Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total		Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss
Shares, Outstanding at Dec. 31, 2016			24,223			(7,736)
Beginning Balance at Dec. 31, 2016	$ 469,900			$ 347,100	$ 569,900	$ (395,300)	$ (51,800)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	97,300				97,300
Performance share and restricted stock unit awards (in shares)			46
Performance share and restricted stock unit awards	5,300			5,300
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	7,800						7,800
Purchase of treasury stock (in shares)						(85)
Purchase of treasury stock	(4,900)					$ (4,900)
Treasury Stock, Shares, Retired			7,821			7,821
Treasury Stock, Retired, Cost Method, Amount	0			351,300	48,900	$ 400,200
Shares, Outstanding at Dec. 31, 2017			16,448
Ending Balance at Dec. 31, 2017	$ 575,400			1,100	618,300		(44,000)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	7 years 2 months
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	$ (143,800)				(143,800)	$ 0
Performance share and restricted stock unit awards (in shares)			34
Performance share and restricted stock unit awards	5,300			5,300
Tax Cuts and Jobs Act, Reclassification from AOCI to Retained Earnings, Tax Effect	(12,800)	[1]			12,800
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	(10,500)						(10,500)
Shares, Outstanding at Dec. 31, 2018			16,482			0
Ending Balance at Dec. 31, 2018	$ 426,400		$ 0	6,400	487,300	$ 0	(67,300)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	5 years 9 months
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	6 years 2 months
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	$ (5,600)				(5,600)
Performance share and restricted stock unit awards (in shares)			33
Performance share and restricted stock unit awards	3,400			3,400			0
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	7,800		$ 0			$ 0	7,800
Shares, Outstanding at Dec. 31, 2019			16,515			0
Ending Balance at Dec. 31, 2019	$ 432,000		$ 0	$ 9,800	$ 481,700	$ 0	$ (59,500)

[1] In February 2018, the FASB issued ASU No. 2018-2, Income Statement – Reporting Comprehensive Income (Topic 220), Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income, which allows a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the December 22, 2017, H.R. 1, Tax Cuts and Jobs Act (the Act). During 2018, we reclassified the income tax effects of the Act on pension and other postretirement employee benefits within accumulated other comprehensive loss to retained earnings.