Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2012	Sep. 30, 2011	Mar. 31, 2011
Current assets:
Allowances for doubtful accounts on accounts receivable	$ 8,900	$ 6,368	$ 13,558
Accumulated depreciation and amortization on property, plant and equipment	$ 800,423	$ 782,665	$ 770,842
Common stockholder's equity:
Common stock, par value	$ 2.25	$ 2.25	$ 2.25
Common stock, shares authorized	40,000,000	40,000,000	40,000,000
Common stock, shares issued	0	0	0
Common stock, shares outstanding	26,781,785	26,781,785	26,781,785