Share-Based Compensation (Weighted-Average Assumptions Used in Estimating Grant Date Fair Values of Stock Option Awards) (Details) - Stock Options [Member] - $ / shares		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Key assumptions used in estimating the grant date fair values of stock option awards granted
Total stock options granted		664,000	539,000	274,000
Weighted average grant date fair value		$ 11.09	$ 13.11	$ 5.31
Risk-free rate (as a percent)		2.60%	1.80%	1.20%
Expected life of options	[1]	5 years 9 months 18 days	4 years 9 months 18 days	4 years 2 months 12 days
Expected volatility (as a percent)	[2]	42.20%	43.10%	40.60%

[1] Calculated using the simplified method due to the terms of the stock options and the limited pool of grantees.

[2] Calculated using historical volatility of the Company's common stock over periods commensurate with the expected life of the option.