Stock-Based Compensation - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award
Stock compensation expense	$ 3,959	$ 3,634	$ 2,936
Tax benefits from stock-based compensation	1,443	1,390	1,122
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award
Stock compensation expense	481	905	1,390
Tax benefits from stock-based compensation	184	346	531
Intrinsic value of fully-vested stock options outstanding	15,218
Total intrinsic value of options exercised	3,931	7,363	7,108
Tax benefit realized from stock option exercises	1,504	2,594	1,963
Proceeds from stock options exercised	3,369	6,299	9,271
Common stock redeemed for payment of stock option exercises, aggregate value	2,507	6,829	8,721
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 52
Unrecognized compensation cost related to nonvested restricted stock to be recognized over weighted average period (in years)	1 month 13 days
Share-Based CompensationaArrangement By Share Based Payment Award, Options, Vested In Period, Fair Value	$ 843
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award
Stock compensation expense	2,887	2,109	1,546
Tax benefits from stock-based compensation	$ 1,104	$ 807	$ 591
Unrecognized compensation cost related to nonvested restricted stock to be recognized over weighted average period (in years)	1 year 9 months 18 days
Stock issued during period, shares, restricted stock award	169,577
Unrecognized compensation cost related to nonvested restricted stock awards	$ 4,444
Restricted Stock \| Upon Achievement of Performance Goals
Share-based Compensation Arrangement by Share-based Payment Award
Stock issued during period, shares, restricted stock award	78,378
Restricted Stock \| Upon Achievement of Defined Return on Asset Performance Goals
Share-based Compensation Arrangement by Share-based Payment Award
Stock issued during period, shares, restricted stock award	26,126
Restricted Stock \| Upon Achievement of Defined Return on Equity Performance Goals
Share-based Compensation Arrangement by Share-based Payment Award
Stock issued during period, shares, restricted stock award	26,126
Restricted Stock \| Upon Achievement of Defined Total Return to Shareholder Goals
Share-based Compensation Arrangement by Share-based Payment Award
Stock issued during period, shares, restricted stock award	26,126
Restricted Stock \| Upon One-Third Annual Anniversary
Share-based Compensation Arrangement by Share-based Payment Award
Stock issued during period, shares, restricted stock award	91,199
2006 Plan \| Stock Option
Share-based Compensation Arrangement by Share-based Payment Award
Shares available for grant	1,987,379

Common Stock Redeemed For Payment of Stock Option Exercises, Aggregate Value

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Share-Based CompensationaArrangement By Share Based Payment Award, Options, Vested In Period, Fair Value

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Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Unrecognized cost of unvested share-based compensation awards.

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

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The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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Disclosure of the aggregate tax benefit realized from the exercise of stock options and the conversion of similar instruments during the annual period.

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The cash inflow associated with the amount received from holders exercising their stock options. This item inherently excludes any excess tax benefit, which the entity may have realized and reported separately.

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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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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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Amount by which the current fair value of the underlying stock exceeds the exercise price of fully vested and expected to vest options outstanding.

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Number of shares issued during the period related to Restricted Stock Awards, net of any shares forfeited.

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