Condensed Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement of Comprehensive Income [Abstract]
Net earnings	$ 19,826	$ 16,632
Unrealized gains (losses) on securities:
Net unrealized holding gains (losses) arising during period	11,002	(1,125)
Net unrealized liquidity gains (losses)	23	138
Reclassification adjustment for net amounts included in net earnings	(425)	(1,359)
Amortization of net unrealized (gains) losses related to transferred securities	0	0
Net unrealized gains (losses) on securities	10,600	(2,346)
Foreign currency translation adjustments	(511)	590
Benefit plans:
Amortization of net prior service cost and net loss	(176)	381
Other comprehensive income	9,913	(1,375)
Comprehensive income	$ 29,739	$ 15,257