Stock Compensation - Additional Information (Detail) (USD $)	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total intrinsic value of stock options exercised	$ 163,500	$ 668,300
Unrecognized stock option compensation cost	4,400,000
Weighted-average recognition period	2 years 4 months 24 days
Stock compensation expense	750,000us-gaap_ShareBasedCompensation	726,000us-gaap_ShareBasedCompensation
Stock compensation expense, stock option	597,000us-gaap_StockOptionPlanExpense	648,000us-gaap_StockOptionPlanExpense
Stock compensation expense, restricted share	100,000us-gaap_RestrictedStockExpense	78,000us-gaap_RestrictedStockExpense
Stock compensation expense, stock awards granted in 2015	53,000
Options available for grant in period	199,022
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average recognition period	7 months 6 days
Restricted stock granted in period	1,471
Restricted stock vesting period	3 months
Fair value of restricted stock at weighted average grant date	$ 15.65
Unrecognized restricted stock compensation cost	$ 140,000

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

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- Definition

Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

+ References

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Unrecognized cost of unvested options awarded to employees as compensation.

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The noncash expense that represents the cost of restricted stock or unit distributed to employees as compensation.

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The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

+ References

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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- Definition

Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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- Definition

Value, after forfeitures, of stock or other type of equity granted of any equity-based compensation plan other than an employee stock ownership plan (ESOP).

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The noncash expense that accounts for the value of stock or unit options distributed to employees as compensation.

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