Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Capital in Excess of Par Value [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Stock [Member]
Beginning Balance at Dec. 31, 2017	$ 708,928	$ 544	$ 62,594	$ 948,411	$ (140,675)	$ (161,946)
Reclassification pursuant to ASU No. 2018-02				22,298	(22,298)
Net income (loss)	(97,512)			(97,512)
Other comprehensive income (loss)	8,338				8,338
Comprehensive income (loss)	(89,174)
Cash dividends declared	(17,079)			(17,079)
Share-based compensation expense	4,594		4,594
Delivery of treasury shares
RSUs and PSAs	(483)		(2,397)			1,914
Employee stock options exercised — net	(540)		(1,162)			622
Ending Balance at Sep. 30, 2018	606,246	544	63,629	856,118	(154,635)	(159,410)
Beginning Balance at Jun. 30, 2018	686,952	544	62,827	957,643	(174,606)	(159,456)
Net income (loss)	(95,831)			(95,831)
Other comprehensive income (loss)	19,971				19,971
Comprehensive income (loss)	(75,860)
Cash dividends declared	(5,694)			(5,694)
Share-based compensation expense	890		890
Delivery of treasury shares
RSUs and PSAs	(7)		(21)			14
Employee stock options exercised — net	(35)		(67)			32
Ending Balance at Sep. 30, 2018	606,246	544	63,629	856,118	(154,635)	(159,410)
Beginning Balance at Dec. 31, 2018	538,898	544	62,239	770,305	(137,440)	(156,750)
Net income (loss)	23,341			23,341
Other comprehensive income (loss)	(8,187)				(8,187)
Comprehensive income (loss)	15,154
Cash dividends declared	(17,222)			(17,222)
Share-based compensation expense	2,683		2,683
Delivery of treasury shares
RSUs and PSAs	(324)		(2,421)			2,097
Employee stock options exercised — net	(432)		(1,536)			1,104
Ending Balance at Sep. 30, 2019	538,757	544	60,965	776,424	(145,627)	(153,549)
Beginning Balance at Jun. 30, 2019	543,119	544	59,920	769,940	(133,736)	(153,549)
Net income (loss)	12,224			12,224
Other comprehensive income (loss)	(11,891)				(11,891)
Comprehensive income (loss)	333
Cash dividends declared	(5,740)			(5,740)
Share-based compensation expense	1,045		1,045
Ending Balance at Sep. 30, 2019	$ 538,757	$ 544	$ 60,965	$ 776,424	$ (145,627)	$ (153,549)

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Adjustment to stock issued during period value stock options exercised.

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Amount of increase to additional paid-in capital (APIC) from recognition of equity-based compensation.

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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