Stockholders' Equity (Schedule of Exercise of Stock Options) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stockholders' Equity Note [Abstract]
Intrinsic value of stock options exercised	$ 13,204	$ 9,424	$ 7,860
Cash receipts from stock options exercised	2,772	3,280	3,333
Income tax benefits from stock option exercises	4,435	2,885	3,660
Grant date fair value of stock options vested	$ 506	$ 1,055	$ 1,561