16. Stock-Based Compensation

The Company has an Omnibus Incentive and Equity Plan (the “Plan”) under which officers, employees and directors may be granted equity-based awards, including restricted stock units (“RSUs”), stock options and unrestricted shares of common stock. At December 31, 2014, 427,781 shares of common stock remain available for issuance of the 1,800,000 shares that were reserved for issuance under the Plan. Each RSU entitles the holder to one share of common stock when the restriction expires. RSUs generally have a term of one to three years and may be time-vested or performance-contingent. Stock options generally cliff vest after three years and have a contractual life of ten years. Stock options are granted with an exercise price equal to the fair market value of the shares at the date of grant. The fair value of each RSU is estimated using the intrinsic value method, which is based on the fair market value price on the date of grant unless it contains a performance metric that is considered a market condition. RSUs that contain a market condition are valued using a simulation valuation model. Shares that are issued upon exercise of stock options and vesting of RSUs are newly issued shares from the Plan and are not issued from treasury stock.

Stock-based compensation expense is summarized as follows:


	Years Ended December 31,
	2014		2013		2012
*($ in thousands)*
Stock-based compensation expense	$	9,778	$	7,960	$	6,927

RSU activity for the year ended December 31, 2014 is summarized as follows:


	Number of shares			Weighted Average Grant Date Fair Value
Outstanding at December 31, 2013		233,763		$	87.97
Granted		77,947		$	183.83
Forfeited		(13,860	)	$	139.61
Settled		(117,914	)	$	60.91

Outstanding at December 31, 2014		179,936		$	143.25

The grant-date intrinsic value of RSUs granted during the year ended December 31, 2014 was $14.3 million. At December 31, 2014, outstanding RSUs have a weighted average remaining contractual life of 1.1 years. The weighted-average grant-date fair value of RSUs granted during the years ended December 31, 2014, 2013 and 2012 was $183.83, $188.36 and $81.47 per share, respectively. The total fair value of RSUs vested during the years ended December 31, 2014, 2013 and 2012 was $21.1 million, $17.9 million and $30.7 million, respectively. For the years ended December 31, 2014, 2013 and 2012, a total of 50,952, 38,222 and 143,102 RSUs, respectively, were withheld through net share settlement by the Company to settle minimum employee tax withholding obligations. The Company paid $9.1 million, $7.5 million and $11.5 million for the years ended December 31, 2014, 2013 and 2012, respectively, in minimum employee tax withholding obligations related to RSUs withheld. These net share settlements had the effect of share repurchases by the Company as they reduced the number of shares that would have been otherwise issued as a result of the vesting.

As of December 31, 2014, unamortized stock-based compensation expense for outstanding RSUs was $12.6 million, with a weighted average remaining amortization period of 1.1 years. As of December 31, 2013, unamortized stock-based compensation expense for outstanding RSUs and stock options was $8.9 million and $0.1 million, respectively, with weighted average remaining amortization periods of 1.0 years and 0.2 years, respectively. The Company did not capitalize any stock-based compensation expenses during the years ended December 31, 2014, 2013 and 2012. There were no unvested stock options at December 31, 2014.

During the year ended December 31, 2014, the Company granted 27,782 RSUs which contain two performance based metrics in addition to a service condition. The two performance metrics are based on the Company’s growth in operating income, as adjusted, relative to peers over a one year period and total shareholder return (“TSR”) relative to peers over a three year period. For the year ended December 31, 2014, total stock-based compensation expense included $1.4 million for these performance contingent RSUs. As of December 31, 2014, unamortized stock-based compensation expense related to these performance contingent RSUs was $3.5 million.

Compensation expense for these performance contingent awards is recognized over the three year service period based upon the value determined under the intrinsic value method for the growth in operating income, as adjusted portion of the awards and the Monte Carlo simulation valuation model for the TSR portion of the awards since it represents a market condition. Compensation expense for the TSR portion of the awards is fixed at the date of grant and will not be adjusted in future periods based upon the achievement of the TSR performance metric. Compensation expense for the growth in operating income, as adjusted, portion of the awards is recorded each period based upon a probability assessment of the expected outcome of the performance metric with a final adjustment upon the final outcome.

Stock option activity for the year ended December 31, 2014 is summarized as follows:


	Number of shares			Weighted Average Exercise Price
Outstanding at December 31, 2013		190,160		$	20.11
Granted		—		$	—
Exercised		(27,336	)	$	27.97
Forfeited		—		$	—

Outstanding at December 31, 2014		162,824		$	18.79

Vested and exercisable at December 31, 2014		162,824		$	18.79

The weighted-average remaining contractual term for stock options outstanding at December 31, 2014 and December 31, 2013 was 3.9 and 4.8 years, respectively. The weighted-average remaining contractual term for stock options vested and exercisable at December 31, 2014 was 3.9 years. At December 31, 2014, the aggregate intrinsic value of stock options outstanding and vested and exercisable was $24.7 million. The total grant-date fair value of stock options vested during the years ended December 31, 2014, 2013 and 2012 was $0.4 million, $0.2 million and $1.2 million, respectively. The total intrinsic value of stock options exercised for the years ended December 31, 2014, 2013 and 2012 was $4.2 million, $5.1 million, $9.2 million, respectively. Cash received from stock option exercises was $0.8 million, $0.6 million and $2.6 million for 2014, 2013 and 2012, respectively.

Employee Stock Purchase Plan

The Company offers an employee stock purchase plan that allows employees to purchase shares of common stock on the open market at market price through after-tax payroll deductions. The initial transaction fees are paid for by the Company and shares of common stock are purchased on a quarterly basis. The Company does not reserve shares for this plan or discount the purchase price of the shares.