Number of Institutional Investors that Purchased Warrant

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Approved Payroll Deduction to Purchase Shares, Percentage

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Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares To Be Granted

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- Definition

Shareholder Rights Plan, Percentage Of Share Ownership Defining Acquiring Person

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- Definition

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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- Definition

Exercise price per share or per unit of warrants or rights outstanding.

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Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

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- Definition

Aggregate dividends declared during the period for each share of common stock outstanding.

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Unrecognized cost of unvested share-based compensation awards.

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- Definition

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

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- Definition

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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- Definition

Face amount per share of no-par value preferred stock nonredeemable or redeemable solely at the option of the issuer.

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The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws.

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- Definition

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.

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Discount rate from fair value on purchase date that participants pay for shares.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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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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Net number of share options (or share units) granted during the period.

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Number of share instruments newly issued under a share-based compensation plan.

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Percentage of vesting of share-based compensation awards.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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- Definition

Number of new stock issued during the period.

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Stockholders' Equity and Stock Plans - Narrative (Details) $ / shares in Units, $ in Thousands		1 Months Ended		12 Months Ended
	Jan. 20, 2017 $ / shares	Sep. 30, 2015 $ / shares shares	Nov. 30, 2011 investor	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) shares	Jun. 17, 2016	May 11, 2010 shares	Jul. 02, 2007	Jul. 01, 2007 shares	May 08, 2007 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of institutional investors that purchased warrant \| investor			2
Unrecognized compensation expense \| $				$ 1,600
Total compensation cost for share-based payment arrangements \| $				994	$ 636	$ 446
Share-based compensation income tax benefit recognized \| $				318	194	128
Tax benefit realized from disqualifying dispositions of incentive stock options \| $				$ 70	$ 49	76
Percentage of share ownership defining an acquiring person							10.00%		15.00%
Preferred stock, authorized (in shares)				5,000,000	5,000,000
Preferred stock, no par value (in dollars per share) \| $ / shares				$ 0	$ 0
Subsequent event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividends declared per common share (usd per share) \| $ / shares	$ 0.27
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total grant-date fair value of option shares vested \| $				$ 282	$ 202	187
Stock options \| During 2006 through 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period				5 years
Expiration period of grants				10 years
Stock options \| During 2006 through 2014 \| Vesting Rate, Year One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Stock options \| During 2006 through 2014 \| Vesting Rate, Year Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Stock options \| During 2006 through 2014 \| Vesting Rate, Year Three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Stock options \| During 2006 through 2014 \| Vesting Rate Year Four
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Stock options \| During 2006 through 2014 \| Vesting Rate Year Five
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Stock options \| Prior to 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period				4 years
Expiration period of grants				7 years
Stock options \| Prior to 2016 \| Immediately Upon Grant
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Stock options \| Prior to 2016 \| Vesting Rate, Year One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Stock options \| Prior to 2016 \| Vesting Rate, Year Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Stock options \| Prior to 2016 \| Vesting Rate, Year Three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Stock options \| Prior to 2016 \| Vesting Rate Year Four
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Stock options \| After 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				33.00%
Award vesting period				3 years
Expiration period of grants				10 years
Stock options \| During 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				33.00%
Award vesting period				3 years
Expiration period of grants				10 years
Restricted stock award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total grant-date fair value of option shares vested \| $				$ 380	$ 262	$ 227
Restricted stock award \| During 2006 through 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period				5 years
Expiration period of grants				10 years
Restricted stock award \| During 2006 through 2014 \| Vesting Rate, Year One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Restricted stock award \| During 2006 through 2014 \| Vesting Rate, Year Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Restricted stock award \| During 2006 through 2014 \| Vesting Rate, Year Three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Restricted stock award \| During 2006 through 2014 \| Vesting Rate Year Four
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Restricted stock award \| During 2006 through 2014 \| Vesting Rate Year Five
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Performance shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period				3 years
Minimum \| Performance shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				0.00%
Maximum \| Performance shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				200.00%
Director Stock Plan, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common shares approved to be issued in each plan								150,000
Number of shares available for future grants under plan				113,842
Equity Plan, 2007
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common shares approved to be issued in each plan											500,000
Number of shares available for future grants under plan				155,750
Number of shares to be granted				250,000
Employee Stock Purchase Plan, 2007
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common shares approved to be issued in each plan										200,000
Number of shares available for future grants under plan				192,965
Discount from closing market price at end of each quarter				5.00%
Employee Stock Purchase Plan, 2007 \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Approved payroll deduction to purchase shares, percentage				1.00%
Employee Stock Purchase Plan, 2007 \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Approved payroll deduction to purchase shares, percentage				15.00%
Former 1999 Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options granted				0
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock shares authorized to be purchased by warrant		157,711
Exercise price of warrant to purchase common stock \| $ / shares		$ 26.63
Net issuance of shares of common stock from cashless exercise (in shares)		70,591
Common Stock \| Director Stock Plan, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares awarded in period from plan				4,607	5,295	5,306
Common Stock \| U.S. Treasury Capital Purchase Program (TCPP)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock shares authorized to be purchased by warrant				154,242
Exercise price of warrant to purchase common stock \| $ / shares				$ 27.23