Quarterly report pursuant to Section 13 or 15(d)

Line of Credit - Additional Information (Detail)

v2.4.0.8
Line of Credit - Additional Information (Detail) (USD $)
 6 Months Ended
Jun. 30, 2014
Line of Credit Facility [Line Items]  
Revolving credit facility $ 80,000,000
Revolving credit facility, maturity date Dec. 31, 2014
Revolving credit facility, interest rate above LIBOR 1.50%
Revolving credit facility, interest rate description Amounts borrowed under the Credit Facility bear interest, at our option, at either the prime lending rate established by JPMorgan Chase Bank, N.A. or LIBOR plus 1.5 percent.
Revolving credit facility, unused annual commitment fee 0.25%
Revolving credit facility, amount outstanding 0
Total outstanding letters of credit 47,800,000
Revolving credit facility, unused portion 32,200,000
Line of credit covenant, debt to net worth 0.5
Line of credit covenant, Earnings before interest, taxes, depreciation and amortization (EBITDA) to interest expense ratio 4.0
Line of credit covenant, minimum net worth required $ 250,300,000
Minimum [Member]
  
Line of Credit Facility [Line Items]  
Line of credit covenant, current ratio 1.25