Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Net earnings	$ 40,266	$ 40,394	$ 77,328
Other comprehensive income (loss), net of tax:
Net gain (loss) arising during the period, net of tax of $(21,960), $5,132, and $(7,664)	(34,347)	8,027	(11,987)
Prior service (cost) credit arising during the period, net of tax of $2,264, $(279), and $29,712	3,541	(436)	46,474
Amortization of actuarial loss included in net periodic cost, net of tax of $5,414, $4,994, and $3,251	8,469	7,811	5,084
Amortization of prior service cost (credit) included in net periodic cost, net of tax of $(3,062), $(3,001), and $3	(4,790)	(4,695)	6
Recognition of deferred taxes related to actuarial gain on OPEB obligations	0	3,015	0
Other comprehensive income (loss), net of tax	(27,127)	13,722	39,577
Comprehensive income	$ 13,139	$ 54,116	$ 116,905