Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Numerator:
Income (Loss) from Continuing Operations Attributable to Parent	$ 82.5	$ 48.2	$ 120.7	$ 114.1
Less Undistributed Earnings (Loss) Allocated to Nonvested Stock	$ 0.0	$ 0.0	$ 0.0	$ 0.0
Income (Loss) from Continuing Operations, Per Basic and Diluted Share	$ 82,500,000	$ 48,200,000	$ 120,700,000	$ 114,100,000
Denominator:
Weighted Average Number of Shares Outstanding, Basic	77,931,576	78,671,509	77,814,438	79,225,703
Effect of dilutive securities:
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	1,097,821	641,265	1,129,991	654,519
Weighted average number of shares outstanding, assuming dilution of stock options and awards	79,029,397	79,312,774	78,944,429	79,880,222
Basic earnings per share	$ 1.06	$ 0.61	$ 1.55	$ 1.44
Diluted earnings per share	$ 1.04	$ 0.61	$ 1.53	$ 1.43