Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Restructuring expenses	$ (88)	$ (198)
Revenue	406,814	379,472
Gross profit	191,321	177,690
Net earnings	$ 42,571	$ 1,125
Basic earnings per share:
Basic earnings per share (in dollars per share)	$ 0.31	$ 0.01
Diluted earnings per share:
Diluted earnings per share (in dollars per share)	$ 0.31	$ 0.01