Acquisitions - Additional Information (Detail) (USD $)	9 Months Ended			9 Months Ended							0 Months Ended		0 Months Ended															0 Months Ended												0 Months Ended
	Jun. 30, 2013	Jul. 01, 2012	Sep. 30, 2012	Jun. 30, 2013 Minimum [Member]	Jun. 30, 2013 Maximum [Member]	Jun. 30, 2013 VOBA [Member]	Jun. 30, 2013 Technology assets [Member] Minimum [Member]	Jun. 30, 2013 Technology assets [Member] Maximum [Member]	Jun. 30, 2013 Customer relationships [Member] Minimum [Member]	Jun. 30, 2013 Customer relationships [Member] Maximum [Member]	Dec. 17, 2012 HHI Business [Member]	Jun. 30, 2013 HHI Business [Member]	Dec. 17, 2012 HHI Business [Member] Technology assets [Member]	Dec. 17, 2012 HHI Business [Member] Technology assets [Member] Minimum [Member]	Dec. 17, 2012 HHI Business [Member] Technology assets [Member] Maximum [Member]	Dec. 17, 2012 HHI Business [Member] Trade name license agreement [Member]	Dec. 17, 2012 HHI Business [Member] Trade name license agreement [Member] Minimum [Member]	Dec. 17, 2012 HHI Business [Member] Trade name license agreement [Member] Maximum [Member]	Dec. 17, 2012 HHI Business [Member] Trade name [Member]	Dec. 17, 2012 HHI Business [Member] Trade name [Member] Minimum [Member]	Dec. 17, 2012 HHI Business [Member] Trade name [Member] Maximum [Member]	Dec. 17, 2012 HHI Business [Member] Customer relationships [Member]	Dec. 17, 2012 HHI Business [Member] Trademarks and trade names [Member]	Dec. 17, 2012 HHI Business [Member] Trademarks and trade names [Member] Minimum [Member]	Dec. 17, 2012 HHI Business [Member] Trademarks and trade names [Member] Maximum [Member]	Jun. 30, 2013 Shaser Biosciences, Inc. [Member]	Nov. 08, 2012 Shaser Biosciences, Inc. [Member]	Nov. 08, 2012 Shaser Biosciences, Inc. [Member] Non-controlling Interest [Member]	Nov. 08, 2012 Shaser Biosciences, Inc. [Member] Technology assets [Member]	Nov. 08, 2012 Shaser Biosciences, Inc. [Member] Call Option exercisable between January 1, 2017 and March 31, 2017 [Member]	Jun. 30, 2013 Shaser Biosciences, Inc. [Member] Business Combination Measurement Period Adjustment [Member]	Feb. 14, 2013 EXCO/HGI JV [Member] EXCO [Member]	Feb. 14, 2013 EXCO/HGI JV [Member] HGI [Member]	Feb. 14, 2013 EXCO/HGI JV [Member] HGI Energy Holdings, LLC [Member]	Feb. 14, 2013 EXCO/HGI JV [Member] EXCO/HGI General Partner [Member]	Feb. 14, 2013 EXCO/HGI JV [Member]	Mar. 05, 2013 Cotton-Valley Oil and Gas Properties [Member]	Mar. 05, 2013 Cotton-Valley Oil and Gas Properties [Member] HGI [Member]	Mar. 05, 2013 Cotton-Valley Oil and Gas Properties [Member] EXCO/HGI JV [Member]	Apr. 06, 2011 FGL [Member]	Jun. 30, 2013 FGL [Member]
Business Acquisition [Line Items]
Goodwill	$ 1,470,200,000		$ 694,200,000								$ 662,100,000	$ 720,800,000														$ 65,600,000	$ 63,900,000				$ 1,700,000
Deferred tax liability - long-term											104,700,000	117,800,000
Property, plant and equipment											104,500,000	136,200,000
Inventory											207,200,000	205,900,000
Inventory adjustment to fair value											31,000,000
Property, plant and equipment, net adjustment to fair value											4,000,000
Intangible asset											470,000,000	487,100,000														32,800,000	35,500,000				(2,700,000)
Estimated sales growth rate														2.50%	31.00%		2.50%	5.00%		2.50%	5.00%	3.00%		2.50%	5.00%			3.00%	3.00%
Customer retention rate																						95.00%
Estimated Income tax rate	35.00%												35.00%			35.00%			35.00%			35.00%	35.00%					35.00%	35.00%
Discounted rate													12.00%			12.00%			12.00%			12.00%	12.00%					12.00%	11.00%
Carrying value, intangible asset													51,000,000			12,000,000			4,100,000			90,000,000	330,000,000						32,800,000
Amortization period, intangible asset				1 year	20 years	4 years 10 months 24 days	4 years	17 years	15 years	20 years						5 years			8 years			20 years							13 years
Royalty rate														4.00%	5.00%	4.00%			3.50%					3.00%	5.00%				10.50%
Expected terminal year growth rate																							2.50%
Remaining legal life											10 years
Deferred tax liabilities, net											125,000,000
Business Acquisition Percentage Of Equity Interests Acquired																											56.00%			44.00%		24.50%	74.50%	73.50%	2.00%
Business Combination Purchase Consideration Transferred																																725,000,000	349,800,000			574,800,000
Trailing revenues																														100.00%
Adjusted trailing EBITDA																														700.00%
Non-controlling interest											2,200,000	4,400,000														39,000,000	39,000,000	39,000,000			0	119,100,000
Preliminary working capital and other adjustments											(10,700,000)	(7,700,000)															(400,000)						30,500,000
Purchase price											629,500,000	658,700,000														23,000,000	24,700,000				(1,700,000)		694,500,000			517,600,000	130,900,000	130,900,000	97,500,000
Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Oil And Natural Gas Properties																																	697,300,000			519,500,000		138,400,000	103,100,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Gas Gathering Assets																																				21,500,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Asset Retirement Obligation																																				18,500,000			5,600,000
Cash consideration	2,013,700,000	185,100,000																																						350,000,000
Cash consideration re-characterized as expense																																								5,000,000
Reduction in purchase price																																								50,000,000
Insurance obligations under annuity contract																																								3,000,000,000
Maximum amount of asset securing reinsurance obligations																																								1,000,000,000
Maximum amount required to pay under Front Street Reinsurance Transaction																																								50,000,000
Fair value assigned to the contingent purchase price reduction																																								0
Business Combination, Contingent Consideration, Asset																																									$ 41,000,000