CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Total
Balance at Dec. 31, 2018	$ 21,454		$ 947,711	$ (18,746)	$ 950,419
Balance (in shares) at Dec. 31, 2018	214,544
Increase (Decrease) in Stockholders' Equity
Stock issued for stock incentive plans, net	$ 84	$ 2,368			2,452
Stock issued for stock incentive plans, net (in shares)	843
Stock purchased and retired	$ (24)	(2,368)	(306)		(2,698)
Stock purchased and retired (in shares)	(245)
Net loss			(739)		(739)
Dividends			(21,486)		(21,486)
Pension adjustment, net of taxes				173	173
Foreign currency translation				98	98
Balance at Mar. 31, 2019	$ 21,514		927,556	(21,207)	927,863
Balance (in shares) at Mar. 31, 2019	215,142
Increase (Decrease) in Stockholders' Equity
Adoption of accounting standard (Note 14)			2,376	(2,732)	(356)
Balance at Dec. 31, 2019	$ 21,443		832,113	(23,223)	830,333
Balance (in shares) at Dec. 31, 2019	214,423
Increase (Decrease) in Stockholders' Equity
Stock issued for stock incentive plans, net	$ 100	1,997			2,097
Stock issued for stock incentive plans, net (in shares)	1,014
Stock purchased and retired	$ (17)	$ (1,997)	1,222		(792)
Stock purchased and retired (in shares)	(177)
Net loss			(160,423)		(160,423)
Pension adjustment, net of taxes				732	732
Foreign currency translation				(712)	(712)
Balance at Mar. 31, 2020	$ 21,526		$ 672,912	$ (23,203)	$ 671,235
Balance (in shares) at Mar. 31, 2020	215,260