Net Periodic Pension Cost (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service Cost	$ 830	$ 720
Interest Cost	983	963
Expected Return on Plan Assets	(1,100)	(770)
Recognized Actuarial Losses	893	597
Amortization of Prior Service Costs	16	18
Net Periodic Pension Cost	1,622	1,528
Supplemental Executive Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Service Cost	204	110
Interest Cost	106	93
Recognized Actuarial Losses	94
Amortization of Prior Service Costs	105	105
Net Periodic Pension Cost	$ 509	$ 308