individuals as material inducement to their employment with the Company (the "Inducement Grants"). The Inducement Grants awarded stock options and restricted stock to the two individuals. Amounts shown below are inclusive of the Plans and the Inducement Grants.

The Company accounts for the expense of all share-based compensation by measuring the awards at fair value on the date of grant. The Company recognizes expense on a straight-line basis over the vesting period for awards that have cliff vesting, and on a graded vesting basis for time-restricted awards that have graded vesting. Options issued by the Company under its stock option plans have a term of ten years and generally vest ratably over a period of three to four years. Stock options issued under the current plan must have an exercise price that may not be less than the fair market value of the Company’s common stock on the date of grant.

Time-restricted stock awards are expensed over the vesting period of the award, which is typically two to three years. The number of performance-restricted award shares that ultimately vest depends upon achievement of certain targets over a performance period, as more fully described under "Performance-Restricted Shares" below. Performance-restricted awards with a market condition are expensed over the performance period, which is typically three years. Compensation expense for performance-restricted awards with a performance condition, granted prior to December 2018, was recorded based upon the service period and management's assessment of the probability of achieving performance goals. The Company estimates the grant date value of performance-restricted awards that contain a market condition using a Monte Carlo simulation model on the date of grant. The Plans provide for automatic acceleration of vesting in the event of a change in control of the Company.

The Company incurred equity compensation expense of $3.5 million, $2.9 million, and $2.1 million for the years ended December 31, 2020, 2019, and 2018, respectively, for all stock-based compensation plans, including restricted stock awards. No compensation costs were capitalized as part of inventory. The associated tax benefit realized was $0.5 million, $0.2 million, and $1.3 million for the years ended December 31, 2020, 2019, and 2018, respectively.


	For the Year Ended December 31,
	2020		2019		2018
Risk-free interest rate	1.0	%	1.7	%	2.7	%
Expected life	5.2 years		5.3 years		5.5 years
Expected volatility	43	%	37	%	34	%
Expected dividend yield	—	%	—	%	—	%


	For the Year Ended December 31,
In thousands, except per share amounts	2020			2019			2018
Outstanding Options	Shares	Weighted-Average Exercise Price		Shares	Weighted-Average Exercise Price		Shares	Weighted-Average Exercise Price
Outstanding at beginning of period	683	$	27.15	623	$	30.14	433	$	33.37
Granted	180	17.37		242	19.35		246	21.49
Exercised	(102)	21.24		(40)	11.47		(54)	16.48
Forfeited or Expired	(273)	32.09		(142)	31.36		(2)	36.08
Outstanding at end of period	488	$	22.03	683	$	27.15	623	$	30.14

Exercisable	179	$	27.35	318	$	33.01	254	$	29.36
Unvested	309	$	18.94	365	$	22.04	369	$	30.68

The total intrinsic value for options exercised during 2020 was $0.8 million and the associated tax benefit realized from stock options exercised was $0.2 million. The total intrinsic value for options exercised during 2019 was $0.4 million and the associated tax benefit realized from stock options exercised was $0.1 million. The total intrinsic value for options exercised during 2018 was $1.4 million and the associated tax benefit realized from stock options exercised was $0.3 million. The amount of cash received from the exercise of stock options was $2.5 million in 2020, $0.4 million in 2019, and $0.9 million in 2018.

At December 31, 2020, the total unrecognized compensation cost related to non-vested stock option awards was approximately $1.9 million, with a weighted average expected amortization period of 2.5 years. At December 31, 2020, the intrinsic value of exercisable stock options was $1.3 million, and the intrinsic value of unvested stock options was $3.6 million.


	For the Year Ended December 31,
In thousands, except per share amounts	2020			2019			2018
Outstanding Time-Restricted Shares	Shares	Weighted-Average Grant-Date Fair Value		Shares	Weighted-Average Grant-Date Fair Value		Shares	Weighted-Average Grant-Date Fair Value
Unvested at the beginning of the period	159	$	24.33	114	$	37.67	80	$	48.65
Granted	84	17.92		98	20.99		73	26.52
Vested	(37)	31.00		(23)	56.45		(31)	36.45
Forfeited or Expired	(29)	23.09		(30)	39.58		(8)	50.56
Unvested at the end of the period	177	$	20.11	159	$	24.33	114	$	37.67

At December 31, 2020, the total unrecognized compensation cost related to unvested time-restricted shares was approximately $2.1 million, with a weighted-average expected amortization period of 1.8 years. The intrinsic value of unvested time-restricted shares at December 31, 2020 was $5.3 million.

The fair values of each performance-restricted share award that contains a market condition were estimated on the date of grant using a Monte Carlo simulation with the following weighted-average assumptions:


	For the Year Ended December 31,
	2020		2019		2018
Performance period	1/1/20-12/31/22		1/1/20-12/31/22		1/1/19 - 12/31/21
Compounded risk-free interest rate	0.9	%	1.5	%	2.7	%
Lookback term	2.7 years		3.2 years		3.1 years
Historical volatility	51	%	42	%	35	%
Peer group	S&P 600 Industrials Index		S&P 600 Industrials Index		S&P 600 Industrials Index
Expected dividend yield	—	%	—	%	—	%

These performance-restricted awards vest according to the Company's relative Total Shareholder Return ("rTSR") performance as compared to the peer group over the performance period, according to the following table, where rTSR is calculated as ending stock price less beginning stock price, plus reinvested dividends, divided by beginning stock price:

Performance Level

Percentile Ranking

Vesting Percentage of Award

Maximum

75th Percentile or Higher

150%

Target

50th Percentile

100%

Threshold

25th Percentile

50%

Below Threshold

Below the 25th Percentile

—%


	For the Year Ended December 31,
In thousands, except per share amounts	2020			2019			2018
Outstanding Performance-Restricted Shares	Shares	Weighted-Average Grant-Date Fair Value		Shares	Weighted-Average Grant-Date Fair Value		Shares	Weighted-Average Grant-Date Fair Value
Unvested at the beginning of the period	129	$	28.36	190	$	36.63	139	$	42.53
Granted	70	19.05		60	20.90		99	24.22
Vested	—	—		—	—		(48)	27.96
Forfeited or Expired	(57)	33.47		(121)	37.71		—	—
Unvested at the end of the period	142	$	21.67	129	$	28.36	190	$	36.63

At December 31, 2020, the total unrecognized compensation cost related to unvested performance-restricted shares was approximately $1.6 million, with a weighted average expected amortization period of 2.1 years. The intrinsic value of unvested performance-restricted shares at December 31, 2020 was $4.0 million.

During the year ended December 31, 2020, the Company acquired 11,329 shares of common stock valued at $0.3 million, through withholding, pursuant to provisions in agreements with recipients of restricted stock granted under the Company's equity compensation plans, which provide for the Company to withhold the number of shares having fair value equal to each recipient's tax withholding due.