Marketable Investment Securities (Tables)

3 Months Ended

Sep. 30, 2019

Investments Debt And Equity Securities [Abstract]

Schedule of Fair Value for Available-for-Sale Securities by Major Security Type and Class of Security

The amortized cost, gross unrealized holding gains, gross unrealized holding losses, and fair value for available-for-sale securities by major security type and class of security at September 30, 2019 and June 30, 2019 were as follows:

			Gross		Gross
			unrealized		unrealized
	Amortized		holding		holding		Estimated
	cost		gains		losses		fair value
At September 30, 2019:
Cash and cash equivalents:
Cash	$	67.2	$	—	$	—	$	67.2
Cash equivalents		22.7		—		—	$	22.7
Total cash and cash equivalents		89.9		—		—		89.9
Available-for-sale:
Corporate bonds and notes		68.7		0.4				69.1
Municipal bonds		15.0		0.1				15.1
Federal agency issues		7.0		—		—		7.0
US government securities		12.9		0.1		—		13.0
Total	$	193.5	$	0.6	$	—	$	194.1

			Gross		Gross
			unrealized		unrealized
	Amortized		holding		holding		Estimated
	cost		gains		losses		fair value
At June 30, 2019:
Cash and cash equivalents:
Cash	$	68.7	$	—	$	—	$	68.7
Cash equivalents		24.5		—		—		24.5
Total cash and cash equivalents		93.2		—		—		93.2
Available-for-sale:
Corporate bonds and notes		64.0		0.6		—		64.6
Municipal bonds		15.3		—		—		15.3
Federal agency issues		9.0		—		—		9.0
US government securities		9.7		—		—		9.7
Total	$	191.2	$	0.6	$	—	$	191.8

Schedule of Maturities of Debt Securities Classified as Cash Equivalents and Available-For-Sale Securities

Cash, cash equivalents, and maturities of debt securities classified as available-for-sale securities are as follows at September 30, 2019:

	Amortized		Estimated
	cost		fair value
Cash	$	67.2	$	67.2
Cash equivalents		22.7		22.7
Available-for-sale:
Due within one year		54.9		55.0
Due after one year through five years		48.7		49.2
Due after five years		—		—
Total	$	193.5	$	194.1