Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total stockholders equity	Preferred Stock [Member]	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 in Equity [Member]	Retained Earnings [Member]	Treasury Stock at Cost [Member]	Treasury Stock Held for Deferred Compensaton [Member]	Total
Balances at Sep. 30, 2015	$ 1,153,104		$ 106	$ 131,231	$ (51,458)	$ (21,610)	$ 166	$ (30,014)	$ 4,322	$ 1,495,274	$ (422,049)	$ (4,322)
Balance, Preferred Stock, shares at Sep. 30, 2015		0
Balance, Common Stock, shares at Sep. 30, 2015			72,960,000
Balance, Treasury Stock, shares at Sep. 30, 2015											(9,763,000)
Balance, Treasury stock held for deferred compensation, Shares at Sep. 30, 2015												(173,000)
Net earnings	25,820									25,820			$ 25,820
Other comprehensive income (loss), net of tax	(8,587)				(8,587)	(9,086)	18	481
Cash dividends paid	(6,321)									(6,321)
Purchases of treasury stock	(30,712)										$ (30,712)
Purchases of treasury stock, shares											(624,000)
Sales of treasury stock	1,252			(406)							$ 1,658
Sales of treasury stock, shares											49,000
Common shares issued from treasury stock to settle employee liabilities													0
Stock-based compensation	8,451			8,451
Purchases of stock by deferred compensation plan									1,027			$ (1,027)
Purchases of stock by deferred compensation plan, shares												(21,000)
Distribution of stock from deferred compensation plan									(4)			$ 4
Distribution of stock from deferred compensation plan, shares												(1,000)
Balances at Dec. 31, 2015	1,143,007		$ 106	139,276	(60,045)	(30,696)	184	(29,533)	5,345	1,514,773	$ (451,103)	$ (5,345)
Balance, Preferred Stock, shares at Dec. 31, 2015		0
Balance, Common Stock, shares at Dec. 31, 2015			72,960,000
Balance, Treasury Stock, shares at Dec. 31, 2015											(10,338,000)
Balance, Treasury stock held for deferred compensation, Shares at Dec. 31, 2015												(195,000)
Balances at Sep. 30, 2016	1,212,595		$ 106	141,570	(65,705)	(25,971)	179	(39,913)	5,089	1,649,506	$ (512,882)	$ (5,089)	$ 1,212,595
Balance, Preferred Stock, shares at Sep. 30, 2016		0											0
Balance, Common Stock, shares at Sep. 30, 2016			72,960,000										72,960,000
Balance, Treasury Stock, shares at Sep. 30, 2016											(11,374,000)		(11,374,000)
Balance, Treasury stock held for deferred compensation, Shares at Sep. 30, 2016												(157,000)	(157,000)
Net earnings	46,548									46,548			$ 46,548
Other comprehensive income (loss), net of tax	(13,863)				(13,863)	(15,111)	(11)	1,259
Cash dividends paid	(6,779)									(6,779)
Purchases of treasury stock	(24,004)										$ (24,004)
Purchases of treasury stock, shares											(350,000)
Sales of treasury stock	4,843			(907)							$ 5,750
Sales of treasury stock, shares											139,000
Common shares issued from treasury stock to settle employee liabilities	1,767			740					1,767		$ 1,027	$ (1,767)	1,767
Common shares issued from treasury stock to settle employee liabilities, shares											26,000	(26,000)
Stock-based compensation	1,261			1,261
Purchases of stock by deferred compensation plan									37			$ (37)
Distribution of stock from deferred compensation plan									(4)			$ 4
Distribution of stock from deferred compensation plan, shares												0
Balances at Dec. 31, 2016	$ 1,222,368		$ 106	$ 142,664	$ (79,568)	$ (41,082)	$ 168	$ (38,654)	$ 6,889	$ 1,689,275	$ (530,109)	$ (6,889)	$ 1,222,368
Balance, Preferred Stock, shares at Dec. 31, 2016		0											0
Balance, Common Stock, shares at Dec. 31, 2016			72,960,000										72,960,000
Balance, Treasury Stock, shares at Dec. 31, 2016											(11,559,000)		(11,374,000)
Balance, Treasury stock held for deferred compensation, Shares at Dec. 31, 2016												(183,000)	(157,000)