Earnings per Share (Schedule of Earnings per Share, Basic and Diluted) (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Weighted average common shares outstanding, used in computing basic earnings per share	69,614	69,759	69,683
Effect of dilutive stock options and restricted stock units	787	694	949
Weighted-average common shares outstanding, used in computing diluted earnings per share	70,401	70,453	70,632
Basic	$ 3.85	$ 1.51	$ 2.75
Diluted	$ 3.81	$ 1.49	$ 2.72