Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net Earnings	$ 196,210	$ 292,536	$ 139,283
Other Comprehensive (Loss) Income:
Foreign Currency Translation Adjustment	(1,861)	1,305	(14)
Total Other Comprehensive (Loss) Income	(1,861)	1,305	(14)
Comprehensive Income	$ 194,349	$ 293,841	$ 139,269