim Period Statements [Line Items]            
Excess workers' compensation insurance coverage with ACE group 1,000,000          
ACE Group [Member] | Maryland [Member] | Maximum [Member]            
Basis Of Presentation Of Interim Period Statements [Line Items]            
Excess workers' compensation insurance coverage with ACE group $ 25,000,000          
ACE Group [Member] | Colorado [Member]            
Basis Of Presentation Of Interim Period Statements [Line Items]            
Excess workers' compensation insurance coverage with American Insurance Company Statutory limits          
ACE Group [Member] | Colorado [Member] | Minimum [Member]            
Basis Of Presentation Of Interim Period Statements [Line Items]            
Excess workers' compensation insurance coverage with ACE group $ 2,000,000          
Barrett Business Services Inc [Member]            
Basis Of Presentation Of Interim Period Statements [Line Items]            
Worker's compensation risk claim 5,000,000          
Worker's compensation risk claim maximum $ 5,000,000