Stock-Based Compensation

Stock Grants

There were 16,428 and 32,180 authorized vested stock grants to certain directors for the nine months ended September 30, 2017 and 2016, respectively.

The table below shows the Company's stock-based compensation expense related to the vested stock grants for the three and nine months ended September 30, 2017 and 2016, respectively and is included in General and administrative expenses within the Condensed Consolidated Statements of Income.



	Three Months Ended				Nine Months Ended
(millions) (unaudited)	September 30, 2017		September 30, 2016		September 30, 2017		September 30, 2016
Stock-based compensation expense	$	—	$	—	$	0.5	$	0.7

Restricted Stock Units

During the nine months ended September 30, 2017, no restricted stock units were authorized by the Company. During the nine months ended September 30, 2017 and 2016, 4,399, and 1,415 restricted stock units vested, respectively. During the nine months ended September 30, 2017 and 2016, 4,537 and 4,124 restricted stock units, respectively, were forfeited under the Company's Amended and Restated Long-Term Incentive Plan and became available for reissuance.

The table below shows the Company's stock-based compensation expense related to the restricted stock units for the three and nine months ended September 30, 2017 and 2016, respectively, which is included in General and administrative expenses within the Condensed Consolidated Statements of Income.



	Three Months Ended				Nine Months Ended
(millions) (unaudited)	September 30, 2017		September 30, 2016		September 30, 2017		September 30, 2016
Stock-based compensation expense	$	0.2	$	0.2	$	0.6	$	0.6

As of September 30, 2017, there was $1.1 million of unrecognized stock-based compensation costs related to the restricted stock units that are expected to be recognized over a weighted average remaining period of approximately 2.3 years.

Performance Share Units

In September 2014, the Board of Directors authorized a performance-based incentive program under the Company’s Amended and Restated Long-Term Incentive Plan (“Performance-Based Incentive Program”), whereby the Company will issue performance share units to certain executive management individuals that represent shares potentially issuable in the future. The objective of the Performance-Based Incentive Program is to link compensation to business performance, encourage ownership of Company stock, retain executive talent, and reward executive performance. The Performance-Based Incentive Program provides participating executive management individuals with the opportunity to earn vested common stock if certain performance targets for pre-tax free cash flow are achieved over a three year performance period and recipients satisfy service-based vesting requirements. The stock-based compensation expense associated with unvested performance share units are recognized on a straight-line basis over the shorter of the vesting period or minimum service period and dependent upon the probable outcome of the number of shares that will ultimately be issued based on the achievement of pre-tax free cash flow over the cumulative three year period. During the nine months ended September 30, 2017 and 2016, the Company granted 76,120 and 98,078 performance share units, respectively, to certain individuals within executive management. During the nine months ended September 30, 2017 and 2016, 11,770 and 4,493, performance share units, respectively, were forfeited under the Amended and Restated Long-Term Incentive Plan and became available for reissuance. As of September 30, 2017, 14,195 shares were vested related to certain participating executives being eligible for retirement.

The table below shows the Company's stock-based compensation expense related to the Performance-Based Incentive Program for the three and nine months ended September 30, 2017 and 2016, respectively, and is included in General and administrative expenses within the Condensed Consolidated Statements of Income.



	Three Months Ended				Nine Months Ended
(millions) (unaudited)	September 30, 2017		September 30, 2016		September 30, 2017		September 30, 2016
Stock-based compensation expense	$	0.6	$	0.5	$	1.8	$	1.5

Future compensation expense for currently outstanding awards under the Performance-Based Incentive Program could reach a maximum of $9.0 million. Stock-based compensation for the Performance-Based Incentive Program is expected to be recognized over a weighted average period of 1.8 years.

Adoption of ASU 2016-09

Refer to Note 1. Significant Accounting Policies and Practices for the impact of adopting ASU 2016-09 on the Company's stock-based compensation, income taxes, and net income per common share.