Consolidated Statement 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 income	$ 18,599	$ 25,599	$ 28,730	$ 41,744
Amortization of prior service credit included in net periodic cost, net of tax of $(836), $(765), $(2,548) and $(2,297)	(1,308)	(1,198)	(3,986)	(3,592)
Amortization of actuarial loss included in net periodic cost, net of tax of $1,801, $1,354, $5,405 and $4,061	2,819	2,117	8,457	6,351
Other comprehensive income, net of tax	1,511	919	4,471	2,759
Comprehensive income	$ 20,110	$ 26,518	$ 33,201	$ 44,503