8. Share-Based Compensation

The Company recognizes compensation expense based on estimated grant date fair values for all share-based awards issued to employees and directors, including stock options, restricted stock units and performance share units. The total compensation expense related to all share-based compensation plans was $3.5 million and $3.8 million for the three months ended March 31, 2015 and 2014, respectively.

Stock Options

There were no options granted during the three months ended March 31, 2015 and 2014.

Stock option awards as of December 31, 2014 and March 31, 2015, and changes during the three months ended March 31, 2015, were as follows:

						Weighted
						Average
				Weighted		Remaining		Aggregate
				Average		Contractual		Intrinsic
	Shares Under Option			Exercise		Term		Value
	(Thousands)			Price		(Years)		(millions)
Outstanding at December 31, 2014		3,847		$	19.43		4.7	$	12.6
Exercised		(92	)		13.21
Outstanding at March 31, 2015		3,755			19.58		4.4		16.6
Vested and expected to vest at March 31, 2015		3,745			19.60		4.4		16.6
Exercisable at March 31, 2015		1,729		$	10.48		5.2	$	15.1

The aggregate intrinsic value in the table above represents the total pre-tax intrinsic value (the difference between the Company’s closing stock price on March 31, 2015 and December 31, 2014, respectively, and the exercise price, multiplied by the number of in-the-money options) that would have been received by the option holders had all option holders exercised their in-the-money options on March 31, 2015 and December 31, 2014. This amount will change in future periods based on the fair market value of the Company’s stock and the number of options outstanding. Total intrinsic value of options exercised for the three months ended March 31, 2015 and 2014 was $0.5 million and $1.0 million, respectively. Excess tax benefits on stock option exercises, shown as financing cash inflows in the Condensed Consolidated Statements of Cash Flows were $0.1 million and $0.3 million for the three months ended March 31, 2015 and 2014, respectively.

Compensation expense related to stock options for the three months ended March 31, 2015 and 2014 was $0.2 million and $0.3 million, respectively. As of March 31, 2015, $0.5 million of total unrecognized compensation expense related to stock options is expected to be recognized over a weighted average period of 0.9 years.

Restricted Stock Units

Nonvested restricted stock unit awards as of December 31, 2014 and March 31, 2015, and changes during the three months ended March 31, 2015, were as follows:

				Weighted Average
	Shares			Grant Date
	(Thousands)			Fair Value
Nonvested at December 31, 2014		2,045		$	12.54
Granted		575			16.73
Vested		(880	)		12.94
Nonvested at March 31, 2015		1,740		$	13.71

Compensation expense related to restricted stock units for the three months ended March 31, 2015 and 2014 was $2.6 million and $2.9 million, respectively. As of March 31, 2015, there was $19.7 million of unrecognized share-based compensation expense related to approximately 1.7 million of restricted stock unit awards, with a weighted average grant date fair market value of $13.71, that are expected to vest over a weighted average period of 2.5 years. The fair value of these awards was determined based on the Company’s stock price on the grant date reduced by the present value of expected dividends through the vesting period.

Excess tax benefits on restricted stock units that vested, shown as financing cash inflows in the Condensed Consolidated Statements of Cash Flows, were $2.1 million and $2.2 million for the three months ended March 31, 2015 and 2014, respectively.

Performance Share Units

Nonvested performance share unit awards as of December 31, 2014 and March 31, 2015, and changes during the three months ended March 31, 2015, were as follows:

			Weighted Average
	Shares		Grant Date
	(Thousands)		Fair Value
Nonvested at December 31, 2014		804	$	11.87
Granted		418		16.73
Nonvested at March 31, 2015		1,222	$	13.53

During the three months ended March 31, 2015, 418,000 performance share unit awards were granted to certain executive and senior officers, payable upon the achievement of certain established performance targets. The performance period for the shares awarded is January 1, 2015 through December 31, 2017. Distributions under these awards are payable at the end of the performance period in common stock or cash, at the Company’s discretion. The total potential payouts for awards granted during the three months ended March 31, 2015 range from 209,000 to 627,000 shares, should certain performance targets be achieved. The fair value of these awards was determined based on the Company’s stock price on the grant date reduced by the present value of expected dividends through the vesting period. These awards are subject to forfeiture upon termination of employment prior to vesting, subject in some cases to early vesting upon specified events, including death or permanent disability of the grantee or a change in control of the Company. In addition, certain of these awards provide for continued vesting upon same terms and conditions that would have applied had grantee's employment not terminated upon a termination without cause by the Company or for good reason by the grantee.

Compensation expense for the performance share unit awards granted in 2015 is being recognized based on 100% payout or 418,000 shares. Compensation expense for the performance share unit awards granted in 2014 and 2013 is being recognized based on the maximum estimated payout of 319,000 and 485,000 shares, for each respective period. Compensation expense related to performance share unit awards for the three months ended March 31, 2015 and 2014 was $0.7 million and $0.6 million, respectively. As of March 31, 2015, there was $11.1 million of unrecognized compensation expense related to performance share unit awards, which is expected to be recognized over a weighted average period of 2.3 years.