XML 29 R31.htm IDEA: XBRL DOCUMENT v2.4.0.8
Summary of Stock Option (Detail) (USD $)
 6 Months Ended
Jun. 30, 2013
Options  
Beginning Balance 2,528,177
Grants 390,800
Exercises (165,677)
Cancellations (45,000)
Expirations (231,500)
Ending Balance 2,476,800
Options exercisable at End of Period 1,566,750
Weighted-average exercise price  
Beginning Balance $ 13.06
Grants $ 12.26
Exercises $ 4.08
Cancellations $ 19.37
Expirations $ 22.46
Ending Balance $ 12.54
Options exercisable at End of Period $ 12.84
Weighted Average Remaining Contractual Term  
Options outstanding, Ending balance 6 years 8 months 16 days
Options exercisable, Ending balance 5 years 9 months 29 days
Aggregate Intrinsic Value  
Options outstanding, end of period $ 7,203,758
Options exercisable, end of period $ 5,793,539