Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
Allowances for doubtful accounts	$ 20,020	$ 17,217	$ 18,438
Depreciation and amortization on property, plant and equipment	$ 1,113,802	$ 1,075,528	$ 964,403
Common units, issued (in units)	92,812,417	92,801,347	57,127,796