Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2016

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of share-based compensation arrangement, vested stock options

Below is a summary of Company authorized vested stock grants to certain directors for the nine months ended September 30, 2016 and 2015. In 2016, vested stock grants were authorized on April 21. In 2015, vested stock grants were authorized on April 21 and September 29. Stock-based compensation expense related to vested stock grants are included in General and administrative expenses within the Condensed Consolidated Statements of Income.

	Three Months Ended				Nine Months Ended
(millions) (unaudited)	September 30, 2016		September 30, 2015		September 30, 2016		September 30, 2015
Vested stock grants	—		8,624		32,180		40,981
Stock-based compensation expense	$	—	$	0.2	$	0.7	$	0.9

Schedule of share-based compensation, performance-based units

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, 2016 and 2015 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, 2016		September 30, 2015		September 30, 2016		September 30, 2015
Stock-based compensation expense	$	0.2	$	0.4	$	0.6	$	1.2

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, 2016 and 2015 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, 2016		September 30, 2015		September 30, 2016		September 30, 2015
Stock-based compensation expense	$	0.5	$	0.3	$	1.5	$	0.9