Earnings Per Share (Tables)

9 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

Schedule of Weighted Average Shares Outstanding

The effects of potential common stock were determined using the treasury stock method. Weighted average shares outstanding are shown below:

	Three months ended September 30,		Nine months ended September 30,
	2018	2017	2018	2017
Basic shares outstanding	103.4	102.3	103.2	102.1
Effect of potential common stock:
Common stock awards	1.2	1.4	1.2	1.3
Diluted shares outstanding	104.6	103.7	104.4	103.4