Stock Options - Additional Information (Detail) (USD $)
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12 Months Ended | ||
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Dec. 31, 2012
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Dec. 31, 2011
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Dec. 31, 2010
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Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Intrinsic value of options granted | $ 132,935 | ||
Total intrinsic value of options exercised | $ 32,620 | 46,505 | |
Directors Stock Option Plan
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Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Stock options granted | 13,500 | 13,500 | 13,500 |
Stock options granted, exercisable period | 6 months | ||
Stock options granted, expiration period | 10 years | ||
Intrinsic value of options granted | $ 49,500 | ||
Directors Stock Option Plan | Maximum
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Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Stock options granted | 210,000 | ||
Employee Stock Option
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Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Stock options granted, expiration period | 10 years | ||
Intrinsic value of options granted | $ 83,435 |