Reconciliations of Equity - Reconciliations of Total Equity (Detail) - USD ($) $ in Thousands		3 Months Ended				9 Months Ended
		Sep. 30, 2019		Sep. 30, 2018		Sep. 30, 2019		Sep. 30, 2018
Reconciliations of total equity
Beginning Balance		$ 858,397		$ 789,096		$ 808,185	[1],[2]	$ 766,218	[2]
Issuance of common stock under stock option plan		667		214		2,830		3,488
Purchase of common stock		(7,003)		(1,500)		(13,184)		(13,500)
Stock-based and deferred compensation		1,408		2,311		2,657		3,618
Net income	[1],[3]	25,880		21,754	[2]	81,068		87,151	[2]
Other comprehensive income		(18,816)		(1,748)		(9,738)		(26,490)
Cash dividends paid:
Common stock		(5,626)		(5,065)		(16,911)		(15,225)
Other	[4]							(198)
Ending Balance		854,907	[1]	805,062		854,907	[1]	805,062
Common Stock [Member]
Reconciliations of total equity
Beginning Balance		26,453		26,279		26,309	[2]	26,071	[2]
Issuance of common stock under stock option plan		13		5		56		85
Stock-based and deferred compensation		15		3		116		131
Cash dividends paid:
Ending Balance		26,481		26,287		26,481		26,287
Additional Paid-in Capital [Member]
Reconciliations of total equity
Beginning Balance		188,781		177,779		182,881	[2]	170,408	[2]
Issuance of common stock under stock option plan		654		209		2,774		3,403
Stock-based and deferred compensation		1,969		2,380		5,749		6,557
Cash dividends paid:
Ending Balance		191,404		180,368		191,404		180,368
Treasury Stock [Member]
Reconciliations of total equity
Beginning Balance		(106,202)		(93,559)		(97,389)	[2]	(78,561)	[2]
Purchase of common stock		(7,003)		(1,500)		(13,184)		(13,500)
Stock-based and deferred compensation		(576)		(72)		(3,208)		(3,070)
Cash dividends paid:
Ending Balance		(113,781)		(95,131)		(113,781)		(95,131)
Accumulated Other Comprehensive Income (Loss) [Member]
Reconciliations of total equity
Beginning Balance		(137,723)		(124,290)		(141,483)	[2]	(99,563)	[2]
Other comprehensive income		(18,784)		(1,717)		(9,699)		(26,444)
Cash dividends paid:
Other	[5]					(5,325)
Ending Balance		(156,507)		(126,007)		(156,507)		(126,007)
Retained Earnings [Member]
Reconciliations of total equity
Beginning Balance		886,349		802,093		837,107	[2]	747,045	[2]
Net income		25,889		21,754	[2]	81,091		87,160	[2]
Cash dividends paid:
Common stock		(5,626)		(5,065)		(16,911)		(15,225)
Other						5,325	[5]	(198)	[4]
Ending Balance		906,612		818,782		906,612		818,782
Noncontrolling Interest [Member]
Reconciliations of total equity
Beginning Balance	[6]	739		794		760	[2]	818	[2]
Net income	[6]	(9)				(23)		(9)	[2]
Other comprehensive income	[6]	(32)		(31)		(39)		(46)
Cash dividends paid:
Ending Balance	[6]	$ 698		$ 763		$ 698		$ 763

[1] 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.

[2] The retained earnings and net income amounts for the noted line items have been 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 the last in, first out (LIFO) basis to the first in, first out (FIFO) basis.

[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] 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.  See Note 19 for more details.

[6] Reflects the noncontrolling interest in the Company’s China joint venture.