Under the Company’s long-term incentive plan, the Company’s common shares have been made available for grant, at the discretion of the Compensation Committee of the Board of Directors, to officers and key employees in the form of stock option awards. Stock option awards typically have a ten-year term and generally vest in 25% increments annually beginning on the first anniversary of the date of grant. In addition to stock option awards, the Company has granted restricted shares, deferred shares, performance-based restricted stock units and time-vested restricted stock units under the long-term incentive plan.

During 2015, 2014 and 2013, the Company recognized stock-based compensation expense of $6.6 million ($4.1 million after tax or $0.05 per diluted share), $13.7 million ($8.5 million after tax or $0.09 per diluted share) and $12.1 million ($7.6 million after tax or $0.08 per diluted share), respectively, for stock option awards.

The fair value of stock option awards granted during 2015, 2014 and 2013 was estimated at the date of grant using a Black-Scholes option-pricing method with the following assumptions:



	2015			2014			2013
Weighted-average fair value per option (Pre-Spinoff for 2014 and 2013)	$	11.67		$	23.09		$	21.17
Risk-free interest rate	1.58		%	1.64		%	1.09		%
Dividend yield	2.29		%	1.75		%	2.29		%
Expected stock volatility	36.53		%	50.96		%	50.66		%
Expected life - years	5			5			6

Historical information was the primary basis for the selection of the expected dividend yield, expected volatility and the expected lives of the options. The dividend yield was calculated based upon the last dividend prior to the grant compared to the trailing 12 months' daily stock prices. The risk-free interest rate was based upon yields of U.S. zero coupon issues with a term equal to the expected life of the option being valued. Forfeitures were estimated at 2.3%.

A summary of stock option award activity for the year ended December 31, 2015 is presented below:



	Number of Shares		Weighted-average Exercise Price		Weighted-average Remaining Contractual Term	Aggregate Intrinsic Value (millions)
Outstanding - beginning of year	3,168,363		$	33.57
Granted - new awards	491,615		41.56
Exercised	(297,765	)	22.35
Canceled or expired	(82,345	)	40.95
Outstanding - end of year	3,279,868		$	35.60	6 years	$	5.9
Options expected to vest	3,257,113		$	35.55	6 years	$	5.9
Options exercisable	2,034,395		$	32.41	5 years	$	5.9

The total intrinsic value of stock option awards exercised during the years ended December 31, 2015, 2014 and 2013 was $5.6 million, $21.5 million and $25.2 million, respectively. Net cash proceeds from the exercise of stock option awards were $4.1 million, $16.8 million and $13.1 million, respectively. Income tax benefits were $1.3 million, $5.9 million and $8.9 million for the years ended December 31, 2015, 2014 and 2013, respectively.

In 2015, the Company issued 288,585 performance-based restricted stock units and 211,980 time-vesting restricted stock units to officers and key employees. These performance-based restricted stock units vest based on achievement of specified performance objectives and cliff-vest after 3 years. These performance-based restricted stock units settle in either cash or shares, with 8,580 shares expected to settle in cash and 280,005 expected to settle in shares. Time-vesting restricted stock units vest in 25% increments annually beginning on the first anniversary of the grant or cliff-vest after five years. Time-vesting restricted stock units also settle in either cash or shares, with 6,010 time-vesting restricted stock units expected to settle in cash and 205,970 time-vesting restricted stock units expected to settle in common shares. For time-vesting restricted stock units that are expected to settle in cash, the Company had $6.1 million and $15.3 million, accrued in salaries, wages and benefits as of December 31, 2015 and 2014, respectively, on the Consolidated Balance Sheets.

A summary of stock award activity, including restricted shares, deferred shares, performance-based restricted stock units and time-vested restricted stock units that will settle in common shares, for the year ended December 31, 2015 is as follows:



	Number of Shares		Weighted-average Grant Date Fair Value
Outstanding - beginning of year	687,030		$	39.61
Granted - new awards	485,975		41.39
Vested	(103,953	)	36.37
Canceled or expired	(54,282	)	41.44
Outstanding - end of year	1,014,770		$	40.69

As of December 31, 2015, a total of 1,014,770 stock awards have been awarded that have not yet vested. The Company distributed 103,953, 171,135 and 221,542 shares in 2015, 2014 and 2013, respectively, due to the vesting of these awards. The shares awarded in 2015, 2014 and 2013 totaled 485,975, 520,912 and 111,640, respectively. The Company recognized compensation expense of $11.8 million, $10.1 million and $6.5 million, for the years ended December 31, 2015, 2014 and 2013, respectively, relating to restricted shares.

As of December 31, 2015, the Company had unrecognized compensation expense of $28.7 million related to stock option awards and restricted shares. The unrecognized compensation expense is expected to be recognized over a total weighted-average period of two years. The number of shares available for future grants for all plans at December 31, 2015 was 8,285,028.