Stock-Based Compensation

The Company’s incentive compensation plans allow the Company to grant awards to employees in the form of stock options, stock awards, restricted stock units, stock appreciation rights, performance stock units, dividend equivalents and other awards. Compensation related to these awards is determined based on the grant-date fair value and is amortized to expense over the vesting period. The Company recognizes compensation expense based on the earlier of the vesting date or the date when the employee becomes eligible to retire without forfeiture of the award. If awards can be settled in cash, these awards are recorded as liabilities and marked to market.

The following table discloses the amount of stock-based compensation expense:



	Stock-Based Compensation
	2017		2016		2015
Stock options	$	14	$	506	$	3,986
Restricted stock units	3,302		5,595		4,879
Performance stock units	693		7,469		6,054
Total stock-based compensation	$	4,009	$	13,570	$	14,919

Stock Options

The 2006, 2010 and 2014 incentive compensation plans provide for granting options to key employees to purchase common shares at prices not less than market at the date of grant. Options under these plans may have terms of up to ten years becoming exercisable in whole or in consecutive installments, cumulative or otherwise. The plans allow the granting of nonqualified stock options which are not intended to qualify for the tax treatment applicable to incentive stock options under provisions of the Internal Revenue Code.

In February 2012, executives participating in the 2012 – 2014 Long-Term Incentive Plan were granted 589,934 stock options which vested one-third each year through February 2015. In February 2013, executives participating in the 2013-2015 Long-Term Incentive Plan were granted 330,639 stock options, which vested one-third each year through February 2016. In February 2014, executives participating in the 2014-2016 Long-Term Incentive Plan were granted 380,064 stock options, which will vest one-third each year through February 2017. No stock options were granted in 2015, 2016 or 2017 to executives participating in the Long-Term Incentive Plan. Outstanding options do not contain any performance-based criteria. The Company recognizes compensation expense based on the earlier of the vesting date or the date when the employee becomes eligible to retire.

Summarized information for the plans follows:



	Number of Shares		Weighted Average Exercise Price (per share)		Aggregate Intrinsic Value (thousands)
Outstanding at December 31, 2016	495,704		$	21.24
Granted	—		—
Exercised	(210,125	)	20.10
Expired	—		—
Canceled	—		—
Outstanding at December 31, 2017	285,579		22.08		$	3,790
Exercisable at December 31, 2017	285,579		22.08		3,790



	Year ended December 31,
	2017		2016		2015
Weighted average grant-date fair value of options granted (per share)	$	—	$	—	$	—
Aggregate intrinsic value of options exercised (thousands)	$	4,194	$	2,640	$	20,100
Weighted average grant-date fair value of shares vested (thousands)	$	1,400	$	2,633	$	4,602

The weighted average remaining contractual life of options outstanding at December 31, 2017 is 4.8 years. All outstanding stock options are exercisable.

Segregated disclosure of options outstanding at December 31, 2017 was as follows:



	Range of Exercise Prices
	Less than or equal to $15.63		Greater than $15.63
Options outstanding	47,501		238,078
Weighted average exercise price	$	12.86	$	23.72
Remaining contractual life	3.3		5.1
Options exercisable	47,501		238,078
Weighted average exercise price	$	12.44	$	24.00

At December 31, 2017, the Company had fully amortized all expense related to its stock option awards.

Restricted Stock Units

Under the 1998, 2001, and 2014 Incentive Compensation Plans, restricted stock units may be granted to officers and certain other employees as awards for exceptional performance, as a hiring or retention incentive or as part of the Long-Term Incentive Plan. The restricted stock units granted in 2015, 2016 and 2017 have vesting periods of three to four years. In February 2015, employees participating in the 2015-2017 Long-Term Incentive Plan were granted 105,102 restricted stock units which vest one-third each year through February 2018. In February 2016, employees participating in the 2016-2018 Long-Term Incentive Plan were granted 106,287 restricted stock units which vest one-third each year through February 2019. In February 2017, employees participating in the 2017-2019 Long-Term Incentive Plan were granted 82,563 restricted stock units which vest one-third each year through February 2020. Compensation expense related to the restricted stock units granted is determined based on the fair value of the Company’s stock on the date of grant. The Company recognizes compensation expense based on the earlier of the vesting date or the date when the employee becomes eligible to retire. Employees must remain employed for at least six months to vest in the restricted stock units, even if retirement eligible.

