Condensed Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Net earnings	$ 24,322	$ 19,265	$ 67,309	$ 51,265
Unrealized gains (losses) on securities:
Net unrealized holding gains arising during period	15,202	5,543	28,578	11,318
Net unrealized liquidity gains (losses)	(3)	(498)	134	(148)
Reclassification adjustment for net amounts included in net earnings	(1,175)	(2,069)	(3,873)	(4,148)
Amortization of net unrealized (gains) losses related to transferred securities	(1)	11	0	18
Net unrealized gains (losses) on securities	14,023	2,987	24,839	7,040
Foreign currency translation adjustments	22	(21)	307	(155)
Benefit plans:
Amortization of net prior service cost and net gain (loss)	(19)	236	429	819
Other comprehensive income	14,026	3,202	25,575	7,704
Comprehensive income	$ 38,348	$ 22,467	$ 92,884	$ 58,969