Stock-Based Compensation (Stock Options Activity) (Details) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2017 USD ($) $ / shares shares
Stock Option Activity (in shares)
Options Outstanding, Beginning | shares	1,739,972
Granted | shares	33,636
Exercised | shares	(343,898)
Forfeited or expired | shares	(9,490)
Options Outstanding, Ending | shares	1,420,220
Options Exercisable | shares	1,164,993
Weighted Average Exercise Price (in dollars per share)
Options Outstanding, Beginning | $ / shares	$ 28.26
Granted | $ / shares	29.55
Exercised | $ / shares	21.66
Forfeited or expired | $ / shares	45.82
Options Outstanding, Ending | $ / shares	29.77
Options Exercisable | $ / shares	$ 27.94
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options Outstanding, Weighted Average Remaining Contractual Term	6 years 5 months 1 day
Options Exercisable, Weighted Average Remaining Contractual Term	5 years 9 months 18 days
Options Outstanding, Intrinsic Value | $	$ 17.8
Options Exercisable, Intrinsic Value | $	$ 16.1