Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Net earnings	$ 863	$ 901	$ 16,415	$ 40,211
Defined benefit pension and other postretirement employee benefits:
Amortization of actuarial loss included in net periodic cost, net of tax of $319, $248, $967 and $1,113	487	384	1,475	1,723
Amortization of prior service credit included in net periodic cost, net of tax of $(152), $(165), $(454) and $(497)	(230)	(257)	(691)	(770)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, net of Tax	0	1,632	0	1,632
Other comprehensive income (loss), net of tax	257	1,759	784	2,585
Comprehensive income	$ 1,120	$ 2,660	$ 17,199	$ 42,796