Postretirement Benefits - Additional Information (Detail) (USD $)	12 Months Ended			3 Months Ended	12 Months Ended	3 Months Ended		12 Months Ended				12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2012 Nexus Plan	Sep. 30, 2013 Nexus Plan	Sep. 30, 2013 Helix Plan	Sep. 30, 2012 Helix Plan	Sep. 30, 2013 Helix Plan	Sep. 30, 2013 Taiwan Plan Assets	Sep. 30, 2013 Market Related Valuation of Assets	Sep. 30, 2013 Other actuarial losses	Sep. 30, 2013 Worldwide Defined Contribution Plans	Sep. 30, 2012 Worldwide Defined Contribution Plans	Sep. 30, 2010 Worldwide Defined Contribution Plans
Defined Benefit Plan Disclosure [Line Items]
Accelerated amortization of prior pension losses				$ 100,000	$ 100,000		$ 8,900,000
Settlements paid	1,383,000	18,928,000					6,400,000
Investment gains or losses recognition period										5 years
Unrecognized net actuarial gains (losses)	500,000	(1,100,000)								100,000	400,000
Fair value of plan assets	5,996,000	8,015,000	20,173,000		5,500,000				500,000
Voluntary contribution						100,000
Required minimum contributions	300,000							200,000
Expected contribution to the Plan to meet minimum funding targets	200,000
Employer contributions	$ 292,000	$ 7,684,000										$ 3,200,000	$ 3,100,000	$ 2,900,000