CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement of Stockholders' Equity [Abstract]
Exercise of stock options, shares	330,895	93,839	878,658
Shares issued under stock incentive plan	441,629	315,030	762,004
Shares issued under employee stock purchase plan	0	0	2,567
Shares issued to Board of Directors in lieu of cash	2,987	3,391	2,739
Cash dividend (in dollars per share)	$ 0.48	$ 0.44	$ 0.36
Purchase of common stock, shares	328,127	310,252	768,780

Number of shares issued during the period as a result of an employee stock purchase plan.

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Number of shares (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP), net of any shares forfeited. Shares issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans.

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- Definition

Number of share options (or share units) exercised during the current period.

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- Definition

Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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