Condensed Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Total Accumulated Other Comprehensive (Loss) Earnings [Member]	Foreign Currency Translation Adjustments [Member]	Unrealized Derivative Gains (Losses) [Member]	Minimum Retirement Benefit Liability Adjustments [Member]	Deferred Compensation [Member]	Retained Earnings [Member]	Treasury Stock at Cost [Member]	Treasury Stock Held for Deferred Compensaton [Member]	Total
Balances at Sep. 30, 2018	$ 106	$ 185,705	$ (74,942)	$ (39,794)	$ (20,942)	$ (14,206)	$ 8,431	$ 1,966,643	$ (539,408)	$ (8,431)	$ 1,538,104
Balance, Common Stock, shares at Sep. 30, 2018	72,960
Balance, Treasury Stock, shares at Sep. 30, 2018									(11,203)
Balance, Treasury stock held for deferred compensation, shares at Sep. 30, 2018										(202)
Net earnings								49,120			49,120
Other comprehensive earnings (loss), net of tax			10,336	(702)	10,529	509					10,336
Cash dividends paid								(8,808)			(8,808)
Sales of treasury stock		(662)							$ 4,046		3,384
Sales of treasury stock, shares									107
Stock-based compensation		10,851									10,851
Purchases and transfers of stock by/to deferred compensation plan							591			$ (591)
Purchases and transfer of stock by/to deferred compensation plan, shares										(8)
Distribution of stock from deferred compensation plan							(7)			$ 7
Distribution of stock from deferred compensation plan, shares										1
Balances at Dec. 31, 2018	$ 106	195,894	(64,651)	(40,541)	(10,413)	(13,697)	9,015	2,044,695	$ (535,362)	$ (9,015)	1,640,682
Balance, Common Stock, shares at Dec. 31, 2018	72,960
Balance, Treasury Stock, shares at Dec. 31, 2018									(11,096)
Balance, Treasury stock held for deferred compensation, shares at Dec. 31, 2018										(209)
Cumulative effect from adoption | ASC 606 [Member]			(45)	(45)				38,745			38,700
Cumulative effect from adoption | ASU 2016-16 [Member]								(1,005)			(1,005)
Balances at Sep. 30, 2019	$ 106	207,120	(103,306)	(53,235)	(4,955)	(45,116)	9,382	2,224,919	$ (602,098)	$ (9,382)	$ 1,726,741
Balance, Common Stock, shares at Sep. 30, 2019	72,960										72,960
Balance, Treasury Stock, shares at Sep. 30, 2019									(11,040)		(11,040)
Balance, Treasury stock held for deferred compensation, shares at Sep. 30, 2019										(211)	(211)
Net earnings								53,373			$ 53,373
Other comprehensive earnings (loss), net of tax			9,758	9,768	380	(390)					9,758
Cash dividends paid								(10,064)			(10,064)
Sales of treasury stock		(1,944)							$ 9,502		7,558
Sales of treasury stock, shares									226
Stock-based compensation		10,982									10,982
Purchases and transfers of stock by/to deferred compensation plan							543			$ (543)
Purchases and transfer of stock by/to deferred compensation plan, shares										(5)
Distribution of stock from deferred compensation plan							(14)			$ 14
Distribution of stock from deferred compensation plan, shares										1
Balances at Dec. 31, 2019	$ 106	$ 216,158	$ (93,548)	$ (43,467)	$ (4,575)	$ (45,506)	$ 9,911	2,268,483	$ (592,596)	$ (9,911)	$ 1,798,603
Balance, Common Stock, shares at Dec. 31, 2019	72,960										72,960
Balance, Treasury Stock, shares at Dec. 31, 2019									(10,814)		(10,814)
Balance, Treasury stock held for deferred compensation, shares at Dec. 31, 2019										(215)	(215)
Cumulative effect from adoption | ASC 842 [Member]								$ 255			$ 255