Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net earnings	$ 468,636	$ 465,339	$ 357,818
arising during the year	143,019	(52,559)	42,190
(losses) arising during the year	(40,058)	15,015	(17,481)
net of tax	102,961	(37,544)	24,709
Reclassification adjustment for net (gains) losses included in net earnings (1)	(25,445)	(8,176)	541	[1]
Income tax expense (benefit) related to reclassification adjustment	7,217	2,338	(61)
net earnings, net of tax	(18,228)	(5,838)	480
Other comprehensive income (loss), net of tax	84,733	(43,382)	25,189
Comprehensive income	$ 553,369	$ 421,957	$ 383,007

[1] Entire amount recognized in "Gain (loss) on sale of securities" on the Consolidated Statements of Earnings.