Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Nov. 30, 2012	Aug. 31, 2012
Accounts receivable, allowance for doubtful accounts	$ 1,038	$ 4,459
Property, plant and equipment, accumulated depreciation	553,099	535,728
Intangibles, accumulated amortization	$ 20,262	$ 19,023
Preferred stock, shares authorized	20,000,000	20,000,000
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares issued	0	0
Common Class A [Member]
Common stock, shares authorized	75,000,000	75,000,000
Common stock, par value	$ 1	$ 1
Common stock, shares issued	25,684,000	25,219,000
Common stock, shares outstanding	25,684,000	25,219,000
Common Class B [Member]
Common stock, shares authorized	25,000,000	25,000,000
Common stock, par value	$ 1	$ 1
Common stock, shares issued	720,000	1,113,000
Common stock, shares outstanding	720,000	1,113,000