12.	Share-Based Compensation

The Company has a long-term equity incentive plan, which allows for grants of stock options, stock appreciation rights, restricted stock, and performance awards to directors, officers, and employees, as well as others who engage in services for PCA. The plan, as amended, terminates May 1, 2023, and authorizes 10.6 million shares of common stock for grant over the life of the plan. As of December 31, 2017, 1.0 million shares remained available for future issuance under the plan. Forfeitures are added back to the pool of shares of common stock available to be granted at a future date.

Restricted Stock

Restricted stock awards granted to officers and employees generally vest at the end of a four-year period, and restricted stock awards granted to directors vest immediately. The fair value of restricted stock is determined based on the closing price of the Company’s stock on the grant date. A summary of the Company’s restricted stock activity follows:

	2017					2016					2015
	Shares			Weighted Average Grant- Date Fair Value		Shares			Weighted Average Grant- Date Fair Value		Shares			Weighted Average Grant- Date Fair Value
Restricted stock at January 1		786,079		$	63.44		1,007,794		$	49.47		1,184,299		$	41.71
Granted		173,199			107.57		242,835			67.48		218,957			65.16
Vested (a)		(213,992	)		51.37		(443,627	)		34.11		(389,481	)		32.77
Forfeitures		(5,554	)		69.03		(20,923	)		59.63		(5,981	)		66.42
Restricted stock at December 31		739,732		$	77.23		786,079		$	63.44		1,007,794		$	49.47

(a)	The total fair value of awards upon vesting for the years ended December 31, 2017, 2016, and 2015 was $23.3 million, $28.8 million, and $26.3 million, respectively.

Performance Units

Performance award units granted to certain key employees vest four years after the grant date based on the achievement of defined performance rankings compared to a peer group. The performance units are paid out entirely in shares of the Company’s common stock. The awards are valued at the closing price of the Company’s stock on the grant date and expensed over the requisite service period based on the most probable number of awards expected to vest.

	2017					2016					2015
	Units			Weighted Average Grant- Date Fair Value		Units			Weighted Average Grant- Date Fair Value		Units			Weighted Average Grant- Date Fair Value
Performance units at January 1		232,088		$	62.68		175,675		$	59.94		127,489		$	58.25
Granted		61,861			108.19		77,017			67.57		53,102			65.04
Vested (a)		(67,391	)		56.08		(20,604	)		57.58		(4,916	)		71.19
Performance units at December 31		226,558		$	77.07		232,088		$	62.68		175,675		$	59.94

(a)

The total fair value of awards upon vesting for the years ended December 31, 2017, 2016, and 2015 was $7.5 million, $1.1 million, and $0.3 million, respectively. Upon vesting of the awards in 2016 and 2015, PCA issued 21,111 and 5,090 shares, which included 507 and 174 shares, respectively, for dividends accrued during the vesting period.

Compensation Expense

Our share-based compensation expense is recorded in “Selling, general, and administrative expenses.” Compensation expense for share-based awards recognized in the Consolidated Statements of Income, net of forfeitures was as follows (dollars in millions):

	Year Ended December 31
	2017			2016			2015
Restricted stock	$	15.0		$	15.8		$	15.2
Performance units		5.6			3.9			3.0
Impact on income before income taxes		20.6			19.7			18.2
Income tax benefit		(7.9	)		(7.7	)		(7.1	)
Impact on net income	$	12.7		$	12.0		$	11.1

The fair value of restricted stock and performance units is determined based on the closing price of the Company’s common stock on the grant date. As PCA’s Board of Directors has the ability to accelerate vesting of share-based awards upon an employee’s retirement, the Company accelerates the recognition of compensation expense for certain employees approaching normal retirement age.

The unrecognized compensation expense for all share-based awards was as follows (dollars in millions):

	December 31, 2017
	Unrecognized Compensation Expense		Remaining Weighted Average Recognition Period (in years)
Restricted stock	$	30.6	2.5
Performance units		9.8	2.8
Total unrecognized share-based compensation expense	$	40.4	2.6

We evaluate share-based compensation expense on a quarterly basis based on our estimate of expected forfeitures, review of recent forfeiture activity, and expected future turnover. We recognize the effect of adjusting the forfeiture rate for all expense amortization in the period that we change the forfeiture estimate. The effect of forfeiture adjustments was insignificant in all periods presented.