Earnings per Share (Schedule of Earnings per Share, Basic and Diluted) (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Weighted average common shares outstanding, used in computing basic earnings per share	69,683	70,162	69,807
Effect of dilutive stock options and restricted stock units	949	902	874
Weighted-average common shares outstanding, used in computing diluted earnings per share	70,632	71,064	70,681
Basic	$ 2.75	$ 2.48	$ 1.97
Diluted	$ 2.72	$ 2.45	$ 1.94