Consolidated Statements of Comprehensive Income (Loss) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Statement of Other Comprehensive Income [Abstract]
Net earnings	$ 209,979	$ 169,777	$ 118,170
Change in unrealized components of defined benefit plans:
Net actuarial loss during the period	(109,765)	(282,943)	(35,819)
Amortization	28,674	17,917	16,865
Settlements	0	0	1,487
Change in unrealized componenets of defined benefit plans	(81,091)	(265,026)	(17,467)
Change in cumulative translation adjustment and other	29,641	(17,768)	12,995
Other comprehensive loss before taxes	(51,450)	(282,794)	(4,472)
Benefit for taxes	30,996	92,228	6,792
Other comprehensive (loss) income, net of taxes	(20,454)	(190,566)	2,320
Comprehensive income (loss)	$ 189,525	$ (20,789)	$ 120,490