Stock-Based Compensation

3 Months Ended

Mar. 31, 2013

Stock-Based Compensation

Stock-Based Compensation

6. Stock-Based Compensation

        The Company maintains two award plans under which stock-based compensation has been granted, the 2006 Stock Option Plan (the "2006 Plan") and the 2007 Long-Term Incentive Plan (Amended and Restated as of May 5, 2011) (the "LTIP"). Upon the adoption of the LTIP, awards were no longer granted under the 2006 Plan. The LTIP provides for grants of (a) incentive stock options qualified as such under U.S. federal income tax laws, (b) stock options that do not qualify as incentive stock options, (c) stock appreciation rights, (d) restricted stock awards, (e) performance awards, (f) phantom stock, (g) stock bonuses, (h) dividend equivalents, and (i) any combination of such awards.

        All awards are made with an exercise price or base price, as the case may be, that is not less than the fair market value per share. The Company uses the Black-Scholes-Merton option-pricing model to estimate the fair value of each stock option grant as of the date of grant. The grant date fair value of restricted stock and performance awards is equal to the closing market price of the Company's common stock on the date of grant.

Stock Options

        The following summarizes the stock option activity for the three months ended March 31, 2013:

	Options			Weighted-Average Exercise Price
Outstanding at January 1, 2013		1,432,228		$	10.34
Granted		111,147		$	24.68
Exercised		(156,665	)	$	6.13
Forfeited		(2,896	)	$	19.36
Outstanding at March 31, 2013		1,383,814		$	11.95

        The following summarizes the fair value and the assumptions used in determining the fair value of stock options granted for fixed awards with graded vesting schedules during the three months ended March 31, 2013 and 2012.

	2013	2012
Risk-free interest rate	1.0%	1.2 - 1.4%
Expected dividend yield	0.0%	0.0%
Weighted average expected volatility	50%	50%
Expected term	6.0 years	6.0 - 6.3 years
Weighted average grant-date fair value	$11.74	$8.57

Restricted Stock

        The following summarizes restricted stock activity for the three months ended March 31, 2013:

	Shares			Weighted-Average Grant Date Fair Value
Outstanding at January 1, 2013		185,764		$	19.54
Granted		69,882		$	24.68
Vested		(45,939	)	$	19.50
Forfeited		(1,562	)	$	19.16
Outstanding at March 31, 2013		208,145		$	21.27

        The shares of restricted stock that vested became taxable to the individual holders of the awards upon vest. The Company received 11,449 of those shares as payment for withholding taxes due by holders of the restricted stock awards. The withheld shares were returned to authorized but unissued stock.

Performance Awards

        The following summarizes performance awards activity for the three months ended March 31, 2013:

	Shares		Weighted-Average Grant Date Fair Value
Outstanding at January 1, 2013		74,923	$	20.51
Granted		46,106	$	24.68
Outstanding at March 31, 2013		121,029	$	22.10