Annual report pursuant to Section 13 and 15(d)

Line of Credit - Additional Information (Detail)

v3.3.1.900
Line of Credit - Additional Information (Detail)
 12 Months Ended
Feb. 29, 2016
USD ($)
Dec. 31, 2015
USD ($)
Line of Credit Facility [Line Items]    
Revolving credit facility   $ 80,000,000
Available borrowings for general corporate purposes   20,000,000
Financial covenants, minimum net worth   $ 254,100,000
Financial covenants, minimum interest coverage ratio   4.0
Borrowings under credit agreement   $ 0
Total outstanding letters of credit   $ 20,500,000
Financial covenants, minimum current ratio   1.25
Financial covenants, maximum debt to net worth ratio   0.5
Subsequent Event    
Line of Credit Facility [Line Items]    
Available borrowings for general corporate purposes $ 20,000,000.0  
Financial covenants, minimum net worth $ 250,000,000  
Financial covenants, percent of net income added to net worth requirement 50.00%  
Financial covenants, percent of proceeds from stock issuance added to net worth requirement 100.00%  
Financial covenants, maximum EBITDA ratio 3.0  
Financial covenants, minimum interest coverage ratio 2.0  
London Interbank Offered Rate (LIBOR)    
Line of Credit Facility [Line Items]    
Basis spread on variable interest rate   2.00%
Revolving Credit Facility    
Line of Credit Facility [Line Items]    
Revolving credit facility, unused portion   $ 20,000,000
Revolving Credit Facility | Minimum | Subsequent Event    
Line of Credit Facility [Line Items]    
Fees on unused borrowings, percent 0.25%  
Revolving Credit Facility | Maximum | Subsequent Event    
Line of Credit Facility [Line Items]    
Fees on unused borrowings, percent 0.50%  
Letter of Credit    
Line of Credit Facility [Line Items]    
Revolving credit facility, unused portion   $ 59,500,000
Letter of Credit | Subsequent Event    
Line of Credit Facility [Line Items]    
Fees on unused borrowings, percent 2.00%