Other Comprehensive Income Details 3 (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Net earnings	$ 111,468	$ 101,580	$ 204,772	$ 194,046	$ 375,972
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(29,205)	32,734	(315)	56,612	$ 89,592
Comprehensive Income, Net of Tax (Note 9)	$ 82,263	$ 134,314	$ 204,457	$ 250,658