Net Periodic Benefit Cost for Period Reconciliation of Changes in Plan Assets Projected Benefit Obligations and Amounts Recognized in Other Comprehensive Income and Accumulated Other Comprehensive Income (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Pension Plan Assets, Ending Balance	$ 60,028
Frozen Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Pension Plan Assets, Beginning Balance	60,303	52,434	49,323
Net Periodic Pension Cost in Income Statement, Interest cost	2,477	2,858	2,993
Net Periodic Pension Cost in Income Statement, Actual return on plan assets	(332)	(8,727)	(3,984)
Net Periodic Pension Cost in Income Statement, Investment and other expenses	(285)	(374)	(377)
Net Periodic Pension Cost in Income Statement, Difference between actual and expected return on plan assets	(3,475)	5,075	597
Net Periodic Pension Cost in Income Statement, Anticipated expenses	302	262	246
Net Periodic Pension Cost in Income Statement, Amortization of unrecognized net actuarial loss	2,655	2,751	2,765
Net Periodic Pension Cost in Income Statement, Annual cost/change	1,342	1,845	2,240
Cash, Employer contributions/ Annual cost/change	(3,476)	(3,365)	(3,224)
Fair Value of Pension Plan Assets, Actual return on plan assets	332	8,727	3,984
Fair Value of Pension Plan Assets, Employer contributions	3,476	3,365	3,224
Fair Value of Pension Plan Assets, Benefit payments	(4,083)	(4,223)	(4,097)
Fair Value of Pension Plan Assets, Annual cost/change	(275)	7,869	3,111
Fair Value of Pension Plan Assets, Ending Balance	60,028	60,303	52,434
Projected Benefit Obligation, Beginning balance	(73,051)	(67,878)	(65,922)
Projected Benefit Obligation, Interest cost	(2,477)	(2,858)	(2,993)
Projected Benefit Obligation, Benefit payments	4,083	4,223	4,097
Projected Benefit Obligation, Investment and other expenses	285	374	377
Projected Benefit Obligation , Anticipated expenses	(302)	(262)	(246)
Projected Benefit Obligation, Actuarial gain (loss)	7,157	(6,650)	(3,191)
Projected Benefit Obligation , Annual cost/change	8,746	(5,173)	(1,956)
Projected Benefit Obligation, Ending balance	(64,305)	(73,051)	(67,878)
Funded status at the end of the year	(4,277)	(12,748)	(15,444)
Other Comprehensive (Income) / Loss, Difference between actual and expected return on plan assets	3,475	(5,075)	(597)
Other Comprehensive (Income) / Loss, Actuarial loss	(7,157)	6,650	3,191
Other Comprehensive (Income) / Loss, Amortization of unrecognized net actuarial loss	(2,655)	(2,751)	(2,765)
Other Comprehensive (Income) / Loss, Annual cost/change	(6,337)	(1,176)	(171)
Gross Pension Related Accumulated Other Comprehensive Income, Beginning Balance	31,865	33,041	33,212
Gross Pension Related Accumulated Other Comprehensive Income, Annual cost/change	(6,337)	(1,176)	(171)
Gross Pension Related Accumulated Other Comprehensive Income, Ending Balance	$ 25,528	$ 31,865	$ 33,041