Stock Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2014

Fair Value of Options Granted

The Company used the Black-Scholes option-pricing model to determine the fair value of stock option grants made using the following assumptions:

	Years Ended December 31,
	2014	2013	2012
Risk-free interest rate	0.95% - 1.32%	0.55% - 1.03%	0.50% - 0.66%
Expected dividend yield	0%	0%	0%
Expected option life	3-4 years	4 years	4 years
Expected volatility	42.5% - 45.4%	46.1% - 48.4%	50.4% - 50.7%
Weighted-average expected volatility	42.6%	48.2%	50.7%

Summary of Stock Option Activity

A summary of stock option activity and weighted average exercise prices follows:

	Options			Weighted- Average Exercise Price		Weighted-Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value as of December 31, 2014
Outstanding at January 1, 2014		814,291		$	39.56
Granted		248,388			56.81
Forfeited		(59,545	)		43.47
Exercised		(104,705	)		35.48
Outstanding at December 31, 2014		898,429		$	44.40		4.3	$	16,427
Options exercisable at December 31, 2014		446,760		$	36.78		2.9	$	11,569

Summary of Restricted Stock Activity

The following table summarizes the restricted stock activity and weighted average grant-date fair values for the year ended December 31, 2014:

	Shares			Weighted-Average Grant Date Fair Value
Non-vested at January 1, 2014		31,448		$	41.39
Granted		13,706			43.43
Forfeited		—			—
Vested		(31,199	)		41.31
Non-vested at December 31, 2014		13,955		$	43.57