Condensed Consolidated Statements of Comprehensive Earnings - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net earnings	$ 32,727	$ 30,737	$ 51,067	$ 57,089
Other comprehensive earnings (loss)
Unrealized gain (loss) on marketable securities, net of tax	4,497	(1,828)	9,082	(3,372)
Other comprehensive earnings (loss)	4,497	(1,828)	9,082	(3,372)
Comprehensive earnings	$ 37,224	$ 28,909	$ 60,149	$ 53,717

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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