Financial Instruments and Fair Value Measurement (Tables)

6 Months Ended

12 Months Ended

Mar. 31, 2015

Sep. 30, 2014

FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENT

Summary of available-for-sale securities

			Gross		Gross		Estimated
			Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value
	(in thousands)
Equity securities March 31, 2015	$	64,462	$	86,986	$	—	$	151,448
Equity securities September 30, 2014	$	64,462	$	157,838	$	—	$	222,300

	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
	(in thousands)
Equity Securities:
September 30, 2014	$	64,462	$	157,838	$	—	$	222,300
September 30, 2013	$	68,434	$	237,214	$	—	$	305,648

Summary of assets measured at fair value on a recurring basis

The following table summarizes our assets measured at fair value on a recurring basis presented in our Consolidated Condensed Balance Sheet as of March 31, 2015:

			Quoted Prices
	Total		in Active		Significant
	Measure		Markets for		Other		Significant
	at		Identical		Observable		Unobservable
	Fair		Assets		Inputs		Inputs
	Value		(Level 1)		(Level 2)		(Level 3)
	(in thousands)
Assets:
Cash and cash equivalents	$	719,127	$	719,127	$	—	$	—
Equity securities	151,448		151,448		—		—
Other current assets	36,340		36,090		250		—
Other assets	2,000		2,000		—		—
Total assets measured at fair value	$	908,915	$	908,665	$	250	$	—

        The following table summarizes our assets measured at fair value on a recurring basis presented in our Consolidated Balance Sheets as of September 30, 2014:

	Total Measured at Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
	(in thousands)
Assets:
Cash and cash equivalents	$	360,909	$	360,909	$	—	$	—
Investments		222,300		222,300		—		—
Other current assets		35,450		35,200		250		—
Other assets		2,000		2,000		—		—
Total assets measured at fair value	$	620,659	$	620,409	$	250	$	—

Summary of supplemental fair value information about long-term fixed-rate debt

	March 31,		September 30,
	2015		2014
	(in millions)
Carrying value of long-term fixed-rate debt	$	572.1	$	79.0
Fair value of long-term fixed-rate debt	$	597.2	$	84.3

	September 30,
	2014 (as adjusted)		2013 (as adjusted)
	(in millions)
Carrying value of long-term fixed-rate debt	$	79.0	$	193.7
Fair value of long-term fixed-rate debt	$	84.3	$	205.4