Share Based Award Options exercised data (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Intrinsic value of options exercised	$ 51,105	$ 71,283	$ 25,065
Cash received from exercise of stock options	14,275	32,003	17,346
Tax benefit from stock option exercises	$ 12,617	$ 20,004	$ 7,556