The following table provides details of the nonvested restricted stock units for 2017:



	Number of Restricted Units		Weighted Average Grant-Date Fair Value (per share)
Nonvested at December 31, 2016	240,574		$	35.75
Granted	103,207		38.33
Vested	(157,344	)	35.76
Canceled	(8,479	)	37.76
Accrued dividend equivalents	2,430		36.70
Nonvested at December 31, 2017	180,388		$	37.14



	Year ended December 31,
	2017		2016		2015
Weighted average grant-date fair value of restricted shares granted (per share)	$	38.33	$	36.02	$	36.35
Weighted average grant-date fair value of shares vested (thousands)	$	5,627	$	3,195	$	2,629

The number of vested restricted stock units at December 31, 2017 and 2016 was 2,499 and 93,440, respectively. At December 31, 2017, the Company has $2,021 of unvested compensation cost related to restricted stock units and this cost will be recognized as expense over a weighted average period of 24 months.

Performance Stock Units

Compensation related to the performance stock units is determined based on the fair value of the Company’s stock on the date of grant combined with performance metrics. During 2013, executives participating in the Company’s Long-Term Incentive Plan earned 33,405 performance stock units based on the Company’s financial performance in 2013. Of these units, 9,821 vested in 2013, 13,373 vested in 2014 and 8,701 vested in 2015. During 2014, executives participating in the Company’s Long-Term Incentive Plan earned 123,788 performance stock units based on the Company’s financial performance in 2014. Of these units, 49,248 vested in 2014, 32,074 vested in 2015 and 38,091 vested in 2016. During 2015, executives participating in the Company’s Long-Term Incentive Plan earned 231,543 performance stock units based on the Company’s financial performance in 2015. Of these units, 69,912 vested in 2015, 83,371 vested in 2016 and 66,909 vested in 2017. During 2016, executives participating in the Company’s Long-Term Incentive Plan earned 179,865 performance stock units based on the Company’s financial performance in 2016. Of these units, 55,570 vested in 2016, 45,435 vested in 2017 and 48,459 will vest in 2018, respectively. During 2017, executives participating in the Company’s Long-Term Incentive Plan did not earn any performance stock units based on the Company’s financial performance in 2017. The Company recognizes compensation expense based on the earlier of the vesting date or the date when the employee becomes eligible to retire.

The following table provides details of the nonvested performance stock units earned under the Company’s Long-Term Incentive Plan:



	Number of Performance Units		Weighted Average Grant- Date Fair Value (per share)
Nonvested at December 31, 2016	163,967		$	36.77
Earned	—		—
Vested	(114,569	)	36.77
Canceled	(2,309	)	36.77
Accrued dividend equivalents	1,962		36.77
Nonvested at December 31, 2017	49,051		$	36.76

The weighted average fair value of performance stock units granted in 2017, 2016 and 2015 was $38.23, $36.76 and $36.62, respectively.

At December 31, 2017, the Company had $221 of unvested compensation cost related to performance stock units and this cost will be recognized as expense over a weighted average period of 12 months.

The Company’s nonvested restricted stock units and performance stock units are not participating securities. These units will be converted into shares of Company common stock in accordance with the distribution date indicated in the agreements. Restricted stock units earn dividend equivalents from the time of the award until distribution is made in common shares. Performance stock units earn dividend equivalents from the time the units have been earned based upon Company performance metrics until distribution is made in common shares. Dividend equivalents are only earned subject to vesting of the underlying restricted stock units or performance stock units. Accordingly, such units do not represent participating securities.

At December 31, 2017, the company had 2,332,604 shares available for future issuance under equity compensation plans.

The Company recognized $274 and $4,323 of excess tax benefits on stock based compensation transactions as a financing cash inflow for the years ended December 31, 2016 and 2015, respectively. In 2017, $1,877 of excess tax benefits was recognized as a discrete item in the provision for income taxes and included as an operating activity in the Consolidated Statement of Cash Flows as a result of the adoption of ASU 2016-09, “Improvements to Employee Share-Based Payment Accounting.” Refer to the "Recent Accounting Pronouncements" section in Footnote 1 for details regarding the adoption of ASU 2016-09.