Quarterly report pursuant to Section 13 or 15(d)

Summary of Stock Option Activity (Detail)

v3.10.0.1
Summary of Stock Option Activity (Detail) - 2003 Plan - $ / shares
6 Months Ended 12 Months Ended
Jun. 30, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Number of Options 24,875 24,875
Number of Options, Exercisable, June 30, 2018 24,875  
Weighted Average Exercise Price, Beginning Balance $ 44.45  
Weighted Average Exercise Price, Ending Balance 44.45 $ 44.45
Weighted Average Exercise Price, Exercisable, June 30, 2018 $ 44.45  
Weighted Average Contractual Life 2 years 6 months 25 days 2 years 6 months 25 days
Weighted Average Contractual Life, Exercisable, June 30, 2018 2 years 6 months 25 days