Financial Instruments and Fair Value Measurement (Tables)

6 Months Ended

Mar. 31, 2016

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, 2016	$	64,462	$	30,765	$	24,069	$	71,158
Equity securities September 30, 2015	$	64,462	$	28,530	$	1,509	$	91,483

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, 2016:

	Total		Level 1		Level 2		Level 3
	(in thousands)
Short-term investments:
Corporate debt securities	$	18,427	$	—	$	18,427	$	—
U.S. government and federal agency securities	27,099		16,661		10,438		—
Total short-term investments	45,526		16,661		28,865		—
Cash and cash equivalents	898,013		898,013		—
Investments	71,158		71,158		—		—
Other current assets	28,912		28,662		250		—
Other assets	2,000		2,000		—		—
Total assets measured at fair value	$	1,045,609	$	1,016,494	$	29,115	$	—

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

	March 31,		September 30,
	2016		2015
	(in millions)
Carrying value of long-term fixed-rate debt	$	532.1	$	531.5
Fair value of long-term fixed-rate debt	$	533.2	$	553.5