Consolidated Statements of Equity - USD ($) $ in Thousands		Total		Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Noncontrolling Interests [Member]
Beginning Balance at Dec. 31, 2016	[1]	$ 652,024		$ 25,895	$ 158,042	$ (70,938)	$ (127,465)	$ 665,178	$ 1,312
Issuance of common stock under stock option plan		3,370		104	3,266
Purchase of common stock		(6,000)				(6,000)
Stock-based and deferred compensation		7,549		72	9,100	(1,623)
Net income	[1]	100,743	[2]					100,774	(31)
Other comprehensive income		27,981					27,902		79
Cash dividends paid:
Common stock		(18,907)						(18,907)
Payment of cash dividends to noncontrolling interest		(542)							(542)
Ending Balance at Dec. 31, 2017	[1]	766,218		26,071	170,408	(78,561)	(99,563)	747,045	818
Issuance of common stock under stock option plan		4,163		97	4,066
Purchase of common stock		(15,500)				(15,500)
Stock-based and deferred compensation		5,220		141	8,407	(3,328)
Net income	[1]	111,105	[2],[3]					111,117	(12)
Other comprehensive income		(41,966)					(41,920)		(46)
Cash dividends paid:
Common stock		(20,857)						(20,857)
Other	[4]	(198)						(198)
Ending Balance at Dec. 31, 2018	[1],[6]	808,185	[5]	26,309	182,881	(97,389)	(141,483)	837,107	760
Issuance of common stock under stock option plan		3,037		60	2,977
Purchase of common stock		(13,184)				(13,184)
Stock-based and deferred compensation		3,835		124	7,277	(3,566)
Net income		103,101	[2]					103,129	(28)
Other comprehensive income		10,619					10,638		(19)
Cash dividends paid:
Common stock		(23,097)						(23,097)
Other	[7]						(5,325)	5,325
Ending Balance at Dec. 31, 2019		$ 892,496	[5]	$ 26,493	$ 193,135	$ (114,139)	$ (136,170)	$ 922,464	$ 713

[1] The retained earnings and net income amounts for the noted line items have been retrospectively changed from the amounts originally reported as a result of the Company’s first quarter 2019 change in method of accounting for U.S. inventory valuation from LIFO to FIFO.

[2] The 2018 and 2017 amounts for the noted line items have been retrospectively changed from the amounts originally reported as a result of the Company’s first quarter 2019 change in method of accounting for U.S. inventory valuation from LIFO to FIFO.

[3] The 2018 amounts for the noted line items have been retrospectively changed from the amounts originally reported as a result of the Company’s first quarter 2019 change in method of accounting for U.S. inventory valuation from LIFO to FIFO

[4] Reflects beginning retained earnings adjustment as a result of the Company’s first quarter 2018 adoption of ASU No. 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory.

[5] The 2018 amounts for the noted line items have been retrospectively changed from the amounts originally reported as a result of the Company’s first quarter 2019 change in method of accounting for U.S. inventory valuation from LIFO to FIFO.

[6] The retained earnings amount for the noted line item has been retrospectively changed from the amount originally reported as a result of the Company’s first quarter 2019 change in method of accounting for U.S. inventory valuation from LIFO to FIFO.

[7] Reflects beginning retained earnings adjustment as a result of the Company’s first quarter 2019 adoption of ASU No. 2018-02, Income Statement – Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.