Net Periodic Pension and Post-Retirement Costs (Details) (USD $)	3 Months Ended		6 Months Ended
	Feb. 28, 2013	Feb. 29, 2012	Feb. 28, 2013	Feb. 29, 2012
Pension
Net periodic pension and post-retirement costs
Service Cost	$ 541,000	$ 1,117,000	$ 1,083,000	$ 2,233,000
Interest Cost	2,200,000	2,413,000	4,401,000	4,827,000
Expected Return on Plan Assets	(3,489,000)	(3,128,000)	(6,979,000)	(6,256,000)
Amortization of Prior Service Costs	2,000		4,000
Amortization of Net Actuarial (Gain) Loss	2,416,000	1,782,000	4,831,000	3,564,000
Net Periodic Pension Cost	1,670,000	2,184,000	3,340,000	4,368,000
Employer's contribution			2,400,000
Total expected contributions and benefit payments to be made during the current fiscal year	6,800,000		6,800,000
Post-Retirement
Net periodic pension and post-retirement costs
Service Cost	281,000	159,000	561,000	319,000
Interest Cost	382,000	420,000	764,000	840,000
Amortization of Net Actuarial (Gain) Loss	57,000	(176,000)	114,000	(353,000)
Net Periodic Pension Cost	720,000	403,000	1,439,000	806,000
Employer's contribution			800,000
Total expected contributions and benefit payments to be made during the current fiscal year	1,600,000		1,600,000
Supplemental Executive Retirement Plans
Net periodic pension and post-retirement costs
Employer's contribution			50,000
Total expected contributions and benefit payments to be made during the current fiscal year	$ 99,000		$ 99,000