Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net earnings	$ (5,600)	$ (143,800)	$ 97,300
Defined benefit pension and other postretirement employee benefits:
Net (loss) gain arising during the period, net of tax of $0.9, $(5.7) and $2.5	2,700	(16,000)	6,700
Amortization of actuarial loss included in net periodic cost, net of tax of $1.9, $2.4 and $1.3	5,100	6,800	2,000
Amortization of prior service credit included in net periodic cost, net of tax of $-, $(0.4), and $(0.6)	0	1,300	900
Other comprehensive (loss) income, net of tax	7,800	(10,500)	7,800
Comprehensive income	$ 2,200	$ (154,300)	$ 105,100