Postretirement Benefits - Funded Status and Amounts Recognized in Consolidated Balance Sheet (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	$ 10,181	$ 28,068
Service cost	604	787	216
Interest cost	148	984	796
Actuarial loss	(670)	1,235
Benefits paid	(1,421)	(2,203)
Settlement loss	0	1,040
Settlements paid	(1,383)	(18,928)
Defined Benefit Plan, Curtailments	(500)	0
Foreign currency translation	148	(802)
Benefit obligation at end of year	7,107	10,181	28,068
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of assets at beginning of year	8,015	20,173
Actual return on plan assets	304	1,446
Disbursements	(1,573)	(2,463)
Employer contributions	292	7,684
Employee contributions	194	334
Settlements paid	(1,383)	(18,928)
Foreign currency translation	147	(231)
Fair value of assets at end of year	5,996	8,015	20,173
Funded status/accrued benefit liability	$ (1,111)	$ (2,166